"""App-Factory für den Projekt-Hub.

Erzeugt die Flask-App, lädt die Config, bindet die Extensions und registriert
die Blueprints der einzelnen Mini-App-Module. Jedes neue Modul wird hier per
register_blueprint(...) eingebunden und über die zentrale Navigations-Registry
in der Navigation sichtbar gemacht — Kern bleibt unangetastet.
"""

import os

from flask import Flask, redirect, url_for

from .config import get_config
from .extensions import db, migrate, login_manager, mail, limiter, csrf


# --- Zentrale Navigations-Registry ---------------------------------------
# Jedes Modul trägt hier einen Eintrag bei (Label, Endpoint, Icon). base.html
# rendert daraus die gemeinsame Navigation. Neues Modul = neuer Eintrag.
NAV_MODULES = [
    {"label": "Projekte", "endpoint": "projects.index", "icon": "📁"},
]


def create_app(config_name: str | None = None) -> Flask:
    app = Flask(
        __name__,
        instance_relative_config=True,
        instance_path=os.path.join(os.path.dirname(os.path.dirname(__file__)), "instance"),
    )
    app.config.from_object(get_config(config_name))

    # instance/-Ordner sicherstellen (SQLite-Datei landet hier).
    os.makedirs(app.instance_path, exist_ok=True)

    # Relativen sqlite-Pfad in den instance/-Ordner umbiegen.
    uri = app.config.get("SQLALCHEMY_DATABASE_URI", "")
    if uri.startswith("sqlite:///") and not uri.startswith("sqlite:////"):
        db_name = uri.replace("sqlite:///", "", 1)
        abs_path = os.path.join(app.instance_path, db_name)
        app.config["SQLALCHEMY_DATABASE_URI"] = f"sqlite:///{abs_path}"

    _init_extensions(app)
    _register_blueprints(app)
    _register_context(app)

    @app.route("/")
    def index():
        return redirect(url_for("projects.index"))

    return app


def _init_extensions(app: Flask) -> None:
    db.init_app(app)
    migrate.init_app(app, db)
    login_manager.init_app(app)
    mail.init_app(app)
    limiter.init_app(app)
    csrf.init_app(app)

    # Modelle importieren, damit SQLAlchemy/Alembic sie kennen (Autogenerate).
    from . import models  # noqa: F401
    from .projects import models as project_models  # noqa: F401

    from .models import User

    @login_manager.user_loader
    def load_user(user_id):
        return db.session.get(User, int(user_id))


def _register_blueprints(app: Flask) -> None:
    from .auth import bp as auth_bp
    from .projects import bp as projects_bp

    app.register_blueprint(auth_bp)
    app.register_blueprint(projects_bp)


def _register_context(app: Flask) -> None:
    @app.context_processor
    def inject_nav():
        # Navigations-Registry in allen Templates verfügbar machen.
        return {"nav_modules": NAV_MODULES}