from fastapi import FastAPI, HTTPException, File, UploadFile, Form
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from typing import Optional, List, Dict
from pymongo import MongoClient
from datetime import datetime
import numpy as np
import os
from huggingface_hub import InferenceClient

from embedding_service import JinaClipEmbeddingService
from qdrant_service import QdrantVectorService


# Pydantic models
class ChatRequest(BaseModel):
    message: str
    use_rag: bool = True
    top_k: int = 3
    system_message: Optional[str] = "You are a helpful AI assistant."
    max_tokens: int = 512
    temperature: float = 0.7
    top_p: float = 0.95
    hf_token: Optional[str] = None  # Hugging Face token (optional, sẽ dùng env nếu không truyền)


class ChatResponse(BaseModel):
    response: str
    context_used: List[Dict]
    timestamp: str


class AddDocumentRequest(BaseModel):
    text: str
    metadata: Optional[Dict] = None


class AddDocumentResponse(BaseModel):
    success: bool
    doc_id: str
    message: str


class SearchRequest(BaseModel):
    query: str
    top_k: int = 5
    score_threshold: Optional[float] = 0.5


class SearchResponse(BaseModel):
    results: List[Dict]


# Initialize FastAPI
app = FastAPI(
    title="ChatbotRAG API",
    description="API for RAG Chatbot with GPT-OSS-20B + Jina CLIP v2 + MongoDB + Qdrant",
    version="1.0.0"
)

# CORS middleware
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # Cho phép tất cả origins (có thể giới hạn trong production)
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


# ChatbotRAG Service
class ChatbotRAGService:
    """
    ChatbotRAG Service cho API
    """

    def __init__(
        self,
        mongodb_uri: str = "mongodb+srv://truongtn7122003:7KaI9OT5KTUxWjVI@truongtn7122003.xogin4q.mongodb.net/",
        db_name: str = "chatbot_rag",
        collection_name: str = "documents",
        hf_token: Optional[str] = None
    ):
        print("Initializing ChatbotRAG Service...")

        # MongoDB
        self.mongo_client = MongoClient(mongodb_uri)
        self.db = self.mongo_client[db_name]
        self.documents_collection = self.db[collection_name]
        self.chat_history_collection = self.db["chat_history"]

        # Embedding service
        self.embedding_service = JinaClipEmbeddingService(
            model_path="jinaai/jina-clip-v2"
        )

        # Qdrant
        collection_name = os.getenv("COLLECTION_NAME","event_social_media")
        self.qdrant_service = QdrantVectorService(
            collection_name= collection_name,
            vector_size=self.embedding_service.get_embedding_dimension()
        )

        # Hugging Face token (từ env hoặc truyền vào)
        self.hf_token = hf_token or os.getenv("HUGGINGFACE_TOKEN")
        if self.hf_token:
            print("✓ Hugging Face token configured")
        else:
            print("⚠ No Hugging Face token - LLM generation will use placeholder")

        print("✓ ChatbotRAG Service initialized")

    def add_document(self, text: str, metadata: Dict = None) -> str:
        """Add document to knowledge base"""
        # Save to MongoDB
        doc_data = {
            "text": text,
            "metadata": metadata or {},
            "created_at": datetime.utcnow()
        }
        result = self.documents_collection.insert_one(doc_data)
        doc_id = str(result.inserted_id)

        # Generate embedding
        embedding = self.embedding_service.encode_text(text)

        # Index to Qdrant
        self.qdrant_service.index_data(
            doc_id=doc_id,
            embedding=embedding,
            metadata={
                "text": text,
                "source": "api",
                **(metadata or {})
            }
        )

        return doc_id

    def retrieve_context(self, query: str, top_k: int = 3, score_threshold: float = 0.5) -> List[Dict]:
        """Retrieve relevant context from vector DB"""
        # Generate query embedding
        query_embedding = self.embedding_service.encode_text(query)

        # Search in Qdrant
        results = self.qdrant_service.search(
            query_embedding=query_embedding,
            limit=top_k,
            score_threshold=score_threshold
        )

        return results

    def generate_response(
        self,
        message: str,
        context: List[Dict],
        system_message: str,
        max_tokens: int = 512,
        temperature: float = 0.7,
        top_p: float = 0.95,
        hf_token: Optional[str] = None
    ) -> str:
        """
        Generate response using Hugging Face LLM
        """
        # Build context text
        context_text = ""
        if context:
            context_text = "\n\nRelevant Context:\n"
            for i, doc in enumerate(context, 1):
                doc_text = doc["metadata"].get("text", "")
                confidence = doc["confidence"]
                context_text += f"\n[{i}] (Confidence: {confidence:.2f})\n{doc_text}\n"

            # Add context to system message
            system_message = f"{system_message}\n{context_text}\n\nPlease use the above context to answer the user's question when relevant."

        # Use token from request or fallback to service token
        token = hf_token or self.hf_token

        # If no token available, return placeholder
        if not token:
            return f"""[LLM Response Placeholder]

Context retrieved: {len(context)} documents
User question: {message}

To enable actual LLM generation:
1. Set HUGGINGFACE_TOKEN environment variable, OR
2. Pass hf_token in request body

Example:
{{
  "message": "Your question",
  "hf_token": "hf_xxxxxxxxxxxxx"
}}
"""

        # Initialize HF Inference Client
        try:
            client = InferenceClient(
                token=token,
                model="openai/gpt-oss-20b"
            )

            # Build messages
            messages = [
                {"role": "system", "content": system_message},
                {"role": "user", "content": message}
            ]

