use actix_web::{HttpResponse, ResponseError};
use serde::Serialize;
use thiserror::Error;

/// 统一错误响应体（不泄露内部细节）
#[derive(Serialize)]
pub struct ErrorResponse {
    pub code: u32,
    pub message: String,
}

/// 应用错误类型
#[derive(Debug, Error)]
pub enum AppError {
    #[error("参数验证失败: {0}")]
    Validation(String),

    #[error("未授权访问")]
    Unauthorized,

    #[error("资源不存在")]
    NotFound,

    #[error("钱包已存在")]
    WalletAlreadyExists,

    #[error("余额不足")]
    InsufficientBalance,

    #[error("手续费不足")]
    InsufficientFee,

    #[error("内部服务错误")]
    Internal,

    #[error("数据库错误")]
    Database,
}

impl ResponseError for AppError {
    fn error_response(&self) -> HttpResponse {
        // 注意：所有错误响应都使用通用描述，不泄露内部实现细节
        match self {
            AppError::Validation(msg) => HttpResponse::BadRequest().json(ErrorResponse {
                code: 4001,
                message: msg.clone(),
            }),
            AppError::Unauthorized => HttpResponse::Unauthorized().json(ErrorResponse {
                code: 4010,
                message: "未授权访问".to_string(),
            }),
            AppError::NotFound => HttpResponse::NotFound().json(ErrorResponse {
                code: 4040,
                message: "资源不存在".to_string(),
            }),
            AppError::WalletAlreadyExists => HttpResponse::Conflict().json(ErrorResponse {
                code: 4091,
                message: "该用户钱包已存在".to_string(),
            }),
            AppError::InsufficientBalance => HttpResponse::BadRequest().json(ErrorResponse {
                code: 4002,
                message: "余额不足".to_string(),
            }),
            AppError::InsufficientFee => HttpResponse::BadRequest().json(ErrorResponse {
                code: 4003,
                message: "XIC手续费余额不足".to_string(),
            }),
            // 内部错误统一返回500，不暴露细节
            AppError::Internal | AppError::Database => {
                HttpResponse::InternalServerError().json(ErrorResponse {
                    code: 5000,
                    message: "服务暂时不可用，请稍后重试".to_string(),
                })
            }
        }
    }
}