req

var FormEncode = Hook{
	Name: "FormEncode",
	OnRequest: func(r *http.Request) error {
		if r.Header.Get("Content-Type") == "" {
			r.Header.Set("Content-Type", "application/x-www-form-urlencoded")
		}
		return nil
	},
	Encode: func(ctx context.Context, body any) ([]byte, error) {
		v, err := ValuesOf(body)
		if err != nil {
			return nil, err
		}
		return []byte(v.Encode()), nil
	},
}

var JSONDecode = Hook{
	Name: "JsonDecode",
	Decode: func(ctx context.Context, body []byte, out any) error {
		return json.Unmarshal(body, out)
	},
}

var JSONEncode = Hook{
	Name: "JsonEncode",
	OnRequest: func(r *http.Request) error {
		if r.Header.Get("Content-Type") == "" {
			r.Header.Set("Content-Type", "application/json;charset=UTF-8")
		}
		return nil
	},
	Encode: func(ctx context.Context, body any) ([]byte, error) {
		return json.Marshal(body)
	},
}

var MultipartFormEncode = Hook{
	Name: "MultipartFormEncode",
	Encode: func(ctx context.Context, body any) ([]byte, error) {
		buf := &bytes.Buffer{}
		writer := multipart.NewWriter(buf)

		var fieldName, filename string
		var reader io.Reader
		var fields map[string]string

		switch f := body.(type) {
		case *MultipartFile:
			fieldName = f.FieldName
			filename = f.Filename
			reader = f.Reader
			fields = f.Fields
		case fs.File:
			info, err := f.Stat()
			if err != nil {
				return nil, fmt.Errorf("stat file: %w", err)
			}
			filename = info.Name()
			reader = f
		default:
			return nil, fmt.Errorf("MultipartFormEncode: unsupported body type %T, use *MultipartFile or fs.File", body)
		}

		if fieldName == "" {
			fieldName = "file"
		}
		if filename == "" {
			filename = "upload"
		}

		for k, v := range fields {
			if err := writer.WriteField(k, v); err != nil {
				return nil, fmt.Errorf("write field %s: %w", k, err)
			}
		}

		part, err := writer.CreateFormFile(fieldName, filename)
		if err != nil {
			return nil, fmt.Errorf("create form file: %w", err)
		}
		if _, err := io.Copy(part, reader); err != nil {
			return nil, fmt.Errorf("copy file content: %w", err)
		}
		if err := writer.Close(); err != nil {
			return nil, fmt.Errorf("close multipart writer: %w", err)
		}

		return buf.Bytes(), nil
	},
	OnRequest: func(r *http.Request) error {

		if r.Body != nil && r.Header.Get("Content-Type") == "" {

			body, err := io.ReadAll(r.Body)
			if err != nil {
				return err
			}
			if bytes.HasPrefix(body, []byte("--")) {

				idx := bytes.IndexByte(body, '\r')
				if idx < 0 {
					idx = bytes.IndexByte(body, '\n')
				}
				if idx > 2 {
					boundary := string(body[2:idx])
					r.Header.Set("Content-Type", "multipart/form-data; boundary="+boundary)
				}
			}
			r.Body = io.NopCloser(bytes.NewReader(body))
			r.ContentLength = int64(len(body))
		}
		return nil
	},
}