package tools

import (
	"bytes"
	"fmt"
	"github.com/axgle/mahonia"
	"github.com/emersion/go-imap"
	"github.com/emersion/go-imap/client"
	"github.com/emersion/go-message/mail"
	"io"
	"io/ioutil"
	"log"
	"mime"
	"strconv"
	"strings"
)
//验证邮箱密码
func CheckEmailPassword(server string, email string, password string) bool {
	if !strings.Contains(server, ":") {
		return false
	}
	var c *client.Client
	serverSlice := strings.Split(server, ":")
	port, _ := strconv.Atoi(serverSlice[1])
	if port != 993 && port != 143 {
		return false
	}

	// 不要忘了退出
	//defer c.Logout()

	// 登陆
	c=connect(server,email,password)
	if c==nil{
		return false
	}
	return true
}
//获取连接
func connect(server string, email string, password string)*client.Client{
	var c *client.Client
	var err error
	serverSlice := strings.Split(server, ":")
	uri := serverSlice[0]
	port, _ := strconv.Atoi(serverSlice[1])
	if port != 993 && port != 143 {
		return nil
	}
	if port == 993 {
		c, err = client.DialTLS(fmt.Sprintf("%s:%d", uri, port), nil)
	} else {
		c, err = client.Dial(fmt.Sprintf("%s:%d", uri, port))
	}
	if err != nil {
		return nil
	}

	// 登陆
	if err := c.Login(email, password); err != nil {
		return nil
	}
	return c
}
//获取邮件夹
func GetFolders(server string, email string, password string,folder string)map[string]int{
	var c *client.Client
	//defer c.Logout()
	c=connect(server,email,password)
	if c==nil{
		return nil
	}
	// 列邮箱
	mailboxes := make(chan *imap.MailboxInfo, 10)
	done := make(chan error, 1)
	go func() {
		done <- c.List("", "*", mailboxes)
	}()
	// 存储邮件夹
	var folders =make(map[string]int)
	for m := range mailboxes {
		folders[m.Name]=0
	}
	for m,_ := range folders {
		if m==folder {
			mbox, _ := c.Select(m, true)
			if mbox != nil {
				folders[m] = int(mbox.Messages)
			}
			break
		}
	}
	log.Println(folders)
	return folders
}

//获取邮件夹邮件
func GetFolderMail(server string, email string, password string,folder string,currentPage int,pagesize int)[]*MailItem{
	var c *client.Client
	//defer c.Logout()
	c=connect(server,email,password)
	if c==nil{
		return nil
	}

	mbox, _ := c.Select(folder, true)
	to := mbox.Messages-uint32((currentPage-1)*pagesize)
	from := to-uint32(pagesize)
	if to <=uint32(pagesize){
		from=1
	}

	seqset := new(imap.SeqSet)
	seqset.AddRange(from, to)

	messages := make(chan *imap.Message, pagesize)
	done := make(chan error, 1)
	go func() {
		done <- c.Fetch(seqset, []imap.FetchItem{imap.FetchEnvelope}, messages)
	}()
	var mailPagelist=new(MailPageList)

	dec :=GetDecoder()

	for msg:=range messages{

		ret,err:=dec.Decode(msg.Envelope.Subject)
		if err!=nil{
			ret,_=dec.DecodeHeader(msg.Envelope.Subject)
		}
		var mailitem =new(MailItem)
		log.Println(msg.SeqNum)

		mailitem.Subject=ret
		mailitem.Id=msg.SeqNum
		mailitem.Fid=folder
		mailPagelist.MailItems=append(mailPagelist.MailItems,mailitem)
	}
	return mailPagelist.MailItems
}
func GetMessage(server string, email string, password string,folder string,id uint32)*MailItem{
	var c *client.Client
	//defer c.Logout()
	c=connect(server,email,password)
	if c==nil{
		//return nil
	}
	// Select INBOX
	mbox, err := c.Select(folder, false)
	if err != nil {
		log.Fatal(err)
	}

	// Get the last message
	if mbox.Messages == 0 {
		log.Fatal("No message in mailbox")
	}
	seqSet := new(imap.SeqSet)
	seqSet.AddNum(id)