            # Generate response (non-streaming for API)
            response = ""
            for msg in client.chat_completion(
                messages,
                max_tokens=max_tokens,
                stream=True,
                temperature=temperature,
                top_p=top_p,
            ):
                choices = msg.choices
                if len(choices) and choices[0].delta.content:
                    response += choices[0].delta.content

            return response

        except Exception as e:
            return f"Error generating response with LLM: {str(e)}\n\nContext was retrieved successfully, but LLM generation failed."

    def save_chat_history(self, user_message: str, assistant_response: str, context_used: List[Dict]):
        """Save chat to MongoDB"""
        chat_data = {
            "user_message": user_message,
            "assistant_response": assistant_response,
            "context_used": context_used,
            "timestamp": datetime.utcnow()
        }
        self.chat_history_collection.insert_one(chat_data)

    def get_stats(self) -> Dict:
        """Get statistics"""
        return {
            "documents_count": self.documents_collection.count_documents({}),
            "chat_history_count": self.chat_history_collection.count_documents({}),
            "qdrant_info": self.qdrant_service.get_collection_info()
        }


# Initialize service
rag_service = ChatbotRAGService()


# API Endpoints

@app.get("/")
async def root():
    """Health check"""
    return {
        "status": "running",
        "service": "ChatbotRAG API",
        "version": "1.0.0",
        "endpoints": {
            "POST /chat": "Chat with RAG",
            "POST /documents": "Add document to knowledge base",
            "POST /search": "Search in knowledge base",
            "GET /stats": "Get statistics",
            "GET /history": "Get chat history"
        }
    }


@app.post("/chat", response_model=ChatResponse)
async def chat(request: ChatRequest):
    """
    Chat endpoint with RAG

    Body:
    - message: User message
    - use_rag: Enable RAG retrieval (default: true)
    - top_k: Number of documents to retrieve (default: 3)
    - system_message: System prompt (optional)
    - max_tokens: Max tokens for response (default: 512)
    - temperature: Temperature for generation (default: 0.7)

    Returns:
    - response: Generated response
    - context_used: Retrieved context documents
    - timestamp: Response timestamp
    """
    try:
        # Retrieve context if RAG enabled
        context_used = []
        if request.use_rag:
            context_used = rag_service.retrieve_context(
                query=request.message,
                top_k=request.top_k
            )

        # Generate response
        response = rag_service.generate_response(
            message=request.message,
            context=context_used,
            system_message=request.system_message,
            max_tokens=request.max_tokens,
            temperature=request.temperature,
            top_p=request.top_p,
            hf_token=request.hf_token
        )

        # Save to history
        rag_service.save_chat_history(
            user_message=request.message,
            assistant_response=response,
            context_used=context_used
        )

        return ChatResponse(
            response=response,
            context_used=context_used,
            timestamp=datetime.utcnow().isoformat()
        )

    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Error: {str(e)}")


@app.post("/documents", response_model=AddDocumentResponse)
async def add_document(request: AddDocumentRequest):
    """
    Add document to knowledge base

    Body:
    - text: Document text
    - metadata: Additional metadata (optional)

    Returns:
    - success: True/False
    - doc_id: MongoDB document ID
    - message: Status message
    """
    try:
        doc_id = rag_service.add_document(
            text=request.text,
            metadata=request.metadata
        )

        return AddDocumentResponse(
            success=True,
            doc_id=doc_id,
            message=f"Document added successfully with ID: {doc_id}"
        )

    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Error: {str(e)}")


@app.post("/search", response_model=SearchResponse)
async def search(request: SearchRequest):
    """
    Search in knowledge base

    Body:
    - query: Search query
    - top_k: Number of results (default: 5)
    - score_threshold: Minimum score (default: 0.5)

    Returns:
    - results: List of matching documents
    """
    try:
        results = rag_service.retrieve_context(
            query=request.query,
            top_k=request.top_k,
            score_threshold=request.score_threshold
        )

        return SearchResponse(results=results)

    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Error: {str(e)}")


@app.get("/stats")
async def get_stats():
    """
    Get statistics

    Returns:
    - documents_count: Number of documents in MongoDB
    - chat_history_count: Number of chat messages
    - qdrant_info: Qdrant collection info
    """
    try:
        return rag_service.get_stats()
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Error: {str(e)}")


@app.get("/history")
async def get_history(limit: int = 10, skip: int = 0):
    """
    Get chat history

    Query params:
    - limit: Number of messages to return (default: 10)
    - skip: Number of messages to skip (default: 0)

    Returns:
    - history: List of chat messages
    """
    try:
        history = list(
            rag_service.chat_history_collection
            .find({}, {"_id": 0})
            .sort("timestamp", -1)
            .skip(skip)
            .limit(limit)
        )

        # Convert datetime to string
        for msg in history:
            if "timestamp" in msg:
                msg["timestamp"] = msg["timestamp"].isoformat()

        return {"history": history, "total": rag_service.chat_history_collection.count_documents({})}

    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Error: {str(e)}")


@app.delete("/documents/{doc_id}")
async def delete_document(doc_id: str):
    """
    Delete document from knowledge base

    Args:
    - doc_id: Document ID (MongoDB ObjectId)

    Returns:
    - success: True/False
    - message: Status message
    """
    try:
        # Delete from MongoDB
        result = rag_service.documents_collection.delete_one({"_id": doc_id})

        # Delete from Qdrant
        if result.deleted_count > 0:
            rag_service.qdrant_service.delete_by_id(doc_id)
            return {"success": True, "message": f"Document {doc_id} deleted"}
        else:
            raise HTTPException(status_code=404, detail=f"Document {doc_id} not found")

    except HTTPException:
        raise
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Error: {str(e)}")


if __name__ == "__main__":
    import uvicorn
    uvicorn.run(
        app,
        host="0.0.0.0",
        port=8000,
        log_level="info"
    )