import { 
  Controller, 
  Get, 
  Param, 
  Query, 
  UseGuards, 
  Request,
  ParseIntPipe,
  BadRequestException,
} from '@nestjs/common';
import { 
  ApiTags, 
  ApiOperation, 
  ApiResponse, 
  ApiQuery, 
  ApiBearerAuth,
  ApiParam,
} from '@nestjs/swagger';
import { SubscriptionsService } from './subscriptions.service';
import { JwtAuthGuard } from '../auth/guards/jwt-auth.guard';
import { Subscription, SubscriptionList, InvoiceList } from '@customer-portal/shared';

@ApiTags('subscriptions')
@Controller('subscriptions')
@UseGuards(JwtAuthGuard)
@ApiBearerAuth()
export class SubscriptionsController {
  constructor(private readonly subscriptionsService: SubscriptionsService) {}

  @Get()
  @ApiOperation({ 
    summary: 'Get all user subscriptions',
    description: 'Retrieves all subscriptions/services for the authenticated user'
  })
  @ApiQuery({ name: 'status', required: false, type: String, description: 'Filter by subscription status' })
  @ApiResponse({ 
    status: 200, 
    description: 'List of user subscriptions',
    type: Object, // Would be SubscriptionList if we had proper DTO decorators
  })
  async getSubscriptions(
    @Request() req: any,
    @Query('status') status?: string,
  ): Promise<SubscriptionList | Subscription[]> {
    // Validate status if provided
    if (status && !['Active', 'Suspended', 'Terminated', 'Cancelled', 'Pending'].includes(status)) {
      throw new BadRequestException('Invalid status filter');
    }

    if (status) {
      const subscriptions = await this.subscriptionsService.getSubscriptionsByStatus(req.user.id, status);
      return subscriptions;
    }
    
    return this.subscriptionsService.getSubscriptions(req.user.id);
  }

  @Get('active')
  @ApiOperation({ 
    summary: 'Get active subscriptions only',
    description: 'Retrieves only active subscriptions for the authenticated user'
  })
  @ApiResponse({ 
    status: 200, 
    description: 'List of active subscriptions',
    type: [Object], // Would be Subscription[] if we had proper DTO decorators
  })
  async getActiveSubscriptions(
    @Request() req: any,
  ): Promise<Subscription[]> {
    return this.subscriptionsService.getActiveSubscriptions(req.user.id);
  }

  @Get('stats')
  @ApiOperation({ 
    summary: 'Get subscription statistics',
    description: 'Retrieves subscription count statistics by status'
  })
  @ApiResponse({ 
    status: 200, 
    description: 'Subscription statistics',
    type: Object,
  })
  async getSubscriptionStats(
    @Request() req: any,
  ): Promise<{
    total: number;
    active: number;
    suspended: number;
    cancelled: number;
    pending: number;
  }> {
    return this.subscriptionsService.getSubscriptionStats(req.user.id);
  }

  @Get(':id')
  @ApiOperation({ 
    summary: 'Get subscription details by ID',
    description: 'Retrieves detailed information for a specific subscription'
  })
  @ApiParam({ name: 'id', type: Number, description: 'Subscription ID' })
  @ApiResponse({ 
    status: 200, 
    description: 'Subscription details',
    type: Object, // Would be Subscription if we had proper DTO decorators
  })
  @ApiResponse({ status: 404, description: 'Subscription not found' })
  async getSubscriptionById(
    @Request() req: any,
    @Param('id', ParseIntPipe) subscriptionId: number,
  ): Promise<Subscription> {
    if (subscriptionId <= 0) {
      throw new BadRequestException('Subscription ID must be a positive number');
    }
    
    return this.subscriptionsService.getSubscriptionById(req.user.id, subscriptionId);
  }

  @Get(':id/invoices')
  @ApiOperation({ 
    summary: 'Get invoices for a specific subscription',
    description: 'Retrieves all invoices related to a specific subscription'
  })
  @ApiParam({ name: 'id', type: Number, description: 'Subscription ID' })
  @ApiQuery({ name: 'page', required: false, type: Number, description: 'Page number (default: 1)' })
  @ApiQuery({ name: 'limit', required: false, type: Number, description: 'Items per page (default: 10)' })
  @ApiResponse({ 
    status: 200, 
    description: 'List of invoices for the subscription',
    type: Object, // Would be InvoiceList if we had proper DTO decorators
  })
  @ApiResponse({ status: 404, description: 'Subscription not found' })
  async getSubscriptionInvoices(
    @Request() req: any,
    @Param('id', ParseIntPipe) subscriptionId: number,
    @Query('page') page?: string,
    @Query('limit') limit?: string,
  ): Promise<InvoiceList> {
    if (subscriptionId <= 0) {
      throw new BadRequestException('Subscription ID must be a positive number');
    }

    // Validate and sanitize input
    const pageNum = this.validatePositiveInteger(page, 1, 'page');
    const limitNum = this.validatePositiveInteger(limit, 10, 'limit');
    
    // Limit max page size for performance
    if (limitNum > 100) {
      throw new BadRequestException('Limit cannot exceed 100 items per page');
    }
    
    return this.subscriptionsService.getSubscriptionInvoices(
      req.user.id, 
      subscriptionId,
      { page: pageNum, limit: limitNum }
    );
  }

  private validatePositiveInteger(value: string | undefined, defaultValue: number, fieldName: string): number {
    if (!value) {
      return defaultValue;
    }

    const parsed = parseInt(value, 10);
    if (isNaN(parsed) || parsed <= 0) {
      throw new BadRequestException(`${fieldName} must be a positive integer`);
    }

    return parsed;
  }
}