Add mailing sending feature for Anson Chen :)

mail.go

@@ -0,0 +1,198 @@
+package proton_api_bridge
+
+import (
+	"context"
+	"encoding/base64"
+	"io/ioutil"
+	"log"
+	"net/mail"
+	"path/filepath"
+
+	"github.com/ProtonMail/gluon/rfc822"
+	"github.com/ProtonMail/gopenpgp/v2/crypto"
+	"github.com/henrybear327/go-proton-api"
+)
+
+type MailSendingParameters struct {
+	TemplateFile          string
+	EmailSubject          string
+	RecipientEmailAddress string
+	EmailAttachments      []string
+	EmailContentIDs       []string
+}
+
+func (protonDrive *ProtonDrive) SendEmail(ctx context.Context, i int, errChan chan error, config *MailSendingParameters) {
+	log.Println("SendEmail in", i)
+	defer log.Println("SendEmail out", i)
+
+	createDraftResp, err := protonDrive.createDraft(ctx, config)
+	if err != nil {
+		errChan <- err
+	}
+
+	attachments, err := protonDrive.uploadAttachments(ctx, createDraftResp, config)
+	if err != nil {
+		errChan <- err
+	}
+
+	err = protonDrive.sendDraft(ctx, createDraftResp.ID, attachments, config)
+	if err != nil {
+		errChan <- err
+	}
+
+	errChan <- nil
+}
+
+func (protonDrive *ProtonDrive) getHTMLBody(config *MailSendingParameters) ([]byte, error) {
+	htmlTemplate, err := ioutil.ReadFile(config.TemplateFile)
+	if err != nil {
+		return nil, err
+	}
+
+	return htmlTemplate, nil
+}
+
+func (protonDrive *ProtonDrive) createDraft(ctx context.Context, config *MailSendingParameters) (*proton.Message, error) {
+	htmlTemplate, err := protonDrive.getHTMLBody(config)
+	if err != nil {
+		return nil, err
+	}
+
+	createDraftReq := proton.CreateDraftReq{
+		Message: proton.DraftTemplate{
+			Subject: config.EmailSubject,
+			Sender: &mail.Address{
+				Address: protonDrive.signatureAddress,
+			},
+			ToList: []*mail.Address{
+				{
+					Address: config.RecipientEmailAddress,
+				},
+			},
+			CCList:   []*mail.Address{},
+			BCCList:  []*mail.Address{},
+			Body:     string(htmlTemplate), // NOTE: the body here is for yourself to view it! No sender encryption is done yet
+			MIMEType: rfc822.TextHTML,
+			// Unread:   false,
+
+			// ExternalID: "", // FIXME: what's this
+		},
+	}
+
+	createDraftResp, err := protonDrive.c.CreateDraft(ctx, protonDrive.AddrKR, createDraftReq)
+	if err != nil {
+		return nil, err
+	}
+
+	return &createDraftResp, nil
+}
+
+func (protonDrive *ProtonDrive) getAttachmentSessionKeyMap(attachments []*proton.Attachment) (map[string]*crypto.SessionKey, error) {
+	ret := make(map[string]*crypto.SessionKey)
+
+	for i := range attachments {
+		keyPacket, err := base64.StdEncoding.DecodeString(attachments[i].KeyPackets)
+		if err != nil {
+			return nil, err
+		}
+
+		key, err := protonDrive.AddrKR.DecryptSessionKey(keyPacket)
+		if err != nil {
+			return nil, err
+		}
+
+		ret[attachments[i].ID] = key
+	}
+
+	return ret, nil
+}
+
+func (protonDrive *ProtonDrive) uploadAttachments(ctx context.Context, createDraftResp *proton.Message, config *MailSendingParameters) ([]*proton.Attachment, error) {
+	attachments := make([]*proton.Attachment, 0)
+	for i := range config.EmailAttachments {
+		// read out attachment file
+		fileByteArray, err := ioutil.ReadFile(config.EmailAttachments[i])
+		if err != nil {
+			return nil, err
+		}
+
+		req := proton.CreateAttachmentReq{
+			MessageID: createDraftResp.ID,
+
+			Filename:    filepath.Base(config.EmailAttachments[i]),
+			MIMEType:    rfc822.MultipartMixed, // FIXME: what is this?
+			Disposition: proton.InlineDisposition,
+			ContentID:   config.EmailContentIDs[i],
+
+			Body: fileByteArray,
+		}
+
+		uploadAttachmentResp, err := protonDrive.c.UploadAttachment(ctx, protonDrive.AddrKR, req)
+		if err != nil {
+			return nil, err
+		}
+
+		// log.Printf("uploadAttachmentResp %#v", uploadAttachmentResp)
+
+		attachments = append(attachments, &uploadAttachmentResp)
+	}
+
+	return attachments, nil
+}
+
+func (protonDrive *ProtonDrive) sendDraft(ctx context.Context, messageID string, attachents []*proton.Attachment, config *MailSendingParameters) error {
+	// FIXME: repect all sendPrefs
+	// FIXME: respect PGPMIMEScheme, etc.
+
+	recipientPublicKeys, recipientType, err := protonDrive.c.GetPublicKeys(ctx, config.RecipientEmailAddress)
+	if err != nil {
+		return err
+	}
+	if recipientType != proton.RecipientTypeInternal {
+		log.Fatalln("Currently only support internal email sending")
+	}
+	recipientKR, err := recipientPublicKeys.GetKeyRing()
+	if err != nil {
+		return err
+	}
+
+	htmlTemplate, err := protonDrive.getHTMLBody(config)
+	if err != nil {
+		return err
+	}
+
+	atts, err := protonDrive.getAttachmentSessionKeyMap(attachents)
+	if err != nil {
+		return err
+	}
+
+	// send email
+	sendReq := proton.SendDraftReq{
+		// Packages: []*proton.MessagePackage{},
+	}
+
+	// for each of the recipient, we encrypt body for them
+	if err = sendReq.AddTextPackage(protonDrive.AddrKR,
+		string(htmlTemplate),
+		rfc822.TextHTML,
+		map[string]proton.SendPreferences{config.RecipientEmailAddress: {
+			Encrypt:          true,
+			PubKey:           recipientKR,
+			SignatureType:    proton.DetachedSignature,
+			EncryptionScheme: proton.InternalScheme,
+			MIMEType:         rfc822.TextHTML, // FIXME
+		}},
+		atts,
+	); err != nil {
+		return err
+	}
+
+	/* msg */
+	_, err = protonDrive.c.SendDraft(ctx, messageID, sendReq)
+	if err != nil {
+		return err
+	}
+	// log.Println(msg)
+
+	return nil
+}