from __future__ import annotations

import os
import secrets
from datetime import date, timedelta
from pathlib import Path

from flask import Flask, g, send_from_directory

from . import db
from .admin import admin_bp
from .auth import auth_bp
from .constants import (
    CATEGORIES,
    DAYPARTS,
    ITEM_KIND_LABELS,
    ITEM_KIND_SINGULAR_LABELS,
    ROLE_LABELS,
    VISIBILITY_DESCRIPTIONS,
    VISIBILITY_LABELS,
)
from .main import main_bp


WEEKDAY_NAMES = ["Montag", "Dienstag", "Mittwoch", "Donnerstag", "Freitag", "Samstag", "Sonntag"]
WEEKDAY_SHORT_NAMES = ["Mo", "Di", "Mi", "Do", "Fr", "Sa", "So"]


def load_secret_key(data_dir: Path) -> str:
    env_secret = os.environ.get("NOURI_SECRET_KEY")
    if env_secret:
        return env_secret

    secret_path = data_dir / ".secret_key"
    if secret_path.exists():
        return secret_path.read_text(encoding="utf-8").strip()

    secret_value = secrets.token_hex(24)
    try:
        with secret_path.open("x", encoding="utf-8") as handle:
            handle.write(secret_value)
    except FileExistsError:
        return secret_path.read_text(encoding="utf-8").strip()
    return secret_value


def create_app() -> Flask:
    root_dir = Path(__file__).resolve().parent.parent
    data_dir = Path(os.environ.get("NOURI_DATA_DIR", root_dir / "data")).resolve()
    upload_dir = data_dir / "uploads"
    db_path = data_dir / "nouri.sqlite3"

    data_dir.mkdir(parents=True, exist_ok=True)
    upload_dir.mkdir(parents=True, exist_ok=True)

    app = Flask(__name__, instance_relative_config=False)
    app.config.update(
        SECRET_KEY=load_secret_key(data_dir),
        DATABASE_PATH=str(db_path),
        DATA_DIR=str(data_dir),
        UPLOAD_FOLDER=str(upload_dir),
        MAX_CONTENT_LENGTH=int(os.environ.get("NOURI_MAX_UPLOAD_MB", "5")) * 1024 * 1024,
        PERMANENT_SESSION_LIFETIME=timedelta(days=30),
        SESSION_COOKIE_HTTPONLY=True,
        SESSION_COOKIE_SAMESITE="Lax",
    )

    db.init_app(app)
    db.init_db_if_needed(app)

    app.register_blueprint(auth_bp)
    app.register_blueprint(admin_bp)
    app.register_blueprint(main_bp)

    @app.context_processor
    def inject_globals() -> dict[str, object]:
        return {
            "item_kind_labels": ITEM_KIND_LABELS,
            "item_kind_singular_labels": ITEM_KIND_SINGULAR_LABELS,
            "category_suggestions": CATEGORIES,
            "daypart_suggestions": DAYPARTS,
            "visibility_labels": VISIBILITY_LABELS,
            "visibility_descriptions": VISIBILITY_DESCRIPTIONS,
            "role_labels": ROLE_LABELS,
            "today": date.today(),
            "weekday_name": lambda value: WEEKDAY_NAMES[value.weekday()],
            "weekday_short_name": lambda value: WEEKDAY_SHORT_NAMES[value.weekday()],
            "is_admin": lambda: bool(getattr(g, "user", None)) and g.user["role"] == "admin",
        }

    @app.get("/uploads/<path:filename>")
    def uploaded_file(filename: str):
        return send_from_directory(app.config["UPLOAD_FOLDER"], filename)

    return app