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

import fs from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
import type {
  SandboxManager,
  SandboxRequest,
  SandboxedCommand,
} from './sandboxManager.js';
import {
  sanitizeEnvironment,
  type EnvironmentSanitizationConfig,
} from './environmentSanitization.js';
import { debugLogger } from '../utils/debugLogger.js';
import { spawnAsync } from '../utils/shell-utils.js';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

/**
 * A SandboxManager implementation for Windows that uses Restricted Tokens,
 * Job Objects, and Low Integrity levels for process isolation.
 * Uses a native C# helper to bypass PowerShell restrictions.
 */
export class WindowsSandboxManager implements SandboxManager {
  private readonly helperPath: string;
  private readonly platform: string;
  private initialized = false;
  private readonly lowIntegrityCache = new Set<string>();

  constructor(platform: string = process.platform) {
    this.platform = platform;
    this.helperPath = path.resolve(__dirname, 'scripts', 'GeminiSandbox.exe');
  }

  private async ensureInitialized(): Promise<void> {
    if (this.initialized) return;
    if (this.platform !== 'win32') {
      this.initialized = true;
      return;
    }

    try {
      if (!fs.existsSync(this.helperPath)) {
        debugLogger.log(
          `WindowsSandboxManager: Helper not found at ${this.helperPath}. Attempting to compile...`,
        );
        // If the exe doesn't exist, we try to compile it from the .cs file
        const sourcePath = this.helperPath.replace(/\.exe$/, '.cs');
        if (fs.existsSync(sourcePath)) {
          const systemRoot = process.env['SystemRoot'] || 'C:\\Windows';
          const cscPaths = [
            'csc.exe', // Try in PATH first
            path.join(
              systemRoot,
              'Microsoft.NET',
              'Framework64',
              'v4.0.30319',
              'csc.exe',
            ),
            path.join(
              systemRoot,
              'Microsoft.NET',
              'Framework',
              'v4.0.30319',
              'csc.exe',
            ),
            // Added newer framework paths
            path.join(
              systemRoot,
              'Microsoft.NET',
              'Framework64',
              'v4.8',
              'csc.exe',
            ),
            path.join(
              systemRoot,
              'Microsoft.NET',
              'Framework',
              'v4.8',
              'csc.exe',
            ),
            path.join(
              systemRoot,
              'Microsoft.NET',
              'Framework64',
              'v3.5',
              'csc.exe',
            ),
          ];

          let compiled = false;
          for (const csc of cscPaths) {
            try {
              debugLogger.log(
                `WindowsSandboxManager: Trying to compile using ${csc}...`,
              );
              // We use spawnAsync but we don't need to capture output
              await spawnAsync(csc, ['/out:' + this.helperPath, sourcePath]);
              debugLogger.log(
                `WindowsSandboxManager: Successfully compiled sandbox helper at ${this.helperPath}`,
              );
              compiled = true;
              break;
            } catch (e) {
              debugLogger.log(
                `WindowsSandboxManager: Failed to compile using ${csc}: ${e instanceof Error ? e.message : String(e)}`,
              );
            }
          }

          if (!compiled) {
            debugLogger.log(
              'WindowsSandboxManager: Failed to compile sandbox helper from any known CSC path.',
            );
          }
        } else {
          debugLogger.log(
            `WindowsSandboxManager: Source file not found at ${sourcePath}. Cannot compile helper.`,
          );
        }
      } else {
        debugLogger.log(
          `WindowsSandboxManager: Found helper at ${this.helperPath}`,
        );
      }
    } catch (e) {
      debugLogger.log(
        'WindowsSandboxManager: Failed to initialize sandbox helper:',
        e,
      );
    }

    this.initialized = true;
  }

  /**
   * Prepares a command for sandboxed execution on Windows.
   */
  async prepareCommand(req: SandboxRequest): Promise<SandboxedCommand> {
    await this.ensureInitialized();

    const sanitizationConfig: EnvironmentSanitizationConfig = {
      allowedEnvironmentVariables:
        req.config?.sanitizationConfig?.allowedEnvironmentVariables ?? [],
      blockedEnvironmentVariables:
        req.config?.sanitizationConfig?.blockedEnvironmentVariables ?? [],
      enableEnvironmentVariableRedaction:
        req.config?.sanitizationConfig?.enableEnvironmentVariableRedaction ??
        true,
    };

    const sanitizedEnv = sanitizeEnvironment(req.env, sanitizationConfig);

    // 1. Handle filesystem permissions for Low Integrity
    // Grant "Low Mandatory Level" write access to the CWD.
    await this.grantLowIntegrityAccess(req.cwd);

    // Grant "Low Mandatory Level" read access to allowedPaths.
    if (req.config?.allowedPaths) {
      for (const allowedPath of req.config.allowedPaths) {
        await this.grantLowIntegrityAccess(allowedPath);
      }
    }

    // 2. Construct the helper command
    // GeminiSandbox.exe <network:0|1> <cwd> <command> [args...]
    const program = this.helperPath;

    // If the command starts with __, it's an internal command for the sandbox helper itself.
    const args = [
      req.config?.networkAccess ? '1' : '0',
      req.cwd,
      req.command,
      ...req.args,
    ];

    return {
      program,
      args,
      env: sanitizedEnv,
    };
  }

  /**
   * Grants "Low Mandatory Level" access to a path using icacls.
   */
  private async grantLowIntegrityAccess(targetPath: string): Promise<void> {
    if (this.platform !== 'win32') {
      return;
    }

    const resolvedPath = path.resolve(targetPath);
    if (this.lowIntegrityCache.has(resolvedPath)) {
      return;
    }

    // Never modify integrity levels for system directories
    const systemRoot = process.env['SystemRoot'] || 'C:\\Windows';
    const programFiles = process.env['ProgramFiles'] || 'C:\\Program Files';
    const programFilesX86 =
      process.env['ProgramFiles(x86)'] || 'C:\\Program Files (x86)';

    if (
      resolvedPath.toLowerCase().startsWith(systemRoot.toLowerCase()) ||
      resolvedPath.toLowerCase().startsWith(programFiles.toLowerCase()) ||
      resolvedPath.toLowerCase().startsWith(programFilesX86.toLowerCase())
    ) {
      return;
    }

    try {
      await spawnAsync('icacls', [resolvedPath, '/setintegritylevel', 'Low']);
      this.lowIntegrityCache.add(resolvedPath);
    } catch (e) {
      debugLogger.log(
        'WindowsSandboxManager: icacls failed for',
        resolvedPath,
        e,
      );
    }
  }
}