"""
NotebookLM Clone - Main Flask Application
AI-powered document intelligence platform with RAG
Supports Admin/Employee roles and Bucket organization
"""

import os
import uuid
from functools import wraps
from flask import Flask, request, jsonify, send_from_directory, send_file, Response
from flask_cors import CORS
from werkzeug.utils import secure_filename

from config import Config
from services.auth_service import auth_service
from services.document_processor import document_processor
from services.chroma_service import chroma_service
from services.rag_service import rag_service
from services.metadata_extractor import metadata_extractor

# Initialize Flask app
app = Flask(__name__, static_folder='static')
app.config['MAX_CONTENT_LENGTH'] = Config.MAX_CONTENT_LENGTH
CORS(app)

# Ensure upload directory exists
os.makedirs(Config.UPLOAD_FOLDER, exist_ok=True)


# ==================== Auth Decorators ====================

def require_auth(f):
    """Decorator to require authentication"""
    @wraps(f)
    def decorated(*args, **kwargs):
        auth_header = request.headers.get('Authorization')
        
        if not auth_header or not auth_header.startswith('Bearer '):
            return jsonify({"error": "Missing or invalid authorization header"}), 401
        
        token = auth_header.split(' ')[1]
        user = auth_service.get_current_user(token)
        
        if not user:
            return jsonify({"error": "Invalid or expired token"}), 401
        
        request.current_user = user
        return f(*args, **kwargs)
    
    return decorated


def require_admin(f):
    """Decorator to require admin role"""
    @wraps(f)
    def decorated(*args, **kwargs):
        auth_header = request.headers.get('Authorization')
        
        if not auth_header or not auth_header.startswith('Bearer '):
            return jsonify({"error": "Missing or invalid authorization header"}), 401
        
        token = auth_header.split(' ')[1]
        user = auth_service.get_current_user(token)
        
        if not user:
            return jsonify({"error": "Invalid or expired token"}), 401
        
        if user.get('role') != 'admin':
            return jsonify({"error": "Admin access required"}), 403
        
        request.current_user = user
        return f(*args, **kwargs)
    
    return decorated


# ==================== Static Routes ====================

@app.route('/')
def index():
    return send_from_directory(app.static_folder, 'index.html')

@app.route('/<path:path>')
def serve_static(path):
    return send_from_directory(app.static_folder, path)


# ==================== Auth Routes ====================

@app.route('/api/auth/register/admin', methods=['POST'])
def register_admin():
    data = request.get_json()
    
    if not data:
        return jsonify({"error": "No data provided"}), 400
    
    username = data.get('username', '').strip()
    password = data.get('password', '')
    email = data.get('email', '').strip()
    
    result = auth_service.register_admin(username, password, email)
    
    if result['success']:
        return jsonify({
            "token": result['token'],
            "user_id": result['user_id'],
            "username": result['username'],
            "role": result['role']
        })
    else:
        return jsonify({"error": result['error']}), 400


@app.route('/api/auth/login', methods=['POST'])
def login():
    data = request.get_json()
    
    if not data:
        return jsonify({"error": "No data provided"}), 400
    
    username = data.get('username', '').strip()
    password = data.get('password', '')
    role = data.get('role', 'admin')
    
    result = auth_service.login(username, password, role)
    
    if result['success']:
        return jsonify({
            "token": result['token'],
            "user_id": result['user_id'],
            "username": result['username'],
            "role": result['role']
        })
    else:
        return jsonify({"error": result['error']}), 401


@app.route('/api/auth/verify', methods=['GET'])
@require_auth
def verify_token():
    return jsonify({
        "user_id": request.current_user['user_id'],
        "username": request.current_user['username'],
        "role": request.current_user.get('role', 'admin')
    })


# ==================== Admin Employee Management ====================

@app.route('/api/admin/employees', methods=['GET'])
@require_admin
def list_employees():
    employees = auth_service.get_admin_employees(request.current_user['user_id'])
    return jsonify({"employees": employees})


