package sms

import (
	"bytes"
	"crypto/md5"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"net/http"
	"time"
)

const (
	DefaultUserAccount = "8871f88e273edb8c20834c61ce97b287"
	DefaultUserSecret  = "76d9ae4fe2ac3523d7c051e158c1477d"
	DefaultBaseURL     = "https://apiext.szshanyun.com:8443"
)

// ---------------- 工具函数 ----------------

// GenTimestamp 生成 13 位时间戳（毫秒）
func GenTimestamp() string {
	return fmt.Sprintf("%d", time.Now().UnixNano()/1e6)
}

// MD5 md5加密
func MD5(s string) string {
	h := md5.Sum([]byte(s))
	return hex.EncodeToString(h[:])
}

// SignWithBusinessBody 生成发送/状态查询接口签名：md5(businessBody + userSecret + timestamp)
func SignWithBusinessBody(body interface{}, userSecret, timestamp string) (string, error) {
	b, err := json.Marshal(body)
	if err != nil {
		return "", err
	}
	return MD5(string(b) + userSecret + timestamp), nil
}

// SignSimple 生成余额接口签名：md5(userAccount + userSecret + timestamp)
func SignSimple(userAccount, userSecret, timestamp string) string {
	return MD5(userAccount + userSecret + timestamp)
}

// ---------------- 数据结构 ----------------

// SendRequest ===== 短信发送 =====
type SendRequest struct {
	BusinessBody BusinessBody `json:"businessBody"`
	Sign         string       `json:"sign"`
	Timestamp    string       `json:"timestamp"`
	UserAccount  string       `json:"userAccount"`
}

type BusinessBody struct {
	ChildUserNumber *string    `json:"childUserNumber,omitempty"`
	Content         *string    `json:"content,omitempty"`
	ModelID         *string    `json:"modelId,omitempty"`
	Number          *string    `json:"number,omitempty"`
	ReturnURL       *string    `json:"returnUrl,omitempty"`
	SendList        []SendList `json:"sendList"`
	SignatureID     *string    `json:"signatureId,omitempty"`
	SignatureStr    *string    `json:"signatureStr,omitempty"`
}

type SendList struct {
	Content      *string       `json:"content,omitempty"`
	ModelReplace *ModelReplace `json:"modelReplace,omitempty"`
	OutOrderID   string        `json:"outOrderId"`
	PhoneNumber  string        `json:"phoneNumber"`
}

type ModelReplace struct {
	FlowSize  *string `json:"FlowSize,omitempty"`
	ISPNumber *string `json:"ispNumber,omitempty"`
	Time      *string `json:"Time,omitempty"`
	TimeLimit *string `json:"TimeLimit,omitempty"`
}

type SendResponse struct {
	Message    string `json:"message"`
	StatusCode int64  `json:"statusCode"`
}

// BalanceRequest ===== 余额查询 =====
type BalanceRequest struct {
	Sign        string `json:"sign"`
	Timestamp   string `json:"timestamp"`
	UserAccount string `json:"userAccount"`
}

type BalanceResponse struct {
	Data       BalanceData `json:"data"`
	Message    string      `json:"message"`
	StatusCode int64       `json:"statusCode"`
}

type BalanceData struct {
	Balance  string `json:"balance"`
	UserName string `json:"userName"`
}

// StateRequest ===== 状态查询 =====
type StateRequest struct {
	BusinessBody StateBusinessBody `json:"businessBody"`
	Sign         string            `json:"sign"`
	Timestamp    string            `json:"timestamp"`
	UserAccount  string            `json:"userAccount"`
}

type StateBusinessBody struct {
	OutOrderID  string `json:"outOrderId"`
	PhoneNumber string `json:"phoneNumber"`
}

type StateResponse struct {
	Data       StateData `json:"data"`
	Message    string    `json:"message"`
	StatusCode int64     `json:"statusCode"`
}

type StateData struct {
	SendStatus string `json:"sendStatus"`
}

// ---------------- Client 封装 ----------------

type Client struct {
	UserAccount string
	UserSecret  string
	BaseURL     string
}

func NewClient() *Client {
	return &Client{
		UserAccount: DefaultUserAccount,
		UserSecret:  DefaultUserSecret,
		BaseURL:     DefaultBaseURL,
	}
}

// SendSMS 发送短信
func (c *Client) SendSMS(body BusinessBody) (*SendResponse, error) {
	timestamp := GenTimestamp()
	sign, err := SignWithBusinessBody(body, c.UserSecret, timestamp)
	if err != nil {
		return nil, err
	}
	req := SendRequest{
		BusinessBody: body,
		Sign:         sign,
		Timestamp:    timestamp,
		UserAccount:  c.UserAccount,
	}
	return post[SendResponse](c.BaseURL+"/receive", req)
}

// GetBalance 查询余额
func (c *Client) GetBalance() (*BalanceResponse, error) {
	timestamp := GenTimestamp()
	sign := SignSimple(c.UserAccount, c.UserSecret, timestamp)
	req := BalanceRequest{
		Sign:        sign,
		Timestamp:   timestamp,
		UserAccount: c.UserAccount,
	}
	return post[BalanceResponse](c.BaseURL+"/balance", req)
}

// QueryState 查询状态
func (c *Client) QueryState(outOrderID, phone string) (*StateResponse, error) {
	body := StateBusinessBody{
		OutOrderID:  outOrderID,
		PhoneNumber: phone,
	}
	timestamp := GenTimestamp()
	sign, err := SignWithBusinessBody(body, c.UserSecret, timestamp)
	if err != nil {
		return nil, err
	}
	req := StateRequest{
		BusinessBody: body,
		Sign:         sign,
		Timestamp:    timestamp,
		UserAccount:  c.UserAccount,
	}
	return post[StateResponse](c.BaseURL+"/state", req)
}

// ---------------- POST工具 ----------------

func post[T any](url string, payload interface{}) (*T, error) {
	b, err := json.Marshal(payload)
	if err != nil {
		return nil, err
	}
	resp, err := http.Post(url, "application/json", bytes.NewBuffer(b))
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	var result T
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, err
	}
	return &result, nil
}