import jsYaml from 'js-yaml';

export function generateCompose(selectedApps, config) {
  const compose = {
    version: '3.8',
    services: {},
    networks: { stackpilot: { driver: 'bridge' } },
  };

  for (const app of selectedApps) {
    const service = {
      image: app.image,
      container_name: app.id,
      restart: 'unless-stopped',
      networks: ['stackpilot'],
      environment: {
        PUID: '1000',
        PGID: '1000',
        TZ: config.timezone,
        ...app.env,
      },
    };

    // Ports
    if (app.ports && app.ports.length > 0) {
      service.ports = app.ports.map(p =>
        p.protocol === 'udp'
          ? `${p.host}:${p.container}/udp`
          : `${p.host}:${p.container}`
      );
    }

    // Volumes
    if (app.volumes && app.volumes.length > 0) {
      service.volumes = app.volumes.map(v => {
        const hostPath = v.host
          .replace('${CONFIG_PATH}', config.configPath)
          .replace('${MEDIA_PATH}', config.mediaPath)
          .replace('${DOWNLOADS_PATH}', config.downloadsPath);
        return v.readonly ? `${hostPath}:${v.container}:ro` : `${hostPath}:${v.container}`;
      });
    }

    // Cap add
    if (app.capAdd) {
      service.cap_add = app.capAdd;
    }

    // Healthcheck
    if (app.healthcheck) {
      service.healthcheck = {
        test: ['CMD-SHELL', app.healthcheck],
        interval: '30s',
        timeout: '10s',
        retries: 3,
      };
    }

    // VPN routing — if gluetun is selected and this is a download client
    const gluetunSelected = selectedApps.some(a => a.id === 'gluetun');
    if (gluetunSelected && app.links?.providesDownloadClient) {
      service.network_mode = `service:gluetun`;
      delete service.networks;
      delete service.ports;
    }

    // If this IS gluetun, expose download client ports through it
    if (app.id === 'gluetun' && gluetunSelected) {
      const dlClients = selectedApps.filter(a => a.links?.providesDownloadClient);
      const extraPorts = dlClients.flatMap(a => a.ports || []);
      if (extraPorts.length > 0) {
        service.ports = [
          ...(service.ports || []),
          ...extraPorts.map(p =>
            p.protocol === 'udp' ? `${p.host}:${p.container}/udp` : `${p.host}:${p.container}`
          ),
        ];
      }
    }

    compose.services[app.id] = service;
  }

  // Tailscale sidecar
  if (config.tailscale?.enabled) {
    const tsArgs = ['--hostname=' + (config.tailscale.hostname || 'stackpilot')];
    if (config.tailscale.subnetRouter) {
      tsArgs.push('--advertise-routes=172.20.0.0/16');
    }
    if (config.tailscale.funnel) {
      tsArgs.push('--advertise-exit-node');
    }

    compose.services['tailscale-sidecar'] = {
      image: 'tailscale/tailscale:latest',
      container_name: 'tailscale-sidecar',
      restart: 'unless-stopped',
      hostname: config.tailscale.hostname || 'stackpilot',
      networks: ['stackpilot'],
      cap_add: ['NET_ADMIN', 'SYS_MODULE'],
      environment: {
        TS_AUTHKEY: config.tailscale.authKey || '${TS_AUTHKEY}',
        TS_EXTRA_ARGS: tsArgs.join(' '),
        TS_STATE_DIR: '/var/lib/tailscale',
      },
      volumes: [
        `${config.configPath}/tailscale:/var/lib/tailscale`,
        '/dev/net/tun:/dev/net/tun',
      ],
    };
  }

  return jsYaml.dump(compose, { lineWidth: 120, noRefs: true });
}

export function generateEnv(selectedApps, config) {
  const lines = [
    '# StackPilot — Generated Environment File',
    `# Generated: ${new Date().toISOString()}`,
    '',
    '# Paths',
    `CONFIG_PATH=${config.configPath}`,
    `MEDIA_PATH=${config.mediaPath}`,
    `DOWNLOADS_PATH=${config.downloadsPath}`,
    `TZ=${config.timezone}`,
    '',
    '# User/Group IDs',
    'PUID=1000',
    'PGID=1000',
    '',
  ];

  for (const app of selectedApps) {
    if (app.env && Object.keys(app.env).length > 0) {
      const envVarsWithValues = Object.entries(app.env).filter(([, v]) => v !== '');
      if (envVarsWithValues.length > 0) {
        lines.push(`# ${app.name}`);
        for (const [key, value] of envVarsWithValues) {
          lines.push(`${app.id.toUpperCase()}_${key}=${value}`);
        }
        lines.push('');
      }
      // Prompt-style placeholders for empty values
      const envVarsEmpty = Object.entries(app.env).filter(([, v]) => v === '');
      if (envVarsEmpty.length > 0) {
        lines.push(`# ${app.name} — FILL THESE IN`);
        for (const [key] of envVarsEmpty) {
          lines.push(`${app.id.toUpperCase()}_${key}=CHANGE_ME`);
        }
        lines.push('');
      }
    }
  }

  return lines.join('\n');
}