/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import {getCachedSourceFile} from '@angular/compiler-cli/src/ngtsc/testing';
import ts from 'typescript';

interface TsProjectWithInternals {
  // typescript/src/server/project.ts#ConfiguredProject
  setCompilerHost?(host: ts.CompilerHost): void;
}

let patchedLanguageServiceProjectHost = false;

/**
 * Updates `ts.server.Project` to use efficient test caching of source files
 * that aren't expected to be changed. E.g. the default libs.
 */
export function patchLanguageServiceProjectsWithTestHost() {
  if (patchedLanguageServiceProjectHost) {
    return;
  }
  patchedLanguageServiceProjectHost = true;

  (ts.server.Project.prototype as TsProjectWithInternals).setCompilerHost = (host) => {
    const _originalHostGetSourceFile = host.getSourceFile;
    const _originalHostGetSourceFileByPath = host.getSourceFileByPath;

    host.getSourceFile =
        (fileName, languageVersionOrOptions, onError, shouldCreateNewSourceFile) => {
          return getCachedSourceFile(fileName, () => host.readFile(fileName)) ??
              _originalHostGetSourceFile.call(
                  host, fileName, languageVersionOrOptions, onError, shouldCreateNewSourceFile);
        };

    if (_originalHostGetSourceFileByPath !== undefined) {
      host.getSourceFileByPath =
          (fileName, path, languageVersionOrOptions, onError, shouldCreateNewSourceFile) => {
            return getCachedSourceFile(fileName, () => host.readFile(fileName)) ??
                _originalHostGetSourceFileByPath.call(
                    host, fileName, path, languageVersionOrOptions, onError,
                    shouldCreateNewSourceFile);
          };
    }
  };
}