/**
 * @license
 * Copyright 2026 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

import { spawnSync } from 'node:child_process';
import path from 'node:path';
import fs from 'node:fs';
import os from 'node:os';
import {
  type WorkerProvider,
  type SetupOptions,
  type ExecOptions,
  type SyncOptions,
  type WorkspaceStatus,
} from './BaseProvider.ts';
import { GceConnectionManager } from './GceConnectionManager.ts';

export class GceCosProvider implements WorkerProvider {
  private projectId: string;
  private zone: string;
  private instanceName: string;
  private sshConfigPath: string;
  private knownHostsPath: string;
  private sshAlias = 'gcli-worker';
  private conn: GceConnectionManager;

  constructor(
    projectId: string,
    zone: string,
    instanceName: string,
    repoRoot: string,
  ) {
    this.projectId = projectId;
    this.zone = zone;
    this.instanceName = instanceName;
    const workspacesDir = path.join(repoRoot, '.gemini/workspaces');
    if (!fs.existsSync(workspacesDir))
      fs.mkdirSync(workspacesDir, { recursive: true });
    this.sshConfigPath = path.join(workspacesDir, 'ssh_config');
    this.knownHostsPath = path.join(workspacesDir, 'known_hosts');
    this.conn = new GceConnectionManager(projectId, zone, instanceName);
  }

  async provision(): Promise<number> {
    const imageUri =
      'us-docker.pkg.dev/gemini-code-dev/gemini-cli/maintainer:latest';
    const region = this.zone.split('-').slice(0, 2).join('-');
    const vpcName = 'iap-vpc';
    const subnetName = 'iap-subnet';

    console.log(
      `🏗️  Ensuring "Magic" Network Infrastructure in ${this.projectId}...`,
    );

    const vpcCheck = spawnSync(
      'gcloud',
      ['compute', 'networks', 'describe', vpcName, '--project', this.projectId],
      { stdio: 'pipe' },
    );
    if (vpcCheck.status !== 0) {
      spawnSync(
        'gcloud',
        [
          'compute',
          'networks',
          'create',
          vpcName,
          '--project',
          this.projectId,
          '--subnet-mode=custom',
        ],
        { stdio: 'inherit' },
      );
    }

    const subnetCheck = spawnSync(
      'gcloud',
      [
        'compute',
        'networks',
        'subnets',
        'describe',
        subnetName,
        '--project',
        this.projectId,
        '--region',
        region,
      ],
      { stdio: 'pipe' },
    );
    if (subnetCheck.status !== 0) {
      spawnSync(
        'gcloud',
        [
          'compute',
          'networks',
          'subnets',
          'create',
          subnetName,
          '--project',
          this.projectId,
          '--network',
          vpcName,
          '--region',
          region,
          '--range=10.0.0.0/24',
          '--enable-private-ip-google-access',
        ],
        { stdio: 'inherit' },
      );
    } else {
      spawnSync(
        'gcloud',
        [
          'compute',
          'networks',
          'subnets',
          'update',
          subnetName,
          '--project',
          this.projectId,
          '--region',
          region,
          '--enable-private-ip-google-access',
        ],
        { stdio: 'pipe' },
      );
    }

    const fwCheck = spawnSync(
      'gcloud',
      [
        'compute',
        'firewall-rules',
        'describe',
        'allow-corporate-ssh',
        '--project',
        this.projectId,
      ],
      { stdio: 'pipe' },
    );
    if (fwCheck.status !== 0) {
      spawnSync(
        'gcloud',
        [
          'compute',
          'firewall-rules',
          'create',
          'allow-corporate-ssh',
          '--project',
          this.projectId,
          '--network',
          vpcName,
          '--allow=tcp:22',
          '--source-ranges=0.0.0.0/0',
        ],
        { stdio: 'inherit' },
      );
    }

    console.log(
      `🚀 Provisioning GCE COS worker: ${this.instanceName} (Unified Workspace Setup)...`,
    );

    const startupScriptContent = `#!/bin/bash
      set -e
      echo "🚀 Initializing Unified Workspace..."

      # 1. Mount Data Disk
      mkdir -p /mnt/disks/data
      if ! mountpoint -q /mnt/disks/data; then
        DATA_DISK="/dev/disk/by-id/google-data"
        [ -e "$DATA_DISK" ] || DATA_DISK="/dev/sdb"
        
        while [ ! -e "$DATA_DISK" ]; do echo "Waiting for data disk..."; sleep 1; done
        blkid "$DATA_DISK" || mkfs.ext4 -m 0 -F "$DATA_DISK"
        mount -o discard,defaults "$DATA_DISK" /mnt/disks/data
      fi

      # 2. Prepare Stateful Directories (on the persistent disk)
      mkdir -p /mnt/disks/data/main /mnt/disks/data/worktrees /mnt/disks/data/scripts /mnt/disks/data/config /mnt/disks/data/policies
      chmod -R 777 /mnt/disks/data
      
