package services

import (
	"bytes"
	"context"
	"crypto/rand"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
	"time"

	"server/models"
)

// ReminderSender 提醒发送接口
type ReminderSender interface {
	Send(ctx context.Context, reminder *models.PlatformScheduleReminder, title, content string) (success bool, err error)
}

// SMSSender 短信发送实现
type SMSSender struct{}

func (s *SMSSender) Send(ctx context.Context, reminder *models.PlatformScheduleReminder, title, content string) (bool, error) {
	backendURL, apiKey, err := getDefaultSystemSMSConfig()
	if err != nil {
		return false, err
	}
	phone := ""
	if reminder.ReceiverTarget != nil && *reminder.ReceiverTarget != "" {
		phone = *reminder.ReceiverTarget
	} else {
		var user models.AdminUser
		if err := models.Orm.QueryTable(new(models.AdminUser)).Filter("id", reminder.ReceiverUserID).One(&user); err == nil && user.Phone != nil {
			phone = *user.Phone
		}
	}
	if phone == "" {
		return false, fmt.Errorf("未配置手机号")
	}

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

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

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

	if resp.StatusCode != http.StatusOK {
		bodyBytes, _ := io.ReadAll(resp.Body)
		return false, fmt.Errorf("网关返回HTTP状态码: %d, 返回内容: %s", resp.StatusCode, string(bodyBytes))
	}

	return true, nil
}

// EmailSender 邮件发送实现
type EmailSender struct{}

func (s *EmailSender) Send(ctx context.Context, reminder *models.PlatformScheduleReminder, title, content string) (bool, error) {
	emails, err := ListSystemEmails()
	if err != nil || len(emails) == 0 {
		return false, fmt.Errorf("未配置系统邮箱")
	}
	emailCfg := emails[0]
	if emailCfg.FromAddress == "" || emailCfg.Host == "" {
		return false, fmt.Errorf("未配置系统邮箱")
	}

	toEmail := ""
	if reminder.ReceiverTarget != nil && *reminder.ReceiverTarget != "" {
		toEmail = *reminder.ReceiverTarget
	} else {
		var user models.AdminUser
		if err := models.Orm.QueryTable(new(models.AdminUser)).Filter("id", reminder.ReceiverUserID).One(&user); err == nil && user.Email != nil {
			toEmail = *user.Email
		}
	}
	if toEmail == "" {
		return false, fmt.Errorf("未配置收件邮箱")
	}

	sysDomain := models.GetPlatformSettingValue("system_domain", "https://api.yunzer.cn")
	ackToken := ""
	if reminder.AckToken != nil {
		ackToken = *reminder.AckToken
	}

	// 构造 HTML 邮件
	htmlBody := fmt.Sprintf(`
		<div style="font-family: Arial, sans-serif; padding: 20px; border: 1px solid #eee; border-radius: 5px; max-width: 600px; margin: 0 auto;">
			<h2 style="color: #409EFF; margin-bottom: 20px;">日程提醒：%s</h2>
			<p style="font-size: 16px; line-height: 1.6; color: #333;">%s</p>
			<hr style="border: 0; border-top: 1px solid #eee; margin: 20px 0;" />
	`, title, content)

	if ackToken != "" {
		ackURL := fmt.Sprintf("%s/api/schedule/reminder/ack?token=%s", strings.TrimRight(sysDomain, "/"), ackToken)
		htmlBody += fmt.Sprintf(`
			<div style="text-align: center; margin-top: 30px;">
				<a href="%s" target="_blank" style="background-color: #409EFF; color: #fff; padding: 12px 24px; text-decoration: none; border-radius: 4px; font-weight: bold; display: inline-block;">
					收到，确认此提醒
				</a>
			</div>
			<p style="font-size: 12px; color: #999; text-align: center; margin-top: 15px;">确认收到后，系统将不再向您发送该日程的重复提醒。</p>
		`, ackURL)
	}

	htmlBody += "</div>"