@app.route('/api/admin/employees', methods=['POST'])
@require_admin
def add_employee():
    data = request.get_json()
    
    if not data:
        return jsonify({"error": "No data provided"}), 400
    
    email = data.get('email', '').strip()
    password = data.get('password', '')
    
    result = auth_service.register_employee(
        admin_user_id=request.current_user['user_id'],
        email=email,
        password=password
    )
    
    if result['success']:
        return jsonify({"user_id": result['user_id'], "email": result['email']})
    else:
        return jsonify({"error": result['error']}), 400


@app.route('/api/admin/employees/<employee_id>', methods=['DELETE'])
@require_admin
def delete_employee(employee_id):
    success = auth_service.delete_employee(
        admin_user_id=request.current_user['user_id'],
        employee_id=employee_id
    )
    
    if success:
        return jsonify({"success": True})
    else:
        return jsonify({"error": "Employee not found or access denied"}), 404


# ==================== Bucket Routes ====================

@app.route('/api/buckets', methods=['GET'])
@require_auth
def list_buckets():
    """List all buckets for current user"""
    buckets = chroma_service.get_user_buckets(request.current_user['user_id'])
    return jsonify({"buckets": buckets})


@app.route('/api/buckets', methods=['POST'])
@require_auth
def create_bucket():
    """Create a new bucket"""
    data = request.get_json()
    
    if not data or not data.get('name'):
        return jsonify({"error": "Bucket name is required"}), 400
    
    name = data.get('name', '').strip()
    description = data.get('description', '').strip()
    
    result = chroma_service.create_bucket(
        user_id=request.current_user['user_id'],
        name=name,
        description=description
    )
    
    return jsonify(result)


@app.route('/api/buckets/<bucket_id>', methods=['DELETE'])
@require_auth
def delete_bucket(bucket_id):
    """Delete a bucket"""
    success = chroma_service.delete_bucket(
        bucket_id=bucket_id,
        user_id=request.current_user['user_id']
    )
    
    if success:
        return jsonify({"success": True})
    else:
        return jsonify({"error": "Bucket not found or access denied"}), 404


# ==================== Document Routes ====================

# ==================== Async Processing ====================

# Global status store: doc_id -> {status, progress, message, result, error}
processing_status = {}

def process_document_background(doc_id, user_id, file_path, filename, bucket_id):
    """Background task for processing documents"""
    import threading
    
    try:
        processing_status[doc_id] = {
            "status": "processing",
            "progress": 10,
            "message": "Starting processing..."
        }
        
        print(f"[BACKGROUND] Processing file: {filename}")
        
        # Step 1: Text Extraction (OCR)
        processing_status[doc_id]["message"] = "Extracting text (OCR)..."
        processing_status[doc_id]["progress"] = 20
        
        result = document_processor.process(file_path, filename)
        
        if not result['success']:
            processing_status[doc_id] = {
                "status": "failed",
                "error": result['error']
            }
            if os.path.exists(file_path):
                os.remove(file_path)
            return
        
        processing_status[doc_id]["progress"] = 50
        processing_status[doc_id]["message"] = "Storing document..."
        
        # Step 2: Store Metadata
        doc_type = document_processor.get_file_type(filename)
        chroma_service.store_document(
            user_id=user_id,
            doc_id=doc_id,
            filename=filename,
            doc_type=doc_type,
            content=result['text'],
            bucket_id=bucket_id
        )
        
        processing_status[doc_id]["progress"] = 70
        processing_status[doc_id]["message"] = "generating embeddings..."
        
        # Step 3: Chunking & Embeddings
        chunk_count = rag_service.process_document(
            user_id=user_id,
            doc_id=doc_id,
            content=result['text'],
            bucket_id=bucket_id
        )
        
        processing_status[doc_id]["progress"] = 90
        processing_status[doc_id]["message"] = "Generating summary..."
        