      # 3. Handle Unified Path Symlink (/home/node/.workspaces)
      # This ensures absolute paths match perfectly between host and container.
      mkdir -p /home/node
      ln -sfn /mnt/disks/data /home/node/.workspaces
      chown -R 1000:1000 /home/node
      
      # Also ensure host users can find it
      ln -sfn /mnt/disks/data /workspaces
      chmod 777 /workspaces
      for h in /home/*_google_com; do
        [ -d "$h" ] || continue
        ln -sfn /mnt/disks/data "$h/.workspaces"
        chown -h $(basename $h):$(basename $h) "$h/.workspaces"
      done

      # 4. Container Resilience Loop
      until docker info >/dev/null 2>&1; do echo "Waiting for docker..."; sleep 2; done

      for i in {1..5}; do
        docker pull ${imageUri} && break || (echo "Pull failed, retry $i..." && sleep 5)
      done

      if ! docker ps -a | grep -q "maintainer-worker"; then
        docker run -d --name maintainer-worker --restart always \\
          -v /mnt/disks/data:/home/node/.workspaces:rw \\
          -v /mnt/disks/data/gemini-cli-config/.gemini:/home/node/.gemini:rw \\
          -v ~/.config/gh:/home/node/.config/gh:rw \\
          ${imageUri} /bin/bash -c "while true; do sleep 1000; done"
      fi
      echo "✅ Unified Workspace is active."
    `;

    const tmpScriptPath = path.join(
      os.tmpdir(),
      `gcli-startup-${Date.now()}.sh`,
    );
    fs.writeFileSync(tmpScriptPath, startupScriptContent);

    const result = spawnSync(
      'gcloud',
      [
        'compute',
        'instances',
        'create',
        this.instanceName,
        '--project',
        this.projectId,
        '--zone',
        this.zone,
        '--machine-type',
        'n2-standard-8',
        '--image-family',
        'cos-stable',
        '--image-project',
        'cos-cloud',
        '--boot-disk-size',
        '10GB',
        '--boot-disk-type',
        'pd-balanced',
        '--create-disk',
        `name=${this.instanceName}-data,size=200,type=pd-balanced,device-name=data,auto-delete=yes`,
        '--metadata-from-file',
        `startup-script=${tmpScriptPath}`,
        '--metadata',
        'enable-oslogin=TRUE',
        '--network-interface',
        `network=${vpcName},subnet=${subnetName},no-address`,
        '--scopes',
        'https://www.googleapis.com/auth/cloud-platform',
        '--quiet',
      ],
      { stdio: 'inherit' },
    );

    fs.unlinkSync(tmpScriptPath);

    if (result.status === 0) {
      console.log(
        '⏳ Waiting for OS Login and SSH to initialize (this takes ~45s)...',
      );
      await new Promise((r) => setTimeout(r, 45000));
    }

    return result.status ?? 1;
  }

  async ensureReady(): Promise<number> {
    const status = await this.getStatus();
    if (status.status !== 'RUNNING') {
      console.log(
        `⚠️ Worker ${this.instanceName} is ${status.status}. Waking it up...`,
      );
      const res = spawnSync(
        'gcloud',
        [
          'compute',
          'instances',
          'start',
          this.instanceName,
          '--project',
          this.projectId,
          '--zone',
          this.zone,
        ],
        { stdio: 'inherit' },
      );
      if (res.status !== 0) return res.status ?? 1;

      console.log('⏳ Waiting for boot...');
      await new Promise((r) => setTimeout(r, 20000));
    }

    // NEW: Verify the container is actually running AND up to date
    console.log('   - Verifying remote container health and image version...');
    const containerCheck = await this.getExecOutput(
      'sudo docker ps -q --filter "name=maintainer-worker"',
    );

    let needsUpdate = false;
    if (containerCheck.status === 0 && containerCheck.stdout.trim()) {
      // Check if the volume mounts are correct by checking for files inside .workspaces/main
      const mountCheck = await this.getExecOutput(
        'sudo docker exec maintainer-worker ls -A /home/node/.workspaces/main',
      );
      if (mountCheck.status !== 0 || !mountCheck.stdout.trim()) {
        console.log(
          '   ⚠️ Remote container has incorrect or empty mounts. Triggering refresh...',
        );
        needsUpdate = true;
      } else {
        // Check if the running image is stale
        const tmuxCheck = await this.getExecOutput(
          'sudo docker exec maintainer-worker which tmux',
        );
        if (tmuxCheck.status !== 0) {
          console.log(
            '   ⚠️ Remote container is stale (missing tmux). Triggering update...',
          );
          needsUpdate = true;
        }
      }
    } else {
      needsUpdate = true;
    }

