import * as fs from 'fs-extra';
import * as path from 'path';
import semver from 'semver';
import { IEnvironment } from '../types/environment';
import { spawnProcess } from '../util/run';

/**
 * Execute NPM commands
 */
export class NPMExecutor {
  private installed: Record<string, string> = {};
  private packageFile: string = path.join(this.environment.path, 'package.json');

  constructor(
    private environment: IEnvironment,
    private coreModule: string
  ) {}

  /**
   * Create a package.json file and install the core.
   */
  public async init(): Promise<void> {
    // Initialize npm environment
    const c1 = await spawnProcess('npm', ['init', '-y'], this.environment);
    if (c1.code > 0) {
      throw new Error(c1.stderr.join('\n'));
    }

    // Install core module
    const c2 = await spawnProcess('npm', ['install', this.coreModule], this.environment);
    if (c2.code > 0) {
      throw new Error(c2.stderr.join('\n'));
    }
  }

  /**
   * Load a package.json file into memory
   */
  public async loadPackageFile(): Promise<void> {
    if (!await fs.pathExists(this.packageFile)) {
      await this.init();
    }

    const jsonData = await fs.readJson(this.packageFile);
    if (!jsonData.dependencies) {
      return;
    }

    this.installed = jsonData.dependencies;
  }

  /**
   * Install a npm package (examples: `@squeebot/core`, `@squeebot/core@3.3.3`, `node-ical`)
   * @param pkg Package name
   */
  public async installPackage(pkg: string): Promise<void> {
    if (!await fs.pathExists(this.packageFile)) {
      await this.init();
    }

    let spi = 0;
    if (pkg.indexOf('@') === 0) {
      spi = 1;
    }

    const pkgRefSplit = pkg.split('@');
    const pkgFullName = (spi === 1 ? '@' : '') + pkgRefSplit[spi];
    const pkgVersion = this.removeVersionWildcard(pkgRefSplit[spi + 1]);
    const installedVersion = this.installed[pkgFullName];
    if (installedVersion && installedVersion !== 'latest' && pkgVersion !== 'latest') {
      const cardless = this.removeVersionWildcard(installedVersion);
      if (semver.lte(pkgVersion, cardless)) {
        return;
      }
    }

    const { code, stderr, stdout } = await spawnProcess('npm', ['install', pkg], this.environment);
    if (code > 0) {
      throw new Error(stderr.join('\n'));
    }

    await this.loadPackageFile();
  }

  /**
   * Uninstall a npm package.
   *
   * See `installPackage` for more info.
   * @param pkg Package name
   */
  public async uninstallPackage(pkg: string): Promise<void> {
    if (!await fs.pathExists(this.packageFile)) {
      await this.init();
    }

    const { code, stderr, stdout } = await spawnProcess('npm', ['remove', pkg], this.environment);
    if (code > 0) {
      throw new Error(stderr.join('\n'));
    }

    await this.loadPackageFile();
  }

  private removeVersionWildcard(str: string): string {
    return str.replace(/\^|>|=/, '');
  }
}