/**
 * Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the MIT License.
 */
import { PathResolver } from './pathResolver'

/**
 * A class that resolves paths by replacing an alias with a specified prefix and optional postfix.
 * This is useful for transforming paths that use shorthand aliases into fully qualified paths.
 */
export class AliasPathResolver implements PathResolver {
  private readonly alias: string
  private readonly prefix: string
  private readonly postfix: string

  /**
     * Initializes a new instance of the AliasPathResolver class.
     *
     * @param alias Alias name.
     * @param prefix Prefix name.
     * @param postfix Postfix name.
     */
  constructor (alias: string, prefix: string, postfix?: string) {
    this.alias = alias.trim()
    this.prefix = prefix.trim()
    this.postfix = postfix ? postfix.trim() : ''
  }

  /**
     * Transforms the path.
     *
     * @param path Path to inspect.
     * @returns The transformed path.
     */
  transformPath (path: string): string {
    const start = path.indexOf(this.alias)
    if (start === 0) {
      // here we only deals with trailing alias, alias in middle be handled in further breakdown
      // $xxx -> path.xxx
      path = `${this.prefix}${path.substr(start + this.alias.length)}${this.postfix}`
      if (path.endsWith('.')) {
        path = path.substr(0, path.length - 1)
      }
    }

    return path
  }
}