"""
MiroFish Backend - Flask application factory
"""

import os
import warnings

# Suppress multiprocessing resource_tracker warnings (from third-party libraries like transformers)
# Must be set before all other imports
warnings.filterwarnings("ignore", message=".*resource_tracker.*")

from flask import Flask, request
from flask_cors import CORS

from .config import Config
from .utils.logger import setup_logger, get_logger


def create_app(config_class=Config):
    """Flask application factory function"""
    app = Flask(__name__)
    app.config.from_object(config_class)

    # Set JSON encoding: ensure Chinese characters display directly (instead of \uXXXX format)
    # Flask >= 2.3 uses app.json.ensure_ascii, older versions use JSON_AS_ASCII config
    if hasattr(app, "json") and hasattr(app.json, "ensure_ascii"):
        app.json.ensure_ascii = False

    # Set up logging
    logger = setup_logger("mirofish")

    # Only log startup info in the reloader child process (avoid duplicate logs in debug mode)
    is_reloader_process = os.environ.get("WERKZEUG_RUN_MAIN") == "true"
    debug_mode = app.config.get("DEBUG", False)
    should_log_startup = not debug_mode or is_reloader_process

    if should_log_startup:
        logger.info("=" * 50)
        logger.info("MiroFish Backend starting...")
        logger.info("=" * 50)

    # Enable CORS
    CORS(app, resources={r"/api/*": {"origins": "*"}})

    # Register simulation process cleanup function (ensure all simulation processes terminate on server shutdown)
    from .services.simulation_runner import SimulationRunner

    SimulationRunner.register_cleanup()
    if should_log_startup:
        logger.info("Registered simulation process cleanup function")

    # Request logging middleware
    @app.before_request
    def log_request():
        logger = get_logger("mirofish.request")
        logger.debug(f"Request: {request.method} {request.path}")
        if request.content_type and "json" in request.content_type:
            logger.debug(f"Request body: {request.get_json(silent=True)}")

    @app.after_request
    def log_response(response):
        logger = get_logger("mirofish.request")
        logger.debug(f"Response: {response.status_code}")
        return response

    # Register blueprints
    from .api import graph_bp, simulation_bp, report_bp

    app.register_blueprint(graph_bp, url_prefix="/api/graph")
    app.register_blueprint(simulation_bp, url_prefix="/api/simulation")
    app.register_blueprint(report_bp, url_prefix="/api/report")

    # Health check
    @app.route("/health")
    def health():
        return {"status": "ok", "service": "MiroFish Backend"}

    if should_log_startup:
        logger.info("MiroFish Backend startup complete")

    return app