import {
  Controller,
  Get,
  Post,
  Param,
  Query,
  Request,
  ParseIntPipe,
  HttpCode,
  HttpStatus,
  BadRequestException,
} from "@nestjs/common";
import {
  ApiTags,
  ApiOperation,
  ApiResponse,
  ApiOkResponse,
  ApiQuery,
  ApiBearerAuth,
  ApiParam,
} from "@nestjs/swagger";
import { InvoicesOrchestratorService } from "./services/invoices-orchestrator.service";
import { WhmcsService } from "@bff/integrations/whmcs/whmcs.service";
import { MappingsService } from "@bff/modules/id-mappings/mappings.service";

import type {
  Invoice,
  InvoiceList,
  InvoiceSsoLink,
  Subscription,
  PaymentMethodList,
  PaymentGatewayList,
  InvoicePaymentLink,
} from "@customer-portal/domain";

interface AuthenticatedRequest {
  user: { id: string };
}

@ApiTags("invoices")
@Controller("invoices")
@ApiBearerAuth()
export class InvoicesController {
  constructor(
    private readonly invoicesService: InvoicesOrchestratorService,
    private readonly whmcsService: WhmcsService,
    private readonly mappingsService: MappingsService
  ) {}

  @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",
  })
  @ApiOkResponse({ description: "List of invoices with pagination" })
  async getInvoices(
    @Request() req: AuthenticatedRequest,
    @Query("page") page?: string,
    @Query("limit") limit?: string,
    @Query("status") status?: string
  ): Promise<InvoiceList> {
    const validStatuses = ["Paid", "Unpaid", "Overdue", "Cancelled", "Collections"] as const;
    type InvoiceStatus = (typeof validStatuses)[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");
    }

    // Validate status if provided
    if (status && !validStatuses.includes(status as InvoiceStatus)) {
      throw new BadRequestException("Invalid status filter");
    }

    const typedStatus = status ? (status as InvoiceStatus) : undefined;

    return this.invoicesService.getInvoices(req.user.id, {
      page: pageNum,
      limit: limitNum,
      status: typedStatus,
    });
  }

  @Get("payment-methods")
  @ApiOperation({
    summary: "Get user payment methods",
    description: "Retrieves all saved payment methods for the authenticated user",
  })
  @ApiOkResponse({ description: "List of payment methods" })
  async getPaymentMethods(@Request() req: AuthenticatedRequest): Promise<PaymentMethodList> {
    const mapping = await this.mappingsService.findByUserId(req.user.id);
    if (!mapping?.whmcsClientId) {
      throw new Error("WHMCS client mapping not found");
    }
    return this.whmcsService.getPaymentMethods(mapping.whmcsClientId, req.user.id);
  }

  @Get("payment-gateways")
  @ApiOperation({
    summary: "Get available payment gateways",
    description: "Retrieves all active payment gateways available for payments",
  })
  @ApiOkResponse({ description: "List of payment gateways" })
  async getPaymentGateways(): Promise<PaymentGatewayList> {
    return this.whmcsService.getPaymentGateways();
  }

  @Post("payment-methods/refresh")
  @HttpCode(HttpStatus.OK)
  @ApiOperation({
    summary: "Refresh payment methods cache",
    description: "Invalidates and refreshes payment methods cache for the current user",
  })
  @ApiOkResponse({ description: "Payment methods cache refreshed" })
  async refreshPaymentMethods(@Request() req: AuthenticatedRequest): Promise<PaymentMethodList> {
    // Invalidate cache first
    await this.whmcsService.invalidatePaymentMethodsCache(req.user.id);

    // Return fresh payment methods
    const mapping = await this.mappingsService.findByUserId(req.user.id);
    if (!mapping?.whmcsClientId) {
      throw new Error("WHMCS client mapping not found");
    }
    return this.whmcsService.getPaymentMethods(mapping.whmcsClientId, req.user.id);
  }

  @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" })
  @ApiOkResponse({ description: "Invoice details" })
  @ApiResponse({ status: 404, description: "Invoice not found" })
  async getInvoiceById(
    @Request() req: AuthenticatedRequest,
    @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" })
  @ApiOkResponse({ description: "List of related subscriptions" })
  @ApiResponse({ status: 404, description: "Invoice not found" })
  async getInvoiceSubscriptions(
    @Request() req: AuthenticatedRequest,
    @Param("id", ParseIntPipe) invoiceId: number
  ): Promise<Subscription[]> {
    if (invoiceId <= 0) {
      throw new BadRequestException("Invoice ID must be a positive number");
    }

    // This functionality has been moved to WHMCS directly
    // For now, return empty array as subscriptions are managed in WHMCS
    return [];
  }

  @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)",
  })
  @ApiOkResponse({ description: "SSO link created successfully" })
  @ApiResponse({ status: 404, description: "Invoice not found" })
  async createSsoLink(
    @Request() req: AuthenticatedRequest,
    @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"');
    }

    const mapping = await this.mappingsService.findByUserId(req.user.id);
    if (!mapping?.whmcsClientId) {
      throw new Error("WHMCS client mapping not found");
    }
    
    const ssoResult = await this.whmcsService.createSsoToken(
      mapping.whmcsClientId,
      invoiceId ? `index.php?rp=/invoice/${invoiceId}` : undefined
    );
    
    return {
      url: ssoResult.url,
      expiresAt: ssoResult.expiresAt,
    };
  }

  @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",
  })
  @ApiOkResponse({ description: "Payment link created successfully" })
  @ApiResponse({ status: 404, description: "Invoice not found" })
  async createPaymentLink(
    @Request() req: AuthenticatedRequest,
    @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");
    }

    const mapping = await this.mappingsService.findByUserId(req.user.id);
    if (!mapping?.whmcsClientId) {
      throw new Error("WHMCS client mapping not found");
    }
    
    const ssoResult = await this.whmcsService.createPaymentSsoToken(
      mapping.whmcsClientId,
      invoiceId,
      paymentMethodIdNum,
      gatewayName || "stripe"
    );
    
    return {
      url: ssoResult.url,
      expiresAt: ssoResult.expiresAt,
      gatewayName: gatewayName || "stripe",
    };
  }

  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;
  }
}