from pydantic_settings import BaseSettings, SettingsConfigDict
from typing import Optional
import os


class AppSettings(BaseSettings):
    """应用配置"""
    
    # 基础配置
    app_name: str = "xiaoxia-saas"
    app_env: str = "development"  # development / staging / production
    app_version: str = "0.1.0"
    debug: bool = True
    
    # API 配置
    api_host: str = "0.0.0.0"
    api_port: int = 8000
    api_prefix: str = "/api/v1"
    
    # 数据库配置
    database_url: str = "postgresql+psycopg://postgres:postgres@localhost:5432/xiaoxia_saas"
    database_pool_size: int = 20
    database_max_overflow: int = 40
    database_pool_timeout: int = 30
    database_pool_recycle: int = 3600
    
    # Redis 配置
    redis_url: str = "redis://localhost:6379/0"
    redis_max_connections: int = 50
    
    # Celery 配置
    celery_broker_url: str = "redis://localhost:6379/0"
    celery_result_backend: str = "redis://localhost:6379/1"
    celery_worker_concurrency: int = 4
    celery_worker_max_tasks_per_child: int = 1000
    
    # MinIO 配置
    minio_endpoint: str = "localhost:9000"
    minio_access_key: str = "admin"
    minio_secret_key: str = "xiaoxia2026"
    minio_bucket: str = "xiaoxia-assets"
    minio_secure: bool = False
    minio_public_url: str = "http://localhost:9000"
    
    # 日志配置
    log_level: str = "INFO"
    log_format: str = "json"  # json / text
    log_file: Optional[str] = None
    
    # CORS 配置
    cors_origins: str = "http://localhost:3000,http://localhost:8000"
    cors_allow_credentials: bool = True
    
    # 文件上传限制
    max_upload_size_mb: int = 1000
    allowed_file_types: str = "video/mp4,video/quicktime,video/x-msvideo,audio/mpeg,audio/wav,image/jpeg,image/png,image/gif"
    
    # 安全配置
    secret_key: str = "change-me-in-production"
    access_token_expire_minutes: int = 60
    refresh_token_expire_days: int = 7
    
    # 监控配置（可选）
    sentry_dsn: Optional[str] = None
    prometheus_port: Optional[int] = None
    
    model_config = SettingsConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
        case_sensitive=False,
        extra="ignore",
    )
    
    @property
    def cors_origins_list(self) -> list[str]:
        """解析 CORS origins 为列表"""
        return [origin.strip() for origin in self.cors_origins.split(",")]
    
    @property
    def allowed_file_types_list(self) -> list[str]:
        """解析允许的文件类型为列表"""
        return [ft.strip() for ft in self.allowed_file_types.split(",")]
    
    @property
    def is_production(self) -> bool:
        """是否为生产环境"""
        return self.app_env == "production"
    
    @property
    def is_staging(self) -> bool:
        """是否为 staging 环境"""
        return self.app_env == "staging"
    
    @property
    def is_development(self) -> bool:
        """是否为开发环境"""
        return self.app_env == "development"


# 全局配置实例
_settings: Optional[AppSettings] = None


def get_settings() -> AppSettings:
    """获取配置实例（单例模式）"""
    global _settings
    if _settings is None:
        # 根据环境加载不同的 .env 文件
        env = os.getenv("APP_ENV", "development")
        env_file = f".env.{env}" if env != "development" else ".env"
        
        # 如果环境特定的配置文件存在，则使用它
        if os.path.exists(env_file):
            _settings = AppSettings(_env_file=env_file)
        else:
            _settings = AppSettings()
    
    return _settings


def reload_settings():
    """重新加载配置（用于测试）"""
    global _settings
    _settings = None
    return get_settings()