import { Injectable, Logger, OnModuleInit } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { Cron, CronExpression } from '@nestjs/schedule';
import { PrismaService } from '../prisma/prisma.service';
import { probeTlsHosts } from '../common/tls-probe';

@Injectable()
export class InternalSslService implements OnModuleInit {
  private readonly logger = new Logger(InternalSslService.name);
  private refreshRunning = false;

  constructor(
    private readonly prisma: PrismaService,
    private readonly config: ConfigService,
  ) {}

  onModuleInit() {
    // Warm ssl_enabled shortly after boot so lists are accurate without waiting for cron.
    setTimeout(() => {
      void this.refreshSslStatuses('startup');
    }, 5_000);
  }

  private async listActiveDomains(): Promise<Array<{ id: bigint; host: string; sslEnabled: boolean }>> {
    return this.prisma.domain.findMany({
      where: { isActive: true },
      select: { id: true, host: true, sslEnabled: true },
      orderBy: { host: 'asc' },
    });
  }

  private async listActiveApexHosts(): Promise<string[]> {
    const domains = await this.listActiveDomains();
    const hosts: string[] = [];
    for (const { host } of domains) {
      const apex = host.trim().toLowerCase();
      if (apex) hosts.push(apex);
    }
    return hosts;
  }

  /** Dashboards VPS: manage + business./customer. per active apex. */
  async listDashboardHosts(): Promise<{ hosts: string[] }> {
    const adminHost =
      this.config.get<string>('DASHBOARD_ADMIN_HOST')?.trim() || 'manage.meshkee.com';

    const hosts = new Set<string>([adminHost]);
    for (const apex of await this.listActiveApexHosts()) {
      hosts.add(`business.${apex}`);
      hosts.add(`customer.${apex}`);
    }

    return { hosts: [...hosts].sort() };
  }

  /**
   * API VPS: central api host + api.{apex} aliases for each active domain.
   * Same Nest process; nginx terminates TLS for every name on this list.
   */
  async listApiHosts(): Promise<{ hosts: string[] }> {
    const centralHost =
      this.config.get<string>('CENTRAL_API_HOST')?.trim() || 'api.meshkee.com';

    const hosts = new Set<string>([centralHost]);
    for (const apex of await this.listActiveApexHosts()) {
      hosts.add(`api.${apex}`);
    }

    return { hosts: [...hosts].sort() };
  }

  /**
   * Probe each active apex host and sync domains.ssl_enabled to the live result.
   * Runs every 2 hours (and once shortly after API boot).
   */
  @Cron(CronExpression.EVERY_2_HOURS)
  async refreshSslStatusesCron() {
    await this.refreshSslStatuses('cron');
  }

  async refreshSslStatuses(reason: 'cron' | 'startup' | 'manual' = 'manual') {
    if (this.refreshRunning) {
      this.logger.warn(`SSL status refresh skipped (${reason}): already running`);
      return { updated: 0, checked: 0, skipped: true as const };
    }

    this.refreshRunning = true;
    const started = Date.now();
    try {
      const domains = await this.listActiveDomains();
      const hostsToProbe = domains.flatMap((d) => {
        const apex = d.host.trim().toLowerCase();
        if (!apex) return [];
        const www = apex.startsWith('www.') ? apex : `www.${apex}`;
        return [apex, www];
      });
      const sslByHost = await probeTlsHosts(hostsToProbe);

      let updated = 0;
      for (const domain of domains) {
        const hostKey = domain.host.trim().toLowerCase();
        const wwwKey = hostKey.startsWith('www.') ? hostKey : `www.${hostKey}`;
        const sslEnabled =
          (sslByHost.get(hostKey) ?? false) && (sslByHost.get(wwwKey) ?? false);
        if (sslEnabled === domain.sslEnabled) continue;

        await this.prisma.domain.update({
          where: { id: domain.id },
          data: { sslEnabled },
        });
        updated += 1;
        this.logger.log(
          `SSL status ${domain.host}: ${domain.sslEnabled} → ${sslEnabled}`,
        );
      }

      this.logger.log(
        `SSL status refresh (${reason}): checked=${domains.length} updated=${updated} in ${Date.now() - started}ms`,
      );

      return { updated, checked: domains.length, skipped: false as const };
    } finally {
      this.refreshRunning = false;
    }
  }
}