package main

import (
	"bytes"
	"fmt"
	"io"
	"log"
	"mime"
	"mime/multipart"
	"net/mail"
	"os"
	"strings"
)

var email = strings.NewReader(`From: Ali Josie <ajozi@harlemnext.com>
To: feedback@domain.com
Subject: Feedback Report
MIME-Version: 1.0
Content-Type: multipart/report; report-type=feedback-report; 
	boundary="XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"

--XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

This is plain text.

--XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Content-Type: message/feedback-report
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

Feedback-Type: abuse
Original-Mail-From: <ajozi@harlemnext.com>

--XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Content-Type: message/rfc822
Content-Disposition: inline

Date: Mon, 3 Feb 2020 19:16:52 +0000
To: Test <test@gmail.com>
From: Ali Josie <ajozi@harlemnext.com>
Subject: Test 
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii

This is the original email.

--XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX--
`)

func main() {
	msg, err := mail.ReadMessage(email)
	if err != nil {
		log.Fatal(err)
	}
	_, params, err := mime.ParseMediaType(msg.Header.Get("Content-Type"))
	if err != nil {
		log.Fatal(err)
	}
	mr := multipart.NewReader(msg.Body, params["boundary"])
	for {
		part, err := mr.NextRawPart()
		if err == io.EOF {
			break
		}
		if err != nil {
			log.Fatal(err)
		}
		contentType := part.Header.Get("Content-Type")
		fmt.Printf("Content-Type: %v\n", contentType)

		b := new(bytes.Buffer)
		b.ReadFrom(part)
		fmt.Printf("Body: %q\n\n", b.String())


		switch {
		case strings.HasPrefix(contentType, "message"):
			msg, err = mail.ReadMessage(b)
			if err != nil {
				log.Println("error occurred:", err)
				break
			}
			io.Copy(os.Stdout, msg.Body)
		default:
			io.Copy(os.Stdout, b)
		}
		fmt.Println("-----------------------------")
	}
}