# 项目文件：shelf_project/src/shelfweb/__init__.py
import os
from datetime import timedelta
from pathlib import Path

from flask import Flask


def create_app(test_config=None, instance_path=None):
    location = Path(instance_path or os.getenv("SHELF_INSTANCE", "instance")).resolve()
    location.mkdir(parents=True, exist_ok=True)
    app = Flask(__name__, instance_path=str(location))
    app.config.from_mapping(
        DATABASE=str(location / "books.sqlite3"),
        SECRET_KEY=os.getenv("SHELF_SECRET_KEY"),
        SESSION_COOKIE_NAME="shelf_session",
        SESSION_COOKIE_HTTPONLY=True,
        SESSION_COOKIE_SAMESITE="Lax",
        SESSION_COOKIE_SECURE=False,
        SESSION_REFRESH_EACH_REQUEST=False,
        PERMANENT_SESSION_LIFETIME=timedelta(hours=1),
        MAX_CONTENT_LENGTH=16 * 1024,
    )
    key_file = location / "secret.key"
    if app.config["SECRET_KEY"] is None and key_file.is_file():
        app.config["SECRET_KEY"] = key_file.read_text(encoding="utf-8").strip()
    if test_config:
        app.config.update(test_config)
    if not app.config["SECRET_KEY"]:
        raise RuntimeError("请先运行 shelf-books init，或设置 SHELF_SECRET_KEY")

    from . import api, auth, books, db, errors, security

    db.init_app(app)
    app.register_blueprint(auth.bp)  # 先登记用户加载，再登记全局表单检查。
    app.register_blueprint(books.bp)
    app.register_blueprint(api.bp)
    security.init_app(app)
    errors.init_app(app)
    return app