        # Step 4: Summary Generation
        summary_result = rag_service.generate_summary(result['text'], filename)
        summary = summary_result.get('summary', f'Document: {filename}')
        
        # Step 5: Extract and store metadata for aggregate queries (NEW)
        processing_status[doc_id]["progress"] = 95
        processing_status[doc_id]["message"] = "Extracting metadata..."
        
        try:
            # Extract structured metadata from document
            metadata = metadata_extractor.extract_metadata(result['text'], filename)
            
            # Store metadata for aggregate queries
            chroma_service.store_document_metadata(
                doc_id=doc_id,
                user_id=user_id,
                bucket_id=bucket_id,
                metadata=metadata
            )
            
            # Store summary chunk for aggregate queries
            chroma_service.store_summary_chunk(
                doc_id=doc_id,
                user_id=user_id,
                summary=summary,
                bucket_id=bucket_id,
                filename=filename
            )
            print(f"[METADATA] Extracted and stored metadata for {filename}")
        except Exception as e:
            print(f"[METADATA] Warning: Failed to extract metadata for {filename}: {e}")
            # Non-fatal - continue processing
        
        # Complete
        processing_status[doc_id] = {
            "status": "completed",
            "progress": 100,
            "message": "Complete",
            "result": {
                "doc_id": doc_id,
                "filename": filename,
                "doc_type": doc_type,
                "bucket_id": bucket_id,
                "chunk_count": chunk_count,
                "summary": summary
            }
        }
        print(f"[BACKGROUND] Completed {filename}")
        
    except Exception as e:
        import traceback
        print(f"[BACKGROUND ERROR] {str(e)}")
        print(traceback.format_exc())
        processing_status[doc_id] = {
            "status": "failed",
            "error": str(e)
        }
        if os.path.exists(file_path):
            try:
                os.remove(file_path)
            except:
                pass

@app.route('/api/documents/upload', methods=['POST'])
@require_auth
def upload_document():
    """Upload and process a document (Async)"""
    if 'file' not in request.files:
        return jsonify({"error": "No file provided"}), 400
    
    file = request.files['file']
    bucket_id = request.form.get('bucket_id', '')
    
    if file.filename == '':
        return jsonify({"error": "No file selected"}), 400
    
    if not document_processor.is_supported(file.filename):
        return jsonify({"error": "Unsupported file type"}), 400
    
    doc_id = str(uuid.uuid4())
    filename = secure_filename(file.filename)
    
    user_folder = os.path.join(Config.UPLOAD_FOLDER, request.current_user['user_id'])
    os.makedirs(user_folder, exist_ok=True)
    
    file_path = os.path.join(user_folder, f"{doc_id}_{filename}")
    file.save(file_path)
    
    # Initialize status
    processing_status[doc_id] = {
        "status": "queued",
        "progress": 0,
        "message": "Queued for processing..."
    }
    
    # Start background thread
    import threading
    thread = threading.Thread(
        target=process_document_background,
        args=(doc_id, request.current_user['user_id'], file_path, filename, bucket_id)
    )
    thread.daemon = True
    thread.start()
    
    # Return immediately
    return jsonify({
        "status": "queued",
        "doc_id": doc_id,
        "filename": filename,
        "message": "Upload accepted, processing in background"
    }), 202

@app.route('/api/documents/<doc_id>/status', methods=['GET'])
@require_auth
def get_document_status(doc_id):
    """Get processing status of a document"""
    status = processing_status.get(doc_id)
    
    if not status:
        # Check if it exists in DB (might be completed and cleared from memory)
        # For now, just return not found if not in memory or DB check logic here
        # Simple version:
        return jsonify({"status": "unknown"}), 404
        
    return jsonify(status)


@app.route('/api/documents/<doc_id>/summary', methods=['GET'])
@require_auth
def get_document_summary(doc_id):
    """Get or generate summary for a document"""
    doc = chroma_service.get_document(doc_id, request.current_user['user_id'])
    
    if not doc:
        return jsonify({"error": "Document not found"}), 404
    
    # Get the full document content from the stored preview
    # For a more complete summary, we'd need to re-read the document
    content_preview = doc.get('content_preview', '')
    
    # Generate summary
    summary_result = rag_service.generate_summary(content_preview, doc['filename'])
    
    return jsonify({
        "doc_id": doc_id,
        "filename": doc['filename'],
        "summary": summary_result.get('summary', f'Document: {doc["filename"]}'),
        "success": summary_result.get('success', False)
    })


