import { 
  Controller, 
  Get, 
  Post, 
  Param, 
  Query, 
  UseGuards, 
  Request,
  ParseIntPipe,
  HttpCode,
  HttpStatus,
  BadRequestException,
  ValidationPipe,
  UsePipes,
} from '@nestjs/common';
import { 
  ApiTags, 
  ApiOperation, 
  ApiResponse, 
  ApiQuery, 
  ApiBearerAuth,
  ApiParam,
} from '@nestjs/swagger';
import { InvoicesService } from './invoices.service';
import { JwtAuthGuard } from '../auth/guards/jwt-auth.guard';
import { Invoice, InvoiceList, InvoiceSsoLink, Subscription, PaymentMethodList, PaymentGatewayList, InvoicePaymentLink } from '@customer-portal/shared';

@ApiTags('invoices')
@Controller('invoices')
@UseGuards(JwtAuthGuard)
@ApiBearerAuth()
export class InvoicesController {
  constructor(private readonly invoicesService: InvoicesService) {}

  @Get()
  @ApiOperation({ 
    summary: 'Get paginated list of user invoices',
    description: 'Retrieves invoices for the authenticated user with pagination and optional status filtering'
  })
  @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)' })
  @ApiQuery({ name: 'status', required: false, type: String, description: 'Filter by invoice status' })
  @ApiResponse({ 
    status: 200, 
    description: 'List of invoices with pagination',
    type: Object, // Would be InvoiceList if we had proper DTO decorators
  })
  async getInvoices(
    @Request() req: any,
    @Query('page') page?: string,
    @Query('limit') limit?: string,
    @Query('status') status?: string,
  ): Promise<InvoiceList> {
    // 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');
    }

    // Validate status if provided
    if (status && !['Paid', 'Unpaid', 'Overdue', 'Cancelled'].includes(status)) {
      throw new BadRequestException('Invalid status filter');
    }
    
    return this.invoicesService.getInvoices(
      req.user.id,
      { page: pageNum, limit: limitNum, status }
    );
  }

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

  @Get(':id/subscriptions')
  @ApiOperation({ 
    summary: 'Get subscriptions related to an invoice',
    description: 'Retrieves all subscriptions that are referenced in the invoice items'
  })
  @ApiParam({ name: 'id', type: Number, description: 'Invoice ID' })
  @ApiResponse({ 
    status: 200, 
    description: 'List of related subscriptions',
    type: [Object], // Would be Subscription[] if we had proper DTO decorators
  })
  @ApiResponse({ status: 404, description: 'Invoice not found' })
  async getInvoiceSubscriptions(
    @Request() req: any,
    @Param('id', ParseIntPipe) invoiceId: number,
  ): Promise<Subscription[]> {
    if (invoiceId <= 0) {
      throw new BadRequestException('Invoice ID must be a positive number');
    }
    
    return this.invoicesService.getInvoiceSubscriptions(req.user.id, invoiceId);
  }

  @Post(':id/sso-link')
  @HttpCode(HttpStatus.OK)
  @ApiOperation({ 
    summary: 'Create SSO link for invoice',
    description: 'Generates a single sign-on link to view/pay the invoice or download PDF in WHMCS'
  })
  @ApiParam({ name: 'id', type: Number, description: 'Invoice ID' })
  @ApiQuery({ name: 'target', required: false, enum: ['view', 'download', 'pay'], description: 'Link target: view invoice, download PDF, or go to payment page (default: view)' })
  @ApiResponse({ 
    status: 200, 
    description: 'SSO link created successfully',
    type: Object, // Would be InvoiceSsoLink if we had proper DTO decorators
  })
  @ApiResponse({ status: 404, description: 'Invoice not found' })
  async createSsoLink(
    @Request() req: any,
    @Param('id', ParseIntPipe) invoiceId: number,
    @Query('target') target?: 'view' | 'download' | 'pay',
  ): Promise<InvoiceSsoLink> {
    if (invoiceId <= 0) {
      throw new BadRequestException('Invoice ID must be a positive number');
    }

    // Validate target parameter
    if (target && !['view', 'download', 'pay'].includes(target)) {
      throw new BadRequestException('Target must be "view", "download", or "pay"');
    }
    
    return this.invoicesService.createSsoLink(req.user.id, invoiceId, target || 'view');
  }

  @Get('payment-methods')
  @ApiOperation({ 
    summary: 'Get user payment methods',
    description: 'Retrieves all saved payment methods for the authenticated user'
  })
  @ApiResponse({ 
    status: 200, 
    description: 'List of payment methods',
    type: Object, // Would be PaymentMethodList if we had proper DTO decorators
  })
  async getPaymentMethods(
    @Request() req: any,
  ): Promise<PaymentMethodList> {
    return this.invoicesService.getPaymentMethods(req.user.id);
  }

  @Get('payment-gateways')
  @ApiOperation({ 
    summary: 'Get available payment gateways',
    description: 'Retrieves all active payment gateways available for payments'
  })
  @ApiResponse({ 
    status: 200, 
    description: 'List of payment gateways',
    type: Object, // Would be PaymentGatewayList if we had proper DTO decorators
  })
  async getPaymentGateways(): Promise<PaymentGatewayList> {
    return this.invoicesService.getPaymentGateways();
  }

  @Post(':id/payment-link')
  @HttpCode(HttpStatus.OK)
  @ApiOperation({ 
    summary: 'Create payment link for invoice with payment method',
    description: 'Generates a payment link for the invoice with a specific payment method or gateway'
  })
  @ApiParam({ name: 'id', type: Number, description: 'Invoice ID' })
  @ApiQuery({ name: 'paymentMethodId', required: false, type: Number, description: 'Payment method ID' })
  @ApiQuery({ name: 'gatewayName', required: false, type: String, description: 'Payment gateway name' })
  @ApiResponse({ 
    status: 200, 
    description: 'Payment link created successfully',
    type: Object, // Would be InvoicePaymentLink if we had proper DTO decorators
  })
  @ApiResponse({ status: 404, description: 'Invoice not found' })
  async createPaymentLink(
    @Request() req: any,
    @Param('id', ParseIntPipe) invoiceId: number,
    @Query('paymentMethodId') paymentMethodId?: string,
    @Query('gatewayName') gatewayName?: string,
  ): Promise<InvoicePaymentLink> {
    if (invoiceId <= 0) {
      throw new BadRequestException('Invoice ID must be a positive number');
    }

    const paymentMethodIdNum = paymentMethodId ? parseInt(paymentMethodId, 10) : undefined;
    if (paymentMethodId && (isNaN(paymentMethodIdNum!) || paymentMethodIdNum! <= 0)) {
      throw new BadRequestException('Payment method ID must be a positive number');
    }
    
    return this.invoicesService.createPaymentSsoLink(
      req.user.id, 
      invoiceId, 
      paymentMethodIdNum, 
      gatewayName
    );
  }

  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;
  }
}