"""
Service for generating and managing embeddings.
"""

import os
import random
import pinecone
import numpy as np
from typing import List, Dict, Any, Optional, Union
from sentence_transformers import SentenceTransformer

from ai_service.config import config

class EmbeddingService:
    """Service for generating and managing embeddings."""

    def __init__(self, use_mock=True):  # Default to mock implementation
        """Initialize the embedding service."""
        self.use_mock = use_mock

        if not self.use_mock:
            # Use a smaller model for testing
            self.model_name = "paraphrase-MiniLM-L3-v2"  # Smaller model than the default
            try:
                self.model = SentenceTransformer(self.model_name)
                print(f"Loaded embedding model: {self.model_name}")
            except Exception as e:
                print(f"Error loading embedding model: {str(e)}")
                self.use_mock = True
                print("Falling back to mock implementation")
        else:
            print("Using mock embedding implementation")
            self.model_name = "mock-model"
            self.model = None

        self._initialize_pinecone()

    def _initialize_pinecone(self):
        """Initialize Pinecone client."""
        if not config.PINECONE_API_KEY or not config.PINECONE_ENVIRONMENT:
            print("Warning: Pinecone API key or environment not set. Vector storage will not be available.")
            self.index = None
            return

        try:
            pinecone.init(
                api_key=config.PINECONE_API_KEY,
                environment=config.PINECONE_ENVIRONMENT
            )

            # Check if index exists, create if it doesn't
            if config.PINECONE_INDEX_NAME not in pinecone.list_indexes():
                pinecone.create_index(
                    name=config.PINECONE_INDEX_NAME,
                    dimension=self.model.get_sentence_embedding_dimension(),
                    metric="cosine"
                )

            self.index = pinecone.Index(config.PINECONE_INDEX_NAME)
            print(f"Connected to Pinecone index: {config.PINECONE_INDEX_NAME}")
        except Exception as e:
            print(f"Error connecting to Pinecone: {str(e)}")
            self.index = None

    def generate_embedding(self, text: str) -> List[float]:
        """
        Generate an embedding for a text.

        Args:
            text: Text to embed.

        Returns:
            Embedding vector.
        """
        if self.use_mock:
            # Generate a mock embedding vector (384 dimensions for consistency)
            return [random.random() for _ in range(384)]

        embedding = self.model.encode(text)
        return embedding.tolist()

    def generate_embeddings(self, texts: List[str]) -> List[List[float]]:
        """
        Generate embeddings for multiple texts.

        Args:
            texts: List of texts to embed.

        Returns:
            List of embedding vectors.
        """
        if self.use_mock:
            # Generate mock embedding vectors
            return [[random.random() for _ in range(384)] for _ in texts]

        embeddings = self.model.encode(texts)
        return embeddings.tolist()

    def store_embeddings(self, ids: List[str], embeddings: List[List[float]],
                         metadata: Optional[List[Dict[str, Any]]] = None) -> bool:
        """
        Store embeddings in Pinecone.

        Args:
            ids: List of IDs for the embeddings.
            embeddings: List of embedding vectors.
            metadata: Optional list of metadata dictionaries.

        Returns:
            True if storage was successful, False otherwise.
        """
        if self.use_mock:
            print(f"Mock: Stored {len(ids)} embeddings")
            return True

        if self.index is None:
            print("Warning: Pinecone index not available. Embeddings not stored.")
            return False

        if metadata is None:
            metadata = [{} for _ in ids]

        vectors = [
            (id, embedding, meta)
            for id, embedding, meta in zip(ids, embeddings, metadata)
        ]

        try:
            self.index.upsert(vectors=vectors)
            return True
        except Exception as e:
            print(f"Error storing embeddings in Pinecone: {str(e)}")
            return False

    def search_similar(self, query_embedding: List[float], top_k: int = 5) -> List[Dict[str, Any]]:
        """
        Search for similar embeddings in Pinecone.

        Args:
            query_embedding: Query embedding vector.
            top_k: Number of results to return.

        Returns:
            List of similar items with their metadata.
        """
        if self.use_mock:
            # Generate mock search results
            print(f"Mock: Searching for similar embeddings (top_k={top_k})")
            mock_results = []
            for i in range(min(top_k, 3)):  # Return at most 3 mock results
                mock_results.append({
                    'id': f"mock_doc_{i}",
                    'score': 0.9 - (i * 0.1),  # Decreasing similarity scores
                    'metadata': {
                        'document_id': f"mock_doc_{i}",
                        'chunk_index': i,
                        'title': f"Mock Document {i}",
                        'description': f"This is a mock document {i}",
                        'chunk_text': f"This is the content of mock document {i}..."
                    }
                })
            return mock_results

        if self.index is None:
            print("Warning: Pinecone index not available. Search not performed.")
            return []

        try:
            results = self.index.query(
                vector=query_embedding,
                top_k=top_k,
                include_metadata=True
            )

            return [
                {
                    'id': match['id'],
                    'score': match['score'],
                    'metadata': match.get('metadata', {})
                }
                for match in results.get('matches', [])
            ]
        except Exception as e:
            print(f"Error searching in Pinecone: {str(e)}")
            return []

    def delete_embeddings(self, ids: List[str]) -> bool:
        """
        Delete embeddings from Pinecone.

        Args:
            ids: List of IDs to delete.

        Returns:
            True if deletion was successful, False otherwise.
        """
        if self.use_mock:
            print(f"Mock: Deleted {len(ids)} embeddings")
            return True

        if self.index is None:
            print("Warning: Pinecone index not available. Deletion not performed.")
            return False

        try:
            self.index.delete(ids=ids)
            return True
        except Exception as e:
            print(f"Error deleting embeddings from Pinecone: {str(e)}")
            return False


# Create a singleton instance
embedding_service = EmbeddingService()