// src/plugin/files/folder.ts
import { TAbstractFile } from './abstract-file'

/**
 * Represents a folder in the vault.
 */
export class TFolder extends TAbstractFile {
  /** Child files and folders */
  children: TAbstractFile[] = []

  /**
   * Whether this folder is the root folder.
   * Set during construction based on name='' and parent=null.
   * Using a flag avoids stringly-typed checks in isRoot().
   * Uses ES private field to avoid leaking into .d.ts.
   */
  readonly #isRoot: boolean

  /**
   * @internal
   * Constructor is not part of the public API. Use Vault methods to create folders.
   */
  protected constructor(name: string, parent: TFolder | null) {
    super(name, parent)
    // The root folder is the one with empty name AND no parent.
    // This flag is set once at construction and never changes.
    this.#isRoot = name === '' && parent === null
  }

  /** Returns true if this is the root folder */
  isRoot(): boolean {
    return this.#isRoot
  }
}

/**
 * Internal subclass to access protected constructor.
 * Hoisted outside the factory to avoid recreation on every call.
 * @internal
 */
class TFolderFactory extends TFolder {
  constructor(name: string, parent: TFolder | null) {
    super(name, parent)
  }
}

/**
 * Internal factory function to create TFolder instances.
 * This is NOT part of the public Obsidian API. Use Vault.createFolder() for plugin code.
 *
 * Exists to allow internal Reams code (services, tests) to create TFolder instances
 * while keeping the constructor protected to match Obsidian's public API contract.
 *
 * @internal - Not exported from the 'obsidian' module.
 */
export function createTFolder(name: string, parent: TFolder | null): TFolder {
  // TFolderFactory extends TFolder, so instanceof TFolder will work.
  // We don't use Object.setPrototypeOf because it breaks ES private field access.
  return new TFolderFactory(name, parent)
}