import os
import logging
from pathlib import Path
from typing import List, Dict
import chromadb
from chromadb.config import Settings
from sentence_transformers import SentenceTransformer
from .knowledge_base_manager import KnowledgeBaseManager

os.environ['ANONYMIZED_TELEMETRY'] = 'False'
os.environ['CHROMA_TELEMETRY_ENABLED'] = 'false'

logger = logging.getLogger(__name__)

class VectorRAGManager:
    def __init__(self, knowledge_base_path: str, vector_db_path: str = "vector_db", embedding_model: str = "all-MiniLM-L6-v2"):
        self.kb_path = Path(knowledge_base_path)
        self.vector_db_path = Path(vector_db_path)
        self.vector_db_path.mkdir(exist_ok=True, parents=True)
        self.kb_manager = KnowledgeBaseManager(knowledge_base_path)
        self.chroma_client = chromadb.PersistentClient(path=str(self.vector_db_path), settings=Settings(anonymized_telemetry=False))
        self.embedding_model = SentenceTransformer(embedding_model)
        self.collection_name = "tmc_documents"
        self._init_collection()
        self.chunk_size = 800
        self.chunk_overlap = 120

    def _init_collection(self):
        try:
            self.collection = self.chroma_client.get_collection(self.collection_name)
        except:
            self.collection = self.chroma_client.create_collection(self.collection_name)

    def chunk_text(self, text: str) -> List[str]:
        if len(text) <= self.chunk_size:
            return [text]
        chunks = []
        start = 0
        while start < len(text):
            end = min(start + self.chunk_size, len(text))
            if end < len(text):
                for i in range(end, max(start, end-200), -1):
                    if text[i] in '.!?\n':
                        end = i+1
                        break
            chunks.append(text[start:end].strip())
            start = end - self.chunk_overlap
        return [c for c in chunks if len(c) > 50]

    def generate_embedding(self, text: str) -> List[float]:
        return self.embedding_model.encode(text).tolist()

    def index_documents(self, force_reindex: bool = False) -> Dict:
        if force_reindex and self.collection.count() > 0:
            self.chroma_client.delete_collection(self.collection_name)
            self._init_collection()
        self.kb_manager.scan_documents()
        stats = {"documents": 0, "chunks": 0}
        for category, cat_info in self.kb_manager.documents.items():
            if category == 'development':
                logger.info(f"Skipping development folder")
                continue
            for doc in cat_info['documents']:
                content = self.kb_manager.load_document_content(doc['path'])
                if not content:
                    continue
                chunks = self.chunk_text(content)
                if not chunks:
                    continue
                ids = []
                embeds = []
                texts = []
                metas = []
                for i, chunk in enumerate(chunks):
                    cid = f"{doc['filename']}_{i}"
                    ids.append(cid)
                    texts.append(chunk)
                    embeds.append(self.generate_embedding(chunk))
                    metas.append({
                        "document_title": doc['title'],
                        "document_path": doc['path'],
                        "category": category,
                        "chunk_index": i
                    })
                self.collection.add(ids=ids, embeddings=embeds, documents=texts, metadatas=metas)
                stats["documents"] += 1
                stats["chunks"] += len(chunks)
        logger.info(f"Indexed {stats['documents']} docs, {stats['chunks']} chunks")
        return stats

    def semantic_search(self, query: str, n_results: int = 5) -> List[Dict]:
        if self.collection.count() == 0:
            return []
        q_emb = self.generate_embedding(query)
        results = self.collection.query(query_embeddings=[q_emb], n_results=n_results, include=["documents","metadatas","distances"])
        formatted = []
        if results['documents'] and results['documents'][0]:
            for doc, meta, dist in zip(results['documents'][0], results['metadatas'][0], results['distances'][0]):
                similarity = max(0.0, 1.0 - (dist / 2.0))
                formatted.append({"document": doc, "metadata": meta, "similarity": similarity})
        return formatted

    def retrieve_and_rerank_filtered(self, query: str, target_categories: List[str], initial_k: int = 20, final_k: int = 3, similarity_threshold: float = 0.30) -> List[Dict]:
        candidates = self.semantic_search(query, n_results=initial_k)
        filtered = [c for c in candidates if c['similarity'] >= similarity_threshold and c['metadata'].get('category') in target_categories]
        return filtered[:final_k]

    def get_collection_stats(self) -> Dict:
        return {"total_chunks": self.collection.count()}