690525:1320 ADR-028-228-migration #06

backend/src/common/file-storage/file-storage.service.spec.ts

@@ -46,6 +46,13 @@ describe('FileStorageService', () => {
             find: jest.fn(),
             findOne: jest.fn(),
             remove: jest.fn(),
+            createQueryBuilder: jest.fn(() => ({
+              where: jest.fn().mockReturnThis(),
+              andWhere: jest.fn().mockReturnThis(),
+              orderBy: jest.fn().mockReturnThis(),
+              limit: jest.fn().mockReturnThis(),
+              getOne: jest.fn().mockResolvedValue(null),
+            })),
           },
         },
         {

backend/src/common/file-storage/file-storage.service.ts

@@ -56,19 +56,36 @@ export class FileStorageService {
 
   /**
    * Phase 1: Upload (บันทึกไฟล์ลง Temp)
+   * Idempotent: ถ้าไฟล์ checksum เดิมยังอยู่ใน temp (ไม่หมดอายุ) จะคืน record เดิมแทน
+   * ป้องกัน orphan files จาก n8n retry
    */
   async upload(file: Express.Multer.File, userId: number): Promise<Attachment> {
-    const tempId = uuidv4();
     // Fix: แปลงชื่อไฟล์จาก Latin1 → UTF-8 (Multer/busboy decodes as Latin1 by default)
     const originalFilename = this.fixMulterFilename(file.originalname);
-    const fileExt = path.extname(originalFilename);
-    const storedFilename = `${uuidv4()}${fileExt}`;
-    const tempPath = path.join(this.tempDir, storedFilename);
 
     // 1. คำนวณ Checksum (SHA-256) เพื่อความปลอดภัยและความถูกต้องของไฟล์
     const checksum = this.calculateChecksum(file.buffer);
 
-    // 2. บันทึกไฟล์ลง Disk (Temp Folder)
+    // 2. Checksum-based dedup — ถ้า temp attachment เดิมยังไม่หมดอายุ คืน record เดิมทันที
+    const existing = await this.attachmentRepository
+      .createQueryBuilder('a')
+      .where('a.checksum = :checksum', { checksum })
+      .andWhere('a.isTemporary = :isTemp', { isTemp: true })
+      .andWhere('a.uploadedByUserId = :userId', { userId })
+      .andWhere('a.expiresAt > :now', { now: new Date() })
+      .getOne();
+    if (existing) {
+      this.logger.log(
+        `Dedup upload: returning existing temp attachment publicId=${existing.publicId} checksum=${checksum}`
+      );
+      return existing;
+    }
+
+    const fileExt = path.extname(originalFilename);
+    const storedFilename = `${uuidv4()}${fileExt}`;
+    const tempPath = path.join(this.tempDir, storedFilename);
+
+    // 3. บันทึกไฟล์ลง Disk (Temp Folder)
     try {
       await fs.writeFile(tempPath, file.buffer);
     } catch (error) {
@@ -76,7 +93,7 @@ export class FileStorageService {
       throw new BadRequestException('File upload failed');
     }
 
-    // 3. สร้าง Record ใน Database
+    // 4. สร้าง Record ใน Database
     const attachment = this.attachmentRepository.create({
       originalFilename,
       storedFilename: storedFilename,
@@ -84,7 +101,7 @@ export class FileStorageService {
       mimeType: file.mimetype,
       fileSize: file.size,
       isTemporary: true,
-      tempId: tempId,
+      tempId: uuidv4(),
       expiresAt: new Date(Date.now() + 24 * 60 * 60 * 1000), // หมดอายุใน 24 ชม.
       checksum: checksum,
       uploadedByUserId: userId,

backend/src/modules/ai/ai-settings.service.spec.ts

@@ -6,6 +6,7 @@ import { Test, TestingModule } from '@nestjs/testing';
 import { getRepositoryToken } from '@nestjs/typeorm';
 import { AiSettingsService } from './ai-settings.service';
 import { SystemSetting } from './entities/system-setting.entity';
+import { AiAvailableModel } from './entities/ai-available-model.entity';
 
 const DEFAULT_REDIS_TOKEN = 'default_IORedisModuleConnectionToken';
 
