import os
from pathlib import Path

import dj_database_url
from django.core.exceptions import ImproperlyConfigured

BASE_DIR = Path(__file__).resolve().parent.parent
PROJECT_ROOT = BASE_DIR.parent
APP_VERSION = os.getenv("APP_VERSION", "1.2.1")

SECRET_KEY = os.getenv("DJANGO_SECRET_KEY", "dev-only-change-before-production")
DEBUG = os.getenv("DJANGO_DEBUG", "true").lower() == "true"
USE_HTTPS = os.getenv(
    "DJANGO_USE_HTTPS",
    "false" if DEBUG else "true",
).lower() == "true"
if not DEBUG and SECRET_KEY == "dev-only-change-before-production":
    raise ImproperlyConfigured("生产环境必须设置 DJANGO_SECRET_KEY")
ALLOWED_HOSTS = [
    host.strip()
    for host in os.getenv("DJANGO_ALLOWED_HOSTS", "localhost,127.0.0.1,testserver").split(",")
    if host.strip()
]

INSTALLED_APPS = [
    "common.apps.HulumathAdminConfig",
    "django.contrib.auth",
    "django.contrib.contenttypes",
    "django.contrib.sessions",
    "django.contrib.messages",
    "django.contrib.staticfiles",
    "corsheaders",
    "rest_framework",
    "channels",
    "accounts",
    "math_life",
    "contest",
    "progression",
    "latex_lab",
    "content",
    "engagement",
    "toolbox",
    "common",
]

MIDDLEWARE = [
    "django.middleware.security.SecurityMiddleware",
    "whitenoise.middleware.WhiteNoiseMiddleware",
    "corsheaders.middleware.CorsMiddleware",
    "django.contrib.sessions.middleware.SessionMiddleware",
    "django.middleware.common.CommonMiddleware",
    "django.middleware.csrf.CsrfViewMiddleware",
    "django.contrib.auth.middleware.AuthenticationMiddleware",
    "django.contrib.messages.middleware.MessageMiddleware",
    "django.middleware.clickjacking.XFrameOptionsMiddleware",
    "common.middleware.RequestIDMiddleware",
]

ROOT_URLCONF = "config.urls"
TEMPLATES = [
    {
        "BACKEND": "django.template.backends.django.DjangoTemplates",
        "DIRS": [BASE_DIR / "templates"],
        "APP_DIRS": True,
        "OPTIONS": {
            "context_processors": [
                "django.template.context_processors.debug",
                "django.template.context_processors.request",
                "django.contrib.auth.context_processors.auth",
                "django.contrib.messages.context_processors.messages",
            ],
        },
    },
]

WSGI_APPLICATION = "config.wsgi.application"
ASGI_APPLICATION = "config.asgi.application"

DATABASE_URL = os.getenv("DATABASE_URL")
if not DEBUG and not DATABASE_URL:
    raise ImproperlyConfigured("生产环境必须设置 MySQL DATABASE_URL")
if not DEBUG and not DATABASE_URL.startswith("mysql://"):
    raise ImproperlyConfigured("生产环境 DATABASE_URL 必须使用 MySQL")
DATABASES = {
    "default": dj_database_url.parse(
        DATABASE_URL or f"sqlite:///{BASE_DIR / 'db.sqlite3'}",
        conn_max_age=60,
        conn_health_checks=True,
    )
}
if DATABASES["default"]["ENGINE"] == "django.db.backends.mysql":
    DATABASES["default"]["OPTIONS"] = {
        "charset": "utf8mb4",
        "init_command": (
            "SET sql_mode='STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,"
            "NO_ENGINE_SUBSTITUTION'"
        ),
        "isolation_level": "read committed",
    }

AUTH_PASSWORD_VALIDATORS = [
    {"NAME": "django.contrib.auth.password_validation.UserAttributeSimilarityValidator"},
    {"NAME": "django.contrib.auth.password_validation.MinimumLengthValidator"},
    {"NAME": "django.contrib.auth.password_validation.CommonPasswordValidator"},
    {"NAME": "django.contrib.auth.password_validation.NumericPasswordValidator"},
]
AUTH_USER_MODEL = "accounts.User"