	cfg := SMTPConfig{
		FromAddress: emailCfg.FromAddress,
		Host:        emailCfg.Host,
		Port:        emailCfg.Port,
		Password:    emailCfg.Password,
		Encryption:  emailCfg.Encryption,
		Timeout:     emailCfg.Timeout,
	}
	if emailCfg.FromName != nil {
		cfg.FromName = *emailCfg.FromName
	}

	err = SendHTMLEmailSMTP(cfg, toEmail, title, htmlBody)
	if err != nil {
		return false, err
	}

	return true, nil
}

// BarkSender Bark 推送实现
type BarkSender struct{}

func (s *BarkSender) Send(ctx context.Context, reminder *models.PlatformScheduleReminder, title, content string) (bool, error) {
	deviceKey := ""
	if reminder.ReceiverTarget != nil && *reminder.ReceiverTarget != "" {
		deviceKey = *reminder.ReceiverTarget
	} else {
		deviceKey = models.GetPlatformSettingValue("bark_device_key", "")
	}
	if deviceKey == "" {
		return false, fmt.Errorf("Bark 设备 Key 未配置")
	}

	serverURL := models.GetPlatformSettingValue("bark_server_url", "https://api.day.app")
	sysDomain := models.GetPlatformSettingValue("system_domain", "https://api.yunzer.cn")
	ackToken := ""
	if reminder.AckToken != nil {
		ackToken = *reminder.AckToken
	}

	baseURL := strings.TrimRight(serverURL, "/")
	escapedTitle := url.PathEscape(title)
	pushContent := content
	if ackToken != "" {
		pushContent += "\n确认收到请点击→"
	}
	escapedContent := url.PathEscape(pushContent)

	barkURL := fmt.Sprintf("%s/%s/%s/%s", baseURL, deviceKey, escapedTitle, escapedContent)

	if ackToken != "" {
		ackURL := fmt.Sprintf("%s/api/schedule/reminder/ack?token=%s", strings.TrimRight(sysDomain, "/"), ackToken)
		// Bark 官方推送支持 url 参数
		barkURL += "?url=" + url.QueryEscape(ackURL)
	}

	client := &http.Client{Timeout: 10 * time.Second}
	req, err := http.NewRequestWithContext(ctx, "GET", barkURL, nil)
	if err != nil {
		return false, err
	}

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

	if resp.StatusCode != http.StatusOK {
		bodyBytes, _ := io.ReadAll(resp.Body)
		return false, fmt.Errorf("Bark返回HTTP状态码: %d, 返回内容: %s", resp.StatusCode, string(bodyBytes))
	}

	return true, nil
}

// SiteMsgSender 站内信发送实现
type SiteMsgSender struct{}

func (s *SiteMsgSender) Send(ctx context.Context, reminder *models.PlatformScheduleReminder, title, content string) (bool, error) {
	now := time.Now()
	msg := &models.SystemReminderList{
		Title:        title,
		Content:      content,
		SenderID:     0,
		SenderType:   "system",
		ReceiverID:   reminder.ReceiverUserID,
		ReceiverType: "platform", // 平台端用户
		IsRead:       0,
		CreateTime:   &now,
	}
	_, err := models.Orm.Insert(msg)
	if err != nil {
		return false, err
	}
	return true, nil
}

// generateUUID 生成一个安全的随机 UUID 字符
func generateUUID() string {
	b := make([]byte, 16)
	_, _ = rand.Read(b)
	b[6] = (b[6] & 0x0f) | 0x40
	b[8] = (b[8] & 0x3f) | 0x80
	return fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])
}

// StartReminderScheduler 启动定时提醒调度器 (1分钟一次的 Ticker)
func StartReminderScheduler(stopChan chan struct{}) {
	ticker := time.NewTicker(1 * time.Minute)
	go func() {
		for {
			select {
			case <-ticker.C:
				scanAndSendReminders()
			case <-stopChan:
				ticker.Stop()
				return
			}
		}
	}()
}

func scanAndSendReminders() {
	// 1. 生成唯一扫描批次号用于抢占锁定
	scanBatch := generateUUID()
	now := time.Now()

