import { Injectable } from '@nestjs/common';

import type { WhmcsDashboardStatsResponse } from '@hexahost/contracts';

import { getBillingProvider } from '../../billing/billing-provider';
import { PrismaService } from '../../prisma/prisma.service';

type InstallationRef = {
  id: string;
  integrationId: string;
};

@Injectable()
export class WhmcsDashboardService {
  constructor(private readonly prisma: PrismaService) {}

  async getStats(installation: InstallationRef): Promise<WhmcsDashboardStatsResponse> {
    const [
      linkedClients,
      linkedServices,
      pendingEvents,
      deadLetterEvents,
      openIssues,
      exportedUsagePeriods,
      syncCursor,
      lastReconciledLink,
    ] = await Promise.all([
      this.prisma.whmcsClientLink.count({
        where: { installationId: installation.id },
      }),
      this.prisma.whmcsServiceLink.count({
        where: { installationId: installation.id },
      }),
      this.prisma.integrationEvent.count({
        where: { installationId: installation.id, status: 'PENDING' },
      }),
      this.prisma.integrationEvent.count({
        where: { installationId: installation.id, status: 'DEAD_LETTER' },
      }),
      this.prisma.reconciliationIssue.count({
        where: { installationId: installation.id, resolvedAt: null },
      }),
      this.prisma.whmcsUsageExport.count({
        where: { installationId: installation.id, status: { in: ['EXPORTED', 'ADJUSTED'] } },
      }),
      this.prisma.integrationSyncCursor.findUnique({
        where: { installationId: installation.id },
      }),
      this.prisma.whmcsServiceLink.findFirst({
        where: {
          installationId: installation.id,
          lastReconciledAt: { not: null },
        },
        orderBy: { lastReconciledAt: 'desc' },
        select: { lastReconciledAt: true },
      }),
    ]);

    const suspendedServices = await this.prisma.whmcsServiceLink.count({
      where: { installationId: installation.id, status: 'SUSPENDED' },
    });

    const terminatedServices = await this.prisma.whmcsServiceLink.count({
      where: { installationId: installation.id, status: 'TERMINATED' },
    });

    return {
      integrationId: installation.integrationId,
      billingProvider: getBillingProvider(),
      moduleVersion: '1.0.0',
      linkedClients,
      linkedServices,
      suspendedServices,
      terminatedServices,
      pendingEvents,
      deadLetterEvents,
      openReconciliationIssues: openIssues,
      exportedUsagePeriods,
      eventsCursor: syncCursor?.eventsCursor ?? null,
      lastEventSyncAt: syncCursor?.updatedAt.toISOString() ?? null,
      lastReconciliationAt: lastReconciledLink?.lastReconciledAt?.toISOString() ?? null,
    };
  }
}