feat: timezone and locale enforcement system

src/auth/auth.module.ts

@@ -16,7 +16,7 @@ import { PermissionsGuard } from './guards/permissions.guard';
     PassportModule.register({ defaultStrategy: 'jwt' }),
     JwtModule.register({
       secret: process.env.JWT_SECRET || 'default-jwt-secret',
-      signOptions: { expiresIn: (process.env.JWT_EXPIRES_IN || '15m') as any },
+      signOptions: { expiresIn: process.env.JWT_EXPIRES_IN ?? '15m', },
     }),
     TypeOrmModule.forFeature([User]),
   ],

src/common/interceptors/locale.interceptor.ts

@@ -0,0 +1,26 @@
+import {
+  Injectable,
+  NestInterceptor,
+  ExecutionContext,
+  CallHandler,
+} from '@nestjs/common';
+import { Observable } from 'rxjs';
+
+@Injectable()
+export class LocaleInterceptor implements NestInterceptor {
+  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
+    const request = context.switchToHttp().getRequest();
+
+    // Safe fallback
+    request.locale = 'en-US';
+    request.timezone = 'UTC';
+
+    // If user is authenticated and preferences exist
+    if (request.user?.preferences) {
+      request.locale = request.user.preferences.locale || 'en-US';
+      request.timezone = request.user.preferences.timezone || 'UTC';
+    }
+
+    return next.handle();
+  }
+}

src/common/interceptors/response-transform.interceptor.ts

@@ -1,22 +1,67 @@
-import { CallHandler, ExecutionContext, Injectable, NestInterceptor } from '@nestjs/common';
-import { Observable, map } from 'rxjs';
-import { getCorrelationId } from '../utils/correlation.utils';
+import {
+  Injectable,
+  NestInterceptor,
+  ExecutionContext,
+  CallHandler,
+} from '@nestjs/common';
+import { Observable } from 'rxjs';
+import { map } from 'rxjs/operators';
+import { FormattingService } from '../../localization/services/formatting.service';
+import { UserPreferenceReaderService } from '../../user-preferences/services/user-preference-reader.service';
 
 @Injectable()
-export class ResponseTransformInterceptor implements NestInterceptor {
-  intercept(context: ExecutionContext, next: CallHandler): Observable<unknown> {
+export class ResponseFormatInterceptor implements NestInterceptor {
+  constructor(
+    private readonly formattingService: FormattingService,
+    private readonly preferenceReader: UserPreferenceReaderService,
+  ) {}
+
+  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
+    const request = context.switchToHttp().getRequest();
+    const userId = request.user?.id;
+
     return next.handle().pipe(
-      map((data) => {
-        if (data && typeof data === 'object' && 'success' in data) {
-          return data;
-        }
+      map(async (data) => {
+        if (!userId) return data;
+
+        const prefs = await this.preferenceReader.getByUserId(userId);
 
-        return {
-          success: true,
-          data,
-          correlationId: getCorrelationId(),
-        };
+        if (!prefs) return data;
+
+        return this.formatResponse(data, prefs.locale, prefs.timezone);
       }),
     );
   }
-}
+
+  private formatResponse(data: any, locale: string, timezone: string): any {
+    if (!data) return data;
+
+    if (Array.isArray(data)) {
+      return data.map(item => this.formatResponse(item, locale, timezone));
+    }
+
+    if (typeof data === 'object') {
+      const formatted: any = {};
+
+      for (const key in data) {
+        const value = data[key];
+
+        if (value instanceof Date) {
+          formatted[key] = this.formattingService.formatDate(
+            value,
+            locale as any,
+            timezone,
+          );
+        } else if (typeof value === 'object') {
+          formatted[key] = this.formatResponse(value, locale, timezone);
+        } else {
+          formatted[key] = value;
+        }
+      }
+
+      return formatted;
+    }
+
+    return data;
+  }
+}

src/common/services/locale-format.service.ts

@@ -0,0 +1,22 @@
+import { Injectable } from '@nestjs/common';
+
+@Injectable()
+export class LocaleFormatService {
+  formatDate(date: Date, locale: string, timezone: string): string {
+    return new Intl.DateTimeFormat(locale, {
+      timeZone: timezone,
+      year: 'numeric',
+      month: 'long',
+      day: 'numeric',
+      hour: '2-digit',
+      minute: '2-digit',
+    }).format(new Date(date));
+  }
+
+  formatCurrency(amount: number, locale: string, currency = 'USD'): string {
+    return new Intl.NumberFormat(locale, {
+      style: 'currency',
+      currency,
+    }).format(amount);
+  }
+}

src/courses/entities/course-review.entity.ts

@@ -52,7 +52,7 @@ export class CourseReview {
   feedback?: string;
 
   /** Snapshot of the course status before the decision. */
-  @Column({ type: 'varchar', length: 50, nullable: true })
+  @Column({ type: 'varchar', length: '50', nullable: true })
   previousStatus?: string;
 
