package wps

import (
	"crypto/md5"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"reflect"
	"sort"
	"strings"
	"time"

	"github.com/pkg/errors"
)

const (
	DevHost     = "https://uat.api.weipinshang.net/"
	ReleaseHost = "https://api.weipinshang.net/"
)

const (
	GetGoodBrandURL     = "mcang/Mcang/goodBrand"        //查询商品的品牌
	GetGoodsClassifyURL = "mcang/Mcang/getGoodsClassify" //查询商品分类
	GetGoodsListURL     = "mcang/Mcang/getGoodsList"     //获取全部商品列表接口
	GetGoodsdeptURL     = "mcang/Mcang/getGoodsdept"     //（推荐使用）获取后台已选商品列表接口
	GetDetailsGoodsUrl  = "mcang/Mcang/getDetailsGoods"  //获取批量商品详情接口
	GetGoodsDetailsURL  = "mcang/Mcang/getGoodsDetails"  //获取单个商品详情接口
	GetGoodsStockURL    = "mcang/Mcang/getGoodsStock"    //获取单个商品详情接口
)

// Config 客户端配置
type Config struct {
	ChannelType string
	Key         string
	BaseURL     string
	Timeout     time.Duration
}

// WeiPinShangClient 客户端结构体
type WeiPinShangClient struct {
	ChannelType string
	Key         string
	BaseURL     string
	HttpClient  *http.Client
}

// NewWeiPinShangClient 创建客户端
func NewWeiPinShangClient(cfg Config) *WeiPinShangClient {
	if cfg.ChannelType == "" {
		cfg.ChannelType = "AILEHUI"
	}
	if cfg.BaseURL == "" {
		cfg.BaseURL = ReleaseHost
	}
	if cfg.Key == "" {
		cfg.Key = "f654ea5bde7635c3f46191191e5c4c8e"
	}
	if cfg.Timeout == 0 {
		cfg.Timeout = 10 * time.Second
	}
	return &WeiPinShangClient{
		ChannelType: cfg.ChannelType,
		Key:         cfg.Key,
		BaseURL:     cfg.BaseURL,
		HttpClient:  &http.Client{Timeout: cfg.Timeout},
	}
}

// sign 生成签名
func (c *WeiPinShangClient) sign(params map[string]string) string {
	keys := make([]string, 0, len(params))
	for k := range params {
		keys = append(keys, k)
	}
	sort.Strings(keys)

	var sb strings.Builder
	for _, k := range keys {
		v := params[k]
		if v == "" {
			continue
		}
		sb.WriteString(k)
		sb.WriteString("=")
		sb.WriteString(v)
		sb.WriteString("&")
	}
	signStr := strings.TrimRight(sb.String(), "&") + c.ChannelType + c.Key
	hash := md5.Sum([]byte(signStr))
	return hex.EncodeToString(hash[:])
}

// buildHeaders 构建请求头
func (c *WeiPinShangClient) buildHeaders(params map[string]string) http.Header {
	headers := http.Header{}
	headers.Set("channelType", c.ChannelType)
	headers.Set("md5", c.sign(params))
	headers.Set("Content-Type", "application/x-www-form-urlencoded")
	return headers
}

// buildRequest 构造请求对象
func (c *WeiPinShangClient) buildRequest(method, endpoint string, params map[string]string) (*http.Request, error) {
	var (
		req *http.Request
		err error
	)

	if method == http.MethodPost {
		form := url.Values{}
		for k, v := range params {
			form.Set(k, v)
		}
		req, err = http.NewRequest(method, c.BaseURL+endpoint, strings.NewReader(form.Encode()))
	} else {
		query := url.Values{}
		for k, v := range params {
			query.Set(k, v)
		}
		req, err = http.NewRequest(method, fmt.Sprintf("%s%s?%s", c.BaseURL, endpoint, query.Encode()), nil)
	}

	if err != nil {
		return nil, fmt.Errorf("构建请求失败，地址：%s，err:%v", endpoint, err.Error())
	}
	req.Header = c.buildHeaders(params)
	return req, nil
}

// doRequest 执行请求并返回字符串响应
func (c *WeiPinShangClient) doRequest(req *http.Request) (string, error) {
	resp, err := c.HttpClient.Do(req)
	if err != nil {
		return "", errors.Wrap(err, "HTTP request failed")
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("HTTP status error: %s", resp.Status)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", fmt.Errorf("读取response body失败。err:%v", err.Error())
	}
	return string(body), nil
}

// Post 发起 POST 请求
func (c *WeiPinShangClient) Post(endpoint string, params map[string]string) (string, error) {
	req, err := c.buildRequest(http.MethodPost, endpoint, params)
	if err != nil {
		return "", err
	}
	return c.doRequest(req)
}

// Get 发起 GET 请求
func (c *WeiPinShangClient) Get(endpoint string, params map[string]string) (string, error) {
	req, err := c.buildRequest(http.MethodGet, endpoint, params)
	if err != nil {
		return "", err
	}
	return c.doRequest(req)
}

// GetAndParse 发起 GET 请求并解析 JSON 响应
func (c *WeiPinShangClient) GetAndParse(endpoint string, params map[string]string, out interface{}) error {
	respStr, err := c.Get(endpoint, params)
	if err != nil {
		return err
	}
	return json.Unmarshal([]byte(respStr), out)
}

// PostAndParse 发起 POST 请求并解析 JSON 响应
func (c *WeiPinShangClient) PostAndParse(endpoint string, params map[string]string, out interface{}) error {
	respStr, err := c.Post(endpoint, params)
	if err != nil {
		return err
	}
	return json.Unmarshal([]byte(respStr), out)
}

func StructToMapString(obj interface{}) map[string]string {
	result := make(map[string]string)

	v := reflect.ValueOf(obj)
	t := reflect.TypeOf(obj)

	// 支持结构体指针
	if v.Kind() == reflect.Ptr {
		v = v.Elem()
		t = t.Elem()
	}

	for i := 0; i < v.NumField(); i++ {
		field := t.Field(i)
		valueField := v.Field(i)

		// 只导出可访问的字段
		if !valueField.CanInterface() {
			continue
		}

		// 判断是否为零值
		if reflect.DeepEqual(valueField.Interface(), reflect.Zero(valueField.Type()).Interface()) {
			continue
		}

		key := field.Tag.Get("json")
		if key == "" {
			key = field.Name
		}

		result[key] = fmt.Sprintf("%v", valueField.Interface())
	}

	return result
}