"""Django settings for the FablePool backend.

Configuration is environment-driven (twelve-factor): every deployment-specific value
reads from an environment variable with a development-safe default. Production
deployments MUST set FABLEPOOL_SECRET_KEY and FABLEPOOL_DEBUG=false.
"""

from __future__ import annotations

import os
from pathlib import Path

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


def _env_bool(name: str, default: bool) -> bool:
    raw = os.environ.get(name)
    if raw is None:
        return default
    return raw.strip().lower() in {"1", "true", "yes", "on"}


def _env_list(name: str, default: list[str]) -> list[str]:
    raw = os.environ.get(name)
    if raw is None:
        return default
    return [item.strip() for item in raw.split(",") if item.strip()]


# --------------------------------------------------------------------------- core

SECRET_KEY = os.environ.get(
    "FABLEPOOL_SECRET_KEY",
    "dev-only-insecure-key-do-not-use-in-production",
)
DEBUG = _env_bool("FABLEPOOL_DEBUG", True)
ALLOWED_HOSTS = _env_list("FABLEPOOL_ALLOWED_HOSTS", ["localhost", "127.0.0.1"])

INSTALLED_APPS = [
    "django.contrib.admin",
    "django.contrib.auth",
    "django.contrib.contenttypes",
    "django.contrib.sessions",
    "django.contrib.messages",
    "django.contrib.staticfiles",
    "django.contrib.postgres",
    "rest_framework",
    # FablePool apps
    "apps.core",
    "apps.accounts",
    "apps.taxonomy",
    "apps.content",
    "apps.learning",
    "apps.community",
]

MIDDLEWARE = [
    "django.middleware.security.SecurityMiddleware",
    "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",
]

ROOT_URLCONF = "fablepool.urls"

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",
            ],
        },
    },
]

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

# --------------------------------------------------------------------------- database

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": os.environ.get("FABLEPOOL_DB_NAME", "fablepool"),
        "USER": os.environ.get("FABLEPOOL_DB_USER", "fablepool"),
        "PASSWORD": os.environ.get("FABLEPOOL_DB_PASSWORD", "fablepool"),
        "HOST": os.environ.get("FABLEPOOL_DB_HOST", "localhost"),
        "PORT": os.environ.get("FABLEPOOL_DB_PORT", "5432"),
        "CONN_MAX_AGE": int(os.environ.get("FABLEPOOL_DB_CONN_MAX_AGE", "60")),
    }
}

DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"

# --------------------------------------------------------------------------- auth

AUTH_USER_MODEL = "accounts.User"

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"},
]

# --------------------------------------------------------------------------- i18n

LANGUAGE_CODE = "en"
TIME_ZONE = "UTC"
USE_I18N = True
USE_TZ = True

# --------------------------------------------------------------------------- static & media

STATIC_URL = "static/"
STATIC_ROOT = BASE_DIR / "staticfiles"
MEDIA_URL = "media/"
MEDIA_ROOT = BASE_DIR / "mediafiles"

# In production point DEFAULT file storage at S3/MinIO via the STORAGES setting
# (django-storages); the development default keeps everything on local disk so a
# clean checkout works without object storage.

# --------------------------------------------------------------------------- caching

CACHES = {
    "default": {
        # Development default; production deployments swap this for
        # django.core.cache.backends.redis.RedisCache via FABLEPOOL_REDIS_URL.
        "BACKEND": "django.core.cache.backends.locmem.LocMemCache",
    }
}
_redis_url = os.environ.get("FABLEPOOL_REDIS_URL")
if _redis_url:
    CACHES["default"] = {
        "BACKEND": "django.core.cache.backends.redis.RedisCache",
        "LOCATION": _redis_url,
    }

# --------------------------------------------------------------------------- DRF

REST_FRAMEWORK = {
    "DEFAULT_AUTHENTICATION_CLASSES": [
        "rest_framework.authentication.SessionAuthentication",
        "rest_framework.authentication.TokenAuthentication",
    ],
    "DEFAULT_PERMISSION_CLASSES": [
        "rest_framework.permissions.IsAuthenticatedOrReadOnly",
    ],
    "DEFAULT_PAGINATION_CLASS": "rest_framework.pagination.CursorPagination",
    "PAGE_SIZE": 20,
    "DEFAULT_THROTTLE_CLASSES": [
        "rest_framework.throttling.AnonRateThrottle",
        "rest_framework.throttling.UserRateThrottle",
    ],
    "DEFAULT_THROTTLE_RATES": {
        # Matches the rate-limit tiers documented in docs/api-conventions.md
        # and advertised via X-RateLimit-* headers in api/openapi.yaml.
        "anon": "60/min",
        "user": "240/min",
    },
    "DEFAULT_RENDERER_CLASSES": [
        "rest_framework.renderers.JSONRenderer",
    ],
    "EXCEPTION_HANDLER": "rest_framework.views.exception_handler",
}

# --------------------------------------------------------------------------- FablePool

# Directory containing the canonical JSON Schemas for structured content documents.
FABLEPOOL_SCHEMA_DIR = BASE_DIR / "schemas" / "v1"
# Default content license applied to new containers (SPDX identifier).
FABLEPOOL_DEFAULT_CONTENT_LICENSE = "CC-BY-SA-4.0"

# --------------------------------------------------------------------------- logging

LOGGING = {
    "version": 1,
    "disable_existing_loggers": False,
    "formatters": {
        "simple": {"format": "{levelname} {asctime} {name} {message}", "style": "{"},
    },
    "handlers": {
        "console": {"class": "logging.StreamHandler", "formatter": "simple"},
    },
    "root": {"handlers": ["console"], "level": os.environ.get("FABLEPOOL_LOG_LEVEL", "INFO")},
}