feat: split long posts into replies (#10)

* post split text as reply

---------

Co-authored-by: Maurice Renck <maurice@maurice-renck.de>

main.js

@@ -8,8 +8,14 @@ const axios = require("axios");
 const mastodonInstance = process.env.MASTODON_INSTANCE;
 const mastodonUser = process.env.MASTODON_USER;
 
+async function main() {
   // Bluesky agent
   const agent = new BskyAgent({ service: process.env.BLUESKY_ENDPOINT });
+  const loginResponse = await agent.login({
+    identifier: process.env.BLUESKY_HANDLE,
+    password: process.env.BLUESKY_PASSWORD,
+  });
+  if (!loginResponse.success) console.error("🔒 login failed");
 
   // File to store the last processed Mastodon post ID
   const lastProcessedPostIdFile = path.join(
@@ -40,31 +46,62 @@ function saveLastProcessedPostId() {
     }
   }
 
-async function postToBluesky(text) {
-  await agent.login({
-    identifier: process.env.BLUESKY_HANDLE,
-    password: process.env.BLUESKY_PASSWORD,
-  });
-
+  async function createBlueskyMessage(text) {
     const richText = new RichText({ text });
     await richText.detectFacets(agent);
-  await agent.post({
+
+    return {
       text: richText.text,
-    facets: richText.facets,
+      facets: richText.facets
+    };
+  }
+
+  async function postToBluesky(textParts) {
+    const rootMessageResponse = await agent.post(await createBlueskyMessage(textParts[0]));
+
+    if (textParts.length === 1) return;
+
+    let replyMessageResponse = null
+    for (let index = 1; index < textParts.length; index++) {
+      replyMessageResponse = await agent.post({
+        ...(await createBlueskyMessage(textParts[index])),
+        reply: {
+          root: rootMessageResponse,
+          parent: replyMessageResponse ?? rootMessageResponse,
+        }
       });
     }  
+  }
 
   function removeHtmlTags(input) {
     return input.replace(/<[^>]*>/g, "");
   }
 
-function truncate(text, timestampId) {
-  if (text.length > 300) {
-    console.warn(`✂ post '${timestampId}' was truncated`)
-    return text.substring(0, 299) + '…'
+  function splitText(text, maxLength) {
+    // Split the text by spaces
+    const words = text.split(" ");
+
+    let result = [];
+    let currentChunk = "";
+
+    for (const word of words) {
+        // Add the current word to the current chunk
+        const potentialChunk = `${currentChunk} ${word}`.trim();
+
+        if (potentialChunk.length <= maxLength) {
+            // If the current chunk is still under max length, add the word
+            currentChunk = potentialChunk;
+        } else {
+            // Otherwise, add the current chunk to the result and start a new chunk
+            result.push(currentChunk);
+            currentChunk = word;
+        }
     }
 
-  return text
+    // Add the last chunk to the result
+    result.push(currentChunk);
+
+    return result;
   }
 
   // Function to periodically fetch new Mastodon posts
@@ -90,8 +127,8 @@ async function fetchNewPosts() {
       if (currentTimestampId > lastProcessedPostId && lastProcessedPostId != 0) {
         try {
           console.log('📧 posting to BlueSky', currentTimestampId)
-        const text = truncate(removeHtmlTags(item.object.content), currentTimestampId);
-        postToBluesky(text);
+          const textParts = splitText(removeHtmlTags(item.object.content), 300);
+          postToBluesky(textParts);
         } catch (error) {
           console.error('🔥 can\'t post to Bluesky', currentTimestampId, error)
         }
@@ -107,3 +144,6 @@ async function fetchNewPosts() {
   fetchNewPosts();
   // Fetch new posts every 5 minutes (adjust as needed)
   setInterval(fetchNewPosts, (process.env.INTERVAL_MINUTES ?? 5) * 60 * 1000);
+}
+
+main()