code:
/**
 * @fileoverview Main API Class
 * @author Kai Cataldo
 * @author Toru Nagashima
 */

"use strict";

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

const path = require("path");
const fs = require("fs");
const { promisify } = require("util");
const { CLIEngine, getCLIEngineInternalSlots } = require("../cli-engine/cli-engine");
const BuiltinRules = require("../rules");
const {
    Legacy: {
        ConfigOps: {
            getRuleSeverity
        }
    }
} = require("@eslint/eslintrc");
const { version } = require("../../package.json");

//------------------------------------------------------------------------------
// Typedefs
//------------------------------------------------------------------------------

/** @typedef {import("../cli-engine/cli-engine").LintReport} CLIEngineLintReport */
/** @typedef {import("../shared/types").DeprecatedRuleInfo} DeprecatedRuleInfo */
/** @typedef {import("../shared/types").ConfigData} ConfigData */
/** @typedef {import("../shared/types").LintMessage} LintMessage */
/** @typedef {import("../shared/types").SuppressedLintMessage} SuppressedLintMessage */
/** @typedef {import("../shared/types").Plugin} Plugin */
/** @typedef {import("../shared/types").Rule} Rule */
/** @typedef {import("../shared/types").LintResult} LintResult */
/** @typedef {import("../shared/types").ResultsMeta} ResultsMeta */

/**
 * The main formatter object.
 * @typedef LoadedFormatter
 * @property {(results: LintResult[], resultsMeta: ResultsMeta) => string | Promise<string>} format format function.
 */

/**
 * The options with which to configure the ESLint instance.
 * @typedef {Object} ESLintOptions
 * @property {boolean} [allowInlineConfig] Enable or disable inline configuration comments.
 * @property {ConfigData} [baseConfig] Base config object, extended by all configs used with this instance
 * @property {boolean} [cache] Enable result caching.
 * @property {string} [cacheLocation] The cache file to use instead of .eslintcache.
 * @property {"metadata" | "content"} [cacheStrategy] The strategy used to detect changed files.
 * @property {string} [cwd] The value to use for the current working directory.
 * @property {boolean} [errorOnUnmatchedPattern] If `false` then `ESLint#lintFiles()` doesn't throw even if no target files found. Defaults to `true`.
 * @property {string[]} [extensions] An array of file extensions to check.
 * @property {boolean|Function} [fix] Execute in autofix mode. If a function, should return a boolean.
 * @property {string[]} [fixTypes] Array of rule types to apply fixes for.
 * @property {boolean} [globInputPaths] Set to false to skip glob resolution of input file paths to lint (default: true). If false, each input file paths is assumed to be a non-glob path to an existing file.
 * @property {boolean} [ignore] False disables use of .eslintignore.
 * @property {string} [ignorePath] The ignore file to use instead of .eslintignore.
 * @property {ConfigData} [overrideConfig] Override config object, overrides all configs used with this instance
 * @property {string} [overrideConfigFile] The configuration file to use.
 * @property {Record<string,Plugin>|null} [plugins] Preloaded plugins. This is a map-like object, keys are plugin IDs and each value is implementation.
 * @property {"error" | "warn" | "off"} [reportUnusedDisableDirectives] the severity to report unused eslint-disable directives.
 * @property {string} [resolvePluginsRelativeTo] The folder where plugins should be resolved from, defaulting to the CWD.
 * @property {string[]} [rulePaths] An array of directories to load custom rules from.
 * @property {boolean} [useEslintrc] False disables looking for .eslintrc.* files.
 */

/**
 * A rules metadata object.
 * @typedef {Object} RulesMeta
 * @property {string} id The plugin ID.
 * @property {Object} definition The plugin definition.
 */

/**
 * Private members for the `ESLint` instance.
 * @typedef {Object} ESLintPrivateMembers
 * @property {CLIEngine} cliEngine The wrapped CLIEngine instance.
 * @property {ESLintOptions} options The options used to instantiate the ESLint instance.
 */

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

const writeFile = promisify(fs.writeFile);

/**
 * The map with which to store private class members.
 * @type {WeakMap<ESLint, ESLintPrivateMembers>}
 */
const privateMembersMap = new WeakMap();

/**
 * Check if a given value is a non-empty string or not.
 * @param {any} x The value to check.
 * @returns {boolean} `true` if `x` is a non-empty string.
 */
function isNonEmptyString(x) {
    return typeof x === "string" && x.trim() !== "";
}

/**
 * Check if a given value is an array of non-empty strings or not.
 * @param {any} x The value to check.
 * @returns {boolean} `true` if `x` is an array of non-empty strings.
 */
function isArrayOfNonEmptyString(x) {
    return Array.isArray(x) && x.every(isNonEmptyString);
}

/**
 * Check if a given value is a valid fix type or not.
 * @param {any} x The value to check.
 * @returns {boolean} `true` if `x` is valid fix type.
 */
function isFixType(x) {
    return x === "directive" || x === "problem" || x === "suggestion" || x === "layout";
}

/**
 * Check if a given value is an array of fix types or not.
 * @param {any} x The value to check.
 * @returns {boolean} `true` if `x` is an array of fix types.
 */
function isFixTypeArray(x) {
    return Array.isArray(x) && x.every(isFixType);
}

/**
 * The error for invalid options.
 */
class ESLintInvalidOptionsError extends Error {
    constructor(messages) {
        super(`Invalid Options:\n- ${messages.join("\n- ")}`);
        this.code = "ESLINT_INVALID_OPTIONS";
        Error.captureStackTrace(this, ESLintInvalidOptionsError);
    }
}

/**
 * Validates and normalizes options for the wrapped CLIEngine instance.
 * @param {ESLintOptions} options The options to process.
 * @throws {ESLintInvalidOptionsError} If of any of a variety of type errors.
 * @returns {ESLintOptions} The normalized options.
 */
function processOptions({
    allowInlineConfig = true, // ← we cannot use `overrideConfig.noInlineConfig` instead because `allowInlineConfig` has side-effect that suppress warnings that show inline configs are ignored.
    baseConfig = null,
    cache = false,
    cacheLocation = ".eslintcache",
    cacheStrategy = "metadata",
    cwd = process.cwd(),
    errorOnUnmatchedPattern = true,
    extensions = null, // ← should be null by default because if it's an array then it suppresses RFC20 feature.
    fix = false,
    fixTypes = null, // ← should be null by default because if it's an array then it suppresses rules that don't have the `meta.type` property.
    globInputPaths = true,
    ignore = true,
    ignorePath = null, // ← should be null by default because if it's a string then it may throw ENOENT.
    overrideConfig = null,
    overrideConfigFile = null,
    plugins = {},
    reportUnusedDisableDirectives = null, // ← should be null by default because if it's a string then it overrides the 'reportUnusedDisableDirectives' setting in config files. And we cannot use `overrideConfig.reportUnusedDisableDirectives` instead because we cannot configure the `error` severity with that.
    resolvePluginsRelativeTo = null, // ← should be null by default because if it's a string then it suppresses RFC47 feature.
    rulePaths = [],
    useEslintrc = true,
    ...unknownOptions
}) {
    const errors = [];
    const unknownOptionKeys = Object.keys(unknownOptions);