@@ -18,6 +19,15 @@ describe('AiSettingsService', () => {
     },
   };
 
+  const mockAiModelRepo = {
+    find: jest.fn(),
+    findOne: jest.fn(),
+    save: jest.fn(),
+    create: jest.fn(),
+    update: jest.fn(),
+    softDelete: jest.fn(),
+  };
+
   const mockRedis = {
     get: jest.fn(),
     set: jest.fn(),
@@ -35,6 +45,10 @@ describe('AiSettingsService', () => {
           provide: getRepositoryToken(SystemSetting),
           useValue: mockSettingRepo,
         },
+        {
+          provide: getRepositoryToken(AiAvailableModel),
+          useValue: mockAiModelRepo,
+        },
         { provide: DEFAULT_REDIS_TOKEN, useValue: mockRedis },
       ],
     }).compile();

backend/src/modules/ai/ai-settings.service.ts

@@ -2,6 +2,7 @@
 // Change Log
 // - 2026-05-21: เพิ่ม service สำหรับอ่าน/เขียน AI feature toggle พร้อม Redis cache.
 // - 2026-05-22: เพิ่ม try-catch ใน getAiFeaturesEnabled() เพื่อความยืดหยุ่นในกรณีที่ฐานข้อมูลยังไม่ได้อัปเกรดตาราง system_settings
+// - 2026-05-25: เพิ่ม methods สำหรับจัดการรายการโมเดล AI แบบไดนามิก (ADR-027)
 
 import { Injectable, Logger } from '@nestjs/common';
 import { InjectRedis } from '@nestjs-modules/ioredis';
@@ -9,11 +10,17 @@ import { InjectRepository } from '@nestjs/typeorm';
 import type Redis from 'ioredis';
 import { EntityManager, Repository } from 'typeorm';
 import { SystemSetting } from './entities/system-setting.entity';
+import { AiAvailableModel } from './entities/ai-available-model.entity';
+import { NotFoundException } from '../../common/exceptions';
 
 const AI_FEATURES_ENABLED_KEY = 'AI_FEATURES_ENABLED';
 const AI_FEATURES_ENABLED_CACHE_KEY = 'system_settings:AI_FEATURES_ENABLED';
 const AI_FEATURES_ENABLED_TTL_SECONDS = 30;
 
+const AI_ACTIVE_MODEL_KEY = 'AI_ACTIVE_MODEL';
+const AI_ACTIVE_MODEL_CACHE_KEY = 'system_settings:AI_ACTIVE_MODEL';
+const AI_ACTIVE_MODEL_TTL_SECONDS = 30;
+
 /** Service สำหรับจัดการ system_settings ที่เกี่ยวข้องกับ AI Admin Console */
 @Injectable()
 export class AiSettingsService {
@@ -22,6 +29,8 @@ export class AiSettingsService {
   constructor(
     @InjectRepository(SystemSetting)
     private readonly settingRepo: Repository<SystemSetting>,
+    @InjectRepository(AiAvailableModel)
+    private readonly modelRepo: Repository<AiAvailableModel>,
     @InjectRedis() private readonly redis: Redis
   ) {}
 
