/**
 * @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.dev/license
 */

import {
  Rule,
  SchematicsException,
  Tree,
  chain,
  noop,
  schematic,
} from '@angular-devkit/schematics';
import { dirname, join } from 'node:path/posix';
import ts from '../third_party/github.com/Microsoft/TypeScript/lib/typescript';
import {
  addImportToModule,
  addSymbolToNgModuleMetadata,
  findNode,
  findNodes,
  getDecoratorMetadata,
  getSourceNodes,
  insertImport,
  isImported,
} from '../utility/ast-utils';
import { applyToUpdateRecorder } from '../utility/change';
import { getAppModulePath, isStandaloneApp } from '../utility/ng-ast-utils';
import { findBootstrapApplicationCall, getMainFilePath } from '../utility/standalone/util';
import { getWorkspace, updateWorkspace } from '../utility/workspace';
import { Builders } from '../utility/workspace-models';
import { Schema as AppShellOptions } from './schema';

const APP_SHELL_ROUTE = 'shell';

function getSourceFile(host: Tree, path: string): ts.SourceFile {
  const content = host.readText(path);
  const source = ts.createSourceFile(path, content, ts.ScriptTarget.Latest, true);

  return source;
}

function getServerModulePath(host: Tree, sourceRoot: string, mainPath: string): string | null {
  const mainSource = getSourceFile(host, join(sourceRoot, mainPath));
  const allNodes = getSourceNodes(mainSource);
  const expNode = allNodes.find((node) => ts.isExportDeclaration(node));
  if (!expNode) {
    return null;
  }
  const relativePath = expNode.moduleSpecifier as ts.StringLiteral;
  const modulePath = join(sourceRoot, `${relativePath.text}.ts`);

  return modulePath;
}

interface TemplateInfo {
  templateProp?: ts.PropertyAssignment;
  templateUrlProp?: ts.PropertyAssignment;
}

function getComponentTemplateInfo(host: Tree, componentPath: string): TemplateInfo {
  const compSource = getSourceFile(host, componentPath);
  const compMetadata = getDecoratorMetadata(compSource, 'Component', '@angular/core')[0];

  return {
    templateProp: getMetadataProperty(compMetadata, 'template'),
    templateUrlProp: getMetadataProperty(compMetadata, 'templateUrl'),
  };
}

function getComponentTemplate(host: Tree, compPath: string, tmplInfo: TemplateInfo): string {
  let template = '';

  if (tmplInfo.templateProp) {
    template = tmplInfo.templateProp.getFullText();
  } else if (tmplInfo.templateUrlProp) {
    const templateUrl = (tmplInfo.templateUrlProp.initializer as ts.StringLiteral).text;
    const dir = dirname(compPath);
    const templatePath = join(dir, templateUrl);
    try {
      template = host.readText(templatePath);
    } catch {}
  }

  return template;
}

function getBootstrapComponentPath(host: Tree, mainPath: string): string {
  let bootstrappingFilePath: string;
  let bootstrappingSource: ts.SourceFile;
  let componentName: string;

  if (isStandaloneApp(host, mainPath)) {
    // Standalone Application
    const bootstrapCall = findBootstrapApplicationCall(host, mainPath);
    componentName = bootstrapCall.arguments[0].getText();
    bootstrappingFilePath = mainPath;
    bootstrappingSource = getSourceFile(host, mainPath);
  } else {
    // NgModule Application
    const modulePath = getAppModulePath(host, mainPath);
    const moduleSource = getSourceFile(host, modulePath);
    const metadataNode = getDecoratorMetadata(moduleSource, 'NgModule', '@angular/core')[0];
    const bootstrapProperty = getMetadataProperty(metadataNode, 'bootstrap');
    const arrLiteral = bootstrapProperty.initializer as ts.ArrayLiteralExpression;
    componentName = arrLiteral.elements[0].getText();
    bootstrappingSource = moduleSource;
    bootstrappingFilePath = modulePath;
  }

  const componentRelativeFilePath = getSourceNodes(bootstrappingSource)
    .filter(ts.isImportDeclaration)
    .filter((imp) => {
      return findNode(imp, ts.SyntaxKind.Identifier, componentName);
    })
    .map((imp) => {
      const pathStringLiteral = imp.moduleSpecifier as ts.StringLiteral;

      return pathStringLiteral.text;
    })[0];

  return join(dirname(bootstrappingFilePath), componentRelativeFilePath + '.ts');
}
// end helper functions.