    if (unknownOptionKeys.length >= 1) {
        errors.push(`Unknown options: ${unknownOptionKeys.join(", ")}`);
        if (unknownOptionKeys.includes("cacheFile")) {
            errors.push("'cacheFile' has been removed. Please use the 'cacheLocation' option instead.");
        }
        if (unknownOptionKeys.includes("configFile")) {
            errors.push("'configFile' has been removed. Please use the 'overrideConfigFile' option instead.");
        }
        if (unknownOptionKeys.includes("envs")) {
            errors.push("'envs' has been removed. Please use the 'overrideConfig.env' option instead.");
        }
        if (unknownOptionKeys.includes("globals")) {
            errors.push("'globals' has been removed. Please use the 'overrideConfig.globals' option instead.");
        }
        if (unknownOptionKeys.includes("ignorePattern")) {
            errors.push("'ignorePattern' has been removed. Please use the 'overrideConfig.ignorePatterns' option instead.");
        }
        if (unknownOptionKeys.includes("parser")) {
            errors.push("'parser' has been removed. Please use the 'overrideConfig.parser' option instead.");
        }
        if (unknownOptionKeys.includes("parserOptions")) {
            errors.push("'parserOptions' has been removed. Please use the 'overrideConfig.parserOptions' option instead.");
        }
        if (unknownOptionKeys.includes("rules")) {
            errors.push("'rules' has been removed. Please use the 'overrideConfig.rules' option instead.");
        }
    }
    if (typeof allowInlineConfig !== "boolean") {
        errors.push("'allowInlineConfig' must be a boolean.");
    }
    if (typeof baseConfig !== "object") {
        errors.push("'baseConfig' must be an object or null.");
    }
    if (typeof cache !== "boolean") {
        errors.push("'cache' must be a boolean.");
    }
    if (!isNonEmptyString(cacheLocation)) {
        errors.push("'cacheLocation' must be a non-empty string.");
    }
    if (
        cacheStrategy !== "metadata" &&
        cacheStrategy !== "content"
    ) {
        errors.push("'cacheStrategy' must be any of \"metadata\", \"content\".");
    }
    if (!isNonEmptyString(cwd) || !path.isAbsolute(cwd)) {
        errors.push("'cwd' must be an absolute path.");
    }
    if (typeof errorOnUnmatchedPattern !== "boolean") {
        errors.push("'errorOnUnmatchedPattern' must be a boolean.");
    }
    if (!isArrayOfNonEmptyString(extensions) && extensions !== null) {
        errors.push("'extensions' must be an array of non-empty strings or null.");
    }
    if (typeof fix !== "boolean" && typeof fix !== "function") {
        errors.push("'fix' must be a boolean or a function.");
    }
    if (fixTypes !== null && !isFixTypeArray(fixTypes)) {
        errors.push("'fixTypes' must be an array of any of \"directive\", \"problem\", \"suggestion\", and \"layout\".");
    }
    if (typeof globInputPaths !== "boolean") {
        errors.push("'globInputPaths' must be a boolean.");
    }
    if (typeof ignore !== "boolean") {
        errors.push("'ignore' must be a boolean.");
    }
    if (!isNonEmptyString(ignorePath) && ignorePath !== null) {
        errors.push("'ignorePath' must be a non-empty string or null.");
    }
    if (typeof overrideConfig !== "object") {
        errors.push("'overrideConfig' must be an object or null.");
    }
    if (!isNonEmptyString(overrideConfigFile) && overrideConfigFile !== null) {
        errors.push("'overrideConfigFile' must be a non-empty string or null.");
    }
    if (typeof plugins !== "object") {
        errors.push("'plugins' must be an object or null.");
    } else if (plugins !== null && Object.keys(plugins).includes("")) {
        errors.push("'plugins' must not include an empty string.");
    }
    if (Array.isArray(plugins)) {
        errors.push("'plugins' doesn't add plugins to configuration to load. Please use the 'overrideConfig.plugins' option instead.");
    }
    if (
        reportUnusedDisableDirectives !== "error" &&
        reportUnusedDisableDirectives !== "warn" &&
        reportUnusedDisableDirectives !== "off" &&
        reportUnusedDisableDirectives !== null
    ) {
        errors.push("'reportUnusedDisableDirectives' must be any of \"error\", \"warn\", \"off\", and null.");
    }
    if (
        !isNonEmptyString(resolvePluginsRelativeTo) &&
        resolvePluginsRelativeTo !== null
    ) {
        errors.push("'resolvePluginsRelativeTo' must be a non-empty string or null.");
    }
    if (!isArrayOfNonEmptyString(rulePaths)) {
        errors.push("'rulePaths' must be an array of non-empty strings.");
    }
    if (typeof useEslintrc !== "boolean") {
        errors.push("'useEslintrc' must be a boolean.");
    }

    if (errors.length > 0) {
        throw new ESLintInvalidOptionsError(errors);
    }

    return {
        allowInlineConfig,
        baseConfig,
        cache,
        cacheLocation,
        cacheStrategy,
        configFile: overrideConfigFile,
        cwd: path.normalize(cwd),
        errorOnUnmatchedPattern,
        extensions,
        fix,
        fixTypes,
        globInputPaths,
        ignore,
        ignorePath,
        reportUnusedDisableDirectives,
        resolvePluginsRelativeTo,
        rulePaths,
        useEslintrc
    };
}

/**
 * Check if a value has one or more properties and that value is not undefined.
 * @param {any} obj The value to check.
 * @returns {boolean} `true` if `obj` has one or more properties that that value is not undefined.
 */
function hasDefinedProperty(obj) {
    if (typeof obj === "object" && obj !== null) {
        for (const key in obj) {
            if (typeof obj[key] !== "undefined") {
                return true;
            }
        }
    }
    return false;
}

/**
 * Create rulesMeta object.
 * @param {Map<string,Rule>} rules a map of rules from which to generate the object.
 * @returns {Object} metadata for all enabled rules.
 */
function createRulesMeta(rules) {
    return Array.from(rules).reduce((retVal, [id, rule]) => {
        retVal[id] = rule.meta;
        return retVal;
    }, {});
}

/** @type {WeakMap<ExtractedConfig, DeprecatedRuleInfo[]>} */
const usedDeprecatedRulesCache = new WeakMap();

/**
 * Create used deprecated rule list.
 * @param {CLIEngine} cliEngine The CLIEngine instance.
 * @param {string} maybeFilePath The absolute path to a lint target file or `"<text>"`.
 * @returns {DeprecatedRuleInfo[]} The used deprecated rule list.
 */
function getOrFindUsedDeprecatedRules(cliEngine, maybeFilePath) {
    const {
        configArrayFactory,
        options: { cwd }
    } = getCLIEngineInternalSlots(cliEngine);
    const filePath = path.isAbsolute(maybeFilePath)
        ? maybeFilePath
        : path.join(cwd, "__placeholder__.js");
    const configArray = configArrayFactory.getConfigArrayForFile(filePath);
    const config = configArray.extractConfig(filePath);

    // Most files use the same config, so cache it.
    if (!usedDeprecatedRulesCache.has(config)) {
        const pluginRules = configArray.pluginRules;
        const retv = [];

        for (const [ruleId, ruleConf] of Object.entries(config.rules)) {
            if (getRuleSeverity(ruleConf) === 0) {
                continue;
            }
            const rule = pluginRules.get(ruleId) || BuiltinRules.get(ruleId);
            const meta = rule && rule.meta;

            if (meta && meta.deprecated) {
                retv.push({ ruleId, replacedBy: meta.replacedBy || [] });
            }
        }

        usedDeprecatedRulesCache.set(config, Object.freeze(retv));
    }

    return usedDeprecatedRulesCache.get(config);
}

/**
 * Processes the linting results generated by a CLIEngine linting report to
 * match the ESLint class's API.
 * @param {CLIEngine} cliEngine The CLIEngine instance.
 * @param {CLIEngineLintReport} report The CLIEngine linting report to process.
 * @returns {LintResult[]} The processed linting results.
 */
function processCLIEngineLintReport(cliEngine, { results }) {
    const descriptor = {
        configurable: true,
        enumerable: true,
        get() {
            return getOrFindUsedDeprecatedRules(cliEngine, this.filePath);
        }
    };

    for (const result of results) {
        Object.defineProperty(result, "usedDeprecatedRules", descriptor);
    }

    return results;
}

/**
 * An Array.prototype.sort() compatible compare function to order results by their file path.
 * @param {LintResult} a The first lint result.
 * @param {LintResult} b The second lint result.
 * @returns {number} An integer representing the order in which the two results should occur.
 */
function compareResultsByFilePath(a, b) {
    if (a.filePath < b.filePath) {
        return -1;
    }

    if (a.filePath > b.filePath) {
        return 1;
    }

    return 0;
}

/**
 * Main API.
 */
class ESLint {

    /**
     * Creates a new instance of the main ESLint API.
     * @param {ESLintOptions} options The options for this instance.
     */
    constructor(options = {}) {
        const processedOptions = processOptions(options);
        const cliEngine = new CLIEngine(processedOptions, { preloadedPlugins: options.plugins });
        const {
            configArrayFactory,
            lastConfigArrays
        } = getCLIEngineInternalSlots(cliEngine);
        let updated = false;

        /*
         * Address `overrideConfig` to set override config.
         * Operate the `configArrayFactory` internal slot directly because this
         * functionality doesn't exist as the public API of CLIEngine.
         */
        if (hasDefinedProperty(options.overrideConfig)) {
            configArrayFactory.setOverrideConfig(options.overrideConfig);
            updated = true;
        }

        // Update caches.
        if (updated) {
            configArrayFactory.clearCache();
            lastConfigArrays[0] = configArrayFactory.getConfigArrayForFile();
        }

        // Initialize private properties.
        privateMembersMap.set(this, {
            cliEngine,
            options: processedOptions
        });
    }

    /**
     * The version text.
     * @type {string}
     */
    static get version() {
        return version;
    }

    /**
     * Outputs fixes from the given results to files.
     * @param {LintResult[]} results The lint results.
     * @returns {Promise<void>} Returns a promise that is used to track side effects.
     */
    static async outputFixes(results) {
        if (!Array.isArray(results)) {
            throw new Error("'results' must be an array");
        }

        await Promise.all(
            results
                .filter(result => {
                    if (typeof result !== "object" || result === null) {
                        throw new Error("'results' must include only objects");
                    }
                    return (
                        typeof result.output === "string" &&
                        path.isAbsolute(result.filePath)
                    );
                })
                .map(r => writeFile(r.filePath, r.output))
        );
    }

    /**
     * Returns results that only contains errors.
     * @param {LintResult[]} results The results to filter.
     * @returns {LintResult[]} The filtered results.
     */
    static getErrorResults(results) {
        return CLIEngine.getErrorResults(results);
    }

    /**
     * Returns meta objects for each rule represented in the lint results.
     * @param {LintResult[]} results The results to fetch rules meta for.
     * @returns {Object} A mapping of ruleIds to rule meta objects.
     */
    getRulesMetaForResults(results) {

        const resultRuleIds = new Set();

        // first gather all ruleIds from all results

        for (const result of results) {
            for (const { ruleId } of result.messages) {
                resultRuleIds.add(ruleId);
            }
            for (const { ruleId } of result.suppressedMessages) {
                resultRuleIds.add(ruleId);
            }
        }

