"""
Command-line interface for SlideDeck AI.
"""
import argparse
import sys
import shutil
from typing import Any

from slidedeckai.core import SlideDeckAI
from slidedeckai.global_config import GlobalConfig


def group_models_by_provider(models: list[str]) -> dict[str, list[str]]:
    """
    Group model names by their provider.

    Args:
        models (list[str]): List of model names.

    Returns:
        dict[str, list[str]]: Dictionary mapping provider codes to lists of model names.
    """
    provider_models = {}
    for model in sorted(models):
        if match := GlobalConfig.PROVIDER_REGEX.match(model):
            provider = match.group(1)
            if provider not in provider_models:
                provider_models[provider] = []
            provider_models[provider].append(model.strip())

    return provider_models


def format_models_as_bullets(models: list[str]) -> str:
    """
    Format models as a bulleted list, grouped by provider.

    Args:
        models (list[str]): List of model names.

    Returns:
        str: Formatted string of models.
    """
    provider_models = group_models_by_provider(models)
    lines = []
    for provider in sorted(provider_models.keys()):
        lines.append(f'\n{provider}:')
        for model in sorted(provider_models[provider]):
            lines.append(f'  • {model}')

    return '\n'.join(lines)


class CustomHelpFormatter(argparse.HelpFormatter):
    """
    Custom formatter for argparse that improves the display of choices.
    """
    def _format_action_invocation(self, action: Any) -> str:
        if not action.option_strings or action.nargs == 0:
            return super()._format_action_invocation(action)

        default = self._get_default_metavar_for_optional(action)
        args_string = self._format_args(action, default)

        # If there are choices, and it's the model argument, handle it specially
        if action.choices and '--model' in action.option_strings:
            return ', '.join(action.option_strings) + ' MODEL'

        return f"{', '.join(action.option_strings)} {args_string}"

    def _split_lines(self, text: str, width: int) -> list[str]:
        if text.startswith('Model choices:') or text.startswith('choose from'):
            # Special handling for model choices and error messages
            lines = []
            header = 'Available models:'
            separator = '------------------------'  # Fixed-length separator
            lines.append(header)
            lines.append(separator)

            # Extract models from text
            if text.startswith('choose from'):
                models = [
                    m.strip("' ") for m in text.replace('choose from', '').split(',')
                ]
            else:
                models = text.split('\n')[1:]

            # Use the centralized formatting
            lines.extend(format_models_as_bullets(models).split('\n'))
            return lines

        return super()._split_lines(text, width)


class CustomArgumentParser(argparse.ArgumentParser):
    """
    Custom argument parser that formats error messages better.
    """
    def error(self, message: str) -> None:
        """Custom error handler that formats model choices better"""
        if 'invalid choice' in message and '--model' in message:
            # Extract models from the error message
            choices_str = message[message.find('(choose from'):]
            models = [
                m.strip("' ") for m in choices_str.replace(
                    '(choose from', ''
                ).rstrip(')').split(',')
            ]

            error_lines = ['Error: Invalid model choice. Available models:']
            error_lines.extend(format_models_as_bullets(models).split('\n'))

            self.print_help()
            print('\n' + '\n'.join(error_lines), file=sys.stderr)
            sys.exit(2)

        super().error(message)


def format_models_list() -> str:
    """Format the models list in a nice grouped format with descriptions."""
    header = 'Supported SlideDeck AI models:\n'
    models = list(GlobalConfig.VALID_MODELS.keys())
    return header + format_models_as_bullets(models)


def format_model_help() -> str:
    """Format model choices as a grouped bulleted list for help text."""
    return format_models_as_bullets(list(GlobalConfig.VALID_MODELS.keys()))


def main():
    """
    The main function for the CLI.
    """
    parser = CustomArgumentParser(
        description='Generate slide decks with SlideDeck AI.',
        formatter_class=CustomHelpFormatter
    )
    subparsers = parser.add_subparsers(dest='command')

    # Top-level flag to list supported models
    parser.add_argument(
        '-l',
        '--list-models',
        action='store_true',
        help='List supported model keys and exit.',
    )

    # 'generate' command
    parser_generate = subparsers.add_parser(
        'generate',
        help='Generate a new slide deck.',
        formatter_class=CustomHelpFormatter
    )

    parser_generate.add_argument(
        '--model',
        required=True,
        choices=GlobalConfig.VALID_MODELS.keys(),
        help=(
            'Model name to use. Must be one of the supported models in the'
            ' `[provider-code]model_name` format.' + format_model_help()
        ),
        metavar='MODEL'
    )
    parser_generate.add_argument(
        '--topic',
        required=True,
        help='The topic of the slide deck.',
    )
    parser_generate.add_argument(
        '--api-key',
        help=(
            'The API key for the LLM provider. Alternatively, set the appropriate API key'
            ' in the environment variable.'
        ),
    )
    parser_generate.add_argument(
        '--template-id',
        type=int,
        default=0,
        help='The index of the PowerPoint template to use.',
    )
    parser_generate.add_argument(
        '--output-path',
        help='The path to save the generated .pptx file.',
    )

    # Note: the 'launch' command has been intentionally disabled.

    # If no arguments are provided, show help and exit
    if len(sys.argv) == 1:
        parser.print_help()
        return

    args = parser.parse_args()

    # If --list-models flag was provided, print models and exit
    if getattr(args, 'list_models', False):
        print(format_models_list())
        return

    if args.command == 'generate':
        slide_generator = SlideDeckAI(
            model=args.model,
            topic=args.topic,
            api_key=args.api_key,
            template_idx=args.template_id,
        )

        pptx_path = slide_generator.generate()

        if args.output_path:
            shutil.move(str(pptx_path), args.output_path)
            print(f'\n🤖 Slide deck saved to: {args.output_path}')
        else:
            print(f'\n🤖 Slide deck saved to: {pptx_path}')


if __name__ == '__main__':
    main()