import os
from datetime import timedelta
from pathlib import Path
import dj_database_url
from dotenv import load_dotenv

load_dotenv()

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

# SECURITY: Use environment variable for SECRET_KEY in production
SECRET_KEY = os.environ.get('SECRET_KEY', 'django-insecure-change-me-in-production')

DEBUG = os.environ.get('DEBUG', 'False').lower() == 'true'

ALLOWED_HOSTS = os.environ.get('ALLOWED_HOSTS', '*').split(',')

REST_FRAMEWORK = {
    "DEFAULT_AUTHENTICATION_CLASSES": [
        "rest_framework_simplejwt.authentication.JWTAuthentication"
    ],
    "DEFAULT_PERMISSION_CLASSES": [
        "rest_framework.permissions.IsAuthenticated"
    ]
}

SIMPLE_JWT = {
    "ACCESS_TOKEN_LIFETIME": timedelta(minutes=30),
    "REFRESH_TOKEN_LIFETIME": timedelta(days=1),
}

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'api.apps.ApiConfig',
    'rest_framework',
    'corsheaders',
]

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

SESSION_COOKIE_AGE = 3600
SESSION_EXPIRE_AT_BROWSER_CLOSE = True
SESSION_ENGINE = 'django.contrib.sessions.backends.signed_cookies'

ROOT_URLCONF = 'nexus.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 = 'nexus.wsgi.application'

# Database configuration via environment variable
DATABASES = {
    'default': dj_database_url.config(
        default=os.environ.get("PSQL"),
        conn_max_age=600
    )
}

# Redis configuration (optional)
REDIS_URL = os.environ.get('REDIS')

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'},
]

LANGUAGE_CODE = 'en-us'
TIME_ZONE = 'America/Detroit'
USE_I18N = True
USE_TZ = True

STATIC_URL = '/assets/'
STATIC_ROOT = os.path.join(BASE_DIR, 'static')
STATICFILES_STORAGE = 'whitenoise.storage.CompressedManifestStaticFilesStorage'

DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

# CORS Configuration
CORS_ALLOW_ALL_ORIGINS = os.environ.get('CORS_ALLOW_ALL', 'False').lower() == 'true'
CORS_ALLOWED_ORIGINS = [
    origin.strip()
    for origin in os.environ.get('CORS_ALLOWED_ORIGINS', 'http://localhost:5173').split(',')
    if origin.strip()
]
CORS_ALLOW_CREDENTIALS = True

# CSRF Configuration
CSRF_TRUSTED_ORIGINS = [
    origin.strip()
    for origin in os.environ.get('CSRF_TRUSTED_ORIGINS', 'http://localhost:5173').split(',')
    if origin.strip()
]

# Security settings for production
if not DEBUG:
    SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTO', 'https')
    SECURE_SSL_REDIRECT = True
    SESSION_COOKIE_SECURE = True
    CSRF_COOKIE_SECURE = True