"""
app.py — Flask application factory.
Web conversion of the desktop Website Checker application.
Stack: Python 3.11+, Flask, MySQL (mysql-connector-python), Gunicorn, Nginx.
"""

import logging
import os
from flask import Flask
from config import initialize_database, db_log_handler, _stream_handler

# ─── Logging ──────────────────────────────────────────────────────────────────
logging.basicConfig(
    level=logging.INFO,
    handlers=[_stream_handler, db_log_handler],
)
logger = logging.getLogger("app")


def create_app():
    app = Flask(__name__)

    # ── Secret key for session management ─────────────────────────────────────
    secret_key = os.environ.get("SECRET_KEY")
    if not secret_key:
        logger.warning(
            "SECRET_KEY not set in environment. Sessions will break across "
            "Gunicorn workers. Set SECRET_KEY in .env before deploying."
        )
    app.secret_key = secret_key or os.urandom(32)

    # ── Upload size limit (20 MB) ──────────────────────────────────────────────
    app.config["MAX_CONTENT_LENGTH"] = 20 * 1024 * 1024

    # ── Session timeout (30 minutes) ──────────────────────────────────────────
    from datetime import timedelta
    app.permanent_session_lifetime = timedelta(minutes=30)

    # ── Database initialisation ────────────────────────────────────────────────
    try:
        initialize_database()
        db_log_handler.install()
        logger.info("Database initialised successfully.")
    except Exception as e:
        logger.error(f"Database initialisation failed: {e}")

    # ── Register Blueprints ────────────────────────────────────────────────────
    from routes.auth import auth_bp
    from routes.admin_dashboard import admin_dashboard_bp
    from routes.admin_users import admin_users_bp
    from routes.admin_websites import admin_websites_bp
    from routes.admin_shifts import admin_shifts_bp
    from routes.admin_logs import admin_logs_bp
    from routes.admin_reports import admin_reports_bp
    from routes.admin_settings import admin_settings_bp
    from routes.user_dashboard import user_dashboard_bp
    from routes.ai_summary import ai_summary_bp
    from routes.bid_tracker import bid_tracker_bp

    app.register_blueprint(auth_bp)
    app.register_blueprint(admin_dashboard_bp)
    app.register_blueprint(admin_users_bp)
    app.register_blueprint(admin_websites_bp)
    app.register_blueprint(admin_shifts_bp)
    app.register_blueprint(admin_logs_bp)
    app.register_blueprint(admin_reports_bp)
    app.register_blueprint(admin_settings_bp)
    app.register_blueprint(user_dashboard_bp)
    app.register_blueprint(ai_summary_bp)
    app.register_blueprint(bid_tracker_bp)

    # ── CSRF protection (Flask-WTF) ────────────────────────────────────────────
    from flask_wtf.csrf import CSRFProtect
    CSRFProtect(app)

    # ── Security response headers ──────────────────────────────────────────────
    from flask import session, redirect, url_for, g, request, jsonify, flash
    import functools

    @app.after_request
    def set_security_headers(response):
        response.headers["X-Frame-Options"] = "SAMEORIGIN"
        response.headers["X-Content-Type-Options"] = "nosniff"
        response.headers["Referrer-Policy"] = "strict-origin-when-cross-origin"
        return response

    # ── 413 handler: file too large ────────────────────────────────────────────
    from werkzeug.exceptions import RequestEntityTooLarge

    @app.errorhandler(RequestEntityTooLarge)
    def handle_too_large(e):
        max_mb = app.config.get("MAX_CONTENT_LENGTH", 0) // (1024 * 1024)
        msg = f"Upload too large. Maximum allowed size is {max_mb} MB."
        if request.path.startswith("/ai-summary/"):
            return jsonify({"error": msg}), 413
        flash(msg, "danger")
        return redirect(request.referrer or url_for("index")), 413

    # ── Template context processors ────────────────────────────────────────────

    # ── Custom template filter: timedelta/time → "HH:MM" ──────────────────────
    import datetime as _dt

    @app.template_filter('hhmm')
    def hhmm_filter(value):
        """Render a MySQL TIME value (timedelta, time, or str) as HH:MM."""
        if value is None:
            return ''
        if isinstance(value, _dt.timedelta):
            total = int(value.total_seconds())
            h, rem = divmod(abs(total), 3600)
            m = rem // 60
            return f"{h:02d}:{m:02d}"
        if isinstance(value, _dt.time):
            return value.strftime('%H:%M')
        return str(value)[:5]   # already a string like "08:00:00"

    @app.context_processor
    def inject_user():
        return {"current_user": session.get("user")}

    # ── Root redirect ──────────────────────────────────────────────────────────
    @app.route("/")
    def index():
        if "user" in session:
            user = session["user"]
            if user["role"] == "admin":
                return redirect(url_for("admin_dashboard.dashboard"))
            return redirect(url_for("user_dashboard.my_shifts"))
        return redirect(url_for("auth.login"))

    return app


# ─── Dev entry point ──────────────────────────────────────────────────────────
if __name__ == "__main__":
    application = create_app()
    application.run(debug=False, host="0.0.0.0", port=5000)