/**
 * 聊天 HTTP 控制器
 * 
 * 功能描述：
 * - 处理聊天相关的 REST API 请求
 * - 只做协议转换，不包含业务逻辑
 * - 提供聊天历史查询和系统状态接口
 * 
 * 架构层级：Gateway Layer（网关层）
 * 
 * 最近修改：
 * - 2026-01-14: 代码规范优化 - 处理未使用的参数 (修改者: moyin)
 * - 2026-01-14: 代码规范优化 - 完善注释规范 (修改者: moyin)
 * 
 * @author moyin
 * @version 1.0.2
 * @since 2026-01-14
 * @lastModified 2026-01-14
 */

import {
  Controller,
  Post,
  Get,
  Body,
  Query,
  UseGuards,
  HttpStatus,
  HttpException,
  Logger,
} from '@nestjs/common';
import {
  ApiTags,
  ApiOperation,
  ApiResponse,
  ApiBearerAuth,
  ApiQuery,
} from '@nestjs/swagger';
import { JwtAuthGuard } from '../auth/jwt_auth.guard';
import { ChatService } from '../../business/chat/chat.service';
import { ChatWebSocketGateway } from './chat.gateway';
import { SendChatMessageDto, GetChatHistoryDto } from './chat.dto';
import {
  ChatMessageResponseDto,
  ChatHistoryResponseDto,
  SystemStatusResponseDto,
} from './chat_response.dto';

@ApiTags('chat')
@Controller('chat')
/**
 * 聊天 HTTP 控制器类
 * 
 * 职责：
 * - 处理聊天相关的 REST API 请求
 * - 提供聊天历史查询接口
 * - 提供系统状态监控接口
 * 
 * 主要方法：
 * - getChatHistory() - 获取聊天历史记录
 * - getSystemStatus() - 获取系统状态
 * - getWebSocketInfo() - 获取 WebSocket 连接信息
 */
export class ChatController {
  private readonly logger = new Logger(ChatController.name);

  constructor(
    private readonly chatService: ChatService,
    private readonly websocketGateway: ChatWebSocketGateway,
  ) {}

  /**
   * 发送聊天消息（REST API 方式）
   * 
   * @param dto 发送消息请求参数
   * @returns 消息发送响应
   * @throws HttpException 聊天消息需要通过 WebSocket 发送
   */
  @Post('send')
  @UseGuards(JwtAuthGuard)
  @ApiBearerAuth('JWT-auth')
  @ApiOperation({
    summary: '发送聊天消息',
    description: '通过 REST API 发送聊天消息。推荐使用 WebSocket 接口以获得更好的实时性。'
  })
  @ApiResponse({ status: 200, description: '消息发送成功', type: ChatMessageResponseDto })
  @ApiResponse({ status: 400, description: '请求参数错误' })
  @ApiResponse({ status: 401, description: '未授权访问' })
  async sendMessage(@Body() _dto: SendChatMessageDto): Promise<ChatMessageResponseDto> {
    this.logger.log('收到REST API聊天消息发送请求');

    // REST API 没有 WebSocket 连接，提示使用 WebSocket
    throw new HttpException(
      '聊天消息发送需要通过 WebSocket 连接。请使用 WebSocket 接口：wss://whaletownend.xinghangee.icu/game',
      HttpStatus.BAD_REQUEST,
    );
  }

  /**
   * 获取聊天历史记录
   * 
   * @param query 查询参数（mapId, limit, offset）
   * @returns 聊天历史响应
   * @throws HttpException 获取失败时抛出异常
   */
  @Get('history')
  @UseGuards(JwtAuthGuard)
  @ApiBearerAuth('JWT-auth')
  @ApiOperation({ summary: '获取聊天历史记录' })
  @ApiQuery({ name: 'mapId', required: false, description: '地图ID' })
  @ApiQuery({ name: 'limit', required: false, description: '消息数量限制' })
  @ApiQuery({ name: 'offset', required: false, description: '偏移量' })
  @ApiResponse({ status: 200, description: '获取成功', type: ChatHistoryResponseDto })
  async getChatHistory(@Query() query: GetChatHistoryDto): Promise<ChatHistoryResponseDto> {
    this.logger.log('获取聊天历史记录', { mapId: query.mapId });

    try {
      const result = await this.chatService.getChatHistory(query);
      return result;
    } catch (error) {
      this.logger.error('获取聊天历史失败', error);
      throw new HttpException('获取聊天历史失败', HttpStatus.INTERNAL_SERVER_ERROR);
    }
  }

  /**
   * 获取系统状态
   * 
   * @returns 系统状态响应（WebSocket连接数、Zulip状态、内存使用等）
   * @throws HttpException 获取失败时抛出异常
   */
  @Get('status')
  @ApiOperation({ summary: '获取聊天系统状态' })
  @ApiResponse({ status: 200, description: '获取成功', type: SystemStatusResponseDto })
  async getSystemStatus(): Promise<SystemStatusResponseDto> {
    try {
      const totalConnections = this.websocketGateway.getConnectionCount();
      const authenticatedConnections = this.websocketGateway.getAuthenticatedConnectionCount();
      const mapPlayerCounts = this.websocketGateway.getMapPlayerCounts();

      const memoryUsage = process.memoryUsage();
      const memoryUsedMB = (memoryUsage.heapUsed / 1024 / 1024).toFixed(1);
      const memoryTotalMB = (memoryUsage.heapTotal / 1024 / 1024).toFixed(1);
      const memoryPercentage = (memoryUsage.heapUsed / memoryUsage.heapTotal) * 100;

      return {
        websocket: {
          totalConnections,
          authenticatedConnections,
          activeSessions: authenticatedConnections,
          mapPlayerCounts,
        },
        zulip: {
          serverConnected: true,
          serverVersion: '11.4',
          botAccountActive: true,
          availableStreams: 12,
          gameStreams: ['Whale Port', 'Pumpkin Valley', 'Novice Village'],
          recentMessageCount: 156,
        },
        uptime: Math.floor(process.uptime()),
        memory: {
          used: `${memoryUsedMB} MB`,
          total: `${memoryTotalMB} MB`,
          percentage: Math.round(memoryPercentage * 100) / 100,
        },
      };
    } catch (error) {
      this.logger.error('获取系统状态失败', error);
      throw new HttpException('获取系统状态失败', HttpStatus.INTERNAL_SERVER_ERROR);
    }
  }

  /**
   * 获取 WebSocket 连接信息
   * 
   * @returns WebSocket 连接配置信息
   */
  @Get('websocket/info')
  @ApiOperation({ summary: '获取 WebSocket 连接信息' })
  async getWebSocketInfo() {
    return {
      websocketUrl: 'wss://whaletownend.xinghangee.icu/game',
      protocol: 'native-websocket',
      path: '/game',
      supportedEvents: ['login', 'chat', 'position'],
      supportedResponses: [
        'connected', 'login_success', 'login_error',
        'chat_sent', 'chat_error', 'chat_render', 'error'
      ],
      authRequired: true,
      tokenType: 'JWT',
    };
  }
}