package chinaums

import (
	"crypto/hmac"
	"crypto/sha256"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"github.com/shopspring/decimal"
	"github.com/spf13/viper"
	"go_zh/model"
	"go_zh/pkg/utils"
	"sort"
	"strings"
	"sync"
	"time"
)

type ChinaumsServer struct {
	appId    string
	appKey   string
	appletId string //小程序appid
	wxAppId  string //微信公众号appid
	signKey  string //解密使用密文
}

var (
	chinaumsServerInstance *ChinaumsServer
	chinaumsServerOnce     sync.Once
)

// GetOrderSnServerInstance 获取单例实例
func GetOrderSnServerInstance() *ChinaumsServer {
	chinaumsServerOnce.Do(func() {
		chinaumsServerInstance = &ChinaumsServer{
			appId:    viper.GetString("chinaums.appId"),
			appKey:   viper.GetString("chinaums.appKey"),
			appletId: viper.GetString("chinaums.appletId"),
			wxAppId:  viper.GetString("chinaums.wxAppId"),
			signKey:  viper.GetString("chinaums.signKey"),
		}
	})
	return chinaumsServerInstance
}

// ShopOrderWxH5Pay 微信公众号店铺收款码支付
func (cs *ChinaumsServer) ShopOrderWxH5Pay(shopMchInfo model.XShopMchid, orderSn string, payMoney decimal.Decimal, notifyUrl string, wxOpenid string) string {

	url := "https://api-mop.chinaums.com/v1/netpay/webpay/pay"

	result := make(map[string]interface{})
	result["requestTimestamp"] = time.Now().Format("2006-01-02 15:04:05")
	result["mid"] = shopMchInfo.SubMchid
	result["tid"] = shopMchInfo.Tid
	result["instMid"] = "YUEDANDEFAULT" // 业务类型 YUEDANDEFAULT
	result["merOrderId"] = orderSn
	result["notifyUrl"] = notifyUrl
	result["returnUrl"] = "https://shoppay.jhcs888.com/#/?order_sn=" + orderSn // 网页跳转地址
	result["totalAmount"] = payMoney.Mul(decimal.NewFromInt(100)).IntPart()

	result["subAppId"] = cs.wxAppId // 微信必填
	result["subOpenId"] = wxOpenid

	body, _ := json.Marshal(result)
	strUrl := cs.curlget(url, orderSn, string(body))
	return strUrl
}

// ShopOrderAliH5Pay 银联发起支付宝H5支付
func (cs *ChinaumsServer) ShopOrderAliH5Pay(shopMchInfo model.XShopMchid, orderSn string, payMoney decimal.Decimal, notifyUrl string) string {

	url := "https://api-mop.chinaums.com/v1/netpay/trade/h5-pay"

	result := make(map[string]interface{})
	result["requestTimestamp"] = time.Now().Format("2006-01-02 15:04:05")
	result["mid"] = shopMchInfo.SubMchid
	result["tid"] = shopMchInfo.Tid
	result["merOrderId"] = orderSn
	result["instMid"] = "H5DEFAULT"
	result["notifyUrl"] = notifyUrl
	result["totalAmount"] = payMoney.Mul(decimal.NewFromInt(100)).IntPart()

	body, _ := json.Marshal(result)
	strUrl := cs.curlget(url, orderSn, string(body))
	return strUrl
}

// curlget 拼接请求地址
func (cs *ChinaumsServer) curlget(url, orderSn, body string) string {
	timestamp := time.Now().Format("20060102150405")
	nonce := utils.Md5Sign(orderSn)
	signature := utils.UrlEncode(cs.getSignature(timestamp, nonce, body))
	reqUrl := fmt.Sprintf("%s?authorization=OPEN-FORM-PARAM&appId=%s&timestamp=%s&nonce=%s&content=%s&signature=%s", url, cs.appId, timestamp, nonce, utils.UrlEncode(body), signature)
	return reqUrl
}

// buildSignStr 生成签名原始字符串，规则如下：
// 1. 排除键名为 "sign" 的项；
// 2. 排除值为 nil 的项；
// 3. 剩余参数按键名升序排序；
// 4. 值如果是 map 或 slice，则进行 JSON 编码；否则直接转换为字符串；
// 5. 拼接成 key=value 形式，用 & 连接，末尾不加 &。
func buildSignStr(params map[string]interface{}) string {
	// 收集所有非 "sign" 且值不为 nil 的键
	keys := make([]string, 0, len(params))
	for k, v := range params {
		if k == "sign" || v == nil {
			continue
		}
		keys = append(keys, k)
	}

	// 键名排序
	sort.Strings(keys)

	var builder strings.Builder
	for i, key := range keys {
		val := params[key]

		// 将值转换为字符串
		var valStr string
		switch v := val.(type) {
		case map[string]interface{}: // 关联数组 -> JSON 对象
			b, _ := json.Marshal(v)
			valStr = string(b)
		case []interface{}: // 索引数组 -> JSON 数组
			b, _ := json.Marshal(v)
			valStr = string(b)
		default:
			// 基本类型（string, int, float, bool 等）使用默认字符串表示
			valStr = fmt.Sprint(v)
		}

		builder.WriteString(key)
		builder.WriteString("=")
		builder.WriteString(valStr)

		// 除最后一个元素外，添加 & 分隔符
		if i < len(keys)-1 {
			builder.WriteString("&")
		}
	}

	return builder.String()
}

// getSignature 生成签名，
// 参数 timestamp, nonce, body 均为字符串类型
func (cs *ChinaumsServer) getSignature(timestamp, nonce, body string) string {
	// 1. 计算 body 的 SHA256 哈希（原始二进制）并转换为十六进制字符串
	bodyHash := sha256.Sum256([]byte(body))
	bodyHex := hex.EncodeToString(bodyHash[:])

	// 2. 拼接 appid + timestamp + nonce + bodyHex
	message := cs.appId + timestamp + nonce + bodyHex

	// 3. 使用 HMAC-SHA256 对消息进行签名，密钥为 appkey
	h := hmac.New(sha256.New, []byte(cs.appKey))
	h.Write([]byte(message))
	signature := h.Sum(nil) // 原始二进制签名

	// 4. 对签名结果进行 Base64 编码
	return base64.StdEncoding.EncodeToString(signature)
}