package services

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"math/rand"
	"net/http"
	"strings"
	"sync"
	"time"

	"server/models"
)

type loginCodeItem struct {
	Code      string
	Channel   string
	ExpiredAt time.Time
}

var loginCodeStore sync.Map

func codeKey(account, channel string) string {
	return strings.ToLower(strings.TrimSpace(account)) + "|" + strings.TrimSpace(channel)
}

func SendPlatformLoginCode(account, channel string) error {
	account = strings.TrimSpace(account)
	channel = strings.TrimSpace(channel)
	if account == "" {
		return errors.New("账号不能为空")
	}
	if channel != "sms" && channel != "email" {
		return errors.New("仅支持短信或邮箱验证码")
	}

	var u models.AdminUser
	if err := models.Orm.QueryTable(new(models.AdminUser)).Filter("account", account).One(&u); err != nil {
		return errors.New("用户不存在")
	}
	if u.Status == 0 {
		return errors.New("账号已禁用")
	}
	if channel == "sms" && (u.Phone == nil || strings.TrimSpace(*u.Phone) == "") {
		return errors.New("该账号未绑定手机号")
	}
	if channel == "email" && (u.Email == nil || strings.TrimSpace(*u.Email) == "") {
		return errors.New("该账号未绑定邮箱")
	}

	rand.Seed(time.Now().UnixNano())
	code := fmt.Sprintf("%06d", rand.Intn(1000000))
	loginCodeStore.Store(codeKey(account, channel), loginCodeItem{
		Code:      code,
		Channel:   channel,
		ExpiredAt: time.Now().Add(5 * time.Minute),
	})
	// TODO: 接入短信/邮箱发送通道。当前阶段只做服务端验证码校验链路。
	return nil
}

func VerifyPlatformLoginCode(account, channel, code string) error {
	account = strings.TrimSpace(account)
	channel = strings.TrimSpace(channel)
	code = strings.TrimSpace(code)
	if account == "" || code == "" {
		return errors.New("验证码不能为空")
	}
	val, ok := loginCodeStore.Load(codeKey(account, channel))
	if !ok {
		return errors.New("验证码不存在或已失效")
	}
	item, ok := val.(loginCodeItem)
	if !ok {
		return errors.New("验证码状态异常")
	}
	if time.Now().After(item.ExpiredAt) {
		loginCodeStore.Delete(codeKey(account, channel))
		return errors.New("验证码已过期")
	}
	if item.Code != code {
		return errors.New("验证码错误")
	}
	loginCodeStore.Delete(codeKey(account, channel))
	return nil
}

func SendBackendLoginCode(tenantName, account, channel string) error {
	tenantName = strings.TrimSpace(tenantName)
	account = strings.TrimSpace(account)
	channel = strings.TrimSpace(channel)
	if tenantName == "" || account == "" {
		return errors.New("租户名称和账号不能为空")
	}
	if channel != "sms" && channel != "email" {
		return errors.New("仅支持短信或邮箱验证码")
	}
	var tenant models.Tenant
	if err := models.Orm.QueryTable(new(models.Tenant)).Filter("tenant_name", tenantName).One(&tenant); err != nil {
		return errors.New("租户不存在")
	}
	rand.Seed(time.Now().UnixNano())
	code := fmt.Sprintf("%06d", rand.Intn(1000000))

	// 规则：先校验租户，再校验“输入的手机号/邮箱”是否为该租户已绑定的记录
	switch channel {
	case "sms":
		phone := account
		var user models.TenantUser
		if err := models.Orm.QueryTable(new(models.TenantUser)).
			Filter("tid", tenant.ID).
			Filter("phone", phone).
			One(&user); err != nil {
			return errors.New("该手机号非当前企业绑定号码，请重试")
		}
		if user.Status == 0 {
			return errors.New("账号已禁用")
		}
		if user.Phone == nil || strings.TrimSpace(*user.Phone) == "" {
			return errors.New("该手机号非当前企业绑定号码，请重试")
		}

