import {
  Controller,
  Get,
  Post,
  Patch,
  Body,
  Param,
  Query,
  UseGuards,
  HttpCode,
  HttpStatus,
  Inject,
  forwardRef,
} from '@nestjs/common';
import {
  ApiTags,
  ApiOperation,
  ApiResponse,
  ApiBearerAuth,
  ApiQuery,
  ApiParam,
} from '@nestjs/swagger';
import { SupportChatService } from './support-chat.service';
import { SendSupportMessageDto } from './dto';
import { JwtAuthGuard } from '../auth/guards';
import { CurrentUser } from '../auth/decorators';
import { Roles } from '../auth/decorators/roles.decorator';
import { UserRole, SupportChatStatus } from '@prisma/client';
import { MessagesGateway } from '../messages/messages.gateway';

@ApiTags('Support Chat')
@Controller('support-chat')
@UseGuards(JwtAuthGuard)
@ApiBearerAuth('JWT-auth')
export class SupportChatController {
  constructor(
    private readonly supportChatService: SupportChatService,
    @Inject(forwardRef(() => MessagesGateway))
    private readonly messagesGateway: MessagesGateway,
  ) {}

  // ==========================================
  // GET OR CREATE SUPPORT CHAT (User/Agent)
  // ==========================================
  @Post()
  @HttpCode(HttpStatus.OK)
  @ApiOperation({ summary: 'Get or create a support chat for the current user' })
  async getOrCreateChat(@CurrentUser('id') userId: string) {
    return this.supportChatService.getOrCreateChat(userId);
  }

  // ==========================================
  // GET MY SUPPORT CHAT (User/Agent)
  // ==========================================
  @Get('my')
  @ApiOperation({ summary: 'Get current user\'s open support chat' })
  async getMyChat(@CurrentUser('id') userId: string) {
    return this.supportChatService.getOrCreateChat(userId);
  }

  // ==========================================
  // GET MESSAGES
  // ==========================================
  @Get(':id/messages')
  @ApiOperation({ summary: 'Get messages for a support chat' })
  @ApiParam({ name: 'id', description: 'Support Chat ID' })
  @ApiQuery({ name: 'page', required: false, type: Number })
  @ApiQuery({ name: 'limit', required: false, type: Number })
  async getMessages(
    @Param('id') chatId: string,
    @CurrentUser('id') userId: string,
    @CurrentUser('role') role: UserRole,
    @Query('page') page?: string,
    @Query('limit') limit?: string,
  ) {
    // Validate access
    const isAdmin = role === UserRole.ADMIN;
    await this.supportChatService.getChat(chatId, userId, isAdmin);

    return this.supportChatService.getMessages(
      chatId,
      page ? parseInt(page, 10) : 1,
      limit ? parseInt(limit, 10) : 50,
    );
  }

  // ==========================================
  // SEND MESSAGE (REST fallback)
  // ==========================================
  @Post(':id/messages')
  @HttpCode(HttpStatus.CREATED)
  @ApiOperation({ summary: 'Send a message in a support chat' })
  @ApiParam({ name: 'id', description: 'Support Chat ID' })
  async sendMessage(
    @Param('id') chatId: string,
    @CurrentUser('id') userId: string,
    @CurrentUser('role') role: UserRole,
    @Body() dto: SendSupportMessageDto,
  ) {
    // Validate access
    const isAdmin = role === UserRole.ADMIN;
    await this.supportChatService.getChat(chatId, userId, isAdmin);

    const senderRole = role === UserRole.ADMIN ? 'ADMIN' : 'USER';
    const message = await this.supportChatService.sendMessage(chatId, userId, senderRole, dto.content);

    // Emit WebSocket events for real-time updates
    this.messagesGateway.server.to(`support:${chatId}`).emit('support_new_message', message);

    // If user/agent sent the message, notify admins about unread count
    if (senderRole !== 'ADMIN') {
      const unreadTotal = await this.supportChatService.getAdminUnreadTotal();
      this.messagesGateway.server.to('admin_room').emit('support_unread_update', { unreadTotal });
    }

    // If admin sent the message, notify the user directly
    if (senderRole === 'ADMIN') {
      const chat = await this.supportChatService.getChat(chatId, userId, true);
      this.messagesGateway.sendToUser(chat.userId, 'support_new_message', message);
    }

    return message;
  }

  // ==========================================
  // MARK AS READ
  // ==========================================
  @Patch(':id/read')
  @HttpCode(HttpStatus.OK)
  @ApiOperation({ summary: 'Mark support chat messages as read' })
  @ApiParam({ name: 'id', description: 'Support Chat ID' })
  async markAsRead(
    @Param('id') chatId: string,
    @CurrentUser('role') role: UserRole,
  ) {
    const result = await this.supportChatService.markAsRead(chatId, role);

    // If admin marked as read, update sidebar badge for all admins
    if (role === UserRole.ADMIN) {
      const unreadTotal = await this.supportChatService.getAdminUnreadTotal();
      this.messagesGateway.server.to('admin_room').emit('support_unread_update', { unreadTotal });
    }

    return result;
  }

  // ==========================================
  // ADMIN: GET TOTAL UNREAD COUNT
  // ==========================================
  @Get('admin/unread-total')
  @Roles(UserRole.ADMIN)
  @ApiOperation({ summary: 'Admin: Get total unread support message count' })
  @ApiResponse({ status: 200, description: 'Total unread count returned' })
  async getUnreadTotal() {
    return this.supportChatService.getAdminUnreadTotal();
  }

  // ==========================================
  // ADMIN: GET ALL SUPPORT CHATS
  // ==========================================
  @Get('admin/all')
  @Roles(UserRole.ADMIN)
  @ApiOperation({ summary: 'Admin: Get all support chats' })
  @ApiQuery({ name: 'status', required: false, enum: SupportChatStatus })
  async getAllChats(@Query('status') status?: SupportChatStatus) {
    return this.supportChatService.getAllChats(status);
  }

  // ==========================================
  // ADMIN: CLOSE SUPPORT CHAT
  // ==========================================
  @Patch('admin/:id/close')
  @Roles(UserRole.ADMIN)
  @HttpCode(HttpStatus.OK)
  @ApiOperation({ summary: 'Admin: Close a support chat' })
  @ApiParam({ name: 'id', description: 'Support Chat ID' })
  async closeChat(@Param('id') chatId: string) {
    return this.supportChatService.closeChat(chatId);
  }
}