import os
import json
import importlib
import importlib.util

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from flask_login import LoginManager
from flask_wtf.csrf import CSRFProtect
from dotenv import load_dotenv

# Load environment variables
load_dotenv()

# Initialize extensions
db = SQLAlchemy()
migrate = Migrate()
login_manager = LoginManager()
csrf = CSRFProtect()


def create_app():
    app = Flask(__name__)
    app.config.from_object('app.config.Config')

    # Initialize core extensions
    csrf.init_app(app)
    db.init_app(app)
    migrate.init_app(app, db)
    login_manager.init_app(app)
    login_manager.login_view = 'auth.login'

    # Register error handlers
    from .errors import bp as errors_bp
    app.register_blueprint(errors_bp)

    # Auto-discover and register plugins
    plugin_path = os.path.abspath(os.path.join(os.path.dirname(__file__), '..', 'plugins'))
    for plugin in os.listdir(plugin_path):
        if plugin.endswith('.noload'):
            print(f"[⏭] Skipping plugin '{plugin}' (marked as .noload)")
            continue

        plugin_dir = os.path.join(plugin_path, plugin)
        if not os.path.isdir(plugin_dir):
            continue

        # 1. Register routes
        route_file = os.path.join(plugin_dir, 'routes.py')
        if os.path.isfile(route_file):
            try:
                spec = importlib.util.spec_from_file_location(f"plugins.{plugin}.routes", route_file)
                mod = importlib.util.module_from_spec(spec)
                spec.loader.exec_module(mod)
                if hasattr(mod, 'bp'):
                    app.register_blueprint(mod.bp, strict_slashes=False)
            except Exception as e:
                print(f"[⚠️] Failed to load routes from plugin '{plugin}': {e}")

        # Define paths
        init_file  = os.path.join(plugin_dir, '__init__.py')
        plugin_json = os.path.join(plugin_dir, 'plugin.json')
        model_file = os.path.join(plugin_dir, 'models.py')

        # 2. Register CLI commands and run entry point
        if os.path.isfile(init_file):
            try:
                cli_module = importlib.import_module(f"plugins.{plugin}")
                if hasattr(cli_module, 'register_cli'):
                    cli_module.register_cli(app)

                if os.path.isfile(plugin_json):
                    with open(plugin_json, 'r') as f:
                        meta = json.load(f)
                    entry = meta.get('entry_point')
                    if entry and hasattr(cli_module, entry):
                        getattr(cli_module, entry)(app)
            except Exception as e:
                print(f"[⚠️] Failed to load CLI for plugin '{plugin}': {e}")

        ## 3. Auto-load plugin models for migrations
        #if os.path.isfile(model_file):
        #    try:
        #        spec = importlib.util.spec_from_file_location(f"plugins.{plugin}.models", model_file)
        #        mod = importlib.util.module_from_spec(spec)
        #        spec.loader.exec_module(mod)
        #    except Exception as e:
        #        print(f"[⚠️] Failed to load models from plugin '{plugin}': {e}")

    @app.context_processor
    def inject_current_year():
        from datetime import datetime
        return {'current_year': datetime.now().year}

    return app


@login_manager.user_loader
def load_user(user_id):
    from plugins.auth.models import User
    return User.query.get(int(user_id))