LANGUAGE_CODE = "zh-hans"
TIME_ZONE = "Asia/Shanghai"
USE_I18N = True
USE_TZ = True

STATIC_URL = "/static/"
STATIC_ROOT = BASE_DIR / "staticfiles"
STATICFILES_DIRS = [BASE_DIR / "static"]
STORAGES = {
    "default": {"BACKEND": "django.core.files.storage.FileSystemStorage"},
    "staticfiles": {
        "BACKEND": (
            "django.contrib.staticfiles.storage.StaticFilesStorage"
            if DEBUG
            else "whitenoise.storage.CompressedManifestStaticFilesStorage"
        )
    },
}

DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"

REST_FRAMEWORK = {
    "DEFAULT_AUTHENTICATION_CLASSES": [
        "rest_framework.authentication.SessionAuthentication",
    ],
    "DEFAULT_PERMISSION_CLASSES": [
        "rest_framework.permissions.IsAuthenticated",
    ],
    "DEFAULT_PAGINATION_CLASS": "rest_framework.pagination.PageNumberPagination",
    "PAGE_SIZE": 20,
    "EXCEPTION_HANDLER": "common.api.exception_handler",
    "DEFAULT_THROTTLE_CLASSES": [
        "rest_framework.throttling.AnonRateThrottle",
        "rest_framework.throttling.UserRateThrottle",
    ],
    "DEFAULT_THROTTLE_RATES": {
        "anon": os.getenv("API_ANON_RATE", "120/minute"),
        "user": os.getenv("API_USER_RATE", "600/minute"),
        "calculator": os.getenv("CALCULATOR_RATE", "30/minute"),
    },
}

CORS_ALLOWED_ORIGINS = [
    origin.strip()
    for origin in os.getenv("CORS_ALLOWED_ORIGINS", "http://localhost:3000").split(",")
    if origin.strip()
]
CORS_ALLOW_CREDENTIALS = True
CSRF_TRUSTED_ORIGINS = [
    origin.strip()
    for origin in os.getenv("CSRF_TRUSTED_ORIGINS", "").split(",")
    if origin.strip()
]

REDIS_URL = os.getenv("REDIS_URL")
if not DEBUG and not REDIS_URL:
    raise ImproperlyConfigured("生产环境必须设置 Redis REDIS_URL")
if REDIS_URL:
    CHANNEL_LAYERS = {
        "default": {
            "BACKEND": "channels_redis.core.RedisChannelLayer",
            "CONFIG": {"hosts": [REDIS_URL]},
        }
    }
else:
    CHANNEL_LAYERS = {
        "default": {"BACKEND": "channels.layers.InMemoryChannelLayer"}
    }

SESSION_COOKIE_HTTPONLY = True
SESSION_COOKIE_SAMESITE = "Lax"
CSRF_COOKIE_SAMESITE = "Lax"
SECURE_PROXY_SSL_HEADER = ("HTTP_X_FORWARDED_PROTO", "https")
SECURE_CONTENT_TYPE_NOSNIFF = True
X_FRAME_OPTIONS = "DENY"
SECURE_SSL_REDIRECT = USE_HTTPS
SESSION_COOKIE_SECURE = USE_HTTPS
CSRF_COOKIE_SECURE = USE_HTTPS
SECURE_HSTS_SECONDS = int(
    os.getenv("SECURE_HSTS_SECONDS", "31536000" if USE_HTTPS else "0")
)
SECURE_HSTS_INCLUDE_SUBDOMAINS = USE_HTTPS
SECURE_HSTS_PRELOAD = USE_HTTPS

LOGGING = {
    "version": 1,
    "disable_existing_loggers": False,
    "formatters": {
        "standard": {
            "format": "%(asctime)s %(levelname)s %(name)s request_id=%(request_id)s %(message)s"
        }
    },
    "filters": {"request_id": {"()": "common.logging.RequestIDFilter"}},
    "handlers": {
        "console": {
            "class": "logging.StreamHandler",
            "formatter": "standard",
            "filters": ["request_id"],
        }
    },
    "root": {"handlers": ["console"], "level": "INFO"},
}