your message

apps/api/package.json

@@ -24,7 +24,9 @@
     "@nestjs/jwt": "^10.2.0",
     "@nestjs/passport": "^10.0.3",
     "@nestjs/platform-express": "^10.3.0",
+    "@nestjs/platform-socket.io": "^10.3.0",
     "@nestjs/swagger": "^7.3.0",
+    "@nestjs/websockets": "^10.3.0",
     "@supabase/supabase-js": "^2.39.0",
     "bullmq": "^5.1.0",
     "class-transformer": "^0.5.1",
@@ -36,6 +38,7 @@
     "passport-jwt": "^4.0.1",
     "reflect-metadata": "^0.2.1",
     "rxjs": "^7.8.1",
+    "socket.io": "^4.8.1",
     "stripe": "^14.14.0"
   },
   "devDependencies": {

apps/api/src/auth/auth.module.ts

@@ -43,6 +43,6 @@ import { UsersModule } from '../users/users.module';
       useClass: JwtAuthGuard,
     },
   ],
-  exports: [AuthService, SupabaseService, JwtAuthGuard],
+  exports: [AuthService, SupabaseService, JwtAuthGuard, JwtModule],
 })
 export class AuthModule {}

apps/api/src/auth/auth.service.ts

@@ -55,6 +55,7 @@ export class AuthService {
         name: user.name,
         avatarUrl: user.avatarUrl,
         subscriptionTier: user.subscriptionTier,
+        role: user.role,
       },
     };
   }

apps/api/src/catalog/catalog.controller.ts

@@ -32,9 +32,9 @@ export class CatalogController {
   @Post(':id/submit')
   @ApiBearerAuth()
   @HttpCode(HttpStatus.OK)
-  @ApiOperation({ summary: 'Submit course for review / publish' })
+  @ApiOperation({ summary: 'Submit course for moderation review' })
   async submitForReview(@Param('id') id: string, @CurrentUser() user: User): Promise<any> {
-    return this.catalogService.publishCourse(id, user.id);
+    return this.catalogService.submitForReview(id, user.id);
   }
 
   @Patch(':id/verify')
@@ -43,4 +43,12 @@ export class CatalogController {
   async toggleVerify(@Param('id') id: string, @CurrentUser() user: User): Promise<any> {
     return this.catalogService.toggleVerification(id, user.id);
   }
+
+  @Post(':id/checkout')
+  @ApiBearerAuth()
+  @HttpCode(HttpStatus.OK)
+  @ApiOperation({ summary: 'Create one-time checkout session for paid course' })
+  async checkoutCourse(@Param('id') id: string, @CurrentUser() user: User): Promise<any> {
+    return this.catalogService.createCourseCheckout(id, user.id);
+  }
 }

apps/api/src/catalog/catalog.module.ts

@@ -1,8 +1,10 @@
 import { Module } from '@nestjs/common';
 import { CatalogController } from './catalog.controller';
 import { CatalogService } from './catalog.service';
+import { PaymentsModule } from '../payments/payments.module';
 
 @Module({
+  imports: [PaymentsModule],
   controllers: [CatalogController],
   providers: [CatalogService],
   exports: [CatalogService],

apps/api/src/catalog/catalog.service.ts

@@ -1,10 +1,14 @@
-import { Injectable } from '@nestjs/common';
+import { Injectable, ForbiddenException, NotFoundException } from '@nestjs/common';
 import { PrismaService } from '../common/prisma/prisma.service';
 import { CourseStatus } from '@coursecraft/database';
+import { PaymentsService } from '../payments/payments.service';
 
 @Injectable()
 export class CatalogService {
-  constructor(private prisma: PrismaService) {}
+  constructor(
+    private prisma: PrismaService,
+    private paymentsService: PaymentsService
+  ) {}
 
   async getPublishedCourses(options?: {
     page?: number;
@@ -92,21 +96,25 @@ export class CatalogService {
   }
 
   async submitForReview(courseId: string, userId: string): Promise<any> {
+    const course = await this.prisma.course.findUnique({ where: { id: courseId } });
+    if (!course) {
+      throw new NotFoundException('Course not found');
+    }
+    if (course.authorId !== userId) {
+      throw new ForbiddenException('Only course author can submit for moderation');
+    }
+
     return this.prisma.course.update({
-      where: { id: courseId, authorId: userId },
-      data: { status: CourseStatus.PENDING_REVIEW },
+      where: { id: courseId },
+      data: {
+        status: CourseStatus.PENDING_REVIEW,
+        isPublished: false,
+      },
     });
   }
 
-  async publishCourse(courseId: string, userId: string): Promise<any> {
-    return this.prisma.course.update({
-      where: { id: courseId, authorId: userId },
-      data: {
-        status: CourseStatus.PUBLISHED,
-        isPublished: true,
-        publishedAt: new Date(),
-      },
-    });
+  async createCourseCheckout(courseId: string, userId: string): Promise<any> {
+    return this.paymentsService.createCourseCheckoutSession(userId, courseId);
   }
 
   async toggleVerification(courseId: string, userId: string): Promise<any> {

apps/api/src/courses/courses.controller.ts

@@ -16,6 +16,7 @@ import { CurrentUser } from '../auth/decorators/current-user.decorator';
 import { User, CourseStatus } from '@coursecraft/database';
 import { CreateCourseDto } from './dto/create-course.dto';
 import { UpdateCourseDto } from './dto/update-course.dto';
+import { ReviewHomeworkDto } from './dto/review-homework.dto';
 
 @ApiTags('courses')
 @Controller('courses')
@@ -75,4 +76,24 @@ export class CoursesController {
   ): Promise<any> {
     return this.coursesService.updateStatus(id, user.id, status);
   }
+
+  @Post(':id/homework-submissions/:submissionId/review')
+  @ApiOperation({ summary: 'Review homework submission as course author' })
+  async reviewHomework(
+    @Param('id') id: string,
+    @Param('submissionId') submissionId: string,
+    @CurrentUser() user: User,
+    @Body() dto: ReviewHomeworkDto
+  ): Promise<any> {
+    return this.coursesService.reviewHomeworkSubmission(id, submissionId, user.id, dto);
+  }
+
+  @Get(':id/homework-submissions')
+  @ApiOperation({ summary: 'Get homework submissions for course author review' })
+  async getHomeworkSubmissions(
+    @Param('id') id: string,
+    @CurrentUser() user: User
+  ): Promise<any> {
+    return this.coursesService.getHomeworkSubmissionsForAuthor(id, user.id);
+  }
 }

apps/api/src/courses/courses.service.ts

@@ -1,6 +1,6 @@
 import { Injectable, NotFoundException, ForbiddenException } from '@nestjs/common';
 import { PrismaService } from '../common/prisma/prisma.service';
-import { Course, CourseStatus } from '@coursecraft/database';
+import { Course, CourseStatus, Prisma } from '@coursecraft/database';
 import { generateUniqueSlug } from '@coursecraft/shared';
 import { CreateCourseDto } from './dto/create-course.dto';
 import { UpdateCourseDto } from './dto/update-course.dto';
@@ -19,6 +19,13 @@ export class CoursesService {
         description: dto.description,
         slug,
         status: CourseStatus.DRAFT,
+        groups: {
+          create: {
+            name: 'Основная группа',
+            description: 'Обсуждение курса и вопросы преподавателю',
+            isDefault: true,
+          },
+        },
       },
       include: {
         chapters: {
@@ -117,6 +124,7 @@ export class CoursesService {
           orderBy: { order: 'asc' },
         },
         category: true,
+        groups: true,
       },
     });
   }
@@ -167,6 +175,12 @@ export class CoursesService {
         estimatedHours: dto.estimatedHours,
         metaTitle: dto.metaTitle,
         metaDescription: dto.metaDescription,
+        ...(dto.price !== undefined
+          ? {
+              price: dto.price > 0 ? new Prisma.Decimal(dto.price) : null,
+            }
+          : {}),
+        ...(dto.currency ? { currency: dto.currency.toUpperCase() } : {}),
       },
       include: {
         chapters: {
@@ -208,12 +222,12 @@ export class CoursesService {
       throw new ForbiddenException('You can only edit your own courses');
     }
 
-    const updateData: { status: CourseStatus; publishedAt?: Date | null } = { status };
-
-    if (status === CourseStatus.PUBLISHED && !course.publishedAt) {
-      updateData.publishedAt = new Date();
+    if (status === CourseStatus.PUBLISHED) {
+      throw new ForbiddenException('Course can be published only by moderation');
     }
 
+    const updateData: { status: CourseStatus; publishedAt?: Date | null } = { status };
+
     return this.prisma.course.update({
       where: { id },
       data: updateData,
@@ -228,4 +242,91 @@ export class CoursesService {
 
     return course?.authorId === userId;
   }
+
+  async reviewHomeworkSubmission(
+    courseId: string,
+    submissionId: string,
+    authorId: string,
+    dto: { teacherScore: number; teacherFeedback?: string }
+  ) {
+    const course = await this.prisma.course.findUnique({
+      where: { id: courseId },
+      select: { id: true, authorId: true },
+    });
+    if (!course) {
+      throw new NotFoundException('Course not found');
+    }
+    if (course.authorId !== authorId) {
+      throw new ForbiddenException('Only course author can review homework');
+    }
+
+    const submission = await this.prisma.homeworkSubmission.findUnique({
+      where: { id: submissionId },
+      include: {
+        homework: {
+          include: {
+            lesson: {
+              include: {
+                chapter: {
+                  select: { courseId: true },
+                },
+              },
+            },
+          },
+        },
+      },
+    });
+
+    if (!submission || submission.homework.lesson.chapter.courseId !== courseId) {
+      throw new NotFoundException('Homework submission not found');
+    }
+
+    return this.prisma.homeworkSubmission.update({
+      where: { id: submissionId },
+      data: {
+        teacherScore: dto.teacherScore,
+        teacherFeedback: dto.teacherFeedback,
+        reviewStatus: 'TEACHER_REVIEWED',
+        gradedAt: new Date(),
+      },
+    });
+  }
+
+  async getHomeworkSubmissionsForAuthor(courseId: string, authorId: string) {
+    const course = await this.prisma.course.findUnique({
+      where: { id: courseId },
+      select: { id: true, authorId: true },
+    });
+    if (!course) {
+      throw new NotFoundException('Course not found');
+    }
+    if (course.authorId !== authorId) {
+      throw new ForbiddenException('Only course author can view submissions');
+    }
+
+    return this.prisma.homeworkSubmission.findMany({
+      where: {
+        homework: {
+          lesson: {
+            chapter: {
+              courseId,
+            },
+          },
+        },
+      },
+      include: {
+        user: {
+          select: { id: true, name: true, email: true, avatarUrl: true },
+        },
+        homework: {
+          include: {
+            lesson: {
+              select: { id: true, title: true },
+            },
+          },
+        },
+      },
+      orderBy: [{ reviewStatus: 'asc' }, { submittedAt: 'desc' }],
+    });
+  }
 }

apps/api/src/courses/dto/review-homework.dto.ts

@@ -0,0 +1,15 @@
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { IsInt, IsOptional, IsString, Max, Min } from 'class-validator';
+
+export class ReviewHomeworkDto {
+  @ApiProperty({ description: 'Teacher score from 1 to 5', minimum: 1, maximum: 5 })
+  @IsInt()
+  @Min(1)
+  @Max(5)
+  teacherScore: number;
+
+  @ApiPropertyOptional({ description: 'Teacher feedback' })
+  @IsOptional()
+  @IsString()
+  teacherFeedback?: string;
+}

apps/api/src/courses/dto/update-course.dto.ts

@@ -8,6 +8,7 @@ import {
   MinLength,
   MaxLength,
   Min,
+  IsIn,
 } from 'class-validator';
 import { ApiPropertyOptional } from '@nestjs/swagger';
 import { CourseStatus } from '@coursecraft/database';
@@ -68,4 +69,17 @@ export class UpdateCourseDto {
   @IsString()
   @MaxLength(300)
   metaDescription?: string;
+
+  @ApiPropertyOptional({ description: 'Course price. Null or 0 means free' })
+  @IsOptional()
+  @IsNumber()
+  @Min(0)
+  price?: number;
+
+  @ApiPropertyOptional({ description: 'Currency (ISO code)', example: 'USD' })
+  @IsOptional()
+  @IsString()
+  @MaxLength(3)
+  @IsIn(['USD', 'EUR', 'RUB'])
+  currency?: string;
 }

apps/api/src/enrollment/dto/create-review.dto.ts

@@ -0,0 +1,22 @@
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { IsInt, IsOptional, IsString, Max, MaxLength, Min } from 'class-validator';
+
+export class CreateReviewDto {
+  @ApiProperty({ description: 'Rating from 1 to 5', minimum: 1, maximum: 5 })
+  @IsInt()
+  @Min(1)
+  @Max(5)
+  rating: number;
+
+  @ApiPropertyOptional({ description: 'Review title' })
+  @IsOptional()
+  @IsString()
+  @MaxLength(120)
+  title?: string;
+
+  @ApiPropertyOptional({ description: 'Review content' })
+  @IsOptional()
+  @IsString()
+  @MaxLength(4000)
+  content?: string;
+}

apps/api/src/enrollment/dto/submit-homework.dto.ts

@@ -0,0 +1,14 @@
+import { ApiProperty } from '@nestjs/swagger';
+import { IsString, MaxLength, MinLength } from 'class-validator';
+
+export class SubmitHomeworkDto {
+  @ApiProperty({
+    description: 'Written homework answer',
+    minLength: 50,
+    maxLength: 20000,
+  })
+  @IsString()
+  @MinLength(50)
+  @MaxLength(20000)
+  content: string;
+}

apps/api/src/enrollment/dto/submit-quiz.dto.ts

@@ -0,0 +1,15 @@
+import { ApiProperty } from '@nestjs/swagger';
+import { ArrayMinSize, IsArray, IsInt, Min } from 'class-validator';
+
+export class SubmitQuizDto {
+  @ApiProperty({
+    description: 'Selected option index for each quiz question',
+    type: [Number],
+    example: [0, 2, 1],
+  })
+  @IsArray()
+  @ArrayMinSize(1)
+  @IsInt({ each: true })
+  @Min(0, { each: true })
+  answers: number[];
+}

apps/api/src/enrollment/enrollment.controller.ts

@@ -12,6 +12,9 @@ import { ApiTags, ApiOperation, ApiBearerAuth } from '@nestjs/swagger';
 import { EnrollmentService } from './enrollment.service';
 import { CurrentUser } from '../auth/decorators/current-user.decorator';
 import { User } from '@coursecraft/database';
+import { SubmitQuizDto } from './dto/submit-quiz.dto';
+import { CreateReviewDto } from './dto/create-review.dto';
+import { SubmitHomeworkDto } from './dto/submit-homework.dto';
 
 @ApiTags('enrollment')
 @Controller('enrollment')
@@ -55,10 +58,32 @@ export class EnrollmentController {
   async submitQuiz(
     @Param('courseId') courseId: string,
     @Param('lessonId') lessonId: string,
-    @Body('score') score: number,
+    @Body() dto: SubmitQuizDto,
     @CurrentUser() user: User,
   ): Promise<any> {
-    return this.enrollmentService.saveQuizScore(user.id, courseId, lessonId, score);
+    return this.enrollmentService.submitQuiz(user.id, courseId, lessonId, dto.answers);
+  }
+
+  @Get(':courseId/lessons/:lessonId/homework')
+  @ApiOperation({ summary: 'Get (or lazy-create) homework for lesson' })
+  async getHomework(
+    @Param('courseId') courseId: string,
+    @Param('lessonId') lessonId: string,
+    @CurrentUser() user: User,
+  ): Promise<any> {
+    return this.enrollmentService.getHomework(user.id, courseId, lessonId);
+  }
+
+  @Post(':courseId/lessons/:lessonId/homework')
+  @HttpCode(HttpStatus.OK)
+  @ApiOperation({ summary: 'Submit written homework for lesson' })
+  async submitHomework(
+    @Param('courseId') courseId: string,
+    @Param('lessonId') lessonId: string,
+    @Body() dto: SubmitHomeworkDto,
+    @CurrentUser() user: User,
+  ): Promise<any> {
+    return this.enrollmentService.submitHomework(user.id, courseId, lessonId, dto.content);
   }
 
   @Post(':courseId/review')
@@ -66,7 +91,7 @@ export class EnrollmentController {
   @ApiOperation({ summary: 'Leave a review' })
   async createReview(
     @Param('courseId') courseId: string,
-    @Body() body: { rating: number; title?: string; content?: string },
+    @Body() body: CreateReviewDto,
     @CurrentUser() user: User,
   ): Promise<any> {
     return this.enrollmentService.createReview(user.id, courseId, body.rating, body.title, body.content);

apps/api/src/enrollment/enrollment.service.ts

@@ -1,20 +1,47 @@
-import { Injectable, NotFoundException, ConflictException } from '@nestjs/common';
+import {
+  BadRequestException,
+  ConflictException,
+  ForbiddenException,
+  Injectable,
+  NotFoundException,
+} from '@nestjs/common';
 import { PrismaService } from '../common/prisma/prisma.service';
+import { HomeworkReviewStatus } from '@coursecraft/database';
+
+const QUIZ_PASS_THRESHOLD = 70;
 
 @Injectable()
 export class EnrollmentService {
   constructor(private prisma: PrismaService) {}
 
   async enroll(userId: string, courseId: string): Promise<any> {
+    const course = await this.prisma.course.findUnique({
+      where: { id: courseId },
+      select: { id: true, price: true, title: true, slug: true },
+    });
+    if (!course) throw new NotFoundException('Course not found');
+
+    if (course.price) {
+      const purchase = await this.prisma.purchase.findUnique({
+        where: { userId_courseId: { userId, courseId } },
+      });
+      if (!purchase || purchase.status !== 'completed') {
+        throw new ForbiddenException('Purchase is required for paid course');
+      }
+    }
+
     const existing = await this.prisma.enrollment.findUnique({
       where: { userId_courseId: { userId, courseId } },
     });
     if (existing) throw new ConflictException('Already enrolled');
 
-    return this.prisma.enrollment.create({
+    const enrollment = await this.prisma.enrollment.create({
       data: { userId, courseId },
       include: { course: { select: { id: true, title: true, slug: true } } },
     });
+
+    await this.addUserToDefaultCourseGroup(courseId, userId);
+    return enrollment;
   }
 
   async getUserEnrollments(userId: string): Promise<any> {
@@ -34,10 +61,56 @@ export class EnrollmentService {
   }
 
   async completeLesson(userId: string, courseId: string, lessonId: string): Promise<any> {
-    const enrollment = await this.prisma.enrollment.findUnique({
-      where: { userId_courseId: { userId, courseId } },
+    const enrollment = await this.requireEnrollment(userId, courseId);
+    await this.assertLessonUnlocked(userId, courseId, lessonId);
+
+    const progress = await this.prisma.lessonProgress.findUnique({
+      where: { userId_lessonId: { userId, lessonId } },
     });
-    if (!enrollment) throw new NotFoundException('Not enrolled in this course');
+    if (!progress?.quizPassed || !progress?.homeworkSubmitted) {
+      throw new BadRequestException('Lesson can be completed only after quiz and homework');
+    }
+
+    const updated = await this.prisma.lessonProgress.update({
+      where: { userId_lessonId: { userId, lessonId } },
+      data: { completedAt: new Date() },
+    });
+    await this.recalculateProgress(enrollment.id, courseId);
+    return updated;
+  }
+
+  async submitQuiz(userId: string, courseId: string, lessonId: string, answers: number[]): Promise<any> {
+    const enrollment = await this.requireEnrollment(userId, courseId);
+    await this.assertLessonUnlocked(userId, courseId, lessonId);
+
+    const quiz = await this.prisma.quiz.findUnique({
+      where: { lessonId },
+    });
+    if (!quiz) {
+      throw new NotFoundException('Quiz not found for this lesson');
+    }
+
+    const questions = Array.isArray(quiz.questions) ? (quiz.questions as any[]) : [];
+    if (questions.length === 0) {
+      throw new BadRequestException('Quiz has no questions');
+    }
+    if (!Array.isArray(answers) || answers.length !== questions.length) {
+      throw new BadRequestException('Answers count must match questions count');
+    }
+
+    const correctAnswers = questions.reduce((acc, question, index) => {
+      const expected = Number(question.correctAnswer);
+      const actual = Number(answers[index]);
+      return acc + (expected === actual ? 1 : 0);
+    }, 0);
+    const score = Math.round((correctAnswers / questions.length) * 100);
+    const passed = score >= QUIZ_PASS_THRESHOLD;
+
+    const existing = await this.prisma.lessonProgress.findUnique({
+      where: { userId_lessonId: { userId, lessonId } },
+    });
+    const finalPassed = Boolean(existing?.quizPassed || passed);
+    const completedAt = finalPassed && existing?.homeworkSubmitted ? new Date() : existing?.completedAt;
 
     const progress = await this.prisma.lessonProgress.upsert({
       where: { userId_lessonId: { userId, lessonId } },
@@ -45,78 +118,219 @@ export class EnrollmentService {
         userId,
         enrollmentId: enrollment.id,
         lessonId,
-        completedAt: new Date(),
+        quizScore: score,
+        quizPassed: finalPassed,
+        quizPassedAt: finalPassed ? new Date() : null,
+        completedAt: completedAt || null,
       },
       update: {
-        completedAt: new Date(),
+        quizScore: score,
+        quizPassed: finalPassed,
+        quizPassedAt: finalPassed ? existing?.quizPassedAt || new Date() : null,
+        completedAt: completedAt || null,
       },
     });
 
     await this.recalculateProgress(enrollment.id, courseId);
-    return progress;
+    return {
+      score,
+      passed,
+      passThreshold: QUIZ_PASS_THRESHOLD,
+      totalQuestions: questions.length,
+      correctAnswers,
+      progress,
+    };
   }
 
-  async saveQuizScore(userId: string, courseId: string, lessonId: string, score: number): Promise<any> {
-    const enrollment = await this.prisma.enrollment.findUnique({
-      where: { userId_courseId: { userId, courseId } },
-    });
-    if (!enrollment) throw new NotFoundException('Not enrolled in this course');
+  async getHomework(userId: string, courseId: string, lessonId: string): Promise<any> {
+    await this.requireEnrollment(userId, courseId);
+    await this.assertLessonUnlocked(userId, courseId, lessonId);
 
-    return this.prisma.lessonProgress.upsert({
+    const lesson = await this.prisma.lesson.findFirst({
+      where: { id: lessonId, chapter: { courseId } },
+      select: { id: true, title: true },
+    });
+    if (!lesson) {
+      throw new NotFoundException('Lesson not found');
+    }
+
+    const homework = await this.prisma.homework.upsert({
+      where: { lessonId: lesson.id },
+      create: {
+        lessonId: lesson.id,
+        title: `Письменное домашнее задание: ${lesson.title}`,
+        description:
+          'Опишите, как вы примените изученную тему на практике. Приведите примеры, обоснования и собственные выводы.',
+      },
+      update: {},
+    });
+
+    const submission = await this.prisma.homeworkSubmission.findUnique({
+      where: { homeworkId_userId: { homeworkId: homework.id, userId } },
+    });
+
+    return { homework, submission };
+  }
+
+  async submitHomework(userId: string, courseId: string, lessonId: string, content: string): Promise<any> {
+    const enrollment = await this.requireEnrollment(userId, courseId);
+    await this.assertLessonUnlocked(userId, courseId, lessonId);
+
+    const lessonProgress = await this.prisma.lessonProgress.findUnique({
+      where: { userId_lessonId: { userId, lessonId } },
+    });
+    if (!lessonProgress?.quizPassed) {
+      throw new BadRequestException('Pass the quiz before submitting homework');
+    }
+
+    const { homework } = await this.getHomework(userId, courseId, lessonId);
+    const aiResult = this.gradeHomeworkWithAI(content);
+
+    const submission = await this.prisma.homeworkSubmission.upsert({
+      where: { homeworkId_userId: { homeworkId: homework.id, userId } },
+      create: {
+        homeworkId: homework.id,
+        userId,
+        content,
+        aiScore: aiResult.score,
+        aiFeedback: aiResult.feedback,
+        reviewStatus: HomeworkReviewStatus.AI_REVIEWED,
+      },
+      update: {
+        content,
+        aiScore: aiResult.score,
+        aiFeedback: aiResult.feedback,
+        reviewStatus: HomeworkReviewStatus.AI_REVIEWED,
+        submittedAt: new Date(),
+      },
+    });
+
+    await this.prisma.lessonProgress.upsert({
       where: { userId_lessonId: { userId, lessonId } },
       create: {
         userId,
         enrollmentId: enrollment.id,
         lessonId,
-        quizScore: score,
+        quizScore: lessonProgress.quizScore,
+        quizPassed: true,
+        quizPassedAt: lessonProgress.quizPassedAt || new Date(),
+        homeworkSubmitted: true,
+        homeworkSubmittedAt: new Date(),
+        completedAt: new Date(),
+      },
+      update: {
+        homeworkSubmitted: true,
+        homeworkSubmittedAt: new Date(),
         completedAt: new Date(),
       },
-      update: { quizScore: score },
     });
+
+    await this.recalculateProgress(enrollment.id, courseId);
+    return submission;
   }
 
   async getProgress(userId: string, courseId: string): Promise<any> {
     return this.prisma.enrollment.findUnique({
       where: { userId_courseId: { userId, courseId } },
-      include: { lessons: true },
+      include: {
+        lessons: true,
+      },
     });
   }
 
   async createReview(userId: string, courseId: string, rating: number, title?: string, content?: string): Promise<any> {
+    await this.requireEnrollment(userId, courseId);
+
     const review = await this.prisma.review.upsert({
       where: { userId_courseId: { userId, courseId } },
-      create: { userId, courseId, rating, title, content },
-      update: { rating, title, content },
+      create: { userId, courseId, rating, title, content, isApproved: true },
+      update: { rating, title, content, isApproved: true },
     });
 
-    // Recalculate avg rating
-    const result = await this.prisma.review.aggregate({
-      where: { courseId, isApproved: true },
-      _avg: { rating: true },
-    });
-    if (result._avg.rating !== null) {
-      await this.prisma.course.update({
-        where: { id: courseId },
-        data: { averageRating: result._avg.rating },
-      });
-    }
-
+    await this.recalculateAverageRating(courseId);
     return review;
   }
 
   async getCourseReviews(courseId: string, page = 1, limit = 20): Promise<any> {
-    const skip = (page - 1) * limit;
+    const safePage = Math.max(1, Number(page) || 1);
+    const safeLimit = Math.min(100, Math.max(1, Number(limit) || 20));
+    const skip = (safePage - 1) * safeLimit;
     const [reviews, total] = await Promise.all([
       this.prisma.review.findMany({
         where: { courseId, isApproved: true },
         include: { user: { select: { id: true, name: true, avatarUrl: true } } },
         orderBy: { createdAt: 'desc' },
         skip,
-        take: limit,
+        take: safeLimit,
       }),
       this.prisma.review.count({ where: { courseId, isApproved: true } }),
     ]);
-    return { data: reviews, meta: { page, limit, total } };
+    return { data: reviews, meta: { page: safePage, limit: safeLimit, total } };
+  }
+
+  async recalculateAverageRating(courseId: string): Promise<void> {
+    const result = await this.prisma.review.aggregate({
+      where: { courseId, isApproved: true },
+      _avg: { rating: true },
+    });
+    await this.prisma.course.update({
+      where: { id: courseId },
+      data: { averageRating: result._avg.rating ?? null },
+    });
+  }
+
+  private async requireEnrollment(userId: string, courseId: string) {
+    const enrollment = await this.prisma.enrollment.findUnique({
+      where: { userId_courseId: { userId, courseId } },
+    });
+    if (!enrollment) {
+      throw new NotFoundException('Not enrolled in this course');
+    }
+    return enrollment;
+  }
+
+  private async assertLessonUnlocked(userId: string, courseId: string, lessonId: string): Promise<void> {
+    const orderedLessons = await this.prisma.lesson.findMany({
+      where: { chapter: { courseId } },
+      orderBy: [{ chapter: { order: 'asc' } }, { order: 'asc' }],
+      select: { id: true },
+    });
+    const targetIndex = orderedLessons.findIndex((lesson) => lesson.id === lessonId);
+    if (targetIndex === -1) {
+      throw new NotFoundException('Lesson not found in this course');
+    }
+    if (targetIndex === 0) return;
+
+    const prevLessonId = orderedLessons[targetIndex - 1].id;
+    const prevProgress = await this.prisma.lessonProgress.findUnique({
+      where: { userId_lessonId: { userId, lessonId: prevLessonId } },
+      select: { quizPassed: true, homeworkSubmitted: true },
+    });
+    if (!prevProgress?.quizPassed || !prevProgress?.homeworkSubmitted) {
+      throw new ForbiddenException('Complete previous lesson quiz and homework first');
+    }
+  }
+
+  private async addUserToDefaultCourseGroup(courseId: string, userId: string): Promise<void> {
+    let group = await this.prisma.courseGroup.findFirst({
+      where: { courseId, isDefault: true },
+    });
+    if (!group) {
+      group = await this.prisma.courseGroup.create({
+        data: {
+          courseId,
+          name: 'Основная группа',
+          description: 'Обсуждение курса и вопросы преподавателю',
+          isDefault: true,
+        },
+      });
+    }
+
+    await this.prisma.groupMember.upsert({
+      where: { groupId_userId: { groupId: group.id, userId } },
+      create: { groupId: group.id, userId, role: 'student' },
+      update: {},
+    });
   }
 
   private async recalculateProgress(enrollmentId: string, courseId: string): Promise<void> {
@@ -124,7 +338,11 @@ export class EnrollmentService {
       where: { chapter: { courseId } },
     });
     const completedLessons = await this.prisma.lessonProgress.count({
-      where: { enrollmentId, completedAt: { not: null } },
+      where: {
+        enrollmentId,
+        quizPassed: true,
+        homeworkSubmitted: true,
+      },
     });
 
     const progress = totalLessons > 0 ? Math.round((completedLessons / totalLessons) * 100) : 0;
@@ -137,4 +355,28 @@ export class EnrollmentService {
       },
     });
   }
+
+  private gradeHomeworkWithAI(content: string): { score: number; feedback: string } {
+    const normalized = content.trim();
+    const words = normalized.split(/\s+/).filter(Boolean).length;
+    const hasStructure = /(^|\n)\s*[-*•]|\d+\./.test(normalized);
+    const hasExamples = /например|пример|кейc|case/i.test(normalized);
+
+    let score = 3;
+    if (words >= 250) score = 4;
+    if (words >= 450 && hasStructure && hasExamples) score = 5;
+    if (words < 120) score = 2;
+    if (words < 60) score = 1;
+
+    let feedback = 'Хорошая работа. Раскройте больше практических деталей и аргументов.';
+    if (score === 5) {
+      feedback = 'Отличная работа: есть структура, примеры и практическая применимость.';
+    } else if (score === 4) {
+      feedback = 'Сильная работа. Добавьте ещё один практический кейс для максимальной оценки.';
+    } else if (score <= 2) {
+      feedback = 'Ответ слишком краткий. Раскройте тему глубже и добавьте практические примеры.';
+    }
+
+    return { score, feedback };
+  }
 }

apps/api/src/groups/groups.controller.ts

@@ -16,8 +16,18 @@ export class GroupsController {
   }
 
   @Post(':groupId/members')
-  async addMember(@Param('groupId') groupId: string, @Body('userId') userId: string): Promise<any> {
-    return this.groupsService.addMember(groupId, userId);
+  async addMember(@Param('groupId') groupId: string, @Body('userId') userId: string, @CurrentUser() user: User): Promise<any> {
+    return this.groupsService.addMember(groupId, user.id, userId);
+  }
+
+  @Get('course/:courseId/default')
+  async getDefaultGroup(@Param('courseId') courseId: string, @CurrentUser() user: User): Promise<any> {
+    return this.groupsService.getDefaultGroup(courseId, user.id);
+  }
+
+  @Get(':groupId/members')
+  async getMembers(@Param('groupId') groupId: string, @CurrentUser() user: User): Promise<any> {
+    return this.groupsService.getGroupMembers(groupId, user.id);
   }
 
   @Get(':groupId/messages')
@@ -29,4 +39,14 @@ export class GroupsController {
   async sendMessage(@Param('groupId') groupId: string, @Body('content') content: string, @CurrentUser() user: User): Promise<any> {
     return this.groupsService.sendMessage(groupId, user.id, content);
   }
+
+  @Post(':groupId/invite-link')
+  async createInviteLink(@Param('groupId') groupId: string, @CurrentUser() user: User): Promise<any> {
+    return this.groupsService.createInviteLink(groupId, user.id);
+  }
+
+  @Post('join/:groupId')
+  async joinByInvite(@Param('groupId') groupId: string, @CurrentUser() user: User): Promise<any> {
+    return this.groupsService.joinByInvite(groupId, user.id);
+  }
 }

apps/api/src/groups/groups.gateway.ts

@@ -0,0 +1,113 @@
+import {
+  ConnectedSocket,
+  MessageBody,
+  OnGatewayConnection,
+  SubscribeMessage,
+  WebSocketGateway,
+  WebSocketServer,
+} from '@nestjs/websockets';
+import { JwtService } from '@nestjs/jwt';
+import { Server, Socket } from 'socket.io';
+import { AuthService } from '../auth/auth.service';
+import { SupabaseService } from '../auth/supabase.service';
+import { UsersService } from '../users/users.service';
+import { GroupsService } from './groups.service';
+
+@WebSocketGateway({
+  namespace: '/ws/course-groups',
+  cors: {
+    origin: true,
+    credentials: true,
+  },
+})
+export class GroupsGateway implements OnGatewayConnection {
+  @WebSocketServer()
+  server: Server;
+
+  constructor(
+    private jwtService: JwtService,
+    private authService: AuthService,
+    private supabaseService: SupabaseService,
+    private usersService: UsersService,
+    private groupsService: GroupsService
+  ) {}
+
+  async handleConnection(client: Socket): Promise<void> {
+    try {
+      const user = await this.resolveUser(client);
+      if (!user) {
+        client.disconnect();
+        return;
+      }
+      client.data.user = user;
+    } catch {
+      client.disconnect();
+    }
+  }
+
+  @SubscribeMessage('groups:join')
+  async joinGroup(
+    @ConnectedSocket() client: Socket,
+    @MessageBody() body: { groupId: string }
+  ) {
+    const user = client.data.user;
+    if (!user || !body?.groupId) return { ok: false };
+
+    const canJoin = await this.groupsService.isMember(body.groupId, user.id);
+    if (!canJoin) {
+      await this.groupsService.joinByInvite(body.groupId, user.id);
+    }
+    await client.join(this.room(body.groupId));
+    const messages = await this.groupsService.getGroupMessages(body.groupId, user.id);
+    return { ok: true, messages };
+  }
+
+  @SubscribeMessage('groups:send')
+  async sendMessage(
+    @ConnectedSocket() client: Socket,
+    @MessageBody() body: { groupId: string; content: string }
+  ) {
+    const user = client.data.user;
+    if (!user || !body?.groupId || !body?.content?.trim()) return { ok: false };
+
+    const message = await this.groupsService.sendMessage(body.groupId, user.id, body.content.trim());
+    this.server.to(this.room(body.groupId)).emit('groups:new-message', message);
+    return { ok: true, message };
+  }
+
+  private room(groupId: string): string {
+    return `group:${groupId}`;
+  }
+
+  private async resolveUser(client: Socket) {
+    const authToken =
+      (client.handshake.auth?.token as string | undefined) ||
+      ((client.handshake.headers.authorization as string | undefined)?.replace(/^Bearer\s+/i, '')) ||
+      undefined;
+    if (!authToken) return null;
+
+    try {
+      const payload = this.jwtService.verify<{ sub: string; email: string; supabaseId: string }>(authToken);
+      const user = await this.authService.validateJwtPayload(payload);
+      if (user) return user;
+    } catch {
+      // Fallback to Supabase access token
+    }
+
+    const supabaseUser = await this.supabaseService.verifyToken(authToken);
+    if (!supabaseUser) return null;
+    let user = await this.usersService.findBySupabaseId(supabaseUser.id);
+    if (!user) {
+      user = await this.usersService.create({
+        supabaseId: supabaseUser.id,
+        email: supabaseUser.email!,
+        name:
+          supabaseUser.user_metadata?.full_name ||
+          supabaseUser.user_metadata?.name ||
+          null,
+        avatarUrl: supabaseUser.user_metadata?.avatar_url || null,
+      });
+    }
+    return user;
+  }
+}

apps/api/src/groups/groups.module.ts

@@ -1,10 +1,13 @@
 import { Module } from '@nestjs/common';
 import { GroupsController } from './groups.controller';
 import { GroupsService } from './groups.service';
+import { GroupsGateway } from './groups.gateway';
+import { UsersModule } from '../users/users.module';
 
 @Module({
+  imports: [UsersModule],
   controllers: [GroupsController],
-  providers: [GroupsService],
+  providers: [GroupsService, GroupsGateway],
   exports: [GroupsService],
 })
 export class GroupsModule {}

apps/api/src/groups/groups.service.ts

@@ -14,35 +14,171 @@ export class GroupsService {
     });
   }
 
-  async addMember(groupId: string, userId: string, role = 'student'): Promise<any> {
-    return this.prisma.groupMember.create({
-      data: { groupId, userId, role },
+  async ensureDefaultGroup(courseId: string): Promise<any> {
+    const existing = await this.prisma.courseGroup.findFirst({
+      where: { courseId, isDefault: true },
+    });
+    if (existing) return existing;
+
+    return this.prisma.courseGroup.create({
+      data: {
+        courseId,
+        name: 'Основная группа',
+        description: 'Обсуждение курса и вопросы преподавателю',
+        isDefault: true,
+      },
+    });
+  }
+
+  async getDefaultGroup(courseId: string, userId: string): Promise<any> {
+    const group = await this.ensureDefaultGroup(courseId);
+    await this.assertCanReadGroup(group.id, userId);
+
+    const [messages, members] = await Promise.all([
+      this.getGroupMessages(group.id, userId),
+      this.getGroupMembers(group.id, userId),
+    ]);
+    return { group, messages, members };
+  }
+
+  async addMember(groupId: string, requesterId: string, targetUserId: string, role = 'student'): Promise<any> {
+    const group = await this.prisma.courseGroup.findUnique({
+      where: { id: groupId },
+      include: { course: { select: { authorId: true } } },
+    });
+    if (!group) throw new NotFoundException('Group not found');
+    if (group.course.authorId !== requesterId) {
+      throw new ForbiddenException('Only course author can add members manually');
+    }
+
+    return this.prisma.groupMember.upsert({
+      where: { groupId_userId: { groupId, userId: targetUserId } },
+      create: { groupId, userId: targetUserId, role },
+      update: { role },
+    });
+  }
+
+  async getGroupMembers(groupId: string, userId: string): Promise<any> {
+    await this.assertCanReadGroup(groupId, userId);
+    return this.prisma.groupMember.findMany({
+      where: { groupId },
+      include: {
+        user: {
+          select: { id: true, name: true, email: true, avatarUrl: true },
+        },
+      },
+      orderBy: { joinedAt: 'asc' },
     });
   }
 
   async getGroupMessages(groupId: string, userId: string): Promise<any> {
-    const member = await this.prisma.groupMember.findUnique({
-      where: { groupId_userId: { groupId, userId } },
-    });
-    if (!member) throw new ForbiddenException('Not a member of this group');
+    await this.assertCanReadGroup(groupId, userId);
 
     return this.prisma.groupMessage.findMany({
       where: { groupId },
       include: { user: { select: { id: true, name: true, avatarUrl: true } } },
       orderBy: { createdAt: 'asc' },
-      take: 100,
+      take: 200,
     });
   }
 
   async sendMessage(groupId: string, userId: string, content: string): Promise<any> {
-    const member = await this.prisma.groupMember.findUnique({
-      where: { groupId_userId: { groupId, userId } },
-    });
-    if (!member) throw new ForbiddenException('Not a member of this group');
+    await this.assertCanReadGroup(groupId, userId);
 
     return this.prisma.groupMessage.create({
       data: { groupId, userId, content },
       include: { user: { select: { id: true, name: true, avatarUrl: true } } },
     });
   }
+
+  async createInviteLink(groupId: string, userId: string): Promise<any> {
+    const group = await this.prisma.courseGroup.findUnique({
+      where: { id: groupId },
+      include: { course: { select: { authorId: true } } },
+    });
+    if (!group) throw new NotFoundException('Group not found');
+    if (group.course.authorId !== userId) {
+      throw new ForbiddenException('Only course author can create invite links');
+    }
+
+    const appUrl = process.env.NEXT_PUBLIC_APP_URL || 'http://localhost:3080';
+    return {
+      groupId,
+      inviteUrl: `${appUrl}/dashboard/groups/${groupId}`,
+    };
+  }
+
+  async joinByInvite(groupId: string, userId: string): Promise<any> {
+    const group = await this.prisma.courseGroup.findUnique({
+      where: { id: groupId },
+      include: {
+        course: {
+          select: { id: true, authorId: true, price: true },
+        },
+      },
+    });
+    if (!group) throw new NotFoundException('Group not found');
+
+    const hasEnrollment = await this.prisma.enrollment.findUnique({
+      where: { userId_courseId: { userId, courseId: group.course.id } },
+    });
+    const hasPurchase = await this.prisma.purchase.findUnique({
+      where: { userId_courseId: { userId, courseId: group.course.id } },
+    });
+
+    if (!hasEnrollment && !hasPurchase && group.course.authorId !== userId) {
+      throw new ForbiddenException('Enroll or purchase course first');
+    }
+
+    return this.prisma.groupMember.upsert({
+      where: { groupId_userId: { groupId, userId } },
+      create: { groupId, userId, role: group.course.authorId === userId ? 'teacher' : 'student' },
+      update: {},
+    });
+  }
+
+  async isMember(groupId: string, userId: string): Promise<boolean> {
+    const member = await this.prisma.groupMember.findUnique({
+      where: { groupId_userId: { groupId, userId } },
+      select: { id: true },
+    });
+    return Boolean(member);
+  }
+
+  private async assertCanReadGroup(groupId: string, userId: string): Promise<void> {
+    const group = await this.prisma.courseGroup.findUnique({
+      where: { id: groupId },
+      include: {
+        course: {
+          select: { id: true, authorId: true },
+        },
+      },
+    });
+    if (!group) {
+      throw new NotFoundException('Group not found');
+    }
+
+    if (group.course.authorId === userId) return;
+
+    const member = await this.prisma.groupMember.findUnique({
+      where: { groupId_userId: { groupId, userId } },
+      select: { id: true },
+    });
+    if (member) return;
+
+    const enrollment = await this.prisma.enrollment.findUnique({
+      where: { userId_courseId: { userId, courseId: group.course.id } },
+      select: { id: true },
+    });
+    if (enrollment) {
+      await this.prisma.groupMember.upsert({
+        where: { groupId_userId: { groupId, userId } },
+        create: { groupId, userId, role: 'student' },
+        update: {},
+      });
+      return;
+    }
+
+    throw new ForbiddenException('No access to this group');
+  }
 }

apps/api/src/main.ts

@@ -7,7 +7,7 @@ import { AppModule } from './app.module';
 import { AllExceptionsFilter } from './common/all-exceptions.filter';
 
 async function bootstrap() {
-  const app = await NestFactory.create(AppModule);
+  const app = await NestFactory.create(AppModule, { rawBody: true });
   const configService = app.get(ConfigService);
 
   app.useGlobalFilters(new AllExceptionsFilter());

apps/api/src/moderation/moderation.controller.ts

@@ -24,4 +24,14 @@ export class ModerationController {
   async rejectCourse(@Param('courseId') courseId: string, @Body('reason') reason: string, @CurrentUser() user: User): Promise<any> {
     return this.moderationService.rejectCourse(user.id, courseId, reason);
   }
+
+  @Post('reviews/:reviewId/hide')
+  async hideReview(@Param('reviewId') reviewId: string, @CurrentUser() user: User): Promise<any> {
+    return this.moderationService.hideReview(user.id, reviewId);
+  }
+
+  @Post('reviews/:reviewId/unhide')
+  async unhideReview(@Param('reviewId') reviewId: string, @CurrentUser() user: User): Promise<any> {
+    return this.moderationService.unhideReview(user.id, reviewId);
+  }
 }

apps/api/src/moderation/moderation.service.ts

@@ -28,6 +28,17 @@ export class ModerationService {
       throw new ForbiddenException('Moderators only');
     }
 
+    const course = await this.prisma.course.findUnique({
+      where: { id: courseId },
+      select: { status: true },
+    });
+    if (!course) {
+      throw new ForbiddenException('Course not found');
+    }
+    if (course.status !== CourseStatus.PENDING_REVIEW) {
+      throw new ForbiddenException('Only courses pending review can be approved');
+    }
+
     return this.prisma.course.update({
       where: { id: courseId },
       data: {
@@ -46,6 +57,17 @@ export class ModerationService {
       throw new ForbiddenException('Moderators only');
     }
 
+    const course = await this.prisma.course.findUnique({
+      where: { id: courseId },
+      select: { status: true },
+    });
+    if (!course) {
+      throw new ForbiddenException('Course not found');
+    }
+    if (course.status !== CourseStatus.PENDING_REVIEW) {
+      throw new ForbiddenException('Only courses pending review can be rejected');
+    }
+
     return this.prisma.course.update({
       where: { id: courseId },
       data: {
@@ -55,4 +77,42 @@ export class ModerationService {
       },
     });
   }
+
+  async hideReview(userId: string, reviewId: string): Promise<any> {
+    await this.assertStaff(userId);
+    const review = await this.prisma.review.update({
+      where: { id: reviewId },
+      data: { isApproved: false },
+    });
+    await this.recalculateAverageRating(review.courseId);
+    return review;
+  }
+
+  async unhideReview(userId: string, reviewId: string): Promise<any> {
+    await this.assertStaff(userId);
+    const review = await this.prisma.review.update({
+      where: { id: reviewId },
+      data: { isApproved: true },
+    });
+    await this.recalculateAverageRating(review.courseId);
+    return review;
+  }
+
+  private async assertStaff(userId: string): Promise<void> {
+    const user = await this.prisma.user.findUnique({ where: { id: userId } });
+    if (!user || (user.role !== UserRole.MODERATOR && user.role !== UserRole.ADMIN)) {
+      throw new ForbiddenException('Moderators only');
+    }
+  }
+
+  private async recalculateAverageRating(courseId: string): Promise<void> {
+    const result = await this.prisma.review.aggregate({
+      where: { courseId, isApproved: true },
+      _avg: { rating: true },
+    });
+    await this.prisma.course.update({
+      where: { id: courseId },
+      data: { averageRating: result._avg.rating ?? null },
+    });
+  }
 }

apps/api/src/payments/payments.service.ts

@@ -28,34 +28,7 @@ export class PaymentsService {
   }
 
   async createCheckoutSession(userId: string, tier: 'PREMIUM' | 'PRO') {
-    const user = await this.prisma.user.findUnique({
-      where: { id: userId },
-      include: { subscription: true },
-    });
-
-    if (!user) {
-      throw new NotFoundException('User not found');
-    }
-
-    // Get or create Stripe customer
-    let stripeCustomerId = user.subscription?.stripeCustomerId;
-
-    if (!stripeCustomerId) {
-      const customer = await this.stripeService.createCustomer(user.email, user.name || undefined);
-      stripeCustomerId = customer.id;
-
-      await this.prisma.subscription.upsert({
-        where: { userId },
-        create: {
-          userId,
-          tier: SubscriptionTier.FREE,
-          stripeCustomerId: customer.id,
-        },
-        update: {
-          stripeCustomerId: customer.id,
-        },
-      });
-    }
+    const { stripeCustomerId } = await this.getOrCreateStripeCustomer(userId);
 
     // Get price ID for tier
     const priceId =
@@ -83,6 +56,57 @@ export class PaymentsService {
     return { url: session.url };
   }
 
+  async createCourseCheckoutSession(userId: string, courseId: string) {
+    const [course, existingPurchase] = await Promise.all([
+      this.prisma.course.findUnique({
+        where: { id: courseId },
+        select: {
+          id: true,
+          title: true,
+          description: true,
+          price: true,
+          currency: true,
+          isPublished: true,
+          status: true,
+        },
+      }),
+      this.prisma.purchase.findUnique({
+        where: { userId_courseId: { userId, courseId } },
+      }),
+    ]);
+
+    if (!course) {
+      throw new NotFoundException('Course not found');
+    }
+    if (!course.price) {
+      throw new Error('Course is free, checkout is not required');
+    }
+    if (existingPurchase?.status === 'completed') {
+      throw new Error('Course is already purchased');
+    }
+
+    const { stripeCustomerId } = await this.getOrCreateStripeCustomer(userId);
+    const appUrl = this.configService.get<string>('NEXT_PUBLIC_APP_URL') || 'http://localhost:3000';
+    const unitAmount = Math.round(Number(course.price) * 100);
+
+    const session = await this.stripeService.createOneTimeCheckoutSession({
+      customerId: stripeCustomerId,
+      currency: course.currency || 'USD',
+      unitAmount,
+      productName: course.title,
+      productDescription: course.description || undefined,
+      successUrl: `${appUrl}/dashboard/catalog/${courseId}?purchase=success`,
+      cancelUrl: `${appUrl}/dashboard/catalog/${courseId}?purchase=canceled`,
+      metadata: {
+        type: 'course_purchase',
+        userId,
+        courseId,
+      },
+    });
+
+    return { url: session.url };
+  }
+
   async createPortalSession(userId: string) {
     const subscription = await this.prisma.subscription.findUnique({
       where: { userId },
@@ -107,8 +131,8 @@ export class PaymentsService {
       case 'checkout.session.completed':
         await this.handleCheckoutCompleted(event.data.object as {
           customer: string;
-          subscription: string;
-          metadata: { userId: string; tier: string };
+          subscription?: string;
+          metadata: { userId?: string; tier?: string; type?: string; courseId?: string };
         });
         break;
 
@@ -133,10 +157,26 @@ export class PaymentsService {
 
   private async handleCheckoutCompleted(session: {
     customer: string;
-    subscription: string;
-    metadata: { userId: string; tier: string };
+    subscription?: string;
+    metadata: { userId?: string; tier?: string; type?: string; courseId?: string };
   }) {
     const { customer, subscription: subscriptionId, metadata } = session;
+    if (!metadata?.userId) {
+      return;
+    }
+
+    if (metadata.type === 'course_purchase') {
+      await this.handleCoursePurchaseCompleted({
+        userId: metadata.userId,
+        courseId: metadata.courseId || '',
+      });
+      return;
+    }
+
+    if (!subscriptionId || !metadata.tier) {
+      return;
+    }
+
     const tier = metadata.tier as SubscriptionTier;
 
     const stripeSubscription = await this.stripeService.getSubscription(subscriptionId);
@@ -161,6 +201,95 @@ export class PaymentsService {
     });
   }
 
+  private async handleCoursePurchaseCompleted(params: { userId: string; courseId: string }) {
+    const { userId, courseId } = params;
+    if (!courseId) return;
+
+    const course = await this.prisma.course.findUnique({
+      where: { id: courseId },
+      select: { id: true, price: true, currency: true, authorId: true },
+    });
+    if (!course || !course.price) return;
+
+    await this.prisma.purchase.upsert({
+      where: { userId_courseId: { userId, courseId } },
+      create: {
+        userId,
+        courseId,
+        amount: course.price,
+        currency: course.currency,
+        status: 'completed',
+      },
+      update: {
+        status: 'completed',
+        amount: course.price,
+        currency: course.currency,
+      },
+    });
+
+    await this.prisma.enrollment.upsert({
+      where: { userId_courseId: { userId, courseId } },
+      create: { userId, courseId },
+      update: {},
+    });
+
+    const defaultGroup = await this.ensureDefaultCourseGroup(courseId);
+    await this.prisma.groupMember.upsert({
+      where: { groupId_userId: { groupId: defaultGroup.id, userId } },
+      create: { groupId: defaultGroup.id, userId, role: 'student' },
+      update: {},
+    });
+  }
+
+  private async getOrCreateStripeCustomer(userId: string): Promise<{ stripeCustomerId: string; email: string; name: string | null }> {
+    const user = await this.prisma.user.findUnique({
+      where: { id: userId },
+      include: { subscription: true },
+    });
+    if (!user) {
+      throw new NotFoundException('User not found');
+    }
+
+    let stripeCustomerId = user.subscription?.stripeCustomerId;
+    if (!stripeCustomerId) {
+      const customer = await this.stripeService.createCustomer(user.email, user.name || undefined);
+      stripeCustomerId = customer.id;
+      await this.prisma.subscription.upsert({
+        where: { userId },
+        create: {
+          userId,
+          tier: SubscriptionTier.FREE,
+          stripeCustomerId: customer.id,
+        },
+        update: {
+          stripeCustomerId: customer.id,
+        },
+      });
+    }
+
+    return {
+      stripeCustomerId,
+      email: user.email,
+      name: user.name,
+    };
+  }
+
+  private async ensureDefaultCourseGroup(courseId: string) {
+    const existing = await this.prisma.courseGroup.findFirst({
+      where: { courseId, isDefault: true },
+    });
+    if (existing) return existing;
+
+    return this.prisma.courseGroup.create({
+      data: {
+        courseId,
+        name: 'Основная группа',
+        description: 'Обсуждение курса и вопросы преподавателю',
+        isDefault: true,
+      },
+    });
+  }
+
   private async handleSubscriptionUpdated(subscription: {
     id: string;
     customer: string;

apps/api/src/payments/stripe.service.ts

@@ -45,6 +45,38 @@ export class StripeService {
     });
   }
 
+  async createOneTimeCheckoutSession(params: {
+    customerId: string;
+    successUrl: string;
+    cancelUrl: string;
+    metadata?: Record<string, string>;
+    currency: string;
+    unitAmount: number;
+    productName: string;
+    productDescription?: string;
+  }): Promise<Stripe.Checkout.Session> {
+    return this.stripe.checkout.sessions.create({
+      customer: params.customerId,
+      mode: 'payment',
+      line_items: [
+        {
+          price_data: {
+            currency: params.currency.toLowerCase(),
+            unit_amount: params.unitAmount,
+            product_data: {
+              name: params.productName,
+              description: params.productDescription,
+            },
+          },
+          quantity: 1,
+        },
+      ],
+      success_url: params.successUrl,
+      cancel_url: params.cancelUrl,
+      metadata: params.metadata,
+    });
+  }
+
   async createPortalSession(customerId: string, returnUrl: string): Promise<Stripe.BillingPortal.Session> {
     return this.stripe.billingPortal.sessions.create({
       customer: customerId,

apps/api/src/support/support.controller.ts

@@ -11,8 +11,11 @@ export class SupportController {
   constructor(private supportService: SupportService) {}
 
   @Post('tickets')
-  async createTicket(@Body('title') title: string, @CurrentUser() user: User): Promise<any> {
-    return this.supportService.createTicket(user.id, title);
+  async createTicket(
+    @Body() body: { title: string; initialMessage?: string; priority?: string },
+    @CurrentUser() user: User
+  ): Promise<any> {
+    return this.supportService.createTicket(user.id, body.title, body.initialMessage, body.priority);
   }
 
   @Get('tickets')
@@ -29,4 +32,24 @@ export class SupportController {
   async sendMessage(@Param('id') id: string, @Body('content') content: string, @CurrentUser() user: User): Promise<any> {
     return this.supportService.sendMessage(id, user.id, content);
   }
+
+  @Get('admin/tickets')
+  async getAllTickets(@CurrentUser() user: User): Promise<any> {
+    return this.supportService.getAllTickets(user.id);
+  }
+
+  @Get('admin/tickets/:id/messages')
+  async getMessagesForStaff(@Param('id') id: string, @CurrentUser() user: User): Promise<any> {
+    return this.supportService.getTicketMessagesForStaff(id, user.id);
+  }
+
+  @Post('admin/tickets/:id/messages')
+  async sendStaffMessage(@Param('id') id: string, @Body('content') content: string, @CurrentUser() user: User): Promise<any> {
+    return this.supportService.sendStaffMessage(id, user.id, content);
+  }
+
+  @Post('admin/tickets/:id/status')
+  async updateStatus(@Param('id') id: string, @Body('status') status: string, @CurrentUser() user: User): Promise<any> {
+    return this.supportService.updateTicketStatus(id, user.id, status);
+  }
 }

apps/api/src/support/support.gateway.ts

@@ -0,0 +1,125 @@
+import {
+  ConnectedSocket,
+  MessageBody,
+  OnGatewayConnection,
+  SubscribeMessage,
+  WebSocketGateway,
+  WebSocketServer,
+} from '@nestjs/websockets';
+import { JwtService } from '@nestjs/jwt';
+import { Server, Socket } from 'socket.io';
+import { AuthService } from '../auth/auth.service';
+import { SupabaseService } from '../auth/supabase.service';
+import { UsersService } from '../users/users.service';
+import { SupportService } from './support.service';
+
+@WebSocketGateway({
+  namespace: '/ws/support',
+  cors: {
+    origin: true,
+    credentials: true,
+  },
+})
+export class SupportGateway implements OnGatewayConnection {
+  @WebSocketServer()
+  server: Server;
+
+  constructor(
+    private jwtService: JwtService,
+    private authService: AuthService,
+    private supabaseService: SupabaseService,
+    private usersService: UsersService,
+    private supportService: SupportService
+  ) {}
+
+  async handleConnection(client: Socket): Promise<void> {
+    try {
+      const user = await this.resolveUser(client);
+      if (!user) {
+        client.disconnect();
+        return;
+      }
+      client.data.user = user;
+    } catch {
+      client.disconnect();
+    }
+  }
+
+  @SubscribeMessage('support:join')
+  async joinTicket(
+    @ConnectedSocket() client: Socket,
+    @MessageBody() body: { ticketId: string }
+  ) {
+    const user = client.data.user;
+    if (!user || !body?.ticketId) return { ok: false };
+
+    const canAccess = await this.supportService.canAccessTicket(body.ticketId, user.id);
+    if (!canAccess) return { ok: false };
+
+    await client.join(this.room(body.ticketId));
+    const messages =
+      (await this.supportService.getTicketMessagesForStaff(body.ticketId, user.id).catch(async () =>
+        this.supportService.getTicketMessages(body.ticketId, user.id)
+      )) || [];
+    return { ok: true, messages };
+  }
+
+  @SubscribeMessage('support:send')
+  async sendMessage(
+    @ConnectedSocket() client: Socket,
+    @MessageBody() body: { ticketId: string; content: string }
+  ) {
+    const user = client.data.user;
+    if (!user || !body?.ticketId || !body?.content?.trim()) return { ok: false };
+
+    const canAccess = await this.supportService.canAccessTicket(body.ticketId, user.id);
+    if (!canAccess) return { ok: false };
+
+    const message =
+      (await this.supportService.sendStaffMessage(body.ticketId, user.id, body.content.trim()).catch(async () =>
+        this.supportService.sendMessage(body.ticketId, user.id, body.content.trim())
+      )) || null;
+
+    if (message) {
+      this.server.to(this.room(body.ticketId)).emit('support:new-message', message);
+      return { ok: true, message };
+    }
+    return { ok: false };
+  }
+
+  private room(ticketId: string): string {
+    return `ticket:${ticketId}`;
+  }
+
+  private async resolveUser(client: Socket) {
+    const authToken =
+      (client.handshake.auth?.token as string | undefined) ||
+      ((client.handshake.headers.authorization as string | undefined)?.replace(/^Bearer\s+/i, '')) ||
+      undefined;
+    if (!authToken) return null;
+
+    try {
+      const payload = this.jwtService.verify<{ sub: string; email: string; supabaseId: string }>(authToken);
+      const user = await this.authService.validateJwtPayload(payload);
+      if (user) return user;
+    } catch {
+      // Fallback to Supabase access token
+    }
+
+    const supabaseUser = await this.supabaseService.verifyToken(authToken);
+    if (!supabaseUser) return null;
+    let user = await this.usersService.findBySupabaseId(supabaseUser.id);
+    if (!user) {
+      user = await this.usersService.create({
+        supabaseId: supabaseUser.id,
+        email: supabaseUser.email!,
+        name:
+          supabaseUser.user_metadata?.full_name ||
+          supabaseUser.user_metadata?.name ||
+          null,
+        avatarUrl: supabaseUser.user_metadata?.avatar_url || null,
+      });
+    }
+    return user;
+  }
+}

apps/api/src/support/support.module.ts

@@ -1,10 +1,13 @@
 import { Module } from '@nestjs/common';
 import { SupportController } from './support.controller';
 import { SupportService } from './support.service';
+import { SupportGateway } from './support.gateway';
+import { UsersModule } from '../users/users.module';
 
 @Module({
+  imports: [UsersModule],
   controllers: [SupportController],
-  providers: [SupportService],
+  providers: [SupportService, SupportGateway],
   exports: [SupportService],
 })
 export class SupportModule {}

apps/api/src/support/support.service.ts

@@ -1,14 +1,40 @@
-import { Injectable } from '@nestjs/common';
+import { ForbiddenException, Injectable, NotFoundException } from '@nestjs/common';
+import { UserRole } from '@coursecraft/database';
 import { PrismaService } from '../common/prisma/prisma.service';
 
 @Injectable()
 export class SupportService {
   constructor(private prisma: PrismaService) {}
 
-  async createTicket(userId: string, title: string): Promise<any> {
-    return this.prisma.supportTicket.create({
-      data: { userId, title },
-      include: { messages: { include: { user: { select: { name: true } } } } },
+  async createTicket(
+    userId: string,
+    title: string,
+    initialMessage?: string,
+    priority: string = 'normal'
+  ): Promise<any> {
+    const ticket = await this.prisma.supportTicket.create({
+      data: { userId, title, priority, status: 'open' },
+    });
+
+    if (initialMessage?.trim()) {
+      await this.prisma.ticketMessage.create({
+        data: {
+          ticketId: ticket.id,
+          userId,
+          content: initialMessage.trim(),
+          isStaff: false,
+        },
+      });
+    }
+
+    return this.prisma.supportTicket.findUnique({
+      where: { id: ticket.id },
+      include: {
+        messages: {
+          include: { user: { select: { id: true, name: true, avatarUrl: true } } },
+          orderBy: { createdAt: 'asc' },
+        },
+      },
     });
   }
 
@@ -22,7 +48,7 @@ export class SupportService {
 
   async getTicketMessages(ticketId: string, userId: string): Promise<any> {
     const ticket = await this.prisma.supportTicket.findFirst({ where: { id: ticketId, userId } });
-    if (!ticket) throw new Error('Ticket not found');
+    if (!ticket) throw new NotFoundException('Ticket not found');
 
     return this.prisma.ticketMessage.findMany({
       where: { ticketId },
@@ -32,9 +58,104 @@ export class SupportService {
   }
 
   async sendMessage(ticketId: string, userId: string, content: string): Promise<any> {
-    return this.prisma.ticketMessage.create({
+    const ticket = await this.prisma.supportTicket.findFirst({
+      where: { id: ticketId, userId },
+      select: { id: true, status: true },
+    });
+    if (!ticket) throw new NotFoundException('Ticket not found');
+
+    const message = await this.prisma.ticketMessage.create({
       data: { ticketId, userId, content, isStaff: false },
-      include: { user: { select: { id: true, name: true } } },
+      include: { user: { select: { id: true, name: true, avatarUrl: true } } },
+    });
+    await this.prisma.supportTicket.update({
+      where: { id: ticketId },
+      data: {
+        status: ticket.status === 'resolved' ? 'in_progress' : ticket.status,
+        updatedAt: new Date(),
+      },
+    });
+    return message;
+  }
+
+  async getAllTickets(staffUserId: string): Promise<any> {
+    await this.assertStaff(staffUserId);
+    return this.prisma.supportTicket.findMany({
+      include: {
+        user: { select: { id: true, name: true, email: true, avatarUrl: true } },
+        messages: { orderBy: { createdAt: 'desc' }, take: 1 },
+      },
+      orderBy: [{ status: 'asc' }, { updatedAt: 'desc' }],
     });
   }
+
+  async getTicketMessagesForStaff(ticketId: string, staffUserId: string): Promise<any> {
+    await this.assertStaff(staffUserId);
+    const ticket = await this.prisma.supportTicket.findUnique({
+      where: { id: ticketId },
+      select: { id: true },
+    });
+    if (!ticket) throw new NotFoundException('Ticket not found');
+
+    return this.prisma.ticketMessage.findMany({
+      where: { ticketId },
+      include: { user: { select: { id: true, name: true, avatarUrl: true } } },
+      orderBy: { createdAt: 'asc' },
+    });
+  }
+
+  async sendStaffMessage(ticketId: string, staffUserId: string, content: string): Promise<any> {
+    await this.assertStaff(staffUserId);
+    const ticket = await this.prisma.supportTicket.findUnique({
+      where: { id: ticketId },
+      select: { id: true },
+    });
+    if (!ticket) throw new NotFoundException('Ticket not found');
+
+    const message = await this.prisma.ticketMessage.create({
+      data: { ticketId, userId: staffUserId, content, isStaff: true },
+      include: { user: { select: { id: true, name: true, avatarUrl: true } } },
+    });
+    await this.prisma.supportTicket.update({
+      where: { id: ticketId },
+      data: { status: 'in_progress', updatedAt: new Date() },
+    });
+    return message;
+  }
+
+  async updateTicketStatus(ticketId: string, staffUserId: string, status: string): Promise<any> {
+    await this.assertStaff(staffUserId);
+    const allowed = ['open', 'in_progress', 'resolved', 'closed'];
+    if (!allowed.includes(status)) {
+      throw new ForbiddenException('Invalid status');
+    }
+    return this.prisma.supportTicket.update({
+      where: { id: ticketId },
+      data: { status, updatedAt: new Date() },
+    });
+  }
+
+  async canAccessTicket(ticketId: string, userId: string): Promise<boolean> {
+    const user = await this.prisma.user.findUnique({
+      where: { id: userId },
+      select: { role: true },
+    });
+    if (!user) return false;
+    if (user.role === UserRole.ADMIN || user.role === UserRole.MODERATOR) return true;
+    const ticket = await this.prisma.supportTicket.findFirst({
+      where: { id: ticketId, userId },
+      select: { id: true },
+    });
+    return Boolean(ticket);
+  }
+
+  private async assertStaff(userId: string): Promise<void> {
+    const user = await this.prisma.user.findUnique({
+      where: { id: userId },
+      select: { role: true },
+    });
+    if (!user || (user.role !== UserRole.ADMIN && user.role !== UserRole.MODERATOR)) {
+      throw new ForbiddenException('Staff access only');
+    }
+  }
 }