# hp_chatbot/main.py

import asyncio
import os
import sys
import threading
from flask import Flask
from flask_cors import CORS

# Ensure the project directory is in the Python path
current_dir = os.path.dirname(os.path.abspath(__file__))
if current_dir not in sys.path:
    sys.path.insert(0, current_dir)

# Import necessary components from our modules
from config import (
    APPLICATION_ROOT, MAX_CONTENT_LENGTH,
    CORS_ALLOWED_ORIGINS, CORS_SUPPORTS_CREDENTIALS,
    SERVER_HOST, SERVER_PORT, USE_RELOADER, LOG_LEVEL,
    KEEP_ALIVE_TIMEOUT, READ_TIMEOUT, WRITE_TIMEOUT
)
from utils import logger, log_structured
from json_utils import CustomJSONProvider
from ai_core import initialize_global_index, initialize_vector_index, initialize_graphrag_components
from shared_state import global_workflow_agent, is_agent_available, get_graphrag_status
from routes import register_routes
from init_mongodb import init_mongodb # Your MongoDB initialization script

# --- Flask App Initialization ---
app = Flask(__name__)

# Apply custom JSON provider for handling special types (LlamaIndex objects, etc.)
app.json_provider_class = CustomJSONProvider
app.json = CustomJSONProvider(app)

# Configuration
app.config['MAX_CONTENT_LENGTH'] = MAX_CONTENT_LENGTH
if APPLICATION_ROOT:
    app.config['APPLICATION_ROOT'] = APPLICATION_ROOT
    # If using APPLICATION_ROOT, you might need to adjust route prefixes
    # or use a Blueprint with url_prefix=APPLICATION_ROOT
    log_structured('info', f"Flask Application Root set to: {APPLICATION_ROOT}")

# CORS Configuration
CORS(app,
     resources={r"/*": {"origins": CORS_ALLOWED_ORIGINS}},
     supports_credentials=CORS_SUPPORTS_CREDENTIALS,
     # Expose custom headers if needed by the frontend
     # expose_headers=["Content-Disposition"] # Example for downloads
)
log_structured('info', f"CORS configured for origins: {CORS_ALLOWED_ORIGINS}")


# --- Register Routes ---
# Pass the app object to the function in routes.py
register_routes(app)
log_structured('info', "Flask routes registered.")


def _launch_graphrag_background_thread():
    """Launch GraphRAG initialization in a daemon thread with its own event loop.

    Neo4j operations (connect, get_triplets, upsert_nodes, build_communities)
    are synchronous blocking calls. Running them in an asyncio task would block
    the main event loop and prevent Hypercorn from serving requests. A separate
    thread with its own event loop avoids this entirely.
    """
    def _run():
        loop = asyncio.new_event_loop()
        asyncio.set_event_loop(loop)
        try:
            success = loop.run_until_complete(initialize_graphrag_components())
            if success:
                log_structured('info', "Background GraphRAG initialization completed successfully")
            else:
                log_structured('warning', "Background GraphRAG initialization failed — vector search still works")
        except Exception as e:
            log_structured('error', f"Background GraphRAG initialization error: {e}")
        finally:
            loop.close()

    t = threading.Thread(target=_run, name="graphrag-init", daemon=True)
    t.start()


# --- Startup Function ---
async def startup_event() -> bool:
    """Phase 1 (blocking): MongoDB + vector index. Phase 2 (background): GraphRAG.

    Returns:
        bool: True if Phase 1 completed successfully, False otherwise
    """
    log_structured('info', "Application startup sequence initiated.")
    all_success = True

    # 1. Initialize MongoDB Connection & Schema
    log_structured('info', "Initializing MongoDB connection...")
    try:
        if init_mongodb():
            log_structured('info', "MongoDB initialized successfully.")
        else:
            log_structured('warning', "MongoDB initialization script finished, but reported issues.")
            all_success = False
    except Exception as db_err:
        log_structured('critical', "FATAL: MongoDB initialization failed.", {'error': str(db_err)})
        all_success = False

    # 2. Phase 1: Vector index + agent (fast, ~1-2 min)
    log_structured('info', "Phase 1: Initializing vector index and agent...")
    vector_success = await initialize_vector_index()

    if not is_agent_available() or not vector_success:
        log_structured('critical', "Vector initialization failed")
        all_success = False
    else:
        log_structured('info', "Phase 1 complete: server is ready for vector queries")

    # 3. Phase 2: GraphRAG in background thread (non-blocking)
    if vector_success:
        log_structured('info', "Phase 2: Launching GraphRAG initialization in background thread...")
        _launch_graphrag_background_thread()

    log_structured('info', f"Startup complete. Server ready: {all_success}")
    return all_success


# --- Shutdown Function (Optional) ---
async def shutdown_event():
    """Tasks to run when the application stops."""
    log_structured('info', "Application shutdown sequence initiated.")
    # Add any cleanup tasks here (e.g., closing connections if not handled elsewhere)
    # Note: Hypercorn might not always guarantee graceful shutdown execution.
    log_structured('info', "Application shutdown sequence complete.")


# --- Main Execution Block ---
if __name__ == '__main__':
    from hypercorn.config import Config as HypercornConfig
    from hypercorn.asyncio import serve as hypercorn_serve

    # Create Hypercorn config object
    config = HypercornConfig()

    # Basic settings
    config.bind = [f"{SERVER_HOST}:{SERVER_PORT}"]
    config.use_reloader = USE_RELOADER
    config.accesslog = '-'
    config.errorlog = '-'
    config.loglevel = LOG_LEVEL.upper()
    config.worker_class = 'asyncio'

    # Timeouts
    config.keep_alive_timeout = float(KEEP_ALIVE_TIMEOUT)
    config.read_timeout = float(READ_TIMEOUT)
    config.write_timeout = float(WRITE_TIMEOUT)

    # Shutdown hooks (startup is handled manually inside run_server_with_startup)
    config.shutdown_hooks = [shutdown_event]

    log_structured('info', f"Starting Hypercorn server on {SERVER_HOST}:{SERVER_PORT}")
    log_structured('info', f"Reload mode: {'Enabled' if USE_RELOADER else 'Disabled'}")

    async def run_server_with_startup():
        """Run startup (with background GraphRAG init) then serve.

        Phase 1 runs in the main event loop. Phase 2 (GraphRAG) runs in a
        separate daemon thread so blocking Neo4j calls cannot stall Hypercorn.
        """
        await startup_event()

        # Double-check agent
        if not is_agent_available():
            log_structured('critical', "Agent unavailable after startup. Forcing vector re-init...")
            await initialize_vector_index()
            if is_agent_available():
                _launch_graphrag_background_thread()

        # Start serving — background GraphRAG init continues in separate thread
        await hypercorn_serve(app, config)

    try:
        asyncio.run(run_server_with_startup())
    except KeyboardInterrupt:
        log_structured('info', "Server stopped manually (KeyboardInterrupt).")
    except Exception as run_err:
        log_structured('critical', "Hypercorn server failed to run.", {'error': str(run_err)})
        sys.exit(1)