function validateProject(mainPath: string): Rule {
  return (host: Tree) => {
    const routerOutletCheckRegex = /<router-outlet.*?>([\s\S]*?)(?:<\/router-outlet>)?/;

    const componentPath = getBootstrapComponentPath(host, mainPath);
    const tmpl = getComponentTemplateInfo(host, componentPath);
    const template = getComponentTemplate(host, componentPath, tmpl);
    if (!routerOutletCheckRegex.test(template)) {
      throw new SchematicsException(
        `Prerequisite for application shell is to define a router-outlet in your root component.`,
      );
    }
  };
}

function addRouterModule(mainPath: string): Rule {
  return (host: Tree) => {
    const modulePath = getAppModulePath(host, mainPath);
    const moduleSource = getSourceFile(host, modulePath);
    const changes = addImportToModule(moduleSource, modulePath, 'RouterModule', '@angular/router');
    const recorder = host.beginUpdate(modulePath);
    applyToUpdateRecorder(recorder, changes);
    host.commitUpdate(recorder);

    return host;
  };
}

function getMetadataProperty(metadata: ts.Node, propertyName: string): ts.PropertyAssignment {
  const properties = (metadata as ts.ObjectLiteralExpression).properties;
  const property = properties.filter(ts.isPropertyAssignment).filter((prop) => {
    const name = prop.name;
    switch (name.kind) {
      case ts.SyntaxKind.Identifier:
        return name.getText() === propertyName;
      case ts.SyntaxKind.StringLiteral:
        return name.text === propertyName;
    }

    return false;
  })[0];

  return property;
}

function addAppShellConfigToWorkspace(options: AppShellOptions): Rule {
  return updateWorkspace((workspace) => {
    const project = workspace.projects.get(options.project);
    if (!project) {
      return;
    }
    const buildTarget = project.targets.get('build');
    if (
      buildTarget?.builder === Builders.Application ||
      buildTarget?.builder === Builders.BuildApplication
    ) {
      // Application builder configuration.
      const prodConfig = buildTarget.configurations?.production;
      if (!prodConfig) {
        throw new SchematicsException(
          `A "production" configuration is not defined for the "build" builder.`,
        );
      }
      prodConfig.appShell = true;
    }
  });
}

function addServerRoutes(options: AppShellOptions): Rule {
  return async (host: Tree) => {
    // The workspace gets updated so this needs to be reloaded
    const workspace = await getWorkspace(host);
    const project = workspace.projects.get(options.project);
    if (!project) {
      throw new SchematicsException(`Invalid project name (${options.project})`);
    }

    const modulePath = getServerModulePath(host, project.sourceRoot || 'src', 'main.server.ts');
    if (modulePath === null) {
      throw new SchematicsException('Server module not found.');
    }

    let moduleSource = getSourceFile(host, modulePath);
    if (!isImported(moduleSource, 'Routes', '@angular/router')) {
      const recorder = host.beginUpdate(modulePath);
      const routesChange = insertImport(moduleSource, modulePath, 'Routes', '@angular/router');
      if (routesChange) {
        applyToUpdateRecorder(recorder, [routesChange]);
      }

      const imports = getSourceNodes(moduleSource)
        .filter((node) => node.kind === ts.SyntaxKind.ImportDeclaration)
        .sort((a, b) => a.getStart() - b.getStart());
      const insertPosition = imports[imports.length - 1].getEnd();
      const routeText = `\n\nconst routes: Routes = [ { path: '${APP_SHELL_ROUTE}', component: AppShellComponent }];`;
      recorder.insertRight(insertPosition, routeText);
      host.commitUpdate(recorder);
    }

    moduleSource = getSourceFile(host, modulePath);
    if (!isImported(moduleSource, 'RouterModule', '@angular/router')) {
      const recorder = host.beginUpdate(modulePath);
      const routerModuleChange = insertImport(
        moduleSource,
        modulePath,
        'RouterModule',
        '@angular/router',
      );

      if (routerModuleChange) {
        applyToUpdateRecorder(recorder, [routerModuleChange]);
      }

      const metadataChange = addSymbolToNgModuleMetadata(
        moduleSource,
        modulePath,
        'imports',
        'RouterModule.forRoot(routes)',
      );
      if (metadataChange) {
        applyToUpdateRecorder(recorder, metadataChange);
      }
      host.commitUpdate(recorder);
    }
  };
}

function addStandaloneServerRoute(options: AppShellOptions): Rule {
  return async (host: Tree) => {
    const workspace = await getWorkspace(host);
    const project = workspace.projects.get(options.project);
    if (!project) {
      throw new SchematicsException(`Project name "${options.project}" doesn't not exist.`);
    }

    const configFilePath = join(project.sourceRoot ?? 'src', 'app/app.config.server.ts');
    if (!host.exists(configFilePath)) {
      throw new SchematicsException(`Cannot find "${configFilePath}".`);
    }

