fix: Remove userGroup field from usage tracking (fixes #673)

Since users can have multiple groups, it's unclear which group
usage should be attributed to. This change removes the userGroup
field from the usages table.

Changes:
- Add migration to drop userGroup column from usages table
- Remove userGroup field from UsageEntity
- Remove userGroup from usage tracking calls
- Remove group-level quota check from CheckUsageMiddleware
- Update tests to not set userGroup field

The change maintains user-level quota enforcement while removing
ambiguous group-level tracking.

Author: claude

backend/src/controllers/usages/usages.e2e.spec.ts

@@ -244,7 +244,6 @@ async function createUsageEntity(date: Date, userEntity: UserEntity, usageReposi
   const usageEntity = new UsageEntity();
   usageEntity.date = startOfDay(date);
   usageEntity.userId = userEntity.id;
-  usageEntity.userGroup = userEntity.userGroups?.[0]?.id ?? 'admin';
   usageEntity.counter = 'token_usage';
   usageEntity.key = 'azure-open-ai';
   usageEntity.subKey = 'gpt-4o';

backend/src/domain/chat/middlewares/check-usage-middleware.ts

@@ -40,38 +40,29 @@ export class CheckUsageMiddleware implements ChatMiddleware {
       await next(context);
       return;
     }
+
     const userGroup = await this.userGroups.findOneBy({ id: userGroupId });
-    const monthlyTokens = userGroup?.monthlyTokens ?? 0;
     const monthlyUserTokens = userGroup?.monthlyUserTokens ?? 0;
 
-    if (!userGroup || (monthlyTokens < 0 && monthlyUserTokens < 0)) {
+    if (!userGroup || monthlyUserTokens < 0) {
       await next(context);
       return;
     }
 
     const dateFrom = startOfMonth(new Date());
     const dateTo = addMonths(dateFrom, 1);
 
-    if (monthlyTokens > 0) {
-      const groupUsage =
-        (await this.usages.sum('count', {
-          date: And(MoreThanOrEqual(dateFrom), LessThan(dateTo)),
-          userGroup: userGroupId,
-        })) ?? 0;
-
-      if (groupUsage >= monthlyTokens) {
-        throw new HttpException('Monthly token limit exceeded for user group.', HttpStatus.TOO_MANY_REQUESTS);
-      }
-    }
+    // Note: Group-level quota check removed because userGroup field was removed from usage tracking (issue #673)
+    // Only user-level quotas are enforced now
 
     if (monthlyUserTokens > 0) {
-      const groupUsage =
+      const userUsage =
         (await this.usages.sum('count', {
           date: And(MoreThanOrEqual(dateFrom), LessThan(dateTo)),
           userId: user.id,
         })) ?? 0;
 
-      if (groupUsage >= monthlyUserTokens) {
+      if (userUsage >= monthlyUserTokens) {
         throw new HttpException('Monthly token limit exceeded for user.', HttpStatus.TOO_MANY_REQUESTS);
       }
     }

backend/src/domain/chat/middlewares/store-usage-middleware.ts

@@ -28,7 +28,6 @@ export class StorageUsageMiddleware implements ChatMiddleware {
         date: new Date(),
         key: usage.llm,
         subKey: usage.model,
-        userGroup: context.user.userGroupIds?.[0],
         userId: context.user.id,
       });
     } catch (err) {

backend/src/domain/chat/use-cases/rate-message.ts

@@ -56,7 +56,6 @@ export class RateMessageHandler implements ICommandHandler<RateMessage, RateMess
       date: new Date(),
       key: rating,
       subKey: conversation.llm || 'none',
-      userGroup: '', //TODO: fixme
       userId: user.id,
     });
 

backend/src/domain/database/entities/usage.ts

@@ -10,9 +10,6 @@ export class UsageEntity {
   @PrimaryColumn()
   userId!: string;
 
-  @PrimaryColumn()
-  userGroup!: string;
-
   @PrimaryColumn()
   counter!: string;
 

backend/src/migrations/1767451199884-removeUserGroupFromUsages.ts

@@ -0,0 +1,55 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class RemoveUserGroupFromUsages1767451199884 implements MigrationInterface {
+  name = 'RemoveUserGroupFromUsages1767451199884';
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    // Step 1: Create a temporary table with merged usage data
+    // This merges rows that would become duplicates after removing userGroup
+    await queryRunner.query(`
+      CREATE TEMP TABLE usages_merged AS
+      SELECT
+        date,
+        "userId",
+        counter,
+        key,
+        "subKey",
+        SUM(count) as count
+      FROM company_chat.usages
+      GROUP BY date, "userId", counter, key, "subKey"
+    `);
+
+    // Step 2: Drop the old primary key constraint
+    await queryRunner.query(`ALTER TABLE company_chat.usages DROP CONSTRAINT "PK_0acc90e335c519dc4e2140320f1"`);
+
+    // Step 3: Truncate the table and reload with merged data
+    await queryRunner.query(`TRUNCATE company_chat.usages`);
+
+    await queryRunner.query(`
+      INSERT INTO company_chat.usages (date, "userId", "userGroup", counter, key, "subKey", count)
+      SELECT date, "userId", '', counter, key, "subKey", count
+      FROM usages_merged
+    `);
+
+    // Step 4: Drop the userGroup column
+    await queryRunner.query(`ALTER TABLE company_chat.usages DROP COLUMN "userGroup"`);
+
+    // Step 5: Add new primary key constraint without userGroup
+    await queryRunner.query(
+      `ALTER TABLE company_chat.usages ADD CONSTRAINT "PK_usages_without_group" PRIMARY KEY (date, "userId", counter, key, "subKey")`,
+    );
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    // Drop the new primary key
+    await queryRunner.query(`ALTER TABLE company_chat.usages DROP CONSTRAINT "PK_usages_without_group"`);
+
+    // Re-add the userGroup column
+    await queryRunner.query(`ALTER TABLE company_chat.usages ADD COLUMN "userGroup" character varying NOT NULL DEFAULT ''`);
+
+    // Restore the original primary key
+    await queryRunner.query(
+      `ALTER TABLE company_chat.usages ADD CONSTRAINT "PK_0acc90e335c519dc4e2140320f1" PRIMARY KEY (date, "userId", "userGroup", counter, key, "subKey")`,
+    );
+  }
+}