package attachments

import (
	"bytes"
	"encoding/base64"
	"fmt"
	"io"
)

const delimeter = "**=myohmy689407924327"

type EmailAttachment struct {
	File  io.Reader
	Title string
}

func (e EmailAttachment) ReadContent() ([]byte, error) {
	bts, err := io.ReadAll(e.File)
	if err != nil {
		return nil, fmt.Errorf("error loading attachment: %s", err)
	}
	return bts, nil
}

func AttachmentsToBytes(body string, attachments []EmailAttachment) ([]byte, error) {
	var message bytes.Buffer
	message.WriteString("Content-Type: text/html; charset=\"UTF-8\"\r\n\r\n")
	message.WriteString(body + "\r\n\r\n")
	for _, attachment := range attachments {
		attachmentRawFile, err := attachment.ReadContent()
		if err != nil {
			return nil, err
		}
		message.WriteString("--" + delimeter + "\r\n")
		message.WriteString("Content-Disposition: attachment; filename=\"" + attachment.Title + "\"\r\n")
		message.WriteString("Content-Type: application/octet-stream\r\n")
		message.WriteString("Content-Transfer-Encoding: base64\r\n\r\n")
		message.WriteString(base64.StdEncoding.EncodeToString(attachmentRawFile) + "\r\n")
	}
	message.WriteString("--" + delimeter + "--") // End the message
	return message.Bytes(), nil
}