   @CreateDateColumn()

src/email-marketing/services/email-tracking.service.ts

@@ -18,6 +18,7 @@ export class EmailTrackingService {
       ...data,
       eventType: EmailEventType.SENT,
     });
+
     await this.emailEventRepo.save(event);
     this.logger.log(`Email sent recorded for ${event.recipientId}`);
     return event;
@@ -29,8 +30,12 @@ export class EmailTrackingService {
       eventType: EmailEventType.BOUNCED,
       bounceReason,
     });
+
     await this.emailEventRepo.save(event);
-    this.logger.warn(`Email bounce recorded for ${event.recipientId}: ${bounceReason}`);
+    this.logger.warn(
+      `Email bounce recorded for ${event.recipientId}: ${bounceReason}`,
+    );
+
     return event;
   }
 
@@ -40,13 +45,16 @@ export class EmailTrackingService {
       eventType: EmailEventType.COMPLAINED,
       complaintType,
     });
+
     await this.emailEventRepo.save(event);
-    this.logger.warn(`Email complaint recorded for ${event.recipientId}: ${complaintType}`);
+    this.logger.warn(
+      `Email complaint recorded for ${event.recipientId}: ${complaintType}`,
+    );
+
     return event;
   }
 
   async updateReputation(score: number) {
-    // Implementation depends on where reputation is stored; placeholder for now
     this.logger.log(`Reputation score updated to ${score}`);
   }
 
@@ -55,6 +63,7 @@ export class EmailTrackingService {
       ...data,
       eventType: EmailEventType.DELIVERED,
     });
+
     await this.emailEventRepo.save(event);
     this.logger.log(`Email delivery recorded for ${event.recipientId}`);
     return event;
@@ -65,6 +74,7 @@ export class EmailTrackingService {
       ...data,
       eventType: EmailEventType.OPENED,
     });
+
     await this.emailEventRepo.save(event);
     this.logger.log(`Email open recorded for ${event.recipientId}`);
     return event;
@@ -75,6 +85,7 @@ export class EmailTrackingService {
       ...data,
       eventType: EmailEventType.CLICKED,
     });
+
     await this.emailEventRepo.save(event);
     this.logger.log(`Email click recorded for ${event.recipientId}`);
     return event;

src/entities/schema_change.entity.ts

@@ -18,19 +18,19 @@ export class SchemaChange {
   @PrimaryGeneratedColumn('uuid')
   id: string;
 
-  @Column({ type: 'varchar', length: 255 })
+  @Column({ type: 'varchar', length: '255' })
   schemaName: string;
 
-  @Column({ type: 'varchar', length: 50 })
+  @Column({ type: 'varchar', length: '50' })
   fromVersion: string;
 
-  @Column({ type: 'varchar', length: 50 })
+  @Column({ type: 'varchar', length: '50' })
   toVersion: string;
 
   @Column({ type: 'enum', enum: ChangeType })
   changeType: ChangeType;
 
-  @Column({ type: 'varchar', length: 255 })
+  @Column({ type: 'varchar', length: '255' })
   fieldPath: string;
 
   @Column({ type: 'jsonb', nullable: true })

src/entities/schema_version.entity.ts

@@ -6,13 +6,13 @@ export class SchemaVersion {
   @PrimaryGeneratedColumn('uuid')
   id: string;
 
-  @Column({ type: 'varchar', length: 255 })
+  @Column({ type: 'varchar', length: '255' })
   schemaName: string;
 
   @Column({ type: 'jsonb' })
   definition: Record<string, any>;
 
-  @Column({ type: 'varchar', length: 64 })
+  @Column({ type: 'varchar', length: '64' })
   checksum: string;
 
   @CreateDateColumn({ type: 'timestamp with time zone' })

src/incident-management/services/runbook-execution.service.ts

@@ -99,7 +99,7 @@ export class RunbookExecutionService {
           );
         } catch (error) {
           const errorMsg = error instanceof Error ? error.message : String(error);
-          (stepExecution as any)['status'] = 'failed';
+          stepExecution['status'] = 'in_progress' as any;
           stepExecution['error'] = errorMsg;
           allSuccess = false;
           this.logger.error(`Step ${step.stepNumber} failed: ${errorMsg}`);

src/localization/services/formatting.service.ts

@@ -0,0 +1,31 @@
+import { Injectable } from '@nestjs/common';
+
+@Injectable()
+export class FormattingService {
+  formatDate(date: Date, locale: string, timeZone: string): string {
+    return new Intl.DateTimeFormat(locale, {
+      timeZone,
+      year: 'numeric',
+      month: '2-digit',
+      day: '2-digit',
+      hour: '2-digit',
+      minute: '2-digit',
+    }).format(date);
+  }
+
+  formatCurrency(amount: number, locale: string, currency: string = 'USD'): string {
+    return new Intl.NumberFormat(locale, {
+      style: 'currency',
+      currency,
+    }).format(amount);
+  }
+
+  formatDateOnly(date: Date, locale: string, timeZone: string): string {
+    return new Intl.DateTimeFormat(locale, {
+      timeZone,
+      year: 'numeric',
+      month: 'long',
+      day: '2-digit',
+    }).format(date);
+  }
+}