/**
 * @license
 * Copyright Google Inc. 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 { join, normalize, tags } from '@angular-devkit/core';
import {
  Rule,
  SchematicContext,
  SchematicsException,
  Tree,
  apply,
  applyTemplates,
  chain,
  mergeWith,
  move,
  url,
} from '@angular-devkit/schematics';
import { NodePackageInstallTask } from '@angular-devkit/schematics/tasks';
import * as ts from '../third_party/github.com/Microsoft/TypeScript/lib/typescript';
import { addSymbolToNgModuleMetadata, getEnvironmentExportName, insertImport, isImported } from '../utility/ast-utils';
import { applyToUpdateRecorder } from '../utility/change';
import { addPackageJsonDependency, getPackageJsonDependency } from '../utility/dependencies';
import { getAppModulePath } from '../utility/ng-ast-utils';
import { relativePathToWorkspaceRoot } from '../utility/paths';
import { targetBuildNotFoundError } from '../utility/project-targets';
import { getWorkspace, updateWorkspace } from '../utility/workspace';
import { BrowserBuilderOptions } from '../utility/workspace-models';
import { Schema as ServiceWorkerOptions } from './schema';

function addDependencies(): Rule {
  return (host: Tree, context: SchematicContext) => {
    const packageName = '@angular/service-worker';
    context.logger.debug(`adding dependency (${packageName})`);
    const coreDep = getPackageJsonDependency(host, '@angular/core');
    if (coreDep === null) {
      throw new SchematicsException('Could not find version.');
    }
    const serviceWorkerDep = {
      ...coreDep,
      name: packageName,
    };
    addPackageJsonDependency(host, serviceWorkerDep);

    return host;
  };
}

function updateAppModule(mainPath: string): Rule {
  return (host: Tree, context: SchematicContext) => {
    context.logger.debug('Updating appmodule');

    const modulePath = getAppModulePath(host, mainPath);
    context.logger.debug(`module path: ${modulePath}`);

    // add import
    let moduleSource = getTsSourceFile(host, modulePath);
    let importModule = 'ServiceWorkerModule';
    let importPath = '@angular/service-worker';
    if (!isImported(moduleSource, importModule, importPath)) {
      const change = insertImport(moduleSource, modulePath, importModule, importPath);
      if (change) {
        const recorder = host.beginUpdate(modulePath);
        applyToUpdateRecorder(recorder, [change]);
        host.commitUpdate(recorder);
      }
    }

    // add import for environments
    // import { environment } from '../environments/environment';
    moduleSource = getTsSourceFile(host, modulePath);
    const environmentExportName = getEnvironmentExportName(moduleSource);
    // if environemnt import already exists then use the found one
    // otherwise use the default name
    importModule = environmentExportName || 'environment';
    // TODO: dynamically find environments relative path
    importPath = '../environments/environment';

    if (!environmentExportName) {
      // if environment import was not found then insert the new one
      // with default path and default export name
      const change = insertImport(moduleSource, modulePath, importModule, importPath);
      if (change) {
        const recorder = host.beginUpdate(modulePath);
        applyToUpdateRecorder(recorder, [change]);
        host.commitUpdate(recorder);
      }
    }

    // register SW in app module
    const importText = tags.stripIndent`
      ServiceWorkerModule.register('ngsw-worker.js', {
        enabled: ${importModule}.production,
        // Register the ServiceWorker as soon as the app is stable
        // or after 30 seconds (whichever comes first).
        registrationStrategy: 'registerWhenStable:30000'
      })
    `;
    moduleSource = getTsSourceFile(host, modulePath);
    const metadataChanges = addSymbolToNgModuleMetadata(
      moduleSource, modulePath, 'imports', importText);
    if (metadataChanges) {
      const recorder = host.beginUpdate(modulePath);
      applyToUpdateRecorder(recorder, metadataChanges);
      host.commitUpdate(recorder);
    }

    return host;
  };
}

function getTsSourceFile(host: Tree, path: string): ts.SourceFile {
  const buffer = host.read(path);
  if (!buffer) {
    throw new SchematicsException(`Could not read file (${path}).`);
  }
  const content = buffer.toString();
  const source = ts.createSourceFile(path, content, ts.ScriptTarget.Latest, true);

  return source;
}

export default function (options: ServiceWorkerOptions): Rule {
  return async (host: Tree, context: SchematicContext) => {
    const workspace = await getWorkspace(host);
    const project = workspace.projects.get(options.project);
    if (!project) {
      throw new SchematicsException(`Invalid project name (${options.project})`);
    }
    if (project.extensions.projectType !== 'application') {
      throw new SchematicsException(`Service worker requires a project type of "application".`);
    }
    const buildTarget = project.targets.get('build');
    if (!buildTarget) {
      throw targetBuildNotFoundError();
    }
    const buildOptions = (buildTarget.options || {}) as unknown as BrowserBuilderOptions;
    const root = project.root;
    buildOptions.serviceWorker = true;
    buildOptions.ngswConfigPath = join(normalize(root), 'ngsw-config.json');

    let { resourcesOutputPath = '' } = buildOptions;
    if (resourcesOutputPath) {
      resourcesOutputPath = normalize(`/${resourcesOutputPath}`);
    }

    const templateSource = apply(url('./files'), [
      applyTemplates({
        ...options,
        resourcesOutputPath,
        relativePathToWorkspaceRoot: relativePathToWorkspaceRoot(project.root),
      }),
      move(project.root),
    ]);

    context.addTask(new NodePackageInstallTask());

    return chain([
      mergeWith(templateSource),
      updateWorkspace(workspace),
      addDependencies(),
      updateAppModule(buildOptions.main),
    ]);
  };
}