@@ -113,4 +122,171 @@ export class AiSettingsService {
   private toMessage(error: unknown): string {
     return error instanceof Error ? error.message : String(error);
   }
+
+  // --- AI Model Management (ADR-027) ---
+
+  /** ดึงรายการโมเดล AI ทั้งหมดที่ใช้งานได้ (รวมถึงที่ไม่ active) */
+  async getAvailableModels(): Promise<AiAvailableModel[]> {
+    return this.modelRepo.find({
+      order: { isDefault: 'DESC', modelName: 'ASC' },
+    });
+  }
+
+  /** ดึงรายการโมเดล AI ที่ active เท่านั้น */
+  async getActiveModels(): Promise<AiAvailableModel[]> {
+    return this.modelRepo.find({
+      where: { isActive: true },
+      order: { modelName: 'ASC' },
+    });
+  }
+
+  /** ดึงโมเดล AI ที่ใช้งานอยู่ปัจจุบัน (active model) */
+  async getActiveModel(): Promise<string> {
+    try {
+      const cachedValue = await this.redis.get(AI_ACTIVE_MODEL_CACHE_KEY);
+      if (cachedValue) return cachedValue;
+
+      const setting = await this.settingRepo.findOne({
+        where: { settingKey: AI_ACTIVE_MODEL_KEY },
+      });
+
+      const activeModel = setting?.settingValue ?? 'gemma4:e2b';
+      await this.redis.set(
+        AI_ACTIVE_MODEL_CACHE_KEY,
+        activeModel,
+        'EX',
+        AI_ACTIVE_MODEL_TTL_SECONDS
+      );
+      return activeModel;
+    } catch (error: unknown) {
+      this.logger.error(`Failed to get active model: ${this.toMessage(error)}`);
+      return 'gemma4:e2b';
+    }
+  }
+
+  /** ตั้งค่าโมเดล AI ที่ใช้งาน (global) */
+  async setActiveModel(modelName: string, userId: number): Promise<string> {
+    const model = await this.modelRepo.findOne({
+      where: { modelName, isActive: true },
+    });
+
+    if (!model) {
+      throw new NotFoundException('AiAvailableModel', modelName);
+    }
+
+    await this.settingRepo.manager.transaction(
+      async (manager: EntityManager): Promise<void> => {
+        const repo = manager.getRepository(SystemSetting);
+        const existing = await repo.findOne({
+          where: { settingKey: AI_ACTIVE_MODEL_KEY },
+        });
+
+        const setting =
+          existing ??
+          repo.create({
+            settingKey: AI_ACTIVE_MODEL_KEY,
+            dataType: 'string',
+            category: 'ai',
+            description: 'โมเดล AI ที่ใช้งานอยู่ในระบบ (global)',
+            isPublic: true,
+          });
+
+        setting.settingValue = modelName;
+        setting.updatedBy = userId;
+        await repo.save(setting);
+      }
+    );
+
+    await this.redis.del(AI_ACTIVE_MODEL_CACHE_KEY);
+    this.logger.log(
+      `Active AI model changed to ${modelName} by user ${userId}`
+    );
+    return modelName;
+  }
+
+  /** เพิ่มโมเดล AI ใหม่เข้าระบบ (Superadmin only) */
+  async addModel(
+    data: {
+      modelName: string;
+      modelVersion: string;
+      description?: string;
+      vramGb?: number;
+    },
+    userId: number
+  ): Promise<AiAvailableModel> {
+    const existing = await this.modelRepo.findOne({
+      where: { modelName: data.modelName },
+      withDeleted: true,
+    });
+
+    if (existing) {
+      throw new Error(`Model ${data.modelName} already exists`);
+    }
+
+    const model = this.modelRepo.create({
+      ...data,
+      isActive: true,
+      isDefault: false,
+      createdBy: userId,
+    });
+
+    const saved = await this.modelRepo.save(model);
+    this.logger.log(`New AI model added: ${data.modelName} by user ${userId}`);
+    return saved;
+  }
+
+  /** ลบโมเดล AI (soft delete) */
+  async removeModel(modelName: string, userId: number): Promise<void> {
+    const model = await this.modelRepo.findOne({
+      where: { modelName },
+    });
+
+    if (!model) {
+      throw new NotFoundException('AiAvailableModel', modelName);
+    }
+
+    if (model.isDefault) {
+      throw new Error('Cannot remove default model');
+    }
+
+    const activeModel = await this.getActiveModel();
+    if (activeModel === modelName) {
+      throw new Error('Cannot remove currently active model');
+    }
+
+    await this.modelRepo.softRemove(model);
+    this.logger.log(`AI model removed: ${modelName} by user ${userId}`);
+  }
+
+  /** เปลี่ยนสถานะ active/inactive ของโมเดล */
+  async toggleModelActive(
+    modelName: string,
+    userId: number
+  ): Promise<AiAvailableModel> {
+    const model = await this.modelRepo.findOne({
+      where: { modelName },
+    });
+
+    if (!model) {
+      throw new NotFoundException('AiAvailableModel', modelName);
+    }
+
+    if (model.isDefault && model.isActive) {
+      throw new Error('Cannot deactivate default model');
+    }
+
+    const activeModel = await this.getActiveModel();
+    if (activeModel === modelName && model.isActive) {
+      throw new Error('Cannot deactivate currently active model');
+    }
+
+    model.isActive = !model.isActive;
+    model.updatedBy = userId;
+
+    const saved = await this.modelRepo.save(model);
+    this.logger.log(
+      `AI model ${modelName} active status changed to ${model.isActive} by user ${userId}`
+    );
+    return saved;
+  }
 }

