import {
  Body,
  Controller,
  Get,
  Param,
  ParseUUIDPipe,
  Post,
  Query,
  Res,
  UploadedFile,
  UseInterceptors,
} from "@nestjs/common";
import { FileInterceptor } from "@nestjs/platform-express";
import {
  ApiBearerAuth,
  ApiConsumes,
  ApiOperation,
  ApiTags,
} from "@nestjs/swagger";
import type { Response } from "express";

import { CurrentUser } from "@edr/api-common";
import type { TCurrentUser } from "@tria-plc/api-common/modules/auth/types/current-user.type";

import { BookingStaff } from "../../common/booking-guards";
import { resolveAuthUserId } from "../../common/resolve-auth-user-id";
import { FREIGHT_PERMS } from "../../seed/freight-permissions.registry";
import { actorLabel } from "../warehouses/current-actor.util";
import { UserTradeAccessService } from "../user-trade-access/user-trade-access.service";
import { BillingService } from "./billing.service";
import { FilterInvoiceDto } from "./dto/filter-invoice.dto";

@ApiTags("billing")
@Controller("billing")
// Class gate lists every key its routes use: Nest runs class AND method
// guards, so a key missing here would deny before the route's own key runs.
@BookingStaff([
  FREIGHT_PERMS.invoices.view,
  FREIGHT_PERMS.invoices.export,
  FREIGHT_PERMS.invoices.confirmOffline,
])
@ApiBearerAuth()
export class BillingController {
  constructor(
    private readonly billingService: BillingService,
    private readonly userTradeAccessService: UserTradeAccessService,
  ) {}

  @Get("invoices")
  @ApiOperation({
    summary: "List invoices (paginated, filterable by company/status/search)",
  })
  async findAll(
    @Query() query: FilterInvoiceDto,
    @CurrentUser() user: TCurrentUser,
  ) {
    // Per-user trade-direction scope, applied via each invoice's source booking.
    const allowed =
      await this.userTradeAccessService.resolveAllowedDirections(user);
    return this.billingService.findAllPaginated({
      ...query,
      tradeDirections: allowed ?? undefined,
    });
  }

  @Get("invoices/:id")
  @ApiOperation({ summary: "Get an invoice with its line items" })
  findById(@Param("id", ParseUUIDPipe) id: string) {
    return this.billingService.findById(id);
  }

  @Get("offline-usd")
  @ApiOperation({
    summary:
      "Finance worklist: USD invoices settled offline by bank transfer, with booking pay-window context",
  })
  findOfflineUsd(@Query() query: FilterInvoiceDto) {
    return this.billingService.findOfflineUsdPaginated(query);
  }

  @Post("invoices/:id/confirm-offline")
  @BookingStaff(FREIGHT_PERMS.invoices.confirmOffline)
  @UseInterceptors(FileInterceptor("file"))
  @ApiConsumes("multipart/form-data")
  @ApiOperation({
    summary:
      "Finance confirms a USD invoice paid by bank transfer — slip file required, settles the full balance",
  })
  confirmOffline(
    @Param("id", ParseUUIDPipe) id: string,
    @UploadedFile() file: Express.Multer.File | undefined,
    @Body("reference") reference: string | undefined,
    @CurrentUser() user: TCurrentUser,
  ) {
    return this.billingService.confirmOfflinePayment(id, file, {
      reference: reference?.trim() || null,
      userId: resolveAuthUserId(user),
      userName: actorLabel(user) ?? null,
    });
  }

  @Get("invoices/:id/document")
  @BookingStaff(FREIGHT_PERMS.invoices.export)
  @ApiOperation({ summary: "Download the sealed invoice PDF" })
  async document(@Param("id", ParseUUIDPipe) id: string, @Res() res: Response) {
    const { filename, buffer } = await this.billingService.document(id);
    sendPdf(res, filename, buffer);
  }

  @Get("invoices/:id/receipt")
  @BookingStaff(FREIGHT_PERMS.invoices.export)
  @ApiOperation({ summary: "Download the sealed payment receipt PDF" })
  async receipt(@Param("id", ParseUUIDPipe) id: string, @Res() res: Response) {
    const { filename, buffer } = await this.billingService.receipt(id);
    sendPdf(res, filename, buffer);
  }
}

/** Stream a generated PDF as a file download. */
export function sendPdf(res: Response, filename: string, buffer: Buffer): void {
  res.setHeader("Content-Type", "application/pdf");
  res.setHeader("Content-Disposition", `attachment; filename="${filename}"`);
  res.setHeader("Content-Length", buffer.length);
  res.send(buffer);
}