        // create a map of all rules in the results

        const { cliEngine } = privateMembersMap.get(this);
        const rules = cliEngine.getRules();
        const resultRules = new Map();

        for (const [ruleId, rule] of rules) {
            if (resultRuleIds.has(ruleId)) {
                resultRules.set(ruleId, rule);
            }
        }

        return createRulesMeta(resultRules);

    }

    /**
     * Executes the current configuration on an array of file and directory names.
     * @param {string[]} patterns An array of file and directory names.
     * @returns {Promise<LintResult[]>} The results of linting the file patterns given.
     */
    async lintFiles(patterns) {
        if (!isNonEmptyString(patterns) && !isArrayOfNonEmptyString(patterns)) {
            throw new Error("'patterns' must be a non-empty string or an array of non-empty strings");
        }
        const { cliEngine } = privateMembersMap.get(this);

        return processCLIEngineLintReport(
            cliEngine,
            cliEngine.executeOnFiles(patterns)
        );
    }

    /**
     * Executes the current configuration on text.
     * @param {string} code A string of JavaScript code to lint.
     * @param {Object} [options] The options.
     * @param {string} [options.filePath] The path to the file of the source code.
     * @param {boolean} [options.warnIgnored] When set to true, warn if given filePath is an ignored path.
     * @returns {Promise<LintResult[]>} The results of linting the string of code given.
     */
    async lintText(code, options = {}) {
        if (typeof code !== "string") {
            throw new Error("'code' must be a string");
        }
        if (typeof options !== "object") {
            throw new Error("'options' must be an object, null, or undefined");
        }
        const {
            filePath,
            warnIgnored = false,
            ...unknownOptions
        } = options || {};

        const unknownOptionKeys = Object.keys(unknownOptions);

        if (unknownOptionKeys.length > 0) {
            throw new Error(`'options' must not include the unknown option(s): ${unknownOptionKeys.join(", ")}`);
        }

        if (filePath !== void 0 && !isNonEmptyString(filePath)) {
            throw new Error("'options.filePath' must be a non-empty string or undefined");
        }
        if (typeof warnIgnored !== "boolean") {
            throw new Error("'options.warnIgnored' must be a boolean or undefined");
        }

        const { cliEngine } = privateMembersMap.get(this);

        return processCLIEngineLintReport(
            cliEngine,
            cliEngine.executeOnText(code, filePath, warnIgnored)
        );
    }

    /**
     * Returns the formatter representing the given formatter name.
     * @param {string} [name] The name of the formatter to load.
     * The following values are allowed:
     * - `undefined` ... Load `stylish` builtin formatter.
     * - A builtin formatter name ... Load the builtin formatter.
     * - A third-party formatter name:
     *   - `foo` → `eslint-formatter-foo`
     *   - `@foo` → `@foo/eslint-formatter`
     *   - `@foo/bar` → `@foo/eslint-formatter-bar`
     * - A file path ... Load the file.
     * @returns {Promise<LoadedFormatter>} A promise resolving to the formatter object.
     * This promise will be rejected if the given formatter was not found or not
     * a function.
     */
    async loadFormatter(name = "stylish") {
        if (typeof name !== "string") {
            throw new Error("'name' must be a string");
        }

        const { cliEngine, options } = privateMembersMap.get(this);
        const formatter = cliEngine.getFormatter(name);

        if (typeof formatter !== "function") {
            throw new Error(`Formatter must be a function, but got a ${typeof formatter}.`);
        }

        return {

            /**
             * The main formatter method.
             * @param {LintResult[]} results The lint results to format.
             * @param {ResultsMeta} resultsMeta Warning count and max threshold.
             * @returns {string | Promise<string>} The formatted lint results.
             */
            format(results, resultsMeta) {
                let rulesMeta = null;

                results.sort(compareResultsByFilePath);

                return formatter(results, {
                    ...resultsMeta,
                    get cwd() {
                        return options.cwd;
                    },
                    get rulesMeta() {
                        if (!rulesMeta) {
                            rulesMeta = createRulesMeta(cliEngine.getRules());
                        }

                        return rulesMeta;
                    }
                });
            }
        };
    }

    /**
     * Returns a configuration object for the given file based on the CLI options.
     * This is the same logic used by the ESLint CLI executable to determine
     * configuration for each file it processes.
     * @param {string} filePath The path of the file to retrieve a config object for.
     * @returns {Promise<ConfigData>} A configuration object for the file.
     */
    async calculateConfigForFile(filePath) {
        if (!isNonEmptyString(filePath)) {
            throw new Error("'filePath' must be a non-empty string");
        }
        const { cliEngine } = privateMembersMap.get(this);

        return cliEngine.getConfigForFile(filePath);
    }

    /**
     * Checks if a given path is ignored by ESLint.
     * @param {string} filePath The path of the file to check.
     * @returns {Promise<boolean>} Whether or not the given path is ignored.
     */
    async isPathIgnored(filePath) {
        if (!isNonEmptyString(filePath)) {
            throw new Error("'filePath' must be a non-empty string");
        }
        const { cliEngine } = privateMembersMap.get(this);

        return cliEngine.isPathIgnored(filePath);
    }
}

/**
 * The type of configuration used by this class.
 * @type {string}
 * @static
 */
ESLint.configType = "eslintrc";

//------------------------------------------------------------------------------
// Public Interface
//------------------------------------------------------------------------------

module.exports = {
    ESLint,

    /**
     * Get the private class members of a given ESLint instance for tests.
     * @param {ESLint} instance The ESLint instance to get.
     * @returns {ESLintPrivateMembers} The instance's private class members.
     */
    getESLintPrivateMembers(instance) {
        return privateMembersMap.get(instance);
    }
};


code:
/**
 * @fileoverview Main class using flat config
 * @author Nicholas C. Zakas
 */

"use strict";

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

// Note: Node.js 12 does not support fs/promises.
const fs = require("fs").promises;
const { existsSync } = require("fs");
const path = require("path");
const findUp = require("find-up");
const { version } = require("../../package.json");
const { Linter } = require("../linter");
const { getRuleFromConfig } = require("../config/flat-config-helpers");
const {
    Legacy: {
        ConfigOps: {
            getRuleSeverity
        },
        ModuleResolver,
        naming
    }
} = require("@eslint/eslintrc");

const {
    findFiles,
    getCacheFile,

    isNonEmptyString,
    isArrayOfNonEmptyString,

    createIgnoreResult,
    isErrorMessage,

    processOptions
} = require("./eslint-helpers");
const { pathToFileURL } = require("url");
const { FlatConfigArray } = require("../config/flat-config-array");
const LintResultCache = require("../cli-engine/lint-result-cache");

/*
 * This is necessary to allow overwriting writeFile for testing purposes.
 * We can just use fs/promises once we drop Node.js 12 support.
 */

//------------------------------------------------------------------------------
// Typedefs
//------------------------------------------------------------------------------

// For VSCode IntelliSense
/** @typedef {import("../shared/types").ConfigData} ConfigData */
/** @typedef {import("../shared/types").DeprecatedRuleInfo} DeprecatedRuleInfo */
/** @typedef {import("../shared/types").LintMessage} LintMessage */
/** @typedef {import("../shared/types").LintResult} LintResult */
/** @typedef {import("../shared/types").ParserOptions} ParserOptions */
/** @typedef {import("../shared/types").Plugin} Plugin */
/** @typedef {import("../shared/types").ResultsMeta} ResultsMeta */
/** @typedef {import("../shared/types").RuleConf} RuleConf */
/** @typedef {import("../shared/types").Rule} Rule */
/** @typedef {ReturnType<ConfigArray.extractConfig>} ExtractedConfig */

/**
 * The options with which to configure the ESLint instance.
 * @typedef {Object} FlatESLintOptions
 * @property {boolean} [allowInlineConfig] Enable or disable inline configuration comments.
 * @property {ConfigData} [baseConfig] Base config object, extended by all configs used with this instance
 * @property {boolean} [cache] Enable result caching.
 * @property {string} [cacheLocation] The cache file to use instead of .eslintcache.
 * @property {"metadata" | "content"} [cacheStrategy] The strategy used to detect changed files.
 * @property {string} [cwd] The value to use for the current working directory.
 * @property {boolean} [errorOnUnmatchedPattern] If `false` then `ESLint#lintFiles()` doesn't throw even if no target files found. Defaults to `true`.
 * @property {boolean|Function} [fix] Execute in autofix mode. If a function, should return a boolean.
 * @property {string[]} [fixTypes] Array of rule types to apply fixes for.
 * @property {boolean} [globInputPaths] Set to false to skip glob resolution of input file paths to lint (default: true). If false, each input file paths is assumed to be a non-glob path to an existing file.
 * @property {boolean} [ignore] False disables all ignore patterns except for the default ones.
 * @property {string[]} [ignorePatterns] Ignore file patterns to use in addition to config ignores. These patterns are relative to `cwd`.
 * @property {ConfigData} [overrideConfig] Override config object, overrides all configs used with this instance
 * @property {boolean|string} [overrideConfigFile] Searches for default config file when falsy;
 *      doesn't do any config file lookup when `true`; considered to be a config filename
 *      when a string.
 * @property {Record<string,Plugin>} [plugins] An array of plugin implementations.
 * @property {boolean} warnIgnored Show warnings when the file list includes ignored files
 */