    let recorder = host.beginUpdate(configFilePath);
    let configSourceFile = getSourceFile(host, configFilePath);
    if (!isImported(configSourceFile, 'ROUTES', '@angular/router')) {
      const routesChange = insertImport(
        configSourceFile,
        configFilePath,
        'ROUTES',
        '@angular/router',
      );

      if (routesChange) {
        applyToUpdateRecorder(recorder, [routesChange]);
      }
    }

    configSourceFile = getSourceFile(host, configFilePath);
    const providersLiteral = findNodes(configSourceFile, ts.isPropertyAssignment).find(
      (n) => ts.isArrayLiteralExpression(n.initializer) && n.name.getText() === 'providers',
    )?.initializer as ts.ArrayLiteralExpression | undefined;
    if (!providersLiteral) {
      throw new SchematicsException(
        `Cannot find the "providers" configuration in "${configFilePath}".`,
      );
    }

    // Add route to providers literal.
    recorder.remove(providersLiteral.getStart(), providersLiteral.getWidth());
    const updatedProvidersString = [
      ...providersLiteral.elements.map((element) => '    ' + element.getText()),
      `    {
      provide: ROUTES,
      multi: true,
      useValue: [{
        path: '${APP_SHELL_ROUTE}',
        component: AppShellComponent
      }]
    }\n  `,
    ];

    recorder.insertRight(providersLiteral.getStart(), `[\n${updatedProvidersString.join(',\n')}]`);

    if (options.serverRouting) {
      host.commitUpdate(recorder);
      configSourceFile = getSourceFile(host, configFilePath);
      const functionCall = findNodes(configSourceFile, ts.isCallExpression).find(
        (n) =>
          ts.isIdentifier(n.expression) && n.expression.getText() === 'provideServerRoutesConfig',
      );

      if (!functionCall) {
        throw new SchematicsException(
          `Cannot find the "provideServerRoutesConfig" function call in "${configFilePath}".`,
        );
      }

      recorder = host.beginUpdate(configFilePath);
      recorder.insertLeft(functionCall.end - 1, `, { appShellRoute: '${APP_SHELL_ROUTE}' }`);
    }

    // Add AppShellComponent import
    const appShellImportChange = insertImport(
      configSourceFile,
      configFilePath,
      'AppShellComponent',
      './app-shell/app-shell.component',
    );

    applyToUpdateRecorder(recorder, [appShellImportChange]);
    host.commitUpdate(recorder);
  };
}

function addServerRoutingConfig(options: AppShellOptions): Rule {
  return async (host: Tree) => {
    const workspace = await getWorkspace(host);
    const project = workspace.projects.get(options.project);
    if (!project) {
      throw new SchematicsException(`Project name "${options.project}" doesn't not exist.`);
    }

    const configFilePath = join(project.sourceRoot ?? 'src', 'app/app.routes.server.ts');
    if (!host.exists(configFilePath)) {
      throw new SchematicsException(`Cannot find "${configFilePath}".`);
    }

    const sourceFile = getSourceFile(host, configFilePath);
    const nodes = getSourceNodes(sourceFile);

    // Find the serverRoutes variable declaration
    const serverRoutesNode = nodes.find(
      (node) =>
        ts.isVariableDeclaration(node) &&
        node.initializer &&
        ts.isArrayLiteralExpression(node.initializer) &&
        node.type &&
        ts.isArrayTypeNode(node.type) &&
        node.type.getText().includes('ServerRoute'),
    ) as ts.VariableDeclaration | undefined;

    if (!serverRoutesNode) {
      throw new SchematicsException(
        `Cannot find the "ServerRoute" configuration in "${configFilePath}".`,
      );
    }
    const recorder = host.beginUpdate(configFilePath);
    const arrayLiteral = serverRoutesNode.initializer as ts.ArrayLiteralExpression;
    const firstElementPosition =
      arrayLiteral.elements[0]?.getStart() ?? arrayLiteral.getStart() + 1;
    const newRouteString = `{
    path: '${APP_SHELL_ROUTE}',
    renderMode: RenderMode.AppShell
  },\n`;
    recorder.insertLeft(firstElementPosition, newRouteString);

    host.commitUpdate(recorder);
  };
}

export default function (options: AppShellOptions): Rule {
  return async (tree) => {
    const browserEntryPoint = await getMainFilePath(tree, options.project);
    const isStandalone = isStandaloneApp(tree, browserEntryPoint);

    return chain([
      validateProject(browserEntryPoint),
      schematic('server', options),
      ...(isStandalone
        ? [addStandaloneServerRoute(options)]
        : [addRouterModule(browserEntryPoint), addServerRoutes(options)]),
      options.serverRouting ? noop() : addAppShellConfigToWorkspace(options),
      schematic('component', {
        name: 'app-shell',
        module: 'app.module.server.ts',
        project: options.project,
        standalone: isStandalone,
      }),
    ]);
  };
}