//! SaaS 错误类型

use axum::http::StatusCode;
use axum::response::{IntoResponse, Response};
use serde_json::json;

/// SaaS 服务错误类型
#[derive(Debug, thiserror::Error)]
pub enum SaasError {
    #[error("未找到: {0}")]
    NotFound(String),

    #[error("权限不足: {0}")]
    Forbidden(String),

    #[error("未认证")]
    Unauthorized,

    #[error("无效输入: {0}")]
    InvalidInput(String),

    #[error("认证失败: {0}")]
    AuthError(String),

    #[error("用户已存在: {0}")]
    AlreadyExists(String),

    #[error("序列化错误: {0}")]
    Serialization(#[from] serde_json::Error),

    #[error("IO 错误: {0}")]
    Io(#[from] std::io::Error),

    #[error("数据库错误: {0}")]
    Database(#[from] sqlx::Error),

    #[error("配置错误: {0}")]
    Config(#[from] toml::de::Error),

    #[error("JWT 错误: {0}")]
    Jwt(#[from] jsonwebtoken::errors::Error),

    #[error("密码哈希错误: {0}")]
    PasswordHash(String),

    #[error("TOTP 错误: {0}")]
    Totp(String),

    #[error("加密错误: {0}")]
    Encryption(String),

    #[error("中转错误: {0}")]
    Relay(String),

    #[error("通用错误: {0}")]
    General(#[from] anyhow::Error),


    #[error("速率限制: {0}")]
    RateLimited(String),

    #[error("内部错误: {0}")]
    Internal(String),
}

impl SaasError {
    /// 将 sqlx::Error 中的 unique violation 映射为 AlreadyExists (409)，
    /// 其他 DB 错误保持为 Database (500)。
    pub fn from_sqlx_unique(e: sqlx::Error, context: &str) -> Self {
        if let sqlx::Error::Database(ref db_err) = e {
            // PostgreSQL unique_violation = "23505"
            if db_err.code().map(|c| c == "23505").unwrap_or(false) {
                return Self::AlreadyExists(format!("{}已存在", context));
            }
        }
        Self::Database(e)
    }

    /// 获取 HTTP 状态码
    pub fn status_code(&self) -> StatusCode {
        match self {
            Self::NotFound(_) => StatusCode::NOT_FOUND,
            Self::Forbidden(_) => StatusCode::FORBIDDEN,
            Self::Unauthorized => StatusCode::UNAUTHORIZED,
            Self::InvalidInput(_) => StatusCode::BAD_REQUEST,
            Self::AlreadyExists(_) => StatusCode::CONFLICT,
            Self::RateLimited(_) => StatusCode::TOO_MANY_REQUESTS,
            Self::Database(_) | Self::Internal(_) | Self::Io(_) | Self::Serialization(_) => StatusCode::INTERNAL_SERVER_ERROR,
            Self::AuthError(_) => StatusCode::UNAUTHORIZED,
            Self::Jwt(_) | Self::PasswordHash(_) | Self::Encryption(_) => {
                StatusCode::INTERNAL_SERVER_ERROR
            }
            Self::Totp(_) => StatusCode::BAD_REQUEST,
            Self::Config(_) => StatusCode::INTERNAL_SERVER_ERROR,
            Self::Relay(_) => StatusCode::BAD_GATEWAY,
            Self::General(_) => StatusCode::INTERNAL_SERVER_ERROR,
        }
    }

    /// 获取错误代码
    pub fn error_code(&self) -> &str {
        match self {
            Self::NotFound(_) => "NOT_FOUND",
            Self::Forbidden(_) => "FORBIDDEN",
            Self::Unauthorized => "UNAUTHORIZED",
            Self::InvalidInput(_) => "INVALID_INPUT",
            Self::AlreadyExists(_) => "ALREADY_EXISTS",
            Self::RateLimited(_) => "RATE_LIMITED",
            Self::Database(_) => "DATABASE_ERROR",
            Self::Io(_) => "IO_ERROR",
            Self::Serialization(_) => "SERIALIZATION_ERROR",
            Self::Internal(_) => "INTERNAL_ERROR",
            Self::AuthError(_) => "AUTH_ERROR",
            Self::Jwt(_) => "JWT_ERROR",
            Self::PasswordHash(_) => "PASSWORD_HASH_ERROR",
            Self::Totp(_) => "TOTP_ERROR",
            Self::Encryption(_) => "ENCRYPTION_ERROR",
            Self::Config(_) => "CONFIG_ERROR",
            Self::Relay(_) => "RELAY_ERROR",
            Self::General(_) => "GENERAL_ERROR",
        }
    }
}

/// 实现 Axum 响应
impl IntoResponse for SaasError {
    fn into_response(self) -> Response {
        let status = self.status_code();
        let (error_code, message) = match &self {
            // 500 错误不泄露内部细节给客户端 (开发模式除外)
            Self::Database(_) | Self::Internal(_) | Self::Io(_)
            | Self::Jwt(_) | Self::Config(_) => {
                tracing::error!("内部错误 [{}]: {}", self.error_code(), self);
                if std::env::var("ZCLAW_SAAS_DEV").as_deref() == Ok("true") {
                    (self.error_code().to_string(), format!("[DEV] {}", self))
                } else {
                    (self.error_code().to_string(), "服务内部错误".to_string())
                }
            }
            _ => (self.error_code().to_string(), self.to_string()),
        };
        let body = json!({
            "error": error_code,
            "message": message,
        });
        (status, axum::Json(body)).into_response()
    }
}

/// Result 类型别名
pub type SaasResult<T> = std::result::Result<T, SaasError>;