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

const FLAT_CONFIG_FILENAMES = [
    "eslint.config.js",
    "eslint.config.mjs",
    "eslint.config.cjs"
];
const debug = require("debug")("eslint:flat-eslint");
const removedFormatters = new Set(["table", "codeframe"]);
const privateMembers = new WeakMap();
const importedConfigFileModificationTime = new Map();

/**
 * It will calculate the error and warning count for collection of messages per file
 * @param {LintMessage[]} messages Collection of messages
 * @returns {Object} Contains the stats
 * @private
 */
function calculateStatsPerFile(messages) {
    const stat = {
        errorCount: 0,
        fatalErrorCount: 0,
        warningCount: 0,
        fixableErrorCount: 0,
        fixableWarningCount: 0
    };

    for (let i = 0; i < messages.length; i++) {
        const message = messages[i];

        if (message.fatal || message.severity === 2) {
            stat.errorCount++;
            if (message.fatal) {
                stat.fatalErrorCount++;
            }
            if (message.fix) {
                stat.fixableErrorCount++;
            }
        } else {
            stat.warningCount++;
            if (message.fix) {
                stat.fixableWarningCount++;
            }
        }
    }
    return stat;
}

/**
 * Create rulesMeta object.
 * @param {Map<string,Rule>} rules a map of rules from which to generate the object.
 * @returns {Object} metadata for all enabled rules.
 */
function createRulesMeta(rules) {
    return Array.from(rules).reduce((retVal, [id, rule]) => {
        retVal[id] = rule.meta;
        return retVal;
    }, {});
}

/**
 * Return the absolute path of a file named `"__placeholder__.js"` in a given directory.
 * This is used as a replacement for a missing file path.
 * @param {string} cwd An absolute directory path.
 * @returns {string} The absolute path of a file named `"__placeholder__.js"` in the given directory.
 */
function getPlaceholderPath(cwd) {
    return path.join(cwd, "__placeholder__.js");
}

/** @type {WeakMap<ExtractedConfig, DeprecatedRuleInfo[]>} */
const usedDeprecatedRulesCache = new WeakMap();

/**
 * Create used deprecated rule list.
 * @param {CLIEngine} eslint The CLIEngine instance.
 * @param {string} maybeFilePath The absolute path to a lint target file or `"<text>"`.
 * @returns {DeprecatedRuleInfo[]} The used deprecated rule list.
 */
function getOrFindUsedDeprecatedRules(eslint, maybeFilePath) {
    const {
        configs,
        options: { cwd }
    } = privateMembers.get(eslint);
    const filePath = path.isAbsolute(maybeFilePath)
        ? maybeFilePath
        : getPlaceholderPath(cwd);
    const config = configs.getConfig(filePath);

    // Most files use the same config, so cache it.
    if (config && !usedDeprecatedRulesCache.has(config)) {
        const retv = [];

        if (config.rules) {
            for (const [ruleId, ruleConf] of Object.entries(config.rules)) {
                if (getRuleSeverity(ruleConf) === 0) {
                    continue;
                }
                const rule = getRuleFromConfig(ruleId, config);
                const meta = rule && rule.meta;

                if (meta && meta.deprecated) {
                    retv.push({ ruleId, replacedBy: meta.replacedBy || [] });
                }
            }
        }

        usedDeprecatedRulesCache.set(config, Object.freeze(retv));
    }

    return config ? usedDeprecatedRulesCache.get(config) : Object.freeze([]);
}

/**
 * Processes the linting results generated by a CLIEngine linting report to
 * match the ESLint class's API.
 * @param {CLIEngine} eslint The CLIEngine instance.
 * @param {CLIEngineLintReport} report The CLIEngine linting report to process.
 * @returns {LintResult[]} The processed linting results.
 */
function processLintReport(eslint, { results }) {
    const descriptor = {
        configurable: true,
        enumerable: true,
        get() {
            return getOrFindUsedDeprecatedRules(eslint, this.filePath);
        }
    };

    for (const result of results) {
        Object.defineProperty(result, "usedDeprecatedRules", descriptor);
    }

    return results;
}

/**
 * An Array.prototype.sort() compatible compare function to order results by their file path.
 * @param {LintResult} a The first lint result.
 * @param {LintResult} b The second lint result.
 * @returns {number} An integer representing the order in which the two results should occur.
 */
function compareResultsByFilePath(a, b) {
    if (a.filePath < b.filePath) {
        return -1;
    }

    if (a.filePath > b.filePath) {
        return 1;
    }

    return 0;
}

/**
 * Searches from the current working directory up until finding the
 * given flat config filename.
 * @param {string} cwd The current working directory to search from.
 * @returns {Promise<string|undefined>} The filename if found or `undefined` if not.
 */
function findFlatConfigFile(cwd) {
    return findUp(
        FLAT_CONFIG_FILENAMES,
        { cwd }
    );
}

/**
 * Load the config array from the given filename.
 * @param {string} filePath The filename to load from.
 * @returns {Promise<any>} The config loaded from the config file.
 */
async function loadFlatConfigFile(filePath) {
    debug(`Loading config from ${filePath}`);

    const fileURL = pathToFileURL(filePath);

    debug(`Config file URL is ${fileURL}`);

    const mtime = (await fs.stat(filePath)).mtime.getTime();

    /*
     * Append a query with the config file's modification time (`mtime`) in order
     * to import the current version of the config file. Without the query, `import()` would
     * cache the config file module by the pathname only, and then always return
     * the same version (the one that was actual when the module was imported for the first time).
     *
     * This ensures that the config file module is loaded and executed again
     * if it has been changed since the last time it was imported.
     * If it hasn't been changed, `import()` will just return the cached version.
     *
     * Note that we should not overuse queries (e.g., by appending the current time
     * to always reload the config file module) as that could cause memory leaks
     * because entries are never removed from the import cache.
     */
    fileURL.searchParams.append("mtime", mtime);

    /*
     * With queries, we can bypass the import cache. However, when import-ing a CJS module,
     * Node.js uses the require infrastructure under the hood. That includes the require cache,
     * which caches the config file module by its file path (queries have no effect).
     * Therefore, we also need to clear the require cache before importing the config file module.
     * In order to get the same behavior with ESM and CJS config files, in particular - to reload
     * the config file only if it has been changed, we track file modification times and clear
     * the require cache only if the file has been changed.
     */
    if (importedConfigFileModificationTime.get(filePath) !== mtime) {
        delete require.cache[filePath];
    }

    const config = (await import(fileURL)).default;

    importedConfigFileModificationTime.set(filePath, mtime);

    return config;
}

/**
 * Determines which config file to use. This is determined by seeing if an
 * override config file was passed, and if so, using it; otherwise, as long
 * as override config file is not explicitly set to `false`, it will search
 * upwards from the cwd for a file named `eslint.config.js`.
 * @param {import("./eslint").ESLintOptions} options The ESLint instance options.
 * @returns {{configFilePath:string|undefined,basePath:string,error:Error|null}} Location information for
 *      the config file.
 */
async function locateConfigFileToUse({ configFile, cwd }) {

    // determine where to load config file from
    let configFilePath;
    let basePath = cwd;
    let error = null;

    if (typeof configFile === "string") {
        debug(`Override config file path is ${configFile}`);
        configFilePath = path.resolve(cwd, configFile);
    } else if (configFile !== false) {
        debug("Searching for eslint.config.js");
        configFilePath = await findFlatConfigFile(cwd);

        if (configFilePath) {
            basePath = path.resolve(path.dirname(configFilePath));
        } else {
            error = new Error("Could not find config file.");
        }

    }

    return {
        configFilePath,
        basePath,
        error
    };

}

/**
 * Calculates the config array for this run based on inputs.
 * @param {FlatESLint} eslint The instance to create the config array for.
 * @param {import("./eslint").ESLintOptions} options The ESLint instance options.
 * @returns {FlatConfigArray} The config array for `eslint``.
 */
async function calculateConfigArray(eslint, {
    cwd,
    baseConfig,
    overrideConfig,
    configFile,
    ignore: shouldIgnore,
    ignorePatterns
}) {

    // check for cached instance
    const slots = privateMembers.get(eslint);

    if (slots.configs) {
        return slots.configs;
    }

    const { configFilePath, basePath, error } = await locateConfigFileToUse({ configFile, cwd });

    // config file is required to calculate config
    if (error) {
        throw error;
    }

    const configs = new FlatConfigArray(baseConfig || [], { basePath, shouldIgnore });

    // load config file
    if (configFilePath) {
        const fileConfig = await loadFlatConfigFile(configFilePath);

        if (Array.isArray(fileConfig)) {
            configs.push(...fileConfig);
        } else {
            configs.push(fileConfig);
        }
    }

    // add in any configured defaults
    configs.push(...slots.defaultConfigs);

    // append command line ignore patterns
    if (ignorePatterns && ignorePatterns.length > 0) {

        let relativeIgnorePatterns;

