# main.py (HF Space FastAPI)
from contextlib import asynccontextmanager
from fastapi import FastAPI
from document_processor import DocumentProcessor
from vector_store import vector_store
from models import *
import time
import hashlib
import os
import google.generativeai as genai

# Initialize processors
processor = DocumentProcessor()

# Initialize Gemini
genai.configure(api_key=os.getenv('GEMINI_API_KEY'))

@asynccontextmanager
async def lifespan(app: FastAPI):
    # Startup events
    print("🚀 Initializing Document Processor...")
    await processor.initialize()
    print("📚 Initializing Vector Store...")
    vector_store.clause_tagger = processor.clause_tagger
    print("✅ Application startup complete")
    yield
    print("🛑 Shutting down application...")

# Create FastAPI app
app = FastAPI(
    title="Legal Document Analysis API", 
    version="1.0.0", 
    lifespan=lifespan
)

@app.post("/analyze_document")
async def analyze_document(data: AnalyzeDocumentInput):
    """Unified endpoint for complete document analysis WITH optimized vector storage"""
    try:
        start_time = time.time()
        
        if not data.document_text:
            return {"error": "No document text provided"}
        
        # Generate document ID
        doc_id = hashlib.sha256(data.document_text.encode()).hexdigest()[:16]
        
        # Process document completely with pre-computed embeddings
        result, chunk_data = await processor.process_document(data.document_text, doc_id)
        
        # Save embeddings to Pinecone using pre-computed vectors (NO RE-EMBEDDING)
        try:
            success = vector_store.save_document_embeddings_optimized(
                chunk_data=chunk_data,
                document_id=doc_id,
                analysis_results=result
            )
            if success:
                result["vector_storage"] = "success"
                result["chat_ready"] = True
                print(f"✅ Embeddings saved for doc {doc_id}")
            else:
                result["vector_storage"] = "failed"
                result["chat_ready"] = False
        except Exception as e:
            print(f"⚠️ Vector storage failed: {e}")
            result["vector_storage"] = "failed"
            result["chat_ready"] = False
        
        processing_time = time.time() - start_time
        result["total_processing_time"] = f"{processing_time:.2f}s"
        
        return result
        
    except Exception as e:
        return {"error": str(e)}

async def generate_response_with_context(user_question: str, relevant_context: str, document_id: str):
    """Send relevant chunks to Gemini for response generation"""
    try:
        prompt = f"""You are a legal document assistant. Answer the user's question based ONLY on the provided context from their legal document.

Context from document {document_id}:
{relevant_context}

User Question: {user_question}

Instructions:
- Provide a clear, accurate answer based on the context above
- If the answer isn't in the context, say "I cannot find information about this in the provided document"
- Include specific quotes from the document when relevant
- Keep your answer focused on legal implications and key details

Answer:"""
        
        model = genai.GenerativeModel('gemini-1.5-flash')
        response = model.generate_content(prompt)
        return response.text
        
    except Exception as e:
        return f"Error generating response: {str(e)}"

@app.post("/chat")
async def chat_with_document(data: ChatInput):
    """Chat with a specific legal document using RAG"""
    try:
        if not data.message or not data.document_id:
            return {"error": "Message and document_id are required"}
        
        # Get retriever for specific document
        retriever = vector_store.get_retriever(
            clause_tagger=processor.clause_tagger,
            document_id=data.document_id
        )
        
        if not retriever:
            return {"error": "Failed to create retriever or document not found"}
        
        # Get relevant chunks based on similarity
        relevant_chunks = retriever.get_relevant_documents(data.message)
        
        if not relevant_chunks:
            return {
                "response": "I couldn't find relevant information in the document to answer your question.",
                "sources": [],
                "document_id": data.document_id
            }
        
        # Prepare context from relevant chunks
        context = "\n\n".join([doc.page_content for doc in relevant_chunks])
        
        # Generate response using Gemini
        llm_response = await generate_response_with_context(
            user_question=data.message,
            relevant_context=context,
            document_id=data.document_id
        )
        
        # Prepare sources
        sources = []
        for doc in relevant_chunks:
            sources.append({
                "chunk_index": doc.metadata.get("chunk_index", 0),
                "similarity_score": doc.metadata.get("similarity_score", 0),
                "text_preview": doc.page_content[:200] + "..." if len(doc.page_content) > 200 else doc.page_content
            })
        
        return {
            "response": llm_response,
            "sources": sources,
            "document_id": data.document_id,
            "chunks_used": len(relevant_chunks)
        }
        
    except Exception as e:
        return {"error": f"Chat failed: {str(e)}"}

# Keep backward compatibility endpoints
@app.post("/chunk")
def chunk_text(data: ChunkInput):
    return processor.chunk_text(data)

@app.post("/summarize_batch")
def summarize_batch(data: SummarizeBatchInput):
    return processor.summarize_batch(data)

@app.get("/health")
def health_check():
    return {
        "status": "healthy",
        "services": {
            "document_processor": "active",
            "vector_store": "active",
            "gemini_llm": "active"
        }
    }

@app.get("/cache_stats")
def get_cache_stats():
    return processor.get_cache_stats()

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=7860)