	// Get the whole message body
	var section imap.BodySectionName
	items := []imap.FetchItem{section.FetchItem()}

	messages := make(chan *imap.Message, 1)
	go func() {
		if err := c.Fetch(seqSet, items, messages); err != nil {
			log.Fatal(err)
		}
	}()

	msg := <-messages
	if msg == nil {
		log.Fatal("Server didn't returned message")
	}

	r := msg.GetBody(&section)
	if r == nil {
		log.Fatal("Server didn't returned message body")
	}

	// Create a new mail reader
	mr, err := mail.CreateReader(r)
	if err != nil {
		log.Fatal(err)
	}
	var mailitem =new(MailItem)

	// Print some info about the message
	header := mr.Header
	if date, err := header.Date(); err == nil {
		log.Println("Date:", date)
		mailitem.Date=date.String()
	}
	var f string
	dec:=GetDecoder()

	if from, err := header.AddressList("From"); err == nil {
		log.Println("From:", from)
		for _,address:=range from{
			temp,_:=dec.DecodeHeader(address.String())
			f+=" "+temp
		}
	}
	mailitem.From=f
	var t string
	if to, err := header.AddressList("To"); err == nil {
		log.Println("To:", to)
		for _,address:=range to{
			temp,_:=dec.DecodeHeader(address.String())
			t+=" "+temp
		}
	}
	mailitem.To=t
	if subject, err := header.Subject(); err == nil {
		s,err:=dec.Decode(subject)
		if err!=nil{
			s,_=dec.DecodeHeader(subject)
		}
		log.Println("Subject:", s)
		mailitem.Subject=s
	}
	// Process each message's part
	for {
		p, err := mr.NextPart()
		if err == io.EOF {
			break
		} else if err != nil {
			//log.Fatal(err)
		}
		switch h := p.Header.(type) {
		case *mail.InlineHeader:
			// This is the message's text (can be plain-text or HTML)
			b, _ := ioutil.ReadAll(p.Body)
			mailitem.Body+=string(b)
			//body,_:=dec.Decode(string(b))
			log.Println("Got text: ", string(b))
		case *mail.AttachmentHeader:
			// This is an attachment
			filename, _ := h.Filename()
			log.Println("Got attachment: ", filename)
		}
	}
	return mailitem
}
func GetDecoder()*mime.WordDecoder{
	dec :=new(mime.WordDecoder)
	dec.CharsetReader= func(charset string, input io.Reader) (io.Reader, error) {
		switch charset {
		case "gb2312":
			content, err := ioutil.ReadAll(input)
			if err != nil {
				return nil, err
			}
			//ret:=bytes.NewReader(content)
			//ret:=transform.NewReader(bytes.NewReader(content), simplifiedchinese.HZGB2312.NewEncoder())

			utf8str:=ConvertToStr(string(content),"gbk","utf-8")
			t:=bytes.NewReader([]byte(utf8str))
			//ret:=utf8.DecodeRune(t)
			//log.Println(ret)
			return t, nil
		case "gbk":
			content, err := ioutil.ReadAll(input)
			if err != nil {
				return nil, err
			}
			//ret:=bytes.NewReader(content)
			//ret:=transform.NewReader(bytes.NewReader(content), simplifiedchinese.HZGB2312.NewEncoder())

			utf8str:=ConvertToStr(string(content),"gbk","utf-8")
			t:=bytes.NewReader([]byte(utf8str))
			//ret:=utf8.DecodeRune(t)
			//log.Println(ret)
			return t, nil
		case "gb18030":
			content, err := ioutil.ReadAll(input)
			if err != nil {
				return nil, err
			}
			//ret:=bytes.NewReader(content)
			//ret:=transform.NewReader(bytes.NewReader(content), simplifiedchinese.HZGB2312.NewEncoder())

			utf8str:=ConvertToStr(string(content),"gbk","utf-8")
			t:=bytes.NewReader([]byte(utf8str))
			//ret:=utf8.DecodeRune(t)
			//log.Println(ret)
			return t, nil
		default:
			return nil,fmt.Errorf("unhandle charset:%s",charset)

		}
	}
	return dec
}
// 任意编码转特定编码
func ConvertToStr(src string, srcCode string, tagCode string) string {
	srcCoder := mahonia.NewDecoder(srcCode)
	srcResult := srcCoder.ConvertString(src)
	tagCoder := mahonia.NewDecoder(tagCode)
	_, cdata, _ := tagCoder.Translate([]byte(srcResult), true)
	result := string(cdata)
	return result
}