"""Django settings. All deployment-specific values come from environment variables (see .env.example)."""

import ipaddress
import os
from pathlib import Path
from urllib.parse import urlsplit

from django.core.exceptions import ImproperlyConfigured

BASE_DIR = Path(__file__).resolve().parent.parent


def env(name, default=""):
    return os.environ.get(name, default).strip()


def env_bool(name, default=False):
    value = env(name)
    if not value:
        return default
    return value.lower() in {"1", "true", "yes", "on"}


def env_int(name, default):
    value = env(name)
    return int(value) if value else default


def env_list(name, default=""):
    return [item.strip() for item in env(name, default).split(",") if item.strip()]


DEBUG = env_bool("DEBUG")

SECRET_KEY = env("SECRET_KEY")
if not SECRET_KEY:
    raise ImproperlyConfigured("SECRET_KEY ist nicht gesetzt (siehe .env.example).")

APP_BASE_URL = env("APP_BASE_URL", "http://localhost:8000").rstrip("/")
_base = urlsplit(APP_BASE_URL)
if _base.scheme not in {"http", "https"} or not _base.hostname:
    raise ImproperlyConfigured("APP_BASE_URL muss eine absolute http(s)-URL sein.")

# 127.0.0.1/localhost are needed for the container healthcheck.
ALLOWED_HOSTS = [_base.hostname, "localhost", "127.0.0.1", *env_list("ALLOWED_HOSTS")]
CSRF_TRUSTED_ORIGINS = [f"{_base.scheme}://{_base.netloc}"]

TRUSTED_PROXIES = [
    ipaddress.ip_network(net, strict=False)
    for net in env_list("TRUSTED_PROXIES", "127.0.0.1/32,::1/128,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16")
]
CLIENT_IP_HEADER = env("CLIENT_IP_HEADER")

INSTALLED_APPS = [
    "django.contrib.auth",
    "django.contrib.contenttypes",
    "django.contrib.sessions",
    "django.contrib.messages",
    "django.contrib.staticfiles",
    "core",
    "accounts",
    "recipes",
]

MIDDLEWARE = [
    # Must run first: sanitises X-Forwarded-* before anything reads REMOTE_ADDR or is_secure().
    "core.middleware.ProxyMiddleware",
    "django.middleware.security.SecurityMiddleware",
    "whitenoise.middleware.WhiteNoiseMiddleware",
    "core.middleware.SecurityHeadersMiddleware",
    "django.contrib.sessions.middleware.SessionMiddleware",
    "django.middleware.common.CommonMiddleware",
    "django.middleware.csrf.CsrfViewMiddleware",
    "django.contrib.auth.middleware.AuthenticationMiddleware",
    # Every view requires login unless decorated with @login_not_required.
    "django.contrib.auth.middleware.LoginRequiredMiddleware",
    "accounts.middleware.ForcePasswordChangeMiddleware",
    "django.contrib.messages.middleware.MessageMiddleware",
    "django.middleware.clickjacking.XFrameOptionsMiddleware",
]

ROOT_URLCONF = "config.urls"
WSGI_APPLICATION = "config.wsgi.application"

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

if env("POSTGRES_HOST"):
    DATABASES = {
        "default": {
            "ENGINE": "django.db.backends.postgresql",
            "HOST": env("POSTGRES_HOST"),
            "PORT": env("POSTGRES_PORT", "5432"),
            "NAME": env("POSTGRES_DB", "kochbuch"),
            "USER": env("POSTGRES_USER", "kochbuch"),
            "PASSWORD": env("POSTGRES_PASSWORD"),
            "CONN_MAX_AGE": 60,
            "CONN_HEALTH_CHECKS": True,
        }
    }
else:
    # Local development and tests without Docker.
    DATABASES = {"default": {"ENGINE": "django.db.backends.sqlite3", "NAME": BASE_DIR / "db.sqlite3"}}

DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"

AUTH_USER_MODEL = "accounts.User"
LOGIN_URL = "accounts:login"
LOGIN_REDIRECT_URL = "recipes:list"
LOGOUT_REDIRECT_URL = "accounts:login"

PASSWORD_HASHERS = [
    "django.contrib.auth.hashers.Argon2PasswordHasher",
    "django.contrib.auth.hashers.PBKDF2PasswordHasher",
]
AUTH_PASSWORD_VALIDATORS = [
    {"NAME": "django.contrib.auth.password_validation.UserAttributeSimilarityValidator"},
    {"NAME": "django.contrib.auth.password_validation.MinimumLengthValidator", "OPTIONS": {"min_length": 10}},
    {"NAME": "django.contrib.auth.password_validation.CommonPasswordValidator"},
    {"NAME": "django.contrib.auth.password_validation.NumericPasswordValidator"},
]