backend/src/modules/ai/ai.controller.ts

@@ -282,6 +282,116 @@ export class AiController {
     return { aiFeaturesEnabled };
   }
 
+  // ─── AI Model Management (ADR-027) ─────────────────────────────────────────
+
+  @Get('admin/models')
+  @UseGuards(JwtAuthGuard, RbacGuard)
+  @ApiBearerAuth()
+  @RequirePermission('system.manage_all')
+  @ApiOperation({
+    summary: 'AI Models — ดึงรายการโมเดล AI ทั้งหมดที่ใช้งานได้',
+  })
+  async getAvailableModels() {
+    const models = await this.aiSettingsService.getAvailableModels();
+    const activeModel = await this.aiSettingsService.getActiveModel();
+    return { models, activeModel };
+  }
+
+  @Get('admin/models/active')
+  @UseGuards(JwtAuthGuard, RbacGuard)
+  @ApiBearerAuth()
+  @RequirePermission('system.manage_all')
+  @ApiOperation({
+    summary: 'AI Active Model — ดึงโมเดล AI ที่ใช้งานอยู่ปัจจุบัน',
+  })
+  async getActiveModel() {
+    const activeModel = await this.aiSettingsService.getActiveModel();
+    return { activeModel };
+  }
+
+  @Post('admin/models/active')
+  @UseGuards(JwtAuthGuard, RbacGuard)
+  @ApiBearerAuth()
+  @RequirePermission('system.manage_all')
+  @HttpCode(HttpStatus.OK)
+  @ApiOperation({
+    summary: 'AI Set Active Model — ตั้งค่าโมเดล AI ที่ใช้งาน (global)',
+  })
+  async setActiveModel(
+    @Body() dto: { modelName: string },
+    @CurrentUser() user: User
+  ) {
+    const activeModel = await this.aiSettingsService.setActiveModel(
+      dto.modelName,
+      user.user_id
+    );
+    return { activeModel };
+  }
+
+  @Post('admin/models')
+  @UseGuards(JwtAuthGuard, RbacGuard)
+  @ApiBearerAuth()
+  @RequirePermission('system.manage_all')
+  @HttpCode(HttpStatus.CREATED)
+  @ApiOperation({
+    summary: 'AI Add Model — เพิ่มโมเดล AI ใหม่เข้าระบบ (Superadmin only)',
+  })
+  async addModel(
+    @Body()
+    dto: {
+      modelName: string;
+      modelVersion: string;
+      description?: string;
+      vramGb?: number;
+    },
+    @CurrentUser() user: User
+  ) {
+    const model = await this.aiSettingsService.addModel(dto, user.user_id);
+    return { model };
+  }
+
+  @Patch('admin/models/:modelName/toggle')
+  @UseGuards(JwtAuthGuard, RbacGuard)
+  @ApiBearerAuth()
+  @RequirePermission('system.manage_all')
+  @HttpCode(HttpStatus.OK)
+  @ApiOperation({
+    summary: 'AI Toggle Model — เปลี่ยนสถานะ active/inactive ของโมเดล',
+  })
+  @ApiParam({
+    name: 'modelName',
+    description: 'ชื่อโมเดล เช่น gemma4:e4b',
+  })
+  async toggleModelActive(
+    @Param('modelName') modelName: string,
+    @CurrentUser() user: User
+  ) {
+    const model = await this.aiSettingsService.toggleModelActive(
+      modelName,
+      user.user_id
+    );
+    return { model };
+  }
+
+  @Delete('admin/models/:modelName')
+  @UseGuards(JwtAuthGuard, RbacGuard)
+  @ApiBearerAuth()
+  @RequirePermission('system.manage_all')
+  @HttpCode(HttpStatus.NO_CONTENT)
+  @ApiOperation({
+    summary: 'AI Remove Model — ลบโมเดล AI (soft delete)',
+  })
+  @ApiParam({
+    name: 'modelName',
+    description: 'ชื่อโมเดลที่ต้องการลบ',
+  })
+  async removeModel(
+    @Param('modelName') modelName: string,
+    @CurrentUser() user: User
+  ): Promise<void> {
+    await this.aiSettingsService.removeModel(modelName, user.user_id);
+  }
+
   @Get('admin/health')
   @UseGuards(JwtAuthGuard, RbacGuard)
   @ApiBearerAuth()

