import json
import logging
from ipaddress import ip_network
from pathlib import Path

from decouple import Csv, config
from django.core.exceptions import ImproperlyConfigured


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

SECRET_KEY = config("DJANGO_SECRET_KEY", default="unsafe-development-secret-key")
DEBUG = config("DEBUG", default=False, cast=bool)
ALLOWED_HOSTS = config("ALLOWED_HOSTS", default="localhost,127.0.0.1", cast=Csv())

INSTALLED_APPS = [
    "django.contrib.admin",
    "django.contrib.auth",
    "django.contrib.contenttypes",
    "django.contrib.sessions",
    "django.contrib.messages",
    "django.contrib.staticfiles",
    "corsheaders",
    "rest_framework",
    "chat",
]

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

ROOT_URLCONF = "config.urls"

TEMPLATES = [
    {
        "BACKEND": "django.template.backends.django.DjangoTemplates",
        "DIRS": [],
        "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 = "config.wsgi.application"
ASGI_APPLICATION = "config.asgi.application"

# Em producao use PostgreSQL (USE_POSTGRES=true). SQLite fica para desenvolvimento local.
USE_POSTGRES = config("USE_POSTGRES", default=False, cast=bool)

if USE_POSTGRES:
    DATABASES = {
        "default": {
            "ENGINE": "django.db.backends.postgresql",
            "NAME": config("POSTGRES_DB"),
            "USER": config("POSTGRES_USER"),
            "PASSWORD": config("POSTGRES_PASSWORD"),
            "HOST": config("POSTGRES_HOST", default="127.0.0.1"),
            "PORT": config("POSTGRES_PORT", default="5432"),
            "OPTIONS": {"connect_timeout": 10},
        }
    }
else:
    DATABASES = {
        "default": {
            "ENGINE": "django.db.backends.sqlite3",
            "NAME": config("SQLITE_PATH", default=str(BASE_DIR / "db.sqlite3")),
        }
    }

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 = "pt-br"
TIME_ZONE = config("TIME_ZONE", default="UTC")
USE_I18N = True
USE_TZ = True

STATIC_URL = "static/"
STATIC_ROOT = BASE_DIR / "staticfiles"

DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"

CORS_ALLOWED_ORIGINS = config("CORS_ALLOWED_ORIGINS", default="", cast=Csv())
CORS_ALLOW_CREDENTIALS = config("CORS_ALLOW_CREDENTIALS", default=False, cast=bool)

OPENAI_API_KEY = config("OPENAI_API_KEY", default="")
OPENAI_MODEL = config("OPENAI_MODEL", default="gpt-5-nano")
OPENAI_TIMEOUT = config("OPENAI_TIMEOUT", default=30, cast=int)
OPENAI_MAX_OUTPUT_TOKENS = config("OPENAI_MAX_OUTPUT_TOKENS", default=600, cast=int)

INTERNAL_API_KEY = config("INTERNAL_API_KEY", default="change-me")


def _load_internal_api_allowed_networks():
    """
    Lista vazia = não restringe por IP (só API key). Em produção atrás de firewall ou Docker,
    defina CIDRs (ex.: 172.16.0.0/12,127.0.0.1/32).
    """
    raw = config("INTERNAL_API_ALLOWED_CIDRS", default="", cast=Csv())
    networks = []
    for item in raw:
        item = (item or "").strip()
        if not item:
            continue
        try:
            networks.append(ip_network(item, strict=False))
        except ValueError as e:
            raise ImproperlyConfigured(
                f"INTERNAL_API_ALLOWED_CIDRS contém CIDR inválido: {item!r}"
            ) from e
    return networks


INTERNAL_API_ALLOWED_NETWORKS = _load_internal_api_allowed_networks()
INTERNAL_API_TRUST_X_FORWARDED_FOR = config(
    "INTERNAL_API_TRUST_X_FORWARDED_FOR",
    default=False,
    cast=bool,
)
CHAT_SYSTEM_PROMPT = config(
    "CHAT_SYSTEM_PROMPT",
    default="Você é um especialista em seguros e responde de forma clara, objetiva e segura.",
)
MAX_QUESTION_LENGTH = config("MAX_QUESTION_LENGTH", default=2000, cast=int)

REST_FRAMEWORK = {
    "DEFAULT_AUTHENTICATION_CLASSES": [
        "chat.api.authentication.ServiceAPIKeyAuthentication",
    ],
    "DEFAULT_PERMISSION_CLASSES": [
        "rest_framework.permissions.IsAuthenticated",
    ],
    "DEFAULT_THROTTLE_CLASSES": [
        "rest_framework.throttling.AnonRateThrottle",
        "rest_framework.throttling.UserRateThrottle",
        "rest_framework.throttling.ScopedRateThrottle",
    ],
    "DEFAULT_THROTTLE_RATES": {
        "anon": config("API_THROTTLE_ANON", default="10/minute"),
        "user": config("API_THROTTLE_USER", default="60/minute"),
        "chat": config("API_THROTTLE_CHAT", default="30/minute"),
    },
    "EXCEPTION_HANDLER": "chat.api.exceptions.custom_exception_handler",
}

LOG_LEVEL = config("LOG_LEVEL", default="INFO")
DJANGO_LOG_LEVEL = config("DJANGO_LOG_LEVEL", default="WARNING")


class JsonFormatter(logging.Formatter):
    def format(self, record):
        payload = {
            "level": record.levelname,
            "logger": record.name,
            "message": record.getMessage(),
            "module": record.module,
        }
        if record.exc_info:
            payload["exception"] = self.formatException(record.exc_info)
        return json.dumps(payload, ensure_ascii=True)


LOGGING = {
    "version": 1,
    "disable_existing_loggers": False,
    "formatters": {
        "json": {
            "()": JsonFormatter,
        }
    },
    "handlers": {
        "console": {
            "class": "logging.StreamHandler",
            "formatter": "json",
        }
    },
    "root": {
        "handlers": ["console"],
        "level": LOG_LEVEL,
    },
    "loggers": {
        "django": {
            "handlers": ["console"],
            "level": DJANGO_LOG_LEVEL,
            "propagate": False,
        },
        "chat": {
            "handlers": ["console"],
            "level": LOG_LEVEL,
            "propagate": False,
        },
    },
}