fix(db/indexSync.js): update import paths for Conversation and Message models

feat(db/indexSync.js): add synchronization logic between MongoDB collection and MeiliSearch index
fix(models/plugins/mongoMeili.js): update createMeiliMongooseModel function to remove unused parameters and add documentation for syncWithMeili method

api/lib/db/indexSync.js

@@ -1,6 +1,5 @@
-const mongoose = require('mongoose');
-const Conversation = mongoose.models.Conversation;
-const Message = mongoose.models.Message;
+const Conversation = require('../../models/schema/convoSchema');
+const Message = require('../../models/schema/messageSchema');
 const { MeiliSearch } = require('meilisearch');
 let currentTimeout = null;
 
@@ -37,12 +36,12 @@ async function indexSync(req, res, next) {
 
     if (messageCount !== messagesIndexed) {
       console.log('Messages out of sync, indexing');
-      await Message.syncWithMeili();
+      Message.syncWithMeili();
     }
 
     if (convoCount !== convosIndexed) {
       console.log('Convos out of sync, indexing');
-      await Conversation.syncWithMeili();
+      Conversation.syncWithMeili();
     }
   } catch (err) {
     // console.log('in index sync');

api/models/plugins/mongoMeili.js

@@ -14,33 +14,113 @@ const validateOptions = function (options) {
   });
 };
 
-const createMeiliMongooseModel = function ({ index, indexName, client, attributesToIndex }) {
-  // console.log('attributesToIndex', attributesToIndex);
+// const createMeiliMongooseModel = function ({ index, indexName, client, attributesToIndex }) {
+const createMeiliMongooseModel = function ({ index, attributesToIndex }) {
   const primaryKey = attributesToIndex[0];
   // MeiliMongooseModel is of type Mongoose.Model
   class MeiliMongooseModel {
-    // Clear Meili index
-    static async clearMeiliIndex() {
-      await index.delete();
-      // await index.deleteAllDocuments();
-      await this.collection.updateMany({ _meiliIndex: true }, { $set: { _meiliIndex: false } });
-    }
-
-    static async resetIndex() {
-      await this.clearMeiliIndex();
-      await client.createIndex(indexName, { primaryKey });
-    }
-    // Clear Meili index
-    // Push a mongoDB collection to Meili index
+    /**
+     * `syncWithMeili`: synchronizes the data between a MongoDB collection and a MeiliSearch index,
+     * only triggered if there's ever a discrepancy determined by `api\lib\db\indexSync.js`.
+     *
+     * 1. Fetches all documents from the MongoDB collection and the MeiliSearch index.
+     * 2. Compares the documents from both sources.
+     * 3. If a document exists in MeiliSearch but not in MongoDB, it's deleted from MeiliSearch.
+     * 4. If a document exists in MongoDB but not in MeiliSearch, it's added to MeiliSearch.
+     * 5. If a document exists in both but has different `text` or `title` fields (depending on the `primaryKey`), it's updated in MeiliSearch.
+     * 6. After all operations, it updates the `_meiliIndex` field in MongoDB to indicate whether the document is indexed in MeiliSearch.
+     *
+     * Note: This strategy does not use batch operations for Meilisearch as the `index.addDocuments` will discard
+     * the entire batch if there's an error with one document, and will not throw an error if there's an issue.
+     * Also, `index.getDocuments` needs an exact limit on the amount of documents to return, so we build the map in batches.
+     *
+     * @returns {Promise} A promise that resolves when the synchronization is complete.
+     *
+     * @throws {Error} Throws an error if there's an issue with adding a document to MeiliSearch.
+     */
     static async syncWithMeili() {
-      await this.resetIndex();
-      const docs = await this.find({ _meiliIndex: { $in: [null, false] } });
-      console.log('docs', docs.length);
-      const objs = docs.map((doc) => doc.preprocessObjectForIndex());
       try {
-        await index.addDocuments(objs);
-        const ids = docs.map((doc) => doc._id);
-        await this.collection.updateMany({ _id: { $in: ids } }, { $set: { _meiliIndex: true } });
+        let moreDocuments = true;
+        const mongoDocuments = await this.find().lean();
+        const format = (doc) => _.pick(doc, attributesToIndex);
+
+        // Prepare for comparison
+        const mongoMap = new Map(mongoDocuments.map((doc) => [doc[primaryKey], format(doc)]));
+        const indexMap = new Map();
+        let offset = 0;
+        const batchSize = 1000;
+
+        while (moreDocuments) {
+          const batch = await index.getDocuments({ limit: batchSize, offset });
+
+          if (batch.results.length === 0) {
+            moreDocuments = false;
+          }
+
+          for (const doc of batch.results) {
+            indexMap.set(doc[primaryKey], format(doc));
+          }
+
+          offset += batchSize;
+        }
+
+        console.log('indexMap', indexMap.size);
+        console.log('mongoMap', mongoMap.size);
+
+        const updateOps = [];
+
+        // Iterate over Meili index documents
+        for (const [id, doc] of indexMap) {
+          const update = {};
+          update[primaryKey] = id;
+          if (mongoMap.has(id)) {
+            // Case: Update
+            // If document also exists in MongoDB, would be update case
+            if (
+              (doc.text && doc.text !== mongoMap.get(id).text) ||
+              (doc.title && doc.title !== mongoMap.get(id).title)
+            ) {
+              console.log(`${id} had document discrepancy in ${doc.text ? 'text' : 'title'} field`);
+              updateOps.push({
+                updateOne: { filter: update, update: { $set: { _meiliIndex: true } } },
+              });
+              await index.addDocuments([doc]);
+            }
+          } else {
+            // Case: Delete
+            // If document does not exist in MongoDB, its a delete case from meili index
+            await index.deleteDocument(id);
+            updateOps.push({
+              updateOne: { filter: update, update: { $set: { _meiliIndex: false } } },
+            });
+          }
+        }
+
+        // Iterate over MongoDB documents
+        for (const [id, doc] of mongoMap) {
+          const update = {};
+          update[primaryKey] = id;
+          // Case: Insert
+          // If document does not exist in Meili Index, Its an insert case
+          if (!indexMap.has(id)) {
+            console.log(`${id} is not indexed`);
+            await index.addDocuments([doc]);
+            updateOps.push({
+              updateOne: { filter: update, update: { $set: { _meiliIndex: true } } },
+            });
+          } else if (doc._meiliIndex === false) {
+            updateOps.push({
+              updateOne: { filter: update, update: { $set: { _meiliIndex: true } } },
+            });
+          }
+        }
+
+        if (updateOps.length > 0) {
+          await this.collection.bulkWrite(updateOps);
+          console.log(
+            `Finished indexing ${primaryKey === 'messageId' ? 'messages' : 'conversations'}`,
+          );
+        }
       } catch (error) {
         console.log('Error adding document to Meili');
         console.error(error);