backend/src/modules/ai/ai.module.ts

@@ -7,6 +7,7 @@
 // - 2026-05-21: ลงทะเบียน SystemSetting, AiSettingsService และ AiEnabledGuard สำหรับ ADR-027.
 // - 2026-05-22: นำเข้าและลงทะเบียน CleanupTempFilesWorker (T016) เพื่อลบไฟล์แนบชั่วคราวหมดอายุ
 // - 2026-05-23: ลงทะเบียน MigrationProgress + AiMigrationCheckpointService (ADR-023A)
+// - 2026-05-25: ลงทะเบียน AiAvailableModel สำหรับ AI Model Management (ADR-027).
 // Module สำหรับ AI Gateway — ลงทะเบียน Services และ Controllers (ADR-023)
 
 import { Logger, Module, OnModuleInit } from '@nestjs/common';
@@ -36,6 +37,7 @@ import { AiAuditLog } from './entities/ai-audit-log.entity';
 import { MigrationReviewRecord } from './entities/migration-review.entity';
 import { MigrationProgress } from './entities/migration-progress.entity';
 import { SystemSetting } from './entities/system-setting.entity';
+import { AiAvailableModel } from './entities/ai-available-model.entity';
 import { AiMigrationCheckpointService } from './ai-migration-checkpoint.service';
 import { AiEnabledGuard } from './guards/ai-enabled.guard';
 import { UserModule } from '../user/user.module';
@@ -72,6 +74,7 @@ import {
       MigrationReviewRecord,
       MigrationProgress,
       SystemSetting,
+      AiAvailableModel,
       Attachment,
       Project,
       Organization,

backend/src/modules/ai/entities/ai-available-model.entity.ts

@@ -0,0 +1,61 @@
+// File: src/modules/ai/entities/ai-available-model.entity.ts
+// Change Log:
+// - 2026-05-25: สร้าง Entity AiAvailableModel สำหรับจัดการรายการโมเดล AI แบบไดนามิก (ADR-027)
+
+import {
+  Column,
+  CreateDateColumn,
+  DeleteDateColumn,
+  Entity,
+  Index,
+  PrimaryGeneratedColumn,
+  UpdateDateColumn,
+} from 'typeorm';
+
+/** Entity สำหรับเก็บรายการโมเดล AI ที่ให้เลือกใช้งานในระบบ */
+@Entity('ai_available_models')
+@Index(['isActive'])
+@Index(['isDefault'])
+export class AiAvailableModel {
+  @PrimaryGeneratedColumn()
+  id!: number;
+
+  @Column({ name: 'model_name', unique: true, length: 100 })
+  modelName!: string;
+
+  @Column({ name: 'model_version', length: 50 })
+  modelVersion!: string;
+
+  @Column({ length: 500, nullable: true })
+  description?: string;
+
+  @Column({
+    name: 'vram_gb',
+    type: 'decimal',
+    precision: 4,
+    scale: 2,
+    nullable: true,
+  })
+  vramGb?: number;
+
+  @Column({ name: 'is_active', type: 'boolean', default: true })
+  isActive!: boolean;
+
+  @Column({ name: 'is_default', type: 'boolean', default: false })
+  isDefault!: boolean;
+
+  @Column({ name: 'created_by', nullable: true })
+  createdBy?: number;
+
+  @Column({ name: 'updated_by', nullable: true })
+  updatedBy?: number;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt!: Date;
+
+  @UpdateDateColumn({ name: 'updated_at' })
+  updatedAt!: Date;
+
+  @DeleteDateColumn({ name: 'deleted_at' })
+  deletedAt?: Date;
+}