        /*
         * If the config file basePath is different than the cwd, then
         * the ignore patterns won't work correctly. Here, we adjust the
         * ignore pattern to include the correct relative path. Patterns
         * passed as `ignorePatterns` are relative to the cwd, whereas
         * the config file basePath can be an ancestor of the cwd.
         */
        if (basePath === cwd) {
            relativeIgnorePatterns = ignorePatterns;
        } else {

            const relativeIgnorePath = path.relative(basePath, cwd);

            relativeIgnorePatterns = ignorePatterns.map(pattern => {
                const negated = pattern.startsWith("!");
                const basePattern = negated ? pattern.slice(1) : pattern;

                return (negated ? "!" : "") +
                path.posix.join(relativeIgnorePath, basePattern);
            });
        }

        /*
         * Ignore patterns are added to the end of the config array
         * so they can override default ignores.
         */
        configs.push({
            ignores: relativeIgnorePatterns
        });
    }

    if (overrideConfig) {
        if (Array.isArray(overrideConfig)) {
            configs.push(...overrideConfig);
        } else {
            configs.push(overrideConfig);
        }
    }

    await configs.normalize();

    // cache the config array for this instance
    slots.configs = configs;

    return configs;
}

/**
 * Processes an source code using ESLint.
 * @param {Object} config The config object.
 * @param {string} config.text The source code to verify.
 * @param {string} config.cwd The path to the current working directory.
 * @param {string|undefined} config.filePath The path to the file of `text`. If this is undefined, it uses `<text>`.
 * @param {FlatConfigArray} config.configs The config.
 * @param {boolean} config.fix If `true` then it does fix.
 * @param {boolean} config.allowInlineConfig If `true` then it uses directive comments.
 * @param {Linter} config.linter The linter instance to verify.
 * @returns {LintResult} The result of linting.
 * @private
 */
function verifyText({
    text,
    cwd,
    filePath: providedFilePath,
    configs,
    fix,
    allowInlineConfig,
    linter
}) {
    const filePath = providedFilePath || "<text>";

    debug(`Lint ${filePath}`);

    /*
     * Verify.
     * `config.extractConfig(filePath)` requires an absolute path, but `linter`
     * doesn't know CWD, so it gives `linter` an absolute path always.
     */
    const filePathToVerify = filePath === "<text>" ? getPlaceholderPath(cwd) : filePath;
    const { fixed, messages, output } = linter.verifyAndFix(
        text,
        configs,
        {
            allowInlineConfig,
            filename: filePathToVerify,
            fix,

            /**
             * Check if the linter should adopt a given code block or not.
             * @param {string} blockFilename The virtual filename of a code block.
             * @returns {boolean} `true` if the linter should adopt the code block.
             */
            filterCodeBlock(blockFilename) {
                return configs.isExplicitMatch(blockFilename);
            }
        }
    );

    // Tweak and return.
    const result = {
        filePath: filePath === "<text>" ? filePath : path.resolve(filePath),
        messages,
        suppressedMessages: linter.getSuppressedMessages(),
        ...calculateStatsPerFile(messages)
    };

    if (fixed) {
        result.output = output;
    }

    if (
        result.errorCount + result.warningCount > 0 &&
        typeof result.output === "undefined"
    ) {
        result.source = text;
    }

    return result;
}

/**
 * Checks whether a message's rule type should be fixed.
 * @param {LintMessage} message The message to check.
 * @param {FlatConfig} config The config for the file that generated the message.
 * @param {string[]} fixTypes An array of fix types to check.
 * @returns {boolean} Whether the message should be fixed.
 */
function shouldMessageBeFixed(message, config, fixTypes) {
    if (!message.ruleId) {
        return fixTypes.has("directive");
    }

    const rule = message.ruleId && getRuleFromConfig(message.ruleId, config);

    return Boolean(rule && rule.meta && fixTypes.has(rule.meta.type));
}

/**
 * Creates an error to be thrown when an array of results passed to `getRulesMetaForResults` was not created by the current engine.
 * @returns {TypeError} An error object.
 */
function createExtraneousResultsError() {
    return new TypeError("Results object was not created from this ESLint instance.");
}

//-----------------------------------------------------------------------------
// Main API
//-----------------------------------------------------------------------------

/**
 * Primary Node.js API for ESLint.
 */
class FlatESLint {

    /**
     * Creates a new instance of the main ESLint API.
     * @param {FlatESLintOptions} options The options for this instance.
     */
    constructor(options = {}) {

        const defaultConfigs = [];
        const processedOptions = processOptions(options);
        const linter = new Linter({
            cwd: processedOptions.cwd,
            configType: "flat"
        });

        const cacheFilePath = getCacheFile(
            processedOptions.cacheLocation,
            processedOptions.cwd
        );

        const lintResultCache = processedOptions.cache
            ? new LintResultCache(cacheFilePath, processedOptions.cacheStrategy)
            : null;

        privateMembers.set(this, {
            options: processedOptions,
            linter,
            cacheFilePath,
            lintResultCache,
            defaultConfigs,
            configs: null
        });

        /**
         * If additional plugins are passed in, add that to the default
         * configs for this instance.
         */
        if (options.plugins) {

            const plugins = {};

            for (const [pluginName, plugin] of Object.entries(options.plugins)) {
                plugins[naming.getShorthandName(pluginName, "eslint-plugin")] = plugin;
            }

            defaultConfigs.push({
                plugins
            });
        }

    }

    /**
     * The version text.
     * @type {string}
     */
    static get version() {
        return version;
    }

    /**
     * Outputs fixes from the given results to files.
     * @param {LintResult[]} results The lint results.
     * @returns {Promise<void>} Returns a promise that is used to track side effects.
     */
    static async outputFixes(results) {
        if (!Array.isArray(results)) {
            throw new Error("'results' must be an array");
        }

        await Promise.all(
            results
                .filter(result => {
                    if (typeof result !== "object" || result === null) {
                        throw new Error("'results' must include only objects");
                    }
                    return (
                        typeof result.output === "string" &&
                        path.isAbsolute(result.filePath)
                    );
                })
                .map(r => fs.writeFile(r.filePath, r.output))
        );
    }

    /**
     * Returns results that only contains errors.
     * @param {LintResult[]} results The results to filter.
     * @returns {LintResult[]} The filtered results.
     */
    static getErrorResults(results) {
        const filtered = [];

        results.forEach(result => {
            const filteredMessages = result.messages.filter(isErrorMessage);
            const filteredSuppressedMessages = result.suppressedMessages.filter(isErrorMessage);

            if (filteredMessages.length > 0) {
                filtered.push({
                    ...result,
                    messages: filteredMessages,
                    suppressedMessages: filteredSuppressedMessages,
                    errorCount: filteredMessages.length,
                    warningCount: 0,
                    fixableErrorCount: result.fixableErrorCount,
                    fixableWarningCount: 0
                });
            }
        });

        return filtered;
    }

    /**
     * Returns meta objects for each rule represented in the lint results.
     * @param {LintResult[]} results The results to fetch rules meta for.
     * @returns {Object} A mapping of ruleIds to rule meta objects.
     * @throws {TypeError} When the results object wasn't created from this ESLint instance.
     * @throws {TypeError} When a plugin or rule is missing.
     */
    getRulesMetaForResults(results) {

        // short-circuit simple case
        if (results.length === 0) {
            return {};
        }

        const resultRules = new Map();
        const {
            configs,
            options: { cwd }
        } = privateMembers.get(this);

        /*
         * We can only accurately return rules meta information for linting results if the
         * results were created by this instance. Otherwise, the necessary rules data is
         * not available. So if the config array doesn't already exist, just throw an error
         * to let the user know we can't do anything here.
         */
        if (!configs) {
            throw createExtraneousResultsError();
        }

        for (const result of results) {

            /*
             * Normalize filename for <text>.
             */
            const filePath = result.filePath === "<text>"
                ? getPlaceholderPath(cwd) : result.filePath;
            const allMessages = result.messages.concat(result.suppressedMessages);

            for (const { ruleId } of allMessages) {
                if (!ruleId) {
                    continue;
                }

                /*
                 * All of the plugin and rule information is contained within the
                 * calculated config for the given file.
                 */
                const config = configs.getConfig(filePath);

                if (!config) {
                    throw createExtraneousResultsError();
                }
                const rule = getRuleFromConfig(ruleId, config);

                // ignore unknown rules
                if (rule) {
                    resultRules.set(ruleId, rule);
                }
            }
        }

        return createRulesMeta(resultRules);
    }

    /**
     * Executes the current configuration on an array of file and directory names.
     * @param {string|string[]} patterns An array of file and directory names.
     * @returns {Promise<LintResult[]>} The results of linting the file patterns given.
     */
    async lintFiles(patterns) {
        if (!isNonEmptyString(patterns) && !isArrayOfNonEmptyString(patterns)) {
            throw new Error("'patterns' must be a non-empty string or an array of non-empty strings");
        }

        const {
            cacheFilePath,
            lintResultCache,
            linter,
            options: eslintOptions
        } = privateMembers.get(this);
        const configs = await calculateConfigArray(this, eslintOptions);
        const {
            allowInlineConfig,
            cache,
            cwd,
            fix,
            fixTypes,
            globInputPaths,
            errorOnUnmatchedPattern,
            warnIgnored
        } = eslintOptions;
        const startTime = Date.now();
        const fixTypesSet = fixTypes ? new Set(fixTypes) : null;