LOGIN_MAX_FAILURES_PER_EMAIL = env_int("LOGIN_MAX_FAILURES_PER_EMAIL", 5)
LOGIN_MAX_FAILURES_PER_IP = env_int("LOGIN_MAX_FAILURES_PER_IP", 30)
LOGIN_LOCKOUT_MINUTES = env_int("LOGIN_LOCKOUT_MINUTES", 15)

IMAGE_MAX_UPLOAD_MB = env_int("IMAGE_MAX_UPLOAD_MB", 15)
IMAGE_MAX_PER_RECIPE = env_int("IMAGE_MAX_PER_RECIPE", 10)
COMMENT_RATE_LIMIT_PER_HOUR = env_int("COMMENT_RATE_LIMIT_PER_HOUR", 30)
# Request body limit for non-file fields; files are limited per image above.
DATA_UPLOAD_MAX_MEMORY_SIZE = 5 * 1024 * 1024

# --- AI (OpenAI) -------------------------------------------------------------------
OPENAI_API_KEY = env("OPENAI_API_KEY")
OPENAI_MODEL = env("OPENAI_MODEL", "gpt-5-mini")
# For reasoning models (gpt-5*, o*): minimal|low|medium|high. Leave empty for other models.
OPENAI_REASONING_EFFORT = env("OPENAI_REASONING_EFFORT", "low")
OPENAI_TIMEOUT = env_int("OPENAI_TIMEOUT", 90)
# 0 = unlimited (default). Counted per call, including failed ones.
AI_RATE_LIMIT_PER_USER_PER_DAY = env_int("AI_RATE_LIMIT_PER_USER_PER_DAY", 0)
AI_RATE_LIMIT_GLOBAL_PER_DAY = env_int("AI_RATE_LIMIT_GLOBAL_PER_DAY", 0)

INVITATION_VALID_DAYS = 7
PASSWORD_RESET_VALID_HOURS = 24

# --- Cookies & security headers ---------------------------------------------
COOKIE_SECURE = env_bool("COOKIE_SECURE", default=True)
SESSION_COOKIE_SECURE = COOKIE_SECURE
CSRF_COOKIE_SECURE = COOKIE_SECURE
# The __Host- prefix pins the cookie to this exact host; browsers only accept it over HTTPS.
SESSION_COOKIE_NAME = "__Host-kb_session" if COOKIE_SECURE else "kb_session"
CSRF_COOKIE_NAME = "__Host-kb_csrf" if COOKIE_SECURE else "kb_csrf"
SESSION_COOKIE_HTTPONLY = True
SESSION_COOKIE_SAMESITE = "Lax"
CSRF_COOKIE_SAMESITE = "Lax"
SESSION_COOKIE_AGE = 60 * 60 * 24 * 30

SECURE_PROXY_SSL_HEADER = ("HTTP_X_FORWARDED_PROTO", "https")
SECURE_HSTS_SECONDS = env_int("HSTS_SECONDS", 31536000)
SECURE_CONTENT_TYPE_NOSNIFF = True
SECURE_REFERRER_POLICY = "same-origin"
SECURE_CROSS_ORIGIN_OPENER_POLICY = "same-origin"
X_FRAME_OPTIONS = "DENY"
# The reverse proxy redirects to HTTPS; HSTS for other subdomains/preload is the domain owner's call.
SILENCED_SYSTEM_CHECKS = ["security.W005", "security.W008", "security.W021"]

CONTENT_SECURITY_POLICY = (
    "default-src 'self'; img-src 'self' data: blob:; style-src 'self'; script-src 'self'; "
    "font-src 'self'; connect-src 'self'; object-src 'none'; base-uri 'self'; "
    "form-action 'self'; frame-ancestors 'none'"
)
PERMISSIONS_POLICY = "camera=(), microphone=(), geolocation=(), payment=(), usb=(), screen-wake-lock=(self)"

# --- I18N ----------------------------------------------------------------------
LANGUAGE_CODE = "de"
TIME_ZONE = env("TIME_ZONE", "Europe/Berlin")
USE_I18N = True
USE_TZ = True

# --- Static & media --------------------------------------------------------------
STATIC_URL = "/static/"
STATIC_ROOT = BASE_DIR / "staticfiles"
STATICFILES_DIRS = [BASE_DIR / "static"]
STORAGES = {
    "default": {"BACKEND": "django.core.files.storage.FileSystemStorage"},
    "staticfiles": {"BACKEND": "whitenoise.storage.CompressedManifestStaticFilesStorage"},
}
# Uploaded files are never served directly; they go through permission-checked views.
MEDIA_ROOT = Path(env("MEDIA_ROOT", str(BASE_DIR / "data" / "media")))

LOGGING = {
    "version": 1,
    "disable_existing_loggers": False,
    "handlers": {"console": {"class": "logging.StreamHandler"}},
    "root": {"handlers": ["console"], "level": "INFO"},
    "loggers": {"django.request": {"level": "WARNING"}},
}