"""
Core Configuration - ServiceManagerWeb

Configuración centralizada usando Pydantic Settings v2
"""

from functools import lru_cache
from typing import List, Optional
from pydantic_settings import BaseSettings
from pydantic import field_validator, Field
import os


class Settings(BaseSettings):
    """Configuración de la aplicación."""
    
    model_config = {
        "env_file": ".env",
        "env_file_encoding": "utf-8",
        "case_sensitive": False
    }
    
    # ===================================
    # GENERAL
    # ===================================
    ENVIRONMENT: str = Field(default="development", env="ENVIRONMENT")
    DEBUG: bool = Field(default=False, env="DEBUG")
    SECRET_KEY: str = Field(..., env="SECRET_KEY")
    API_VERSION: str = Field(default="v1", env="API_VERSION")
    
    # ===================================
    # DATABASE
    # ===================================
    DATABASE_URL: str = Field(..., env="DATABASE_URL")
    
    # ===================================
    # REDIS
    # ===================================
    REDIS_URL: str = Field(..., env="REDIS_URL")
    
    # ===================================
    # JWT AUTHENTICATION
    # ===================================
    JWT_SECRET_KEY: str = Field(..., env="JWT_SECRET_KEY")
    JWT_ALGORITHM: str = Field(default="HS256", env="JWT_ALGORITHM")
    ACCESS_TOKEN_EXPIRE_MINUTES: int = Field(default=60, env="ACCESS_TOKEN_EXPIRE_MINUTES")
    REFRESH_TOKEN_EXPIRE_DAYS: int = Field(default=7, env="REFRESH_TOKEN_EXPIRE_DAYS")
    
    # ===================================
    # CORS
    # ===================================
    CORS_ORIGINS: str = Field(
        default="http://localhost:3000,http://localhost:3001",
        env="CORS_ORIGINS"
    )
    
    # ===================================
    # EMAIL
    # ===================================
    SMTP_HOST: str = Field(default="localhost", env="SMTP_HOST")
    SMTP_PORT: int = Field(default=587, env="SMTP_PORT")
    SMTP_USER: Optional[str] = Field(default=None, env="SMTP_USER")
    SMTP_PASSWORD: Optional[str] = Field(default=None, env="SMTP_PASSWORD")
    SMTP_USE_TLS: bool = Field(default=True, env="SMTP_USE_TLS")
    SMTP_USE_SSL: bool = Field(default=False, env="SMTP_USE_SSL")
    
    DEFAULT_FROM_EMAIL: str = Field(default="noreply@servicemanager.local", env="DEFAULT_FROM_EMAIL")
    DEFAULT_FROM_NAME: str = Field(default="ServiceManager", env="DEFAULT_FROM_NAME")
    
    # ===================================
    # FILE UPLOADS
    # ===================================
    MAX_UPLOAD_SIZE_MB: int = Field(default=10, env="MAX_UPLOAD_SIZE_MB")
    ALLOWED_FILE_EXTENSIONS: List[str] = Field(
        default=["pdf", "jpg", "jpeg", "png", "doc", "docx", "xls", "xlsx", "txt"],
        env="ALLOWED_FILE_EXTENSIONS"
    )
    UPLOAD_PATH: str = Field(default="/app/uploads", env="UPLOAD_PATH")
    
    @field_validator("ALLOWED_FILE_EXTENSIONS", mode='before')
    @classmethod
    def validate_file_extensions(cls, v):
        if isinstance(v, str):
            return [ext.strip().lower() for ext in v.split(",")]
        return [ext.lower() for ext in v]
    
    # ===================================
    # SECURITY
    # ===================================
    RATE_LIMIT_ENABLED: bool = Field(default=True, env="RATE_LIMIT_ENABLED")
    PASSWORD_MIN_LENGTH: int = Field(default=8, env="PASSWORD_MIN_LENGTH")
    
    # Argon2 settings
    ARGON2_TIME_COST: int = Field(default=3, env="ARGON2_TIME_COST")
    ARGON2_MEMORY_COST: int = Field(default=65536, env="ARGON2_MEMORY_COST")
    ARGON2_PARALLELISM: int = Field(default=4, env="ARGON2_PARALLELISM")
    
    # ===================================
    # LOGGING
    # ===================================
    LOG_LEVEL: str = Field(default="INFO", env="LOG_LEVEL")
    LOG_FORMAT: str = Field(default="json", env="LOG_FORMAT")
    LOG_FILE: Optional[str] = Field(default=None, env="LOG_FILE")
    
    # ===================================
    # FRONTEND URLS
    # ===================================
    CLIENT_FRONTEND_URL: str = Field(default="http://localhost:3000", env="CLIENT_FRONTEND_URL")
    INTERNAL_FRONTEND_URL: str = Field(default="http://localhost:3001", env="INTERNAL_FRONTEND_URL")
    
    # ===================================
    # HEALTH CHECKS
    # ===================================
    HEALTH_CHECK_TIMEOUT: int = Field(default=30, env="HEALTH_CHECK_TIMEOUT")
    
    # ===================================
    # CELERY
    # ===================================
    CELERY_BROKER_URL: str = Field(..., env="CELERY_BROKER_URL")
    CELERY_RESULT_BACKEND: str = Field(..., env="CELERY_RESULT_BACKEND")
    
    def is_production(self) -> bool:
        """Check if environment is production."""
        return self.ENVIRONMENT.lower() == "production"
    
    def is_development(self) -> bool:
        """Check if environment is development."""
        return self.ENVIRONMENT.lower() == "development"
    
    def is_testing(self) -> bool:
        """Check if environment is testing."""
        return self.ENVIRONMENT.lower() == "testing"


@lru_cache()
def get_settings() -> Settings:
    """
    Get cached settings instance.
    
    Using lru_cache to create a singleton pattern for settings.
    """
    return Settings()