        // Delete cache file; should this be done here?
        if (!cache && cacheFilePath) {
            debug(`Deleting cache file at ${cacheFilePath}`);

            try {
                await fs.unlink(cacheFilePath);
            } catch (error) {
                const errorCode = error && error.code;

                // Ignore errors when no such file exists or file system is read only (and cache file does not exist)
                if (errorCode !== "ENOENT" && !(errorCode === "EROFS" && !existsSync(cacheFilePath))) {
                    throw error;
                }
            }
        }

        const filePaths = await findFiles({
            patterns: typeof patterns === "string" ? [patterns] : patterns,
            cwd,
            globInputPaths,
            configs,
            errorOnUnmatchedPattern
        });

        debug(`${filePaths.length} files found in: ${Date.now() - startTime}ms`);

        /*
         * Because we need to process multiple files, including reading from disk,
         * it is most efficient to start by reading each file via promises so that
         * they can be done in parallel. Then, we can lint the returned text. This
         * ensures we are waiting the minimum amount of time in between lints.
         */
        const results = await Promise.all(

            filePaths.map(({ filePath, ignored }) => {

                /*
                 * If a filename was entered that matches an ignore
                 * pattern, then notify the user.
                 */
                if (ignored) {
                    if (warnIgnored) {
                        return createIgnoreResult(filePath, cwd);
                    }

                    return void 0;
                }

                const config = configs.getConfig(filePath);

                /*
                 * Sometimes a file found through a glob pattern will
                 * be ignored. In this case, `config` will be undefined
                 * and we just silently ignore the file.
                 */
                if (!config) {
                    return void 0;
                }

                // Skip if there is cached result.
                if (lintResultCache) {
                    const cachedResult =
                        lintResultCache.getCachedLintResults(filePath, config);

                    if (cachedResult) {
                        const hadMessages =
                            cachedResult.messages &&
                            cachedResult.messages.length > 0;

                        if (hadMessages && fix) {
                            debug(`Reprocessing cached file to allow autofix: ${filePath}`);
                        } else {
                            debug(`Skipping file since it hasn't changed: ${filePath}`);
                            return cachedResult;
                        }
                    }
                }

                // set up fixer for fixTypes if necessary
                let fixer = fix;

                if (fix && fixTypesSet) {

                    // save original value of options.fix in case it's a function
                    const originalFix = (typeof fix === "function")
                        ? fix : () => true;

                    fixer = message => shouldMessageBeFixed(message, config, fixTypesSet) && originalFix(message);
                }

                return fs.readFile(filePath, "utf8")
                    .then(text => {

                        // do the linting
                        const result = verifyText({
                            text,
                            filePath,
                            configs,
                            cwd,
                            fix: fixer,
                            allowInlineConfig,
                            linter
                        });

                        /*
                         * Store the lint result in the LintResultCache.
                         * NOTE: The LintResultCache will remove the file source and any
                         * other properties that are difficult to serialize, and will
                         * hydrate those properties back in on future lint runs.
                         */
                        if (lintResultCache) {
                            lintResultCache.setCachedLintResults(filePath, config, result);
                        }

                        return result;
                    });

            })
        );

        // Persist the cache to disk.
        if (lintResultCache) {
            lintResultCache.reconcile();
        }

        const finalResults = results.filter(result => !!result);

        return processLintReport(this, {
            results: finalResults
        });
    }

    /**
     * Executes the current configuration on text.
     * @param {string} code A string of JavaScript code to lint.
     * @param {Object} [options] The options.
     * @param {string} [options.filePath] The path to the file of the source code.
     * @param {boolean} [options.warnIgnored] When set to true, warn if given filePath is an ignored path.
     * @returns {Promise<LintResult[]>} The results of linting the string of code given.
     */
    async lintText(code, options = {}) {

        // Parameter validation

        if (typeof code !== "string") {
            throw new Error("'code' must be a string");
        }

        if (typeof options !== "object") {
            throw new Error("'options' must be an object, null, or undefined");
        }

        // Options validation

        const {
            filePath,
            warnIgnored,
            ...unknownOptions
        } = options || {};

        const unknownOptionKeys = Object.keys(unknownOptions);

        if (unknownOptionKeys.length > 0) {
            throw new Error(`'options' must not include the unknown option(s): ${unknownOptionKeys.join(", ")}`);
        }

        if (filePath !== void 0 && !isNonEmptyString(filePath)) {
            throw new Error("'options.filePath' must be a non-empty string or undefined");
        }

        if (typeof warnIgnored !== "boolean" && typeof warnIgnored !== "undefined") {
            throw new Error("'options.warnIgnored' must be a boolean or undefined");
        }

        // Now we can get down to linting

        const {
            linter,
            options: eslintOptions
        } = privateMembers.get(this);
        const configs = await calculateConfigArray(this, eslintOptions);
        const {
            allowInlineConfig,
            cwd,
            fix,
            warnIgnored: constructorWarnIgnored
        } = eslintOptions;
        const results = [];
        const startTime = Date.now();
        const resolvedFilename = path.resolve(cwd, filePath || "__placeholder__.js");

        // Clear the last used config arrays.
        if (resolvedFilename && await this.isPathIgnored(resolvedFilename)) {
            const shouldWarnIgnored = typeof warnIgnored === "boolean" ? warnIgnored : constructorWarnIgnored;

            if (shouldWarnIgnored) {
                results.push(createIgnoreResult(resolvedFilename, cwd));
            }
        } else {

            // Do lint.
            results.push(verifyText({
                text: code,
                filePath: resolvedFilename.endsWith("__placeholder__.js") ? "<text>" : resolvedFilename,
                configs,
                cwd,
                fix,
                allowInlineConfig,
                linter
            }));
        }

        debug(`Linting complete in: ${Date.now() - startTime}ms`);

        return processLintReport(this, {
            results
        });

    }

    /**
     * Returns the formatter representing the given formatter name.
     * @param {string} [name] The name of the formatter to load.
     * The following values are allowed:
     * - `undefined` ... Load `stylish` builtin formatter.
     * - A builtin formatter name ... Load the builtin formatter.
     * - A third-party formatter name:
     *   - `foo` → `eslint-formatter-foo`
     *   - `@foo` → `@foo/eslint-formatter`
     *   - `@foo/bar` → `@foo/eslint-formatter-bar`
     * - A file path ... Load the file.
     * @returns {Promise<Formatter>} A promise resolving to the formatter object.
     * This promise will be rejected if the given formatter was not found or not
     * a function.
     */
    async loadFormatter(name = "stylish") {
        if (typeof name !== "string") {
            throw new Error("'name' must be a string");
        }

        // replace \ with / for Windows compatibility
        const normalizedFormatName = name.replace(/\\/gu, "/");
        const namespace = naming.getNamespaceFromTerm(normalizedFormatName);

        // grab our options
        const { cwd } = privateMembers.get(this).options;

        let formatterPath;

        // if there's a slash, then it's a file (TODO: this check seems dubious for scoped npm packages)
        if (!namespace && normalizedFormatName.includes("/")) {
            formatterPath = path.resolve(cwd, normalizedFormatName);
        } else {
            try {
                const npmFormat = naming.normalizePackageName(normalizedFormatName, "eslint-formatter");

                // TODO: This is pretty dirty...would be nice to clean up at some point.
                formatterPath = ModuleResolver.resolve(npmFormat, getPlaceholderPath(cwd));
            } catch {
                formatterPath = path.resolve(__dirname, "../", "cli-engine", "formatters", `${normalizedFormatName}.js`);
            }
        }

        let formatter;

        try {
            formatter = (await import(pathToFileURL(formatterPath))).default;
        } catch (ex) {

            // check for formatters that have been removed
            if (removedFormatters.has(name)) {
                ex.message = `The ${name} formatter is no longer part of core ESLint. Install it manually with \`npm install -D eslint-formatter-${name}\``;
            } else {
                ex.message = `There was a problem loading formatter: ${formatterPath}\nError: ${ex.message}`;
            }

            throw ex;
        }

        if (typeof formatter !== "function") {
            throw new TypeError(`Formatter must be a function, but got a ${typeof formatter}.`);
        }

        const eslint = this;

        return {

            /**
             * The main formatter method.
             * @param {LintResults[]} results The lint results to format.
             * @param {ResultsMeta} resultsMeta Warning count and max threshold.
             * @returns {string} The formatted lint results.
             */
            format(results, resultsMeta) {
                let rulesMeta = null;

                results.sort(compareResultsByFilePath);

                return formatter(results, {
                    ...resultsMeta,
                    cwd,
                    get rulesMeta() {
                        if (!rulesMeta) {
                            rulesMeta = eslint.getRulesMetaForResults(results);
                        }

                        return rulesMeta;
                    }
                });
            }
        };
    }