@app.route('/api/documents', methods=['GET'])
@require_auth
def list_documents():
    """List all documents, optionally filtered by bucket"""
    bucket_id = request.args.get('bucket_id')
    documents = chroma_service.get_user_documents(
        request.current_user['user_id'],
        bucket_id=bucket_id if bucket_id else None
    )
    return jsonify({"documents": documents})


@app.route('/api/documents/<doc_id>', methods=['GET'])
@require_auth
def get_document(doc_id):
    """Get document details"""
    doc = chroma_service.get_document(doc_id, request.current_user['user_id'])
    
    if doc:
        return jsonify(doc)
    else:
        return jsonify({"error": "Document not found"}), 404


@app.route('/api/documents/<doc_id>/view', methods=['GET'])
@require_auth
def view_document(doc_id):
    """View/download the actual document file"""
    doc = chroma_service.get_document(doc_id, request.current_user['user_id'])
    
    if not doc:
        return jsonify({"error": "Document not found"}), 404
    
    user_folder = os.path.join(Config.UPLOAD_FOLDER, request.current_user['user_id'])
    
    # Find the file
    for f in os.listdir(user_folder):
        if f.startswith(doc_id):
            file_path = os.path.join(user_folder, f)
            return send_file(file_path, as_attachment=False)
    
    return jsonify({"error": "File not found on server"}), 404


@app.route('/api/documents/<doc_id>/bucket', methods=['PUT'])
@require_auth
def update_document_bucket(doc_id):
    """Move document to a different bucket"""
    data = request.get_json()
    bucket_id = data.get('bucket_id', '') if data else ''
    
    success = chroma_service.update_document_bucket(
        doc_id=doc_id,
        user_id=request.current_user['user_id'],
        bucket_id=bucket_id
    )
    
    if success:
        return jsonify({"success": True})
    else:
        return jsonify({"error": "Document not found or access denied"}), 404


@app.route('/api/documents/<doc_id>', methods=['DELETE'])
@require_auth
def delete_document(doc_id):
    """Delete a document"""
    success = chroma_service.delete_document(
        doc_id=doc_id,
        user_id=request.current_user['user_id']
    )
    
    if success:
        user_folder = os.path.join(Config.UPLOAD_FOLDER, request.current_user['user_id'])
        try:
            for f in os.listdir(user_folder):
                if f.startswith(doc_id):
                    os.remove(os.path.join(user_folder, f))
                    break
        except:
            pass
        
        return jsonify({"success": True})
    else:
        return jsonify({"error": "Document not found or access denied"}), 404


# ==================== Chat/RAG Routes ====================

@app.route('/api/chat', methods=['POST'])
@require_auth
def chat():
    """Process a chat query using RAG with optional bucket filtering"""
    data = request.get_json()
    
    if not data or not data.get('message'):
        return jsonify({"error": "No message provided"}), 400
    
    message = data.get('message', '').strip()
    doc_ids = data.get('doc_ids')
    bucket_id = data.get('bucket_id')  # New: filter by bucket
    conversation_history = data.get('history', [])
    
    result = rag_service.query(
        user_id=request.current_user['user_id'],
        query=message,
        doc_ids=doc_ids,
        bucket_id=bucket_id,
        conversation_history=conversation_history
    )
    
    if result['success']:
        return jsonify({
            "response": result['response'],
            "model": result.get('model', 'unknown'),
            "sources": result.get('sources', []),
            "source_files": result.get('source_files', []),
            "chunks_used": result.get('chunks_used', 0),
            "chunks_filtered": result.get('chunks_filtered', 0)
        })
    else:
        return jsonify({"error": result['error']}), 500


