"""
Configuración central de la aplicación.

Utiliza Pydantic BaseSettings para cargar variables de entorno
con validación de tipos y valores por defecto.
"""

from functools import lru_cache
from typing import Any, List, Optional

from pydantic import PostgresDsn, field_validator, model_validator
from pydantic_settings import BaseSettings, SettingsConfigDict


class Settings(BaseSettings):
    """Configuración de la aplicación cargada desde variables de entorno."""

    model_config = SettingsConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
        case_sensitive=False,
        extra="ignore",
    )

    # Aplicación
    APP_NAME: str = "Atlas Fleet Monitor"
    APP_VERSION: str = "1.0.0"
    DEBUG: bool = False
    ENVIRONMENT: str = "development"
    API_V1_PREFIX: str = "/api/v1"

    # Servidor
    HOST: str = "0.0.0.0"
    PORT: int = 8000
    WORKERS: int = 4

    # Base de datos PostgreSQL/TimescaleDB
    POSTGRES_HOST: str = "localhost"
    POSTGRES_PORT: int = 5432
    POSTGRES_USER: str = "atlas"
    POSTGRES_PASSWORD: str = "atlas_secret"
    POSTGRES_DB: str = "atlas_fleet"
    DATABASE_URL: Optional[str] = None
    DATABASE_POOL_SIZE: int = 20
    DATABASE_MAX_OVERFLOW: int = 10

    @model_validator(mode="after")
    def build_database_url(self) -> "Settings":
        """Construye la URL de conexión a la base de datos."""
        if not self.DATABASE_URL:
            self.DATABASE_URL = (
                f"postgresql+asyncpg://{self.POSTGRES_USER}:{self.POSTGRES_PASSWORD}"
                f"@{self.POSTGRES_HOST}:{self.POSTGRES_PORT}/{self.POSTGRES_DB}"
            )
        return self

    # Redis
    REDIS_HOST: str = "localhost"
    REDIS_PORT: int = 6379
    REDIS_DB: int = 0
    REDIS_PASSWORD: Optional[str] = None
    REDIS_URL: Optional[str] = None

    @model_validator(mode="after")
    def build_redis_url(self) -> "Settings":
        """Construye la URL de conexión a Redis."""
        if not self.REDIS_URL:
            password_part = f":{self.REDIS_PASSWORD}@" if self.REDIS_PASSWORD else ""
            self.REDIS_URL = f"redis://{password_part}{self.REDIS_HOST}:{self.REDIS_PORT}/{self.REDIS_DB}"
        return self

    # Seguridad JWT
    SECRET_KEY: str = "your-super-secret-key-change-in-production"
    ALGORITHM: str = "HS256"
    ACCESS_TOKEN_EXPIRE_MINUTES: int = 30
    REFRESH_TOKEN_EXPIRE_DAYS: int = 7

    # CORS
    CORS_ORIGINS: List[str] = ["http://localhost:3000", "http://localhost:5173"]
    CORS_ALLOW_CREDENTIALS: bool = True
    CORS_ALLOW_METHODS: List[str] = ["*"]
    CORS_ALLOW_HEADERS: List[str] = ["*"]

    @field_validator("CORS_ORIGINS", mode="before")
    @classmethod
    def parse_cors_origins(cls, v: Any) -> List[str]:
        """Parsea los orígenes CORS desde string separado por comas."""
        if isinstance(v, str):
            return [origin.strip() for origin in v.split(",")]
        return v

    # Traccar Integration
    TRACCAR_HOST: str = "localhost"
    TRACCAR_PORT: int = 5055
    TRACCAR_API_URL: str = "http://localhost:8082/api"
    TRACCAR_USERNAME: Optional[str] = None
    TRACCAR_PASSWORD: Optional[str] = None

    # MediaMTX Video Server
    MEDIAMTX_HOST: str = "localhost"
    MEDIAMTX_API_PORT: int = 9997
    MEDIAMTX_RTSP_PORT: int = 8554
    MEDIAMTX_WEBRTC_PORT: int = 8889

    # Meshtastic
    MESHTASTIC_ENABLED: bool = False
    MESHTASTIC_SERIAL_PORT: Optional[str] = None
    MESHTASTIC_TCP_HOST: Optional[str] = None
    MESHTASTIC_TCP_PORT: int = 4403

    # MQTT (para dispositivos IoT)
    MQTT_ENABLED: bool = False
    MQTT_HOST: str = "localhost"
    MQTT_PORT: int = 1883
    MQTT_USERNAME: Optional[str] = None
    MQTT_PASSWORD: Optional[str] = None
    MQTT_TOPIC_LOCATIONS: str = "atlas/locations/#"
    MQTT_TOPIC_ALERTS: str = "atlas/alerts/#"

    # Email (notificaciones)
    SMTP_HOST: str = "localhost"
    SMTP_PORT: int = 587
    SMTP_USER: Optional[str] = None
    SMTP_PASSWORD: Optional[str] = None
    SMTP_FROM_EMAIL: str = "noreply@atlas-fleet.com"
    SMTP_FROM_NAME: str = "Atlas Fleet Monitor"
    SMTP_TLS: bool = True

    # Push Notifications (Firebase)
    FIREBASE_CREDENTIALS_PATH: Optional[str] = None
    FIREBASE_ENABLED: bool = False

    # Almacenamiento de archivos
    UPLOAD_DIR: str = "/var/lib/atlas/uploads"
    MAX_UPLOAD_SIZE_MB: int = 100
    ALLOWED_IMAGE_TYPES: List[str] = ["image/jpeg", "image/png", "image/webp"]
    ALLOWED_VIDEO_TYPES: List[str] = ["video/mp4", "video/webm"]

    # Reportes
    REPORTS_DIR: str = "/var/lib/atlas/reports"
    REPORT_RETENTION_DAYS: int = 90

    # Geocoding
    GEOCODING_PROVIDER: str = "nominatim"  # nominatim, google, mapbox
    GOOGLE_MAPS_API_KEY: Optional[str] = None
    MAPBOX_ACCESS_TOKEN: Optional[str] = None

    # Alertas y umbrales
    ALERT_SPEED_LIMIT_DEFAULT: int = 120  # km/h
    ALERT_IDLE_MINUTES: int = 15
    ALERT_BATTERY_LOW_PERCENT: int = 20
    ALERT_NO_SIGNAL_MINUTES: int = 30

    # Limpieza de datos
    LOCATION_RETENTION_DAYS: int = 365
    ALERT_RETENTION_DAYS: int = 180
    VIDEO_RETENTION_DAYS: int = 30

    # Logging
    LOG_LEVEL: str = "INFO"
    LOG_FORMAT: str = "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
    LOG_FILE: Optional[str] = None


@lru_cache()
def get_settings() -> Settings:
    """
    Obtiene la instancia de configuración (singleton cacheado).

    Returns:
        Settings: Instancia de configuración de la aplicación.
    """
    return Settings()


# Instancia global de configuración
settings = get_settings()