    /**
     * Returns a configuration object for the given file based on the CLI options.
     * This is the same logic used by the ESLint CLI executable to determine
     * configuration for each file it processes.
     * @param {string} filePath The path of the file to retrieve a config object for.
     * @returns {Promise<ConfigData|undefined>} A configuration object for the file
     *      or `undefined` if there is no configuration data for the object.
     */
    async calculateConfigForFile(filePath) {
        if (!isNonEmptyString(filePath)) {
            throw new Error("'filePath' must be a non-empty string");
        }
        const options = privateMembers.get(this).options;
        const absolutePath = path.resolve(options.cwd, filePath);
        const configs = await calculateConfigArray(this, options);

        return configs.getConfig(absolutePath);
    }

    /**
     * Finds the config file being used by this instance based on the options
     * passed to the constructor.
     * @returns {string|undefined} The path to the config file being used or
     *      `undefined` if no config file is being used.
     */
    async findConfigFile() {
        const options = privateMembers.get(this).options;
        const { configFilePath } = await locateConfigFileToUse(options);

        return configFilePath;
    }

    /**
     * Checks if a given path is ignored by ESLint.
     * @param {string} filePath The path of the file to check.
     * @returns {Promise<boolean>} Whether or not the given path is ignored.
     */
    async isPathIgnored(filePath) {
        const config = await this.calculateConfigForFile(filePath);

        return config === void 0;
    }
}

/**
 * The type of configuration used by this class.
 * @type {string}
 * @static
 */
FlatESLint.configType = "flat";

/**
 * Returns whether flat config should be used.
 * @param {Object} [options] The options for this function.
 * @param {string} [options.cwd] The current working directory.
 * @returns {Promise<boolean>} Whether flat config should be used.
 */
async function shouldUseFlatConfig({ cwd = process.cwd() } = {}) {
    switch (process.env.ESLINT_USE_FLAT_CONFIG) {
        case "true":
            return true;
        case "false":
            return false;
        default:

            /*
             * If neither explicitly enabled nor disabled, then use the presence
             * of a flat config file to determine enablement.
             */
            return !!(await findFlatConfigFile(cwd));
    }
}

//------------------------------------------------------------------------------
// Public Interface
//------------------------------------------------------------------------------

module.exports = {
    FlatESLint,
    shouldUseFlatConfig
};

license: mit


code:
"use strict";

const { ESLint } = require("./eslint");
const { FlatESLint } = require("./flat-eslint");

module.exports = {
    ESLint,
    FlatESLint
};


code:
/**
 * @fileoverview A module that filters reported problems based on `eslint-disable` and `eslint-enable` comments
 * @author Teddy Katz
 */

"use strict";

//------------------------------------------------------------------------------
// Typedefs
//------------------------------------------------------------------------------

/** @typedef {import("../shared/types").LintMessage} LintMessage */

//------------------------------------------------------------------------------
// Module Definition
//------------------------------------------------------------------------------

const escapeRegExp = require("escape-string-regexp");

/**
 * Compares the locations of two objects in a source file
 * @param {{line: number, column: number}} itemA The first object
 * @param {{line: number, column: number}} itemB The second object
 * @returns {number} A value less than 1 if itemA appears before itemB in the source file, greater than 1 if
 * itemA appears after itemB in the source file, or 0 if itemA and itemB have the same location.
 */
function compareLocations(itemA, itemB) {
    return itemA.line - itemB.line || itemA.column - itemB.column;
}

/**
 * Groups a set of directives into sub-arrays by their parent comment.
 * @param {Iterable<Directive>} directives Unused directives to be removed.
 * @returns {Directive[][]} Directives grouped by their parent comment.
 */
function groupByParentComment(directives) {
    const groups = new Map();

    for (const directive of directives) {
        const { unprocessedDirective: { parentComment } } = directive;

        if (groups.has(parentComment)) {
            groups.get(parentComment).push(directive);
        } else {
            groups.set(parentComment, [directive]);
        }
    }

    return [...groups.values()];
}

/**
 * Creates removal details for a set of directives within the same comment.
 * @param {Directive[]} directives Unused directives to be removed.
 * @param {Token} commentToken The backing Comment token.
 * @returns {{ description, fix, unprocessedDirective }[]} Details for later creation of output Problems.
 */
function createIndividualDirectivesRemoval(directives, commentToken) {

    /*
     * `commentToken.value` starts right after `//` or `/*`.
     * All calculated offsets will be relative to this index.
     */
    const commentValueStart = commentToken.range[0] + "//".length;

    // Find where the list of rules starts. `\S+` matches with the directive name (e.g. `eslint-disable-line`)
    const listStartOffset = /^\s*\S+\s+/u.exec(commentToken.value)[0].length;

    /*
     * Get the list text without any surrounding whitespace. In order to preserve the original
     * formatting, we don't want to change that whitespace.
     *
     *     // eslint-disable-line rule-one , rule-two , rule-three -- comment
     *                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     */
    const listText = commentToken.value
        .slice(listStartOffset) // remove directive name and all whitespace before the list
        .split(/\s-{2,}\s/u)[0] // remove `-- comment`, if it exists
        .trimEnd(); // remove all whitespace after the list

    /*
     * We can assume that `listText` contains multiple elements.
     * Otherwise, this function wouldn't be called - if there is
     * only one rule in the list, then the whole comment must be removed.
     */

    return directives.map(directive => {
        const { ruleId } = directive;

        const regex = new RegExp(String.raw`(?:^|\s*,\s*)(?<quote>['"]?)${escapeRegExp(ruleId)}\k<quote>(?:\s*,\s*|$)`, "u");
        const match = regex.exec(listText);
        const matchedText = match[0];
        const matchStartOffset = listStartOffset + match.index;
        const matchEndOffset = matchStartOffset + matchedText.length;

        const firstIndexOfComma = matchedText.indexOf(",");
        const lastIndexOfComma = matchedText.lastIndexOf(",");

        let removalStartOffset, removalEndOffset;

        if (firstIndexOfComma !== lastIndexOfComma) {

            /*
             * Since there are two commas, this must one of the elements in the middle of the list.
             * Matched range starts where the previous rule name ends, and ends where the next rule name starts.
             *
             *     // eslint-disable-line rule-one , rule-two , rule-three -- comment
             *                                    ^^^^^^^^^^^^^^
             *
             * We want to remove only the content between the two commas, and also one of the commas.
             *
             *     // eslint-disable-line rule-one , rule-two , rule-three -- comment
             *                                     ^^^^^^^^^^^
             */
            removalStartOffset = matchStartOffset + firstIndexOfComma;
            removalEndOffset = matchStartOffset + lastIndexOfComma;

        } else {

            /*
             * This is either the first element or the last element.
             *
             * If this is the first element, matched range starts where the first rule name starts
             * and ends where the second rule name starts. This is exactly the range we want
             * to remove so that the second rule name will start where the first one was starting
             * and thus preserve the original formatting.
             *
             *     // eslint-disable-line rule-one , rule-two , rule-three -- comment
             *                            ^^^^^^^^^^^
             *
             * Similarly, if this is the last element, we've already matched the range we want to
             * remove. The previous rule name will end where the last one was ending, relative
             * to the content on the right side.
             *
             *     // eslint-disable-line rule-one , rule-two , rule-three -- comment
             *                                               ^^^^^^^^^^^^^
             */
            removalStartOffset = matchStartOffset;
            removalEndOffset = matchEndOffset;
        }

        return {
            description: `'${ruleId}'`,
            fix: {
                range: [
                    commentValueStart + removalStartOffset,
                    commentValueStart + removalEndOffset
                ],
                text: ""
            },
            unprocessedDirective: directive.unprocessedDirective
        };
    });
}

/**
 * Creates a description of deleting an entire unused disable comment.
 * @param {Directive[]} directives Unused directives to be removed.
 * @param {Token} commentToken The backing Comment token.
 * @returns {{ description, fix, unprocessedDirective }} Details for later creation of an output Problem.
 */
function createCommentRemoval(directives, commentToken) {
    const { range } = commentToken;
    const ruleIds = directives.filter(directive => directive.ruleId).map(directive => `'${directive.ruleId}'`);

    return {
        description: ruleIds.length <= 2
            ? ruleIds.join(" or ")
            : `${ruleIds.slice(0, ruleIds.length - 1).join(", ")}, or ${ruleIds[ruleIds.length - 1]}`,
        fix: {
            range,
            text: " "
        },
        unprocessedDirective: directives[0].unprocessedDirective
    };
}

/**
 * Parses details from directives to create output Problems.
 * @param {Iterable<Directive>} allDirectives Unused directives to be removed.
 * @returns {{ description, fix, unprocessedDirective }[]} Details for later creation of output Problems.
 */
function processUnusedDirectives(allDirectives) {
    const directiveGroups = groupByParentComment(allDirectives);

    return directiveGroups.flatMap(
        directives => {
            const { parentComment } = directives[0].unprocessedDirective;
            const remainingRuleIds = new Set(parentComment.ruleIds);

            for (const directive of directives) {
                remainingRuleIds.delete(directive.ruleId);
            }

            return remainingRuleIds.size
                ? createIndividualDirectivesRemoval(directives, parentComment.commentToken)
                : [createCommentRemoval(directives, parentComment.commentToken)];
        }
    );
}

/**
 * Collect eslint-enable comments that are removing suppressions by eslint-disable comments.
 * @param {Directive[]} directives The directives to check.
 * @returns {Set<Directive>} The used eslint-enable comments
 */
function collectUsedEnableDirectives(directives) {

