From d943dbfdd796e6c689239f9b0c3c139fb7451f48 Mon Sep 17 00:00:00 2001
From: Robert Sesek <rsesek@bluestatic.org>
Date: Sun, 28 Dec 2025 17:11:22 -0500
Subject: [PATCH] Implement the gmailDestination

---
 cmd/mailbox-shuffler/dest.go             | 47 ++++++++++++++++++++++--
 cmd/mailbox-shuffler/mailbox-shuffler.go | 23 +++---------
 cmd/mailbox-shuffler/oauth.go            |  5 +++
 3 files changed, 54 insertions(+), 21 deletions(-)

diff --git a/cmd/mailbox-shuffler/dest.go b/cmd/mailbox-shuffler/dest.go
index 6398481..e82647d 100644
--- a/cmd/mailbox-shuffler/dest.go
+++ b/cmd/mailbox-shuffler/dest.go
@@ -6,9 +6,21 @@
 
 package main
 
-import "go.uber.org/zap"
+import (
+	"context"
+	"encoding/base64"
+
+	"go.uber.org/zap"
+	"google.golang.org/api/gmail/v1"
+	"google.golang.org/api/option"
+)
 
 type Destination interface {
+	// Connect attempts to dial the Destination and return a stateful connection.
+	Connect(context.Context) (DestinationConnection, error)
+}
+
+type DestinationConnection interface {
 	// AddMessage stores the raw RFC 2822 message body in the destination mail
 	// server.
 	AddMessage([]byte) error
@@ -16,7 +28,7 @@ type Destination interface {
 	Close() error
 }
 
-func NewDestination(config ServerConfig, auth *OAuthServer, log *zap.Logger) Destination {
+func NewDestination(config ServerConfig, auth OAuthServer, log *zap.Logger) Destination {
 	switch config.Type {
 	case ServerTypeGmail:
 		return &gmailDestination{
@@ -31,12 +43,39 @@ func NewDestination(config ServerConfig, auth *OAuthServer, log *zap.Logger) Des
 
 type gmailDestination struct {
 	c    ServerConfig
-	auth *OAuthServer
+	auth OAuthServer
 	log  *zap.Logger
+
+	ctx context.Context
+	svc *gmail.Service
+}
+
+func (d *gmailDestination) Connect(ctx context.Context) (DestinationConnection, error) {
+	tokenQ := <-d.auth.GetTokenForUser(ctx, d.c.Email)
+	if tokenQ.Error != nil {
+		return nil, tokenQ.Error
+	}
+
+	auth := option.WithHTTPClient(d.auth.MakeClient(ctx, tokenQ.Token))
+	svc, err := gmail.NewService(ctx, auth, option.WithUserAgent("mailbox-shuffler"))
+	if err != nil {
+		return nil, err
+	}
+	d2 := *d
+	d2.ctx = ctx
+	d2.svc = svc
+	return &d2, nil
 }
 
 func (d *gmailDestination) AddMessage(msg []byte) error {
-	return nil
+	enc := base64.RawURLEncoding.EncodeToString(msg)
+	call := d.svc.Users.Messages.Insert("me", &gmail.Message{
+		LabelIds: []string{"INBOX", "UNREAD"},
+		Raw:      enc,
+	})
+	result, err := call.Do()
+	d.log.Info("Result", zap.Any("result", result), zap.Error(err))
+	return err
 }
 
 func (d *gmailDestination) Close() error {
diff --git a/cmd/mailbox-shuffler/mailbox-shuffler.go b/cmd/mailbox-shuffler/mailbox-shuffler.go
index ddaa324..5c8c319 100644
--- a/cmd/mailbox-shuffler/mailbox-shuffler.go
+++ b/cmd/mailbox-shuffler/mailbox-shuffler.go
@@ -8,7 +8,6 @@ package main
 
 import (
 	"context"
-	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"os"
@@ -18,7 +17,6 @@ import (
 	"go.uber.org/zap"
 	"golang.org/x/oauth2/google"
 	"google.golang.org/api/gmail/v1"
-	"google.golang.org/api/option"
 )
 
 func main() {
@@ -74,23 +72,14 @@ func main() {
 
 	oauthServer := RunOAuthServer(ctx, config.OAuthServer, oauthConfig, log)
 
-	resp := <-oauthServer.GetTokenForUser(ctx, config.Monitor[0].Destination.Email)
-	if resp.Error != nil {
-		log.Fatal("Failed to get OAuth token", zap.Error(resp.Error))
+	dest := NewDestination(config.Monitor[0].Destination, oauthServer, log)
+	destConn, err := dest.Connect(ctx)
+	if err != nil {
+		log.Fatal("Failed to connect to destination", zap.Error(err))
 	}
 
-	auth := option.WithHTTPClient(oauthConfig.Client(ctx, resp.Token))
-	client, err := gmail.NewService(ctx, auth, option.WithUserAgent("mailbox-shuffler"))
+	err = destConn.AddMessage(rawMsg)
 	if err != nil {
-		log.Fatal("Failed to create GMail client", zap.Error(err))
+		log.Fatal("Failed to insert message", zap.Error(err))
 	}
-
-	rawEnc := base64.RawURLEncoding.EncodeToString(rawMsg)
-
-	call := client.Users.Messages.Insert("me", &gmail.Message{
-		LabelIds: []string{"INBOX", "UNREAD"},
-		Raw:      rawEnc,
-	})
-	result, err := call.Do()
-	log.Info("Result", zap.Any("result", result), zap.Error(err))
 }
diff --git a/cmd/mailbox-shuffler/oauth.go b/cmd/mailbox-shuffler/oauth.go
index 14de28a..a9314d6 100644
--- a/cmd/mailbox-shuffler/oauth.go
+++ b/cmd/mailbox-shuffler/oauth.go
@@ -26,6 +26,7 @@ type GetTokenForUserResult struct {
 
 type OAuthServer interface {
 	GetTokenForUser(ctx context.Context, id string) <-chan GetTokenForUserResult
+	MakeClient(context.Context, *oauth2.Token) *http.Client
 }
 
 type oauthServer struct {
@@ -186,3 +187,7 @@ func (s *oauthServer) handleRequest(rw http.ResponseWriter, req *http.Request) {
 	log.Error("Invalid request - missing code", zap.String("id", id))
 	http.Error(rw, "Invalid Code", http.StatusBadRequest)
 }
+
+func (s *oauthServer) MakeClient(ctx context.Context, token *oauth2.Token) *http.Client {
+	return s.o2c.Client(ctx, token)
+}
-- 
2.43.5