/**
 * @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 * as fs from 'fