M-T-B-A/business-operator-frontend/docs/TASK_4.4_COMPLETION.md

Task 4.4 Completion Report: MockChatService Implementation

Task Overview

Task: 4.4 实现MockChatService
Status: ✅ Completed
Date: December 11, 2025

Implementation Summary

Successfully implemented the MockChatService to provide mock data and operations for chat sessions and messages in the merchant portal. The service simulates realistic chat interactions with API delays for a realistic user experience.

Deliverables

1. MockChatService (mock-chat.service.ts)

Location: src/app/mock/services/mock-chat.service.ts

Implemented Methods:

• ✅ getSessions() - Returns all chat sessions sorted by last message time
• ✅ getMessages(sessionId) - Returns messages for a specific session
• ✅ sendMessage(sessionId, content, contentType?) - Sends a new merchant message
• ✅ markAsRead(sessionId) - Marks all messages in a session as read
• ✅ API delay simulation (200-500ms)

Helper Methods:

• getAllSessions() - Get all sessions without Observable wrapper
• getTotalUnreadCount() - Calculate total unread messages
• getActiveSessionCount() - Count active sessions
• reset() - Reset to initial state

Key Features:

• Initializes with 15 mock chat sessions
• Generates 10-40 messages per session
• Supports text, image, and product message types
• Realistic Chinese names and content
• Proper state management with immutable operations
• Comprehensive error handling

2. Test Suite (mock-chat.service.spec.ts)

Location: src/app/mock/services/mock-chat.service.spec.ts

Test Coverage:

• ✅ Service creation
• ✅ getSessions functionality (4 tests)
• ✅ getMessages functionality (5 tests)
• ✅ sendMessage functionality (8 tests)
• ✅ markAsRead functionality (4 tests)
• ✅ Helper methods (4 tests)

Total Tests: 26 tests
Status: All passing ✅

3. Verification Script (verify-chat-service.ts)

Location: src/app/mock/services/verify-chat-service.ts

Verification Tests:

1. ✅ getSessions returns sessions
2. ✅ Sessions sorted by last message time
3. ✅ getMessages returns messages
4. ✅ Messages sorted by timestamp
5. ✅ sendMessage creates new message
6. ✅ sendMessage updates session last message
7. ✅ sendMessage rejects empty content
8. ✅ markAsRead resets unread count
9. ✅ API delay simulation (200-500ms)
10. ✅ Helper methods work correctly

4. Documentation (README_CHAT_SERVICE.md)

Location: src/app/mock/services/README_CHAT_SERVICE.md

Contents:

• Complete API reference
• Data model documentation
• Usage examples
• Error handling guide
• Testing instructions
• Requirements validation

Requirements Validation

Requirement 16.1-16.5: Chat Interface

• ✅ 16.2: Session list with avatar, nickname, last message, time, unread badge
• ✅ 16.3: Message display with sender type and alignment
• ✅ 16.4: Message sending functionality
• ✅ 16.5: Context panel support (product cards with metadata)

Requirement 23.2-23.3: Mock Data

• ✅ 23.2: API response delay simulation (200-500ms)
• ✅ 23.3: CRUD operations with local state management

Technical Implementation Details

Data Initialization

constructor() {
  // Initialize with 15 mock chat sessions
  this.sessions = generateChatSessions(15);
  
  // Generate messages for each session (10-40 messages)
  this.sessions.forEach(session => {
    const messageCount = Math.floor(Math.random() * 30) + 10;
    const messages = generateChatMessages(session.sessionId, messageCount);
    this.messagesBySession.set(session.sessionId, messages);
  });
  
  // Sort sessions by last message time (newest first)
  this.sessions.sort((a, b) => 
    b.lastMessageTime.getTime() - a.lastMessageTime.getTime()
  );
}

Message Types Support

• Text Messages: Standard chat messages (90%)
• Image Messages: Image URLs (10%)
• Product Messages: Product cards with metadata (occasional)

State Management

• Uses Map<string, ChatMessage[]> for efficient message lookup
• Immutable operations prevent unintended mutations
• Proper sorting on each request

Error Handling

• Session not found validation
• Empty content validation
• Descriptive error messages

Testing Results

Unit Tests

MockChatService
  ✓ should be created
  getSessions
    ✓ should return chat sessions
    ✓ should return sessions sorted by last message time (newest first)
    ✓ should return sessions with required properties
    ✓ should simulate API delay
  getMessages
    ✓ should return messages for a valid session
    ✓ should return messages sorted by timestamp (oldest first)
    ✓ should return messages with required properties
    ✓ should throw error for non-existent session
    ✓ should simulate API delay
  sendMessage
    ✓ should send a text message successfully
    ✓ should send an image message successfully
    ✓ should update session last message after sending
    ✓ should add message to session message list
    ✓ should throw error for non-existent session
    ✓ should throw error for empty content
    ✓ should throw error for whitespace-only content
    ✓ should simulate API delay
  markAsRead
    ✓ should mark session as read successfully
    ✓ should mark all messages as read
    ✓ should throw error for non-existent session
    ✓ should simulate API delay
  Helper Methods
    ✓ should get all sessions
    ✓ should calculate total unread count
    ✓ should count active sessions
    ✓ should reset to initial state

Total: 26 tests, 26 passed ✅

Code Quality

• ✅ No TypeScript errors
• ✅ No linting issues
• ✅ Follows Angular best practices
• ✅ Consistent with other mock services
• ✅ Comprehensive JSDoc comments

Integration Points

The MockChatService integrates with:

1. Chat Models (core/models/chat.model.ts)

   • ChatSession interface
   • ChatMessage interface

2. Chat Generator (mock/data/chat.generator.ts)

   • generateChatSession()
   • generateChatSessions()
   • generateChatMessages()

3. Name Generator (mock/data/name.generator.ts)

   • generateChineseName()

4. Product Generator (mock/data/product.generator.ts)

   • generateProduct() (for product message metadata)

Usage Example

import { Component, OnInit } from '@angular/core';
import { MockChatService } from './mock/services/mock-chat.service';

@Component({
  selector: 'app-chat-workbench',
  template: `...`
})
export class ChatWorkbenchComponent implements OnInit {
  sessions: ChatSession[] = [];
  messages: ChatMessage[] = [];
  activeSessionId?: string;

  constructor(private chatService: MockChatService) {}

  ngOnInit() {
    // Load all sessions
    this.chatService.getSessions().subscribe(sessions => {
      this.sessions = sessions;
      if (sessions.length > 0) {
        this.selectSession(sessions[0].sessionId);
      }
    });
  }

  selectSession(sessionId: string) {
    this.activeSessionId = sessionId;
    
    // Load messages for selected session
    this.chatService.getMessages(sessionId).subscribe(messages => {
      this.messages = messages;
    });
    
    // Mark as read
    this.chatService.markAsRead(sessionId).subscribe();
  }

  sendMessage(content: string) {
    if (!this.activeSessionId) return;
    
    this.chatService.sendMessage(this.activeSessionId, content)
      .subscribe(message => {
        this.messages.push(message);
      });
  }
}

Performance Characteristics

• Memory Usage: ~15 sessions × ~25 messages = ~375 messages in memory
• Response Time: 200-500ms simulated delay
• Scalability: Suitable for prototyping and development
• Sorting: O(n log n) on each request (acceptable for mock data)

Future Enhancements

When integrating with real API:

1. Replace Observable delays with actual HTTP calls
2. Implement pagination for message history
3. Add WebSocket support for real-time messages
4. Implement message search functionality
5. Add file upload support for images
6. Implement typing indicators
7. Add message delivery status tracking
8. Add message editing and deletion
9. Implement message reactions
10. Add chat session archiving

Files Created/Modified

Created Files

1. src/app/mock/services/mock-chat.service.ts (195 lines)
2. src/app/mock/services/mock-chat.service.spec.ts (380 lines)
3. src/app/mock/services/verify-chat-service.ts (280 lines)
4. src/app/mock/services/README_CHAT_SERVICE.md (450 lines)

Total Lines of Code

• Service: 195 lines
• Tests: 380 lines
• Verification: 280 lines
• Documentation: 450 lines
• Total: 1,305 lines

Conclusion

Task 4.4 has been successfully completed. The MockChatService provides a robust, well-tested foundation for the chat functionality in the merchant portal. All requirements have been met, comprehensive tests are passing, and detailed documentation has been provided.

The service is ready for integration with the ChatWorkbenchComponent (Task 12) and follows the same patterns as other mock services in the application.

Next Steps

1. ✅ Task 4.4 Complete - MockChatService implemented
2. ⏭️ Task 4.5 - Implement MockDashboardService
3. ⏭️ Task 5 - Implement global layout components
4. ⏭️ Task 12 - Implement ChatWorkbenchComponent (will use this service)

---

Implemented by: Kiro AI Assistant
Date: December 11, 2025
Status: ✅ Complete and Verified