import motor.motor_asyncio
from bson import ObjectId
from typing import List, Dict, Any
import numpy as np
from config import settings

class Database:
    def __init__(self):
        self.client = None
        self.db = None
        self.collection = None
    
    async def connect(self):
        self.client = motor.motor_asyncio.AsyncIOMotorClient(settings.MONGODB_URI)
        self.db = self.client[settings.DATABASE_NAME]
        self.collection = self.db[settings.COLLECTION_NAME]
        print(f"✅ Connected to MongoDB: {settings.DATABASE_NAME}.{settings.COLLECTION_NAME}")
    
    async def similarity_search(self, query_embedding: List[float], limit: int = 3) -> List[Dict]:
        """Search for similar products using MongoDB Atlas Vector Search"""
        try:
            pipeline = [
                {
                    "$vectorSearch": {
                        "index": "vector_index",  # Make sure this matches your Atlas index name
                        "path": "embedding",
                        "queryVector": query_embedding,
                        "numCandidates": 150,
                        "limit": limit
                    }
                },
                {
                    "$project": {
                        "_id": 1,
                        "title": 1,
                        "category": 1,
                        "product_description": 1,
                        "final_price": 1,
                        "score": {"$meta": "vectorSearchScore"}
                    }
                }
            ]
            
            cursor = self.collection.aggregate(pipeline)
            results = []
            async for doc in cursor:
                results.append({
                    "id": str(doc["_id"]),
                    "content": self._create_product_content(doc),
                    "source": doc.get('title', 'product_database'),
                    "metadata": {
                        "category": doc.get('category', 'N/A'),
                        "price": doc.get('final_price', 'N/A'),
                        "similarity_score": doc.get('score', 0)
                    }
                })
            return results
        except Exception as e:
            print(f"❌ Vector search error: {e}")
            # Fallback to text search
            return await self.search_by_text("tops", limit)
    
    def _create_product_content(self, doc: Dict) -> str:
        """Create formatted product content for the LLM"""
        content_parts = [
            f"Product: {doc.get('title', 'N/A')}",
            f"Description: {doc.get('product_description', 'N/A')}",
            f"Category: {doc.get('category', 'N/A')}",
            f"Price: ₹{doc.get('final_price', 'N/A')}"
        ]
        return ". ".join(content_parts)
    
    async def search_by_text(self, query: str, limit: int = 5) -> List[Dict]:
        """Fallback text search if vector search fails"""
        cursor = self.collection.find({
            "$or": [
                {"title": {"$regex": query, "$options": "i"}},
                {"category": {"$regex": query, "$options": "i"}},
                {"product_description": {"$regex": query, "$options": "i"}}
            ]
        }).limit(limit)
        
        results = []
        async for doc in cursor:
            results.append({
                "id": str(doc["_id"]),
                "content": self._create_product_content(doc),
                "source": doc.get('title', 'product_database'),
                "metadata": {
                    "category": doc.get('category', 'N/A'),
                    "price": doc.get('final_price', 'N/A')
                }
            })
        return results
    
    async def search_by_category(self, category: str, limit: int = 5) -> List[Dict]:
        """Search products by category"""
        cursor = self.collection.find(
            {"category": {"$regex": category, "$options": "i"}}
        ).limit(limit)
        
        results = []
        async for doc in cursor:
            results.append({
                "id": str(doc["_id"]),
                "content": self._create_product_content(doc),
                "source": doc.get('title', 'product_database'),
                "metadata": {
                    "category": doc.get('category', 'N/A'),
                    "price": doc.get('final_price', 'N/A')
                }
            })
        return results

    async def insert_documents(self, documents: List[Dict]) -> List[str]:
        """Insert documents into the collection"""
        result = await self.collection.insert_many(documents)
        return [str(id) for id in result.inserted_ids]
    
    async def get_collection_stats(self):
        """Get collection statistics"""
        total_docs = await self.collection.count_documents({})
        docs_with_embeddings = await self.collection.count_documents({"embedding": {"$exists": True}})
        return {
            "total_documents": total_docs,
            "documents_with_embeddings": docs_with_embeddings,
            "embedding_coverage": f"{(docs_with_embeddings/total_docs*100):.1f}%" if total_docs > 0 else "0%"
        }

# Global database instance
db = Database()