import * as fs from 'fs';
import * as path from 'path';

/**
 * Interface for tspublish.json configuration
 */
export interface ITsPublishJson {
  order?: number;
  unpack?: boolean;
  [key: string]: any;
}

/**
 * TsPublishConfig handles loading and parsing tspublish.json files.
 * These configuration files control module-specific settings like
 * compilation order and output unpacking behavior.
 */
export class TsPublishConfig {
  private folderPath: string;
  private cachedConfig: ITsPublishJson | null | undefined = undefined;

  constructor(folderPath: string) {
    this.folderPath = folderPath;
  }

  /**
   * Get the folder path this config is for
   */
  public getFolderPath(): string {
    return this.folderPath;
  }

  /**
   * Load and parse tspublish.json from the folder
   * Returns null if file doesn't exist or is invalid
   */
  public async load(): Promise<ITsPublishJson | null> {
    if (this.cachedConfig !== undefined) {
      return this.cachedConfig;
    }

    try {
      const configPath = path.join(this.folderPath, 'tspublish.json');
      const content = await fs.promises.readFile(configPath, 'utf8');
      this.cachedConfig = JSON.parse(content);
      return this.cachedConfig;
    } catch {
      this.cachedConfig = null;
      return null;
    }
  }

  /**
   * Synchronously load and parse tspublish.json from the folder
   * Returns null if file doesn't exist or is invalid
   */
  public loadSync(): ITsPublishJson | null {
    if (this.cachedConfig !== undefined) {
      return this.cachedConfig;
    }

    try {
      const configPath = path.join(this.folderPath, 'tspublish.json');
      const content = fs.readFileSync(configPath, 'utf8');
      this.cachedConfig = JSON.parse(content);
      return this.cachedConfig;
    } catch {
      this.cachedConfig = null;
      return null;
    }
  }

  /**
   * Check if output should be unpacked (flattened)
   * Default is true if not specified
   */
  public get shouldUnpack(): boolean {
    const config = this.loadSync();
    if (!config || config.unpack === undefined) {
      return true; // Default to true
    }
    return config.unpack === true;
  }

  /**
   * Get the compilation order for tsfolders command
   * Returns Infinity if not specified (sorted last)
   */
  public get order(): number {
    const config = this.loadSync();
    if (!config || config.order === undefined) {
      return Infinity;
    }
    return config.order;
  }

  /**
   * Check if tspublish.json exists in the folder
   */
  public async exists(): Promise<boolean> {
    try {
      const configPath = path.join(this.folderPath, 'tspublish.json');
      await fs.promises.access(configPath, fs.constants.F_OK);
      return true;
    } catch {
      return false;
    }
  }

  /**
   * Clear the cached config (useful for reloading)
   */
  public clearCache(): void {
    this.cachedConfig = undefined;
  }
}