fix: persist chat sessions in db

Signed-off-by: Alexander Alemayhu <alexander@alemayhu.com>

Author: aalemayhu

migrations/20231001_create_sessions_table.js

@@ -0,0 +1,13 @@
+exports.up = async function (knex) {
+  return knex.schema.createTable('sessions', (table) => {
+    table.increments('id').primary();
+    table.string('userId', 255).notNullable();
+    table.jsonb('data').notNullable();
+    table.timestamp('created_at').defaultTo(knex.fn.now());
+    table.timestamp('updated_at').defaultTo(knex.fn.now());
+  });
+};
+
+exports.down = async function (knex) {
+  return knex.schema.dropTable('sessions');
+};

src/data_layer/SessionRepository.ts

@@ -0,0 +1,35 @@
+import { Knex } from 'knex';
+
+class SessionRepository {
+  constructor(private readonly database: Knex) {}
+
+  createSession(userId: string | number, data: any) {
+    console.log('[SESSION] Creating session for user:', userId);
+    return this.database('sessions').insert({ userId, data });
+  }
+
+  getSession(userId: string | number) {
+    console.log('[SESSION] Getting session for user:', userId);
+    return this.database('sessions').where({ userId }).first();
+  }
+
+  async updateSession(userId: string | number, data: any) {
+    console.log('[SESSION] Updating session for user:', userId);
+    const old = await this.getSession(userId);
+    return this.database('sessions')
+      .where({ userId })
+      .update({
+        data: {
+          ...old?.data,
+          ...data,
+        },
+      });
+  }
+
+  deleteSession(userId: string | number) {
+    console.log('[SESSION] Deleting session for user:', userId);
+    return this.database('sessions').where({ userId }).del();
+  }
+}
+
+export default SessionRepository;