package mail

import (
	"errors"
	"eta/eta_email_analysis/global"
	"eta/eta_email_analysis/models/report"
	"fmt"
	"github.com/emersion/go-imap"
	"github.com/emersion/go-imap/client"
	"github.com/emersion/go-message"
	"github.com/emersion/go-message/mail"
	"log"
	"strings"
	"time"
)

func ListenMailV2(c *client.Client, to uint32) (err error) { // 收件箱
	obj := new(report.OutsideEmailBaseInfo)
	// 创建一个序列集，用于批量读取邮件
	seqSet := new(imap.SeqSet)

	var isStopFor bool
	step := uint32(1)
	for i := to; i >= 1; {
		start := i - step + 1
		if start < 0 {
			start = 1
		}

		//fmt.Printf("当前剩余%d封邮件待处理\n", i-minIndex+1)

		seqSet.Clear()
		seqSet.AddRange(start, i) // 添加指定范围内的邮件编号

		// 获取整个消息正文
		// imap.FetchEnvelope：请求获取邮件的信封数据（例如发件人、收件人、主题等元数据）。
		// imap.FetchRFC822：请求获取完整的邮件内容，包括所有头部和正文。
		items := []imap.FetchItem{imap.FetchFlags, imap.FetchEnvelope, imap.FetchRFC822}

		// 获取邮件内容 Start
		messages := make(chan *imap.Message, global.CONFIG.Email.ReadBatchSize) // 创建一个通道，用于接收邮件消息
		fetchDone := make(chan error, 1)                                        // 创建一个通道，用于接收错误消息
		go func() {
			// Fetch方法用于从服务器获取邮件数据，这里请求了邮件的信封和完整内容
			fetchDone <- c.Fetch(seqSet, items, messages)
		}()

		err = <-fetchDone
		if err != nil {
			global.LOG.Errorf("获取邮件信息出现错误：%v \n", err)
			return
		}
		// 获取邮件内容 End

		//log.Println("开始读取邮件内容")
		for msg := range messages {
			// 如果需要终止，那么就不处理了
			if isStopFor {
				continue
			}

			emailMessage, isRead, tmpErr := readEveryMsgV2(msg)
			if tmpErr != nil {
				continue
			}
			if !isRead {
				continue
			}

			// 记录邮件信息
			{
				outEmail, _ := obj.GetByEmailMessageIdAndFolder(emailMessage.Uid, emailMessage.Folder)
				if outEmail == nil || outEmail.EmailMessageUid <= 0 {
					outsideEmail := &report.OutsideEmailBaseInfo{
						Id:              0,
						Folder:          emailMessage.Folder,
						EmailMessageUid: emailMessage.Uid,
						Title:           emailMessage.Title,
						FromAddress:     emailMessage.FromAddress,
						From:            emailMessage.From,
						DeliveryTime:    emailMessage.Date,
						CreateTime:      time.Now(),
					}
					tmpErr := obj.Add(outsideEmail)
					if tmpErr != nil {
						fmt.Println("保存邮件基础信息失败：" + tmpErr.Error())
					}
				}
			}

		}

		if isStopFor {
			// 已经找到了最小的邮件id，那么就退出循环了
		}
		//time.Sleep(time.Second * 5) // 休眠10秒

		i = i - step
	}

	log.Println("读取了所有邮件，完毕！")

	return
}

// document link: https://github.com/emersion/go-imap/wiki/Fetching-messages
func readEveryMsgV2(msg *imap.Message) (emailMessage MailMessage, ok bool, err error) {
	emailMessage = MailMessage{}

	message.CharsetReader = myCharsetReader
	emailMessage.Resources = make(map[string]string)  // 内嵌资源
	emailMessage.Attachment = make(map[string]string) // 附件

	emailMessage.Uid = msg.Uid
	emailMessage.Folder = global.CONFIG.Email.Folder
	if IsHandleMessageIdMap != nil {
		if _, has := IsHandleMessageIdMap[int(emailMessage.Uid)]; has {
			fmt.Println("邮件已处理,邮件下标：", emailMessage.Uid)
			return
		}
	}

	//log.Printf("当前邮件的消息序列号 %+v \n", msg.SeqNum)
	//log.Println("-------------------------")
	// 获取邮件正文
	r := msg.GetBody(&imap.BodySectionName{})
	if r == nil {
		global.FILE_LOG.Info("服务器没有返回消息内容")
	}

	mr, err := mail.CreateReader(r)
	if err != nil {
		//log.Fatalf("邮件读取时出现错误： %v \n", err)
		err = errors.New(fmt.Sprintf("邮件读取时出现错误：%v \n", err))
		return
	}

	// 收件时间
	{
		date, err := mr.Header.Date()
		if err != nil {
			log.Println("收件时间 异常:", err.Error())
		}
		emailMessage.Date = date
		//log.Println("收件时间 Date:", date)
	}

	// 发件人
	{
		fromStr := mr.Header.Get("From")
		//fmt.Println(fromStr)
		// 处理无效地址的情况
		if !strings.Contains(fromStr, "@") {
			emailMessage.FromAddress = fromStr
			emailMessage.From = fromStr
		} else {
			from, tmpErr := mr.Header.AddressList("From")
			if tmpErr != nil {
				log.Println("发件人 异常:", err.Error())
			}
			if len(from) > 0 {
				emailMessage.FromAddress = from[0].Address
				emailMessage.From = from[0].Name
				//mailMessage.From = from[0].String()
				//log.Println("发件人 From:", from)
			}
		}
	}

	//if to, err := mr.Header.AddressList("To"); err == nil {
	//	log.Println("收件人 To:", to)
	//}
	//log.Printf("抄送 Cc: %+v \n", msg.Envelope.Cc)

	// 邮件标题
	subject, err := mr.Header.Subject()
	if err != nil {
		log.Println("邮件主题 Subject ERR:", err)
	} else {
		//log.Println("邮件主题 Subject:", subject)
	}
	emailMessage.Title = subject

	// 过滤
	if isIgnore(emailMessage) {
		ok = false
		return
	}

	ok = true

	return
}