@app.route('/api/chat/stream', methods=['POST'])
@require_auth
def chat_stream():
    """Streaming chat endpoint - sends response chunks as they arrive"""
    import json
    import time
    
    start_time = time.time()
    print(f"[STREAM] Endpoint called")
    
    data = request.get_json()
    
    if not data or not data.get('message'):
        return jsonify({"error": "No message provided"}), 400
    
    message = data.get('message', '').strip()
    bucket_id = data.get('bucket_id')
    chat_id = data.get('chat_id', '')  # Get chat_id from request
    user_id = request.current_user['user_id']
    
    print(f"[STREAM] Request parsed in {time.time()-start_time:.2f}s")
    
    def generate():
        # Immediately yield to start the stream
        yield f"data: {json.dumps({'type': 'start'})}\n\n"
        
        sse_chunk_count = 0
        for chunk in rag_service.query_stream(
            user_id=user_id,
            query=message,
            bucket_id=bucket_id,
            chat_id=chat_id
        ):
            sse_chunk_count += 1
            if sse_chunk_count <= 5:
                print(f"[SSE] Sending chunk {sse_chunk_count}: type={chunk.get('type', 'unknown')}")
            yield f"data: {json.dumps(chunk)}\n\n"
        
        print(f"[SSE] Stream complete, sent {sse_chunk_count} chunks total")
    
    return Response(
        generate(),
        mimetype='text/event-stream',
        headers={
            'Cache-Control': 'no-cache',
            'Connection': 'keep-alive',
            'X-Accel-Buffering': 'no'
        }
    )


@app.route('/api/chat/clear', methods=['POST'])
@require_auth
def clear_chat_memory():
    """Clear conversation memory for the current user"""
    data = request.get_json() or {}
    bucket_id = data.get('bucket_id')
    
    success = rag_service.clear_memory(
        user_id=request.current_user['user_id'],
        bucket_id=bucket_id
    )
    
    if success:
        return jsonify({"success": True, "message": "Conversation memory cleared"})
    else:
        return jsonify({"error": "Failed to clear memory"}), 500


@app.route('/api/cleanup/chunks', methods=['POST'])
@require_auth
def cleanup_user_chunks():
    """Clear ALL chunks for the current user - use to fix stale data issues"""
    deleted_count = chroma_service.clear_all_user_chunks(
        user_id=request.current_user['user_id']
    )
    return jsonify({
        "success": True, 
        "message": f"Deleted {deleted_count} chunks. Please re-upload your documents."
    })



# ==================== Chat History Routes ====================

@app.route('/api/chats', methods=['GET'])
@require_auth
def list_chat_sessions():
    """Get all chat sessions for current user"""
    sessions = chroma_service.get_user_chat_sessions(request.current_user['user_id'])
    return jsonify({"chats": sessions})


@app.route('/api/chats', methods=['POST'])
@require_auth
def save_chat_session():
    """Save or update a chat session"""
    data = request.get_json()
    
    if not data:
        return jsonify({"error": "No data provided"}), 400
    
    chat_id = data.get('id')
    topic = data.get('topic', 'Chat')
    messages = data.get('messages', [])
    bucket_id = data.get('bucket', '')
    
    if not chat_id:
        return jsonify({"error": "Chat ID is required"}), 400
    
    result = chroma_service.save_chat_session(
        user_id=request.current_user['user_id'],
        chat_id=chat_id,
        topic=topic,
        messages=messages,
        bucket_id=bucket_id
    )
    
    return jsonify({"success": True, **result})


@app.route('/api/chats/<chat_id>', methods=['DELETE'])
@require_auth
def delete_chat_session(chat_id):
    """Delete a chat session"""
    success = chroma_service.delete_chat_session(
        user_id=request.current_user['user_id'],
        chat_id=chat_id
    )
    
    if success:
        return jsonify({"success": True})
    else:
        return jsonify({"error": "Chat not found or access denied"}), 404


# ==================== Health Check ====================

@app.route('/api/health', methods=['GET'])
def health_check():
    return jsonify({"status": "healthy", "version": "1.1.0"})


# ==================== Main ====================

if __name__ == '__main__':
    print("=" * 50)
    print("NotebookLM Clone - AI Document Intelligence")
    print("=" * 50)
    print(f"Upload folder: {Config.UPLOAD_FOLDER}")
    print(f"ChromaDB Cloud: {Config.CHROMA_TENANT}/{Config.CHROMA_DATABASE}")
    print("Starting server on http://localhost:5000")
    print("=" * 50)
    
    app.run(host='0.0.0.0', port=5000, debug=True)