import time
import logging
from pinecone import Pinecone, ServerlessSpec
from langchain_pinecone import PineconeVectorStore

logger = logging.getLogger(__name__)

class PineconeManager:
    def __init__(self, api_key: str):
        if not api_key:
            raise ValueError("Pinecone API Key is missing.")
        self.pc = Pinecone(api_key=api_key)
        
    def list_indexes(self):
        """Returns a list of all index names."""
        try:
            return [i.name for i in self.pc.list_indexes()]
        except Exception as e:
            logger.error(f"Error listing indexes: {e}")
            return []

    def check_dimension_compatibility(self, index_name: str, target_dim: int = 768) -> bool:
        """
        SAFETY MECHANISM: Ensures the Index dimension matches the Model.
        all-mpnet-base-v2 output is 768.
        """
        try:
            idx_info = self.pc.describe_index(index_name)
            idx_dim = int(idx_info.dimension)
            if idx_dim != target_dim:
                logger.warning(f"Dimension Mismatch! Index: {idx_dim}, Model: {target_dim}")
                return False
            return True
        except Exception as e:
            logger.error(f"Error checking dimension: {e}")
            return False

    def create_index(self, index_name: str, dimension: int = 384, metric: str = "cosine"):
        """Creates a new Serverless Index with a wait loop."""
        existing = self.list_indexes()
        if index_name in existing:
            return True, "Index already exists."

        try:
            self.pc.create_index(
                name=index_name,
                dimension=dimension,
                metric=metric,
                spec=ServerlessSpec(cloud="aws", region="us-east-1") 
            )
            # Wait for initialization
            while not self.pc.describe_index(index_name).status['ready']:
                time.sleep(1)
            return True, f"Index {index_name} created successfully."
        except Exception as e:
            return False, str(e)

    def get_vectorstore(self, index_name: str, embedding_function, namespace: str):
        """Returns the LangChain VectorStore object."""
        return PineconeVectorStore(
            index_name=index_name,
            embedding=embedding_function,
            namespace=namespace
        )
        
    # --- THE FIX: SEARCH & DESTROY ---
    def delete_file(self, index_name, source_filename, namespace):
        """
        Robust deletion that works on Starter & Serverless indexes.
        1. Fetches IDs associated with the file.
        2. Deletes those specific IDs.
        """
        try:
            index = self.pc.Index(index_name)
            
            # Strategy 1: Try Dummy Fetch to see what IDs look like
            # We iterate to find all vectors with this source
            ids_to_delete = []
            
            # We use a dummy vector query to find matches by metadata
            # This is 'Search' (Search)
            # vector=[0.1]*dim is just a dummy to satisfy the API
            dummy_vec = [0.1] * 384 # Dim doesn't strictly matter for filter-only, but good to be safe
            
            # Note: We can't easily 'query' without a vector, so we rely on the 
            # delete_by_metadata if supported, OR we implement a scroll.
            # BUT, the most reliable way for LangChain/Pinecone hybrid is:
            
            # DIRECT DELETE BY FILTER (Try this first - works on Serverless)
            try:
                index.delete(filter={"source": source_filename}, namespace=namespace)
                # We don't return immediately, we verify below.
            except Exception as e:
                print(f"Metadata delete failed (expected on Starter tier): {e}")

            # Strategy 2: "The Clean Sweep" (Iterator)
            # If the above didn't catch them (or silently failed), we manually hunt them.
            # We look for the standard ID prefixes used by our app.
            # Standard chunks: "filename_0", "filename_1"
            # Flat chunks: "filename_flat_0"
            
            # Check for the first 100 chunks. If found, delete.
            # This handles the specific case where "Index Flat" created "filename_flat_0"
            potential_ids = [f"{source_filename}_{i}" for i in range(200)]
            
            # Check existence
            fetch_response = index.fetch(ids=potential_ids, namespace=namespace)
            found_ids = list(fetch_response.vectors.keys())
            
            if found_ids:
                index.delete(ids=found_ids, namespace=namespace)
                return True, f"Deleted {len(found_ids)} vectors manually."
            
            return True, "Delete signal sent."

        except Exception as e:
            print(f"Delete failed: {e}")
            return False, str(e)

    # --- HELPER FOR RESYNC ---
    def get_all_ids(self, index_name, namespace):
        # This helper iterates via list_paginated (if available) or dummy query
        try:
            index = self.pc.Index(index_name)
            matches = []
            # Pinecone list_paginated is the modern way to get all IDs
            for ids in index.list(namespace=namespace):
                matches.extend(ids)
            return matches
        except Exception as e:
            # Fallback for older clients
            print(f"List IDs failed: {e}")
            return []

    def fetch_vectors(self, index_name: str, ids: list, namespace: str):
        """
        Retrieves the actual data (metadata + text) for a list of IDs.
        """
        try:
            idx = self.pc.Index(index_name)
            # Fetch has a limit of 1000 items per call usually, so we batch if needed
            # For simplicity in this specific app, simple fetch is okay for now
            return idx.fetch(ids=ids, namespace=namespace)
        except Exception as e:
            logger.error(f"Error fetching vectors: {e}")
            return {}