backend/src/modules/ai/processors/ai-batch.processor.ts

@@ -395,7 +395,7 @@ Return ONLY a valid JSON object matching this schema. Do NOT include markdown co
       });
       await this.saveAiAuditLog({
         documentPublicId,
-        aiModel: this.ollamaService.getMainModelName(),
+        aiModel: await this.ollamaService.getMainModelName(),
         status: AiAuditStatus.FAILED,
         errorMessage: errMsg,
         processingTimeMs: Date.now() - startTime,
@@ -421,7 +421,7 @@ Return ONLY a valid JSON object matching this schema. Do NOT include markdown co
       });
       await this.saveAiAuditLog({
         documentPublicId,
-        aiModel: this.ollamaService.getMainModelName(),
+        aiModel: await this.ollamaService.getMainModelName(),
         status: AiAuditStatus.FAILED,
         errorMessage: errMsg,
         processingTimeMs: Date.now() - startTime,
@@ -466,7 +466,7 @@ Return ONLY a valid JSON object matching this schema. Do NOT include markdown co
     });
     await this.saveAiAuditLog({
       documentPublicId,
-      aiModel: this.ollamaService.getMainModelName(),
+      aiModel: await this.ollamaService.getMainModelName(),
       status: AiAuditStatus.SUCCESS,
       aiSuggestionJson: extractedMetadata,
       confidenceScore: confidence,

backend/src/modules/ai/processors/ai-realtime.processor.ts

@@ -114,7 +114,7 @@ export class AiRealtimeProcessor extends WorkerHost {
         this.aiAuditLogRepo.create({
           documentPublicId: job.data.documentPublicId,
           aiModel: 'gemma4',
-          modelName: this.ollamaService.getMainModelName(),
+          modelName: await this.ollamaService.getMainModelName(),
           aiSuggestionJson: normalizedSuggestion,
           confidenceScore: this.extractConfidence(normalizedSuggestion),
           processingTimeMs: Date.now() - startTime,
@@ -136,7 +136,7 @@ export class AiRealtimeProcessor extends WorkerHost {
         this.aiAuditLogRepo.create({
           documentPublicId: job.data.documentPublicId,
           aiModel: 'gemma4',
-          modelName: this.ollamaService.getMainModelName(),
+          modelName: await this.ollamaService.getMainModelName(),
           processingTimeMs: Date.now() - startTime,
           status: AiAuditStatus.FAILED,
           errorMessage: err instanceof Error ? err.message : String(err),

backend/src/modules/ai/services/ollama.service.ts

@@ -2,10 +2,12 @@
 // Change Log
 // - 2026-05-15: เพิ่ม Ollama service สำหรับ ADR-023A 2-model stack.
 // - 2026-05-21: เพิ่ม checkHealth สำหรับตรวจสอบสุขภาพและความเร็ว (Latency) ของ Ollama
+// - 2026-05-25: เพิ่มการใช้งานโมเดลจาก DB (AiSettingsService) แทน ENV เท่านั้น (ADR-027).
 