	// 2. 抢占待处理的数据（乐观锁防并发重复发送）
	_, err := models.Orm.Raw(`
		UPDATE yz_platform_schedule_reminder 
		SET scan_lock = ?, update_time = NOW() 
		WHERE next_remind_time <= ? 
		  AND remind_status IN (0, 1) 
		  AND is_deleted = 0 
		  AND (scan_lock = '' OR scan_lock IS NULL)
	`, scanBatch, now).Exec()
	if err != nil {
		return
	}

	// 3. 查询自己锁定成功的数据
	var list []models.PlatformScheduleReminder
	_, err = models.Orm.QueryTable(new(models.PlatformScheduleReminder)).
		Filter("scan_lock", scanBatch).
		Filter("remind_status__in", 0, 1).
		Filter("is_deleted", 0).
		All(&list)
	if err != nil || len(list) == 0 {
		return
	}

	// 实例分发发送
	senders := map[string]ReminderSender{
		"SMS":      &SMSSender{},
		"EMAIL":    &EmailSender{},
		"BARK":     &BarkSender{},
		"SITE_MSG": &SiteMsgSender{},
	}

	for i := range list {
		reminder := &list[i]

		// 3.1 获取日程信息（主要拿 Content，Title 统一为 "日程提醒"）
		var schedule models.PlatformSchedule
		err := models.Orm.QueryTable(new(models.PlatformSchedule)).
			Filter("id", reminder.ScheduleID).
			One(&schedule)
		title := "日程提醒"
		content := "您有一个待处理的日程时间已到，请注意查收。"
		if err == nil {
			content = schedule.Content
		}

		sender, ok := senders[reminder.RemindChannel]
		if !ok {
			// 未知渠道，直接强制置为结束
			_, _ = models.Orm.QueryTable(new(models.PlatformScheduleReminder)).
				Filter("id", reminder.ID).
				Update(map[string]interface{}{
					"remind_status": 2,
					"scan_lock":     "",
					"update_time":   time.Now(),
				})
			continue
		}

		// 执行发送
		ctx := context.Background()
		success, sendErr := sender.Send(ctx, reminder, title, content)

		// 3.2 记录发送流水日志
		sendResult := int8(0)
		var failReason *string
		if success {
			sendResult = 1
		} else if sendErr != nil {
			errStr := sendErr.Error()
			if len(errStr) > 255 {
				errStr = errStr[:255]
			}
			failReason = &errStr
		}

		logRow := &models.PlatformScheduleReminderSendLog{
			ReminderID: reminder.ID,
			SendTime:   time.Now(),
			SendResult: sendResult,
			FailReason: failReason,
		}
		_, _ = models.Orm.Insert(logRow)

		// 3.3 根据发送渠道分类更新提醒状态和下一次发送时间
		newSendCount := reminder.SendCount + 1
		newStatus := reminder.RemindStatus

		if reminder.RemindChannel == "SMS" || reminder.RemindChannel == "SITE_MSG" {
			// 一次性发送：发送后直接置为结束
			newStatus = 2
		} else {
			// 重复发送渠道 EMAIL / BARK
			// 如果还没被 Ack，且没有达到 max_send_count，继续提醒
			if reminder.AckStatus == 0 && newSendCount < reminder.MaxSendCount {
				newStatus = 1 // 提醒中
				// 更新下次发送时间
				reminder.NextRemindTime = time.Now().Add(time.Duration(reminder.RepeatIntervalMinutes) * time.Minute)
			} else {
				// 达到最大上限或者已 Ack
				newStatus = 2
			}
		}

		// 3.4 回写主表记录
		_, _ = models.Orm.QueryTable(new(models.PlatformScheduleReminder)).
			Filter("id", reminder.ID).
			Update(map[string]interface{}{
				"SendCount":       newSendCount,
				"NextRemindTime": reminder.NextRemindTime,
				"RemindStatus":    newStatus,
				"ScanLock":        "", // 释放扫描锁
				"UpdateTime":      time.Now(),
			})
	}
}