package response

import (
	"context"
	"errors"
	"net/http"
	"os"

	"github.com/zeromicro/go-zero/core/logx"
	"github.com/zeromicro/go-zero/rest/httpx"
	"go.opentelemetry.io/otel/trace"
)

// Body 是统一 HTTP 响应体，格式与前端 API.Result<T> 对齐：
// 成功：{ "success": true, "data": ... }
// 失败：{ "success": false, "errorCode": N, "errorMessage": "...", "showType": N }
type Body struct {
	Success      bool        `json:"success"`
	Data         interface{} `json:"data,omitempty"`
	ErrorCode    int         `json:"errorCode,omitempty"`
	ErrorMessage string      `json:"errorMessage,omitempty"`
	ShowType     int         `json:"showType,omitempty"`
	TraceId      string      `json:"traceId,omitempty"`
	Host         string      `json:"host,omitempty"`
}

// ShowType 与前端 ErrorShowType 枚举对齐
const (
	ShowTypeSilent       = 0 // SILENT
	ShowTypeWarnMessage  = 1 // WARN_MESSAGE
	ShowTypeErrorMessage = 2 // ERROR_MESSAGE
	ShowTypeNotification = 4 // NOTIFICATION
	ShowTypeRedirect     = 9 // REDIRECT
)

var hostname string

func init() {
	hostname, _ = os.Hostname()
}

type CodeError struct {
	code     int
	msg      string
	showType int
}

func NewCodeError(code int, msg string) *CodeError {
	return &CodeError{code: code, msg: msg, showType: ShowTypeErrorMessage}
}

func (e *CodeError) Error() string    { return e.msg }
func (e *CodeError) Code() int        { return e.code }
func (e *CodeError) ShowType() int    { return e.showType }

func ErrBadRequest(msg string) *CodeError      { return NewCodeError(400, msg) }
func ErrUnauthorized(msg string) *CodeError    { return NewCodeError(401, msg) }
func ErrForbidden(msg string) *CodeError       { return NewCodeError(403, msg) }
func ErrNotFound(msg string) *CodeError        { return NewCodeError(404, msg) }
func ErrConflict(msg string) *CodeError        { return NewCodeError(409, msg) }
func ErrTooManyRequests(msg string) *CodeError { return NewCodeError(429, msg) }

func traceIdFromCtx(ctx context.Context) string {
	if sc := trace.SpanFromContext(ctx).SpanContext(); sc.IsValid() {
		return sc.TraceID().String()
	}
	return ""
}

func Setup() {
	httpx.SetOkHandler(func(_ context.Context, v any) any {
		if v == nil {
			return Body{Success: true, Host: hostname}
		}
		return Body{Success: true, Data: v, Host: hostname}
	})

	httpx.SetErrorHandlerCtx(func(ctx context.Context, err error) (int, any) {
		traceId := traceIdFromCtx(ctx)
		var ce *CodeError
		if errors.As(err, &ce) {
			return http.StatusOK, Body{
				Success:      false,
				ErrorCode:    ce.Code(),
				ErrorMessage: ce.Error(),
				ShowType:     ce.ShowType(),
				TraceId:      traceId,
				Host:         hostname,
			}
		}
		logx.WithContext(ctx).Errorf("internal error: %+v", err)
		return http.StatusOK, Body{
			Success:      false,
			ErrorCode:    500,
			ErrorMessage: "服务器内部错误",
			ShowType:     ShowTypeErrorMessage,
			TraceId:      traceId,
			Host:         hostname,
		}
	})
}