		content := "短信验证码：" + code
		if err := enqueueSMSTaskForLogin(tenant.ID, phone, content, code); err != nil {
			return errors.New("短信发送失败，请重试")
		}
	case "email":
		email := account
		var user models.TenantUser
		if err := models.Orm.QueryTable(new(models.TenantUser)).
			Filter("tid", tenant.ID).
			Filter("email", email).
			One(&user); err != nil {
			return errors.New("该账号未绑定邮箱")
		}
		if user.Status == 0 {
			return errors.New("账号已禁用")
		}
		if user.Email == nil || strings.TrimSpace(*user.Email) == "" {
			return errors.New("该账号未绑定邮箱")
		}
	}

	loginCodeStore.Store(codeKey(tenantName+"#"+account, channel), loginCodeItem{
		Code:      code,
		Channel:   channel,
		ExpiredAt: time.Now().Add(5 * time.Minute),
	})
	return nil
}

func VerifyBackendLoginCode(tenantName, account, channel, code string) error {
	return VerifyPlatformLoginCode(tenantName+"#"+account, channel, code)
}

func getDefaultSystemSMSConfig() (backendURL string, apiKey string, err error) {
	var row models.SystemSMS
	err = models.Orm.QueryTable(new(models.SystemSMS)).
		Filter("is_default", 1).
		Filter("status", 1).
		OrderBy("-weight", "-id").
		Limit(1).
		One(&row)
	if err != nil {
		// fallback：自定义网关
		err2 := models.Orm.QueryTable(new(models.SystemSMS)).
			Filter("config_code", "custom").
			OrderBy("-id").
			Limit(1).
			One(&row)
		if err2 != nil {
			return "", "", err2
		}
	}
	backendURL = strings.TrimSpace(row.ApiURL)
	apiKey = strings.TrimSpace(row.ApiKey)
	return backendURL, apiKey, nil
}

// enqueueSMSTaskForLogin 入队短信任务到网关，并写入 yz_system_sms_tasks
func enqueueSMSTaskForLogin(tid uint64, phone, content, code string) error {
	backendURL, apiKey, err := getDefaultSystemSMSConfig()
	if err != nil {
		return err
	}
	if backendURL == "" || apiKey == "" {
		return errors.New("短信网关未配置")
	}

	enqueueURL := strings.TrimRight(backendURL, "/") + "/api/v1/business/outbound-tasks"
	payload := map[string]interface{}{
		"phone":   phone,
		"content": content,
	}
	bs, _ := json.Marshal(payload)

	client := &http.Client{Timeout: 10 * time.Second}
	req, err := http.NewRequest("POST", enqueueURL, bytes.NewReader(bs))
	if err != nil {
		return err
	}
	req.Header.Set("X-Api-Key", apiKey)
	req.Header.Set("Content-Type", "application/json; charset=utf-8")
	req.Header.Set("Accept", "application/json")

	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	bodyBytes, _ := io.ReadAll(resp.Body)
	bodyStr := strings.TrimSpace(string(bodyBytes))

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return fmt.Errorf("gateway http status: %d, body: %s", resp.StatusCode, bodyStr)
	}

	// 2xx：认为已成功提交
	now := time.Now()
	tidCopy := tid
	contentPtr := content
	var reportPtr *string
	if bodyStr != "" {
		reportPtr = &bodyStr
	}

	task := &models.SystemSMSTask{
		Tid:        &tidCopy,
		ApiKey:     apiKey,
		Phone:      phone,
		Content:    &contentPtr,
		Status:     3,
		Code:       code,
		ReportRaw:  reportPtr,
		CreateTime: &now,
		UpdateTime: &now,
	}

	_, insertErr := models.Orm.Insert(task)
	// 入队成功但写任务表失败：不影响用户侧体验
	if insertErr != nil {
		return nil
	}
	return nil
}