1 files changed, 38 insertions, 0 deletions
diff --git a/app/imap.js b/app/imap.js
index 1ac76a4..f2e8cc2 100644
--- a/app/imap.js
+++ b/app/imap.js
@@ -3,6 +3,7 @@ const { ImapFlow } = require('imapflow');
 
 ipcMain.on('imap:listTree:from', listTreeFrom);
 ipcMain.on('imap:listTree:to', listTreeTo);
+ipcMain.on('imap:migrate', migrate);
 
 async function connect (options) {
   const client = new ImapFlow({
@@ -32,3 +33,40 @@ async function listTreeTo (event, options) {
   event.reply('imap:listTree:to:reply', await client.listTree());
   await client.logout();
 }
+
+async function migrate (event, { from, to }) {
+  const fromClient = await connect(from);
+  const toClient = await connect(to);
+
+  const fromFolders = (await fromClient.list()).filter((folder) => folder.subscribed);
+  for (const fromFolder of fromFolders) {
+    try {
+      await toClient.mailboxCreate(fromFolder.path);
+    } catch (e) {}
+
+    const fromMailbox = await fromClient.getMailboxLock(fromFolder.path);
+    const toMailbox = await toClient.getMailboxLock(fromFolder.path);
+    try {
+      const toMsgsGenerator = await toClient.fetch('1:*', { flags: true, envelope: true, source: true });
+      const toMsgs = [];
+      for await (const toMsg of toMsgsGenerator) {
+        toMsgs.push(toMsg);
+      }
+      const fromMsgsGenerator = await fromClient.fetch('1:*', { flags: true, envelope: true, source: true });
+
+      for await (const fromMsg of fromMsgsGenerator) {
+        if (toMsgs.some((toMsg) => Buffer.compare(toMsg.source, fromMsg.source) === 0)) {
+          continue;
+        }
+
+        await toClient.append(fromFolder.path, fromMsg.source, Array.from(fromMsg.flags), fromMsg.envelope.date);
+      }
+    } finally {
+      fromMailbox.release();
+      toMailbox.release();
+    }
+  }
+
+  await fromClient.logout();
+  await toClient.logout();
+}