-import { Injectable, Logger } from '@nestjs/common';
+import { Injectable, Logger, Optional } from '@nestjs/common';
 import { ConfigService } from '@nestjs/config';
 import axios from 'axios';
+import { AiSettingsService } from '../ai-settings.service';
 
 export interface OllamaGenerateOptions {
   timeoutMs?: number;
@@ -17,18 +19,23 @@ export interface OllamaGenerateOptions {
 export class OllamaService {
   private readonly logger = new Logger(OllamaService.name);
   private readonly ollamaUrl: string;
-  private readonly mainModel: string;
+  private readonly defaultMainModel: string;
   private readonly embedModel: string;
   private readonly timeoutMs: number;
 
-  constructor(private readonly configService: ConfigService) {
+  constructor(
+    private readonly configService: ConfigService,
+    @Optional()
+    private readonly aiSettingsService?: AiSettingsService
+  ) {
     this.ollamaUrl = this.configService.get<string>(
       'OLLAMA_URL',
       this.configService.get<string>('AI_HOST_URL', 'http://localhost:11434')
     );
-    this.mainModel = this.configService.get<string>(
+    // Default fallback model (ADR-023A: gemma4:e2b)
+    this.defaultMainModel = this.configService.get<string>(
       'OLLAMA_MODEL_MAIN',
-      'gemma4:e4b'
+      'gemma4:e2b'
     );
     this.embedModel = this.configService.get<string>(
       'OLLAMA_MODEL_EMBED',
@@ -37,16 +44,31 @@ export class OllamaService {
     this.timeoutMs = this.configService.get<number>('AI_TIMEOUT_MS', 30000);
   }
 
-  /** สร้างข้อความตอบกลับจาก gemma4:e4b หรือค่า ENV ที่กำหนด */
+  /** ดึงชื่อโมเดลที่ใช้งานอยู่ (จาก DB หรือ ENV fallback) */
+  private async getActiveModelName(): Promise<string> {
+    if (this.aiSettingsService) {
+      try {
+        return await this.aiSettingsService.getActiveModel();
+      } catch (err: unknown) {
+        this.logger.warn(
+          `Failed to get active model from DB: ${err instanceof Error ? err.message : String(err)}`
+        );
+      }
+    }
+    return this.defaultMainModel;
+  }
+
+  /** สร้างข้อความตอบกลับจากโมเดลที่กำหนด (DB หรือ ENV fallback) */
   async generate(
     prompt: string,
     options: OllamaGenerateOptions = {}
   ): Promise<string> {
+    const modelName = await this.getActiveModelName();
     try {
       const response = await axios.post<{ response: string }>(
         `${this.ollamaUrl}/api/generate`,
         {
-          model: this.mainModel,
+          model: modelName,
           prompt,
           stream: false,
         },
@@ -58,7 +80,7 @@ export class OllamaService {
       return response.data.response ?? '';
     } catch (err) {
       this.logger.error(
-        'Ollama generate failed',
+        `Ollama generate failed with model ${modelName}`,
         err instanceof Error ? err.stack : String(err)
       );
       throw err;
@@ -83,9 +105,14 @@ export class OllamaService {
     }
   }
 
-  /** คืนชื่อ main model สำหรับ audit log */
-  getMainModelName(): string {
-    return this.mainModel;
+  /** คืนชื่อ main model สำหรับ audit log (async เพราะต้องเช็ค DB) */
+  async getMainModelName(): Promise<string> {
+    return this.getActiveModelName();
+  }
+
+  /** คืนชื่อ main model แบบ sync (fallback สำหรับกรณีที่ไม่ต้องการ async) */
+  getMainModelNameSync(): string {
+    return this.defaultMainModel;
   }
 
   /** คืนชื่อ embedding model สำหรับ audit log */
@@ -101,13 +128,14 @@ export class OllamaService {
     error?: string;
   }> {
     const startTime = Date.now();
+    const activeModel = await this.getActiveModelName();
     try {
       await axios.get(`${this.ollamaUrl}/api/tags`, { timeout: 5000 });
       const latencyMs = Date.now() - startTime;
       return {
         status: 'HEALTHY',
         latencyMs,
-        models: [this.mainModel, this.embedModel],
+        models: [activeModel, this.embedModel],
       };
     } catch (err: unknown) {
       const latencyMs = Date.now() - startTime;
@@ -120,7 +148,7 @@ export class OllamaService {
       return {
         status: isTimeout ? 'DEGRADED' : 'DOWN',
         latencyMs,
-        models: [this.mainModel, this.embedModel],
+        models: [activeModel, this.embedModel],
         error,
       };
     }