use axum::{
    http::StatusCode,
    response::{IntoResponse, Response},
};
use serde::Serialize;
use serde_json::Value;

use crate::{api_response::json_error_body, request_context::RequestContext};

#[derive(Debug)]
pub struct AppError {
    status_code: StatusCode,
    code: &'static str,
    message: &'static str,
    details: Option<Value>,
}

#[derive(Clone, Debug, Serialize)]
pub struct ApiErrorPayload {
    pub code: &'static str,
    pub message: &'static str,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub details: Option<Value>,
}

impl AppError {
    pub fn from_status(status_code: StatusCode) -> Self {
        let (code, message) = resolve_http_error(status_code);

        Self {
            status_code,
            code,
            message,
            details: None,
        }
    }

    pub fn code(&self) -> &'static str {
        self.code
    }

    pub fn into_response_with_context(self, request_context: Option<&RequestContext>) -> Response {
        let status_code = self.status_code;
        let payload = self.to_payload();

        (status_code, json_error_body(request_context, &payload)).into_response()
    }

    fn to_payload(&self) -> ApiErrorPayload {
        ApiErrorPayload {
            code: self.code,
            message: self.message,
            details: self.details.clone(),
        }
    }
}

impl IntoResponse for AppError {
    fn into_response(self) -> Response {
        self.into_response_with_context(None)
    }
}

fn resolve_http_error(status_code: StatusCode) -> (&'static str, &'static str) {
    match status_code {
        StatusCode::BAD_REQUEST => ("BAD_REQUEST", "请求参数不合法"),
        StatusCode::UNAUTHORIZED => ("UNAUTHORIZED", "未授权访问"),
        StatusCode::FORBIDDEN => ("FORBIDDEN", "禁止访问"),
        StatusCode::NOT_FOUND => ("NOT_FOUND", "资源不存在"),
        StatusCode::CONFLICT => ("CONFLICT", "请求冲突"),
        StatusCode::TOO_MANY_REQUESTS => ("TOO_MANY_REQUESTS", "请求过于频繁"),
        StatusCode::BAD_GATEWAY => ("UPSTREAM_ERROR", "上游服务请求失败"),
        _ if status_code.is_client_error() => ("BAD_REQUEST", "请求参数不合法"),
        _ => ("INTERNAL_SERVER_ERROR", "服务器内部错误"),
    }
}