package tool

import (
	"errors"
	"fmt"
	"net/url"
	"reflect"
)

// QueryRange 范围查找结构体
type QueryRange struct {
	Query string `json:"query"`
	Start int64  `json:"start"`
	End   int64  `json:"end"`
	Step  int    `json:"step"`
}

// GetStructTag 获取结构体标签
func GetStructTag(s interface{}) (map[string]string, error) {
	getValue := reflect.ValueOf(s)
	if getValue.Kind() != reflect.Struct {
		return nil, errors.New("not struct")
	}
	getType := reflect.TypeOf(s)
	t := map[string]string{}
	for i := 0; i < getValue.NumField(); i++ {
		t[getType.Field(i).Name] = getType.Field(i).Tag.Get("json")
	}
	return t, nil
}

// BuildURLByStruct build url
func BuildURLByStruct(path string, queryRange *QueryRange) (string, error) {
	if queryRange == nil {
		return "", errors.New("query range is nil")
	}
	tagMap, err := GetStructTag(*queryRange)
	if err != nil {
		return "", err
	}
	getValue := reflect.ValueOf(*queryRange)
	urlParamMap := url.Values{}
	for k, v := range tagMap {
		urlParamMap.Set(v, fmt.Sprintf("%v", getValue.FieldByName(k).Interface()))
	}
	base, err := url.Parse(path)
	if err != nil {
		return "", err
	}
	base.RawQuery = urlParamMap.Encode()
	return base.String(), nil
}