    if (needsUpdate) {
      console.log('   ⚠️ Container missing or stale. Attempting refresh...');
      const imageUri =
        'us-docker.pkg.dev/gemini-code-dev/gemini-cli/maintainer:latest';
      // Ensure data mount is available before running
      const recoverCmd = `
          (mountpoint -q /mnt/disks/data || sudo mount /dev/disk/by-id/google-data /mnt/disks/data) && \
          sudo docker pull ${imageUri} && \
          (sudo docker rm -f maintainer-worker || true) && \
          sudo docker run -d --name maintainer-worker --restart always \
            -v /mnt/disks/data:/home/node/.workspaces:rw \
            -v /mnt/disks/data/gemini-cli-config/.gemini:/home/node/.gemini:rw \
            -v ~/.config/gh:/home/node/.config/gh:rw \
            ${imageUri} /bin/bash -c "while true; do sleep 1000; done"
        `;
      const recoverRes = await this.exec(recoverCmd);
      if (recoverRes !== 0) {
        console.error(
          '   ❌ Critical: Failed to refresh maintainer container.',
        );
        return 1;
      }
      console.log('   ✅ Container refreshed.');
    }

    return 0;
  }

  async setup(options: SetupOptions): Promise<number> {
    const dnsSuffix = options.dnsSuffix || '.internal.gcpnode.com';
    const internalHostname = `nic0.${this.instanceName}.${this.zone}.c.${this.projectId}${dnsSuffix.startsWith('.') ? dnsSuffix : '.' + dnsSuffix}`;
    const user = `${process.env.USER || 'node'}_google_com`;

    const sshEntry = `
Host ${this.sshAlias}
    HostName ${internalHostname}
    IdentityFile ~/.ssh/google_compute_engine
    User ${user}
    UserKnownHostsFile /dev/null
    CheckHostIP no
    StrictHostKeyChecking no
    ConnectTimeout 60
    ServerAliveInterval 30
`;

    fs.writeFileSync(this.sshConfigPath, sshEntry);
    console.log(`   ✅ Created project SSH config: ${this.sshConfigPath}`);

    console.log(
      '   - Verifying direct connection (may trigger corporate SSO prompt)...',
    );
    const res = this.conn.run('echo 1');
    if (res.status !== 0) {
      console.error(
        '\n❌ All connection attempts failed. Please ensure you have "gcert" and IAP permissions.',
      );
      return 1;
    }
    console.log(
      '   ✅ Connection verified. Waiting 10s for remote disk initialization...',
    );
    await new Promise((r) => setTimeout(r, 10000));
    return 0;
  }

  getRunCommand(command: string, options: ExecOptions = {}): string {
    let finalCmd = command;
    if (options.wrapContainer) {
      finalCmd = `sudo docker exec ${options.interactive ? '-it' : ''} ${options.cwd ? `-w ${options.cwd}` : ''} ${options.wrapContainer} sh -c ${this.quote(command)}`;
    }
    return this.conn.getRunCommand(finalCmd, {
      interactive: options.interactive,
    });
  }

  async exec(command: string, options: ExecOptions = {}): Promise<number> {
    const res = await this.getExecOutput(command, options);
    return res.status;
  }

  async getExecOutput(
    command: string,
    options: ExecOptions = {},
  ): Promise<{ status: number; stdout: string; stderr: string }> {
    let finalCmd = command;
    if (options.wrapContainer) {
      finalCmd = `sudo docker exec ${options.interactive ? '-it' : ''} ${options.cwd ? `-w ${options.cwd}` : ''} ${options.wrapContainer} sh -c ${this.quote(command)}`;
    }

    return this.conn.run(finalCmd, {
      interactive: options.interactive,
      stdio: options.interactive ? 'inherit' : 'pipe',
    });
  }

  async sync(
    localPath: string,
    remotePath: string,
    options: SyncOptions = {},
  ): Promise<number> {
    console.log(`📦 Syncing ${localPath} to remote:${remotePath}...`);
    return this.conn.sync(localPath, remotePath, options);
  }

  async getStatus(): Promise<WorkspaceStatus> {
    const res = spawnSync(
      'gcloud',
      [
        'compute',
        'instances',
        'describe',
        this.instanceName,
        '--project',
        this.projectId,
        '--zone',
        this.zone,
        '--format',
        'json(name,status,networkInterfaces[0].networkIP)',
      ],
      { stdio: 'pipe' },
    );

    if (res.status !== 0) {
      return { name: this.instanceName, status: 'UNKNOWN' };
    }

    try {
      const data = JSON.parse(res.stdout.toString());
      return {
        name: data.name,
        status: data.status,
        internalIp: data.networkInterfaces?.[0]?.networkIP,
      };
    } catch {
      return { name: this.instanceName, status: 'UNKNOWN' };
    }
  }

  async stop(): Promise<number> {
    const res = spawnSync(
      'gcloud',
      [
        'compute',
        'instances',
        'stop',
        this.instanceName,
        '--project',
        this.projectId,
        '--zone',
        this.zone,
      ],
      { stdio: 'inherit' },
    );
    return res.status ?? 1;
  }

  private quote(str: string) {
    return `'${str.replace(/'/g, "'\\''")}'`;
  }
}