    /**
     * A Map of `eslint-enable` keyed by ruleIds that may be marked as used.
     * If `eslint-enable` does not have a ruleId, the key will be `null`.
     * @type {Map<string|null, Directive>}
     */
    const enabledRules = new Map();

    /**
     * A Set of `eslint-enable` marked as used.
     * It is also the return value of `collectUsedEnableDirectives` function.
     * @type {Set<Directive>}
     */
    const usedEnableDirectives = new Set();

    /*
     * Checks the directives backwards to see if the encountered `eslint-enable` is used by the previous `eslint-disable`,
     * and if so, stores the `eslint-enable` in `usedEnableDirectives`.
     */
    for (let index = directives.length - 1; index >= 0; index--) {
        const directive = directives[index];

        if (directive.type === "disable") {
            if (enabledRules.size === 0) {
                continue;
            }
            if (directive.ruleId === null) {

                // If encounter `eslint-disable` without ruleId,
                // mark all `eslint-enable` currently held in enabledRules as used.
                // e.g.
                //    /* eslint-disable */ <- current directive
                //    /* eslint-enable rule-id1 */ <- used
                //    /* eslint-enable rule-id2 */ <- used
                //    /* eslint-enable */ <- used
                for (const enableDirective of enabledRules.values()) {
                    usedEnableDirectives.add(enableDirective);
                }
                enabledRules.clear();
            } else {
                const enableDirective = enabledRules.get(directive.ruleId);

                if (enableDirective) {

                    // If encounter `eslint-disable` with ruleId, and there is an `eslint-enable` with the same ruleId in enabledRules,
                    // mark `eslint-enable` with ruleId as used.
                    // e.g.
                    //    /* eslint-disable rule-id */ <- current directive
                    //    /* eslint-enable rule-id */ <- used
                    usedEnableDirectives.add(enableDirective);
                } else {
                    const enabledDirectiveWithoutRuleId = enabledRules.get(null);

                    if (enabledDirectiveWithoutRuleId) {

                        // If encounter `eslint-disable` with ruleId, and there is no `eslint-enable` with the same ruleId in enabledRules,
                        // mark `eslint-enable` without ruleId as used.
                        // e.g.
                        //    /* eslint-disable rule-id */ <- current directive
                        //    /* eslint-enable */ <- used
                        usedEnableDirectives.add(enabledDirectiveWithoutRuleId);
                    }
                }
            }
        } else if (directive.type === "enable") {
            if (directive.ruleId === null) {

                // If encounter `eslint-enable` without ruleId, the `eslint-enable` that follows it are unused.
                // So clear enabledRules.
                // e.g.
                //    /* eslint-enable */ <- current directive
                //    /* eslint-enable rule-id *// <- unused
                //    /* eslint-enable */ <- unused
                enabledRules.clear();
                enabledRules.set(null, directive);
            } else {
                enabledRules.set(directive.ruleId, directive);
            }
        }
    }
    return usedEnableDirectives;
}

/**
 * This is the same as the exported function, except that it
 * doesn't handle disable-line and disable-next-line directives, and it always reports unused
 * disable directives.
 * @param {Object} options options for applying directives. This is the same as the options
 * for the exported function, except that `reportUnusedDisableDirectives` is not supported
 * (this function always reports unused disable directives).
 * @returns {{problems: LintMessage[], unusedDirectives: LintMessage[]}} An object with a list
 * of problems (including suppressed ones) and unused eslint-disable directives
 */
function applyDirectives(options) {
    const problems = [];
    const usedDisableDirectives = new Set();

    for (const problem of options.problems) {
        let disableDirectivesForProblem = [];
        let nextDirectiveIndex = 0;

        while (
            nextDirectiveIndex < options.directives.length &&
            compareLocations(options.directives[nextDirectiveIndex], problem) <= 0
        ) {
            const directive = options.directives[nextDirectiveIndex++];

            if (directive.ruleId === null || directive.ruleId === problem.ruleId) {
                switch (directive.type) {
                    case "disable":
                        disableDirectivesForProblem.push(directive);
                        break;

                    case "enable":
                        disableDirectivesForProblem = [];
                        break;

                    // no default
                }
            }
        }

        if (disableDirectivesForProblem.length > 0) {
            const suppressions = disableDirectivesForProblem.map(directive => ({
                kind: "directive",
                justification: directive.unprocessedDirective.justification
            }));

            if (problem.suppressions) {
                problem.suppressions = problem.suppressions.concat(suppressions);
            } else {
                problem.suppressions = suppressions;
                usedDisableDirectives.add(disableDirectivesForProblem[disableDirectivesForProblem.length - 1]);
            }
        }

        problems.push(problem);
    }

    const unusedDisableDirectivesToReport = options.directives
        .filter(directive => directive.type === "disable" && !usedDisableDirectives.has(directive));

    const unusedEnableDirectivesToReport = new Set(
        options.directives.filter(directive => directive.unprocessedDirective.type === "enable")
    );

    /*
     * If directives has the eslint-enable directive,
     * check whether the eslint-enable comment is used.
     */
    if (unusedEnableDirectivesToReport.size > 0) {
        for (const directive of collectUsedEnableDirectives(options.directives)) {
            unusedEnableDirectivesToReport.delete(directive);
        }
    }

    const processed = processUnusedDirectives(unusedDisableDirectivesToReport)
        .concat(processUnusedDirectives(unusedEnableDirectivesToReport));

    const unusedDirectives = processed
        .map(({ description, fix, unprocessedDirective }) => {
            const { parentComment, type, line, column } = unprocessedDirective;

            let message;

            if (type === "enable") {
                message = description
                    ? `Unused eslint-enable directive (no matching eslint-disable directives were found for ${description}).`
                    : "Unused eslint-enable directive (no matching eslint-disable directives were found).";
            } else {
                message = description
                    ? `Unused eslint-disable directive (no problems were reported from ${description}).`
                    : "Unused eslint-disable directive (no problems were reported).";
            }
            return {
                ruleId: null,
                message,
                line: type === "disable-next-line" ? parentComment.commentToken.loc.start.line : line,
                column: type === "disable-next-line" ? parentComment.commentToken.loc.start.column + 1 : column,
                severity: options.reportUnusedDisableDirectives === "warn" ? 1 : 2,
                nodeType: null,
                ...options.disableFixes ? {} : { fix }
            };
        });

    return { problems, unusedDirectives };
}

/**
 * Given a list of directive comments (i.e. metadata about eslint-disable and eslint-enable comments) and a list
 * of reported problems, adds the suppression information to the problems.
 * @param {Object} options Information about directives and problems
 * @param {{
 *      type: ("disable"|"enable"|"disable-line"|"disable-next-line"),
 *      ruleId: (string|null),
 *      line: number,
 *      column: number,
 *      justification: string
 * }} options.directives Directive comments found in the file, with one-based columns.
 * Two directive comments can only have the same location if they also have the same type (e.g. a single eslint-disable
 * comment for two different rules is represented as two directives).
 * @param {{ruleId: (string|null), line: number, column: number}[]} options.problems
 * A list of problems reported by rules, sorted by increasing location in the file, with one-based columns.
 * @param {"off" | "warn" | "error"} options.reportUnusedDisableDirectives If `"warn"` or `"error"`, adds additional problems for unused directives
 * @param {boolean} options.disableFixes If true, it doesn't make `fix` properties.
 * @returns {{ruleId: (string|null), line: number, column: number, suppressions?: {kind: string, justification: string}}[]}
 * An object with a list of reported problems, the suppressed of which contain the suppression information.
 */
module.exports = ({ directives, disableFixes, problems, reportUnusedDisableDirectives = "off" }) => {
    const blockDirectives = directives
        .filter(directive => directive.type === "disable" || directive.type === "enable")
        .map(directive => Object.assign({}, directive, { unprocessedDirective: directive }))
        .sort(compareLocations);

    const lineDirectives = directives.flatMap(directive => {
        switch (directive.type) {
            case "disable":
            case "enable":
                return [];

            case "disable-line":
                return [
                    { type: "disable", line: directive.line, column: 1, ruleId: directive.ruleId, unprocessedDirective: directive },
                    { type: "enable", line: directive.line + 1, column: 0, ruleId: directive.ruleId, unprocessedDirective: directive }
                ];

            case "disable-next-line":
                return [
                    { type: "disable", line: directive.line + 1, column: 1, ruleId: directive.ruleId, unprocessedDirective: directive },
                    { type: "enable", line: directive.line + 2, column: 0, ruleId: directive.ruleId, unprocessedDirective: directive }
                ];

            default:
                throw new TypeError(`Unrecognized directive type '${directive.type}'`);
        }
    }).sort(compareLocations);

    const blockDirectivesResult = applyDirectives({
        problems,
        directives: blockDirectives,
        disableFixes,
        reportUnusedDisableDirectives
    });
    const lineDirectivesResult = applyDirectives({
        problems: blockDirectivesResult.problems,
        directives: lineDirectives,
        disableFixes,
        reportUnusedDisableDirectives
    });

    return reportUnusedDisableDirectives !== "off"
        ? lineDirectivesResult.problems
            .concat(blockDirectivesResult.unusedDirectives)
            .concat(lineDirectivesResult.unusedDirectives)
            .sort(compareLocations)
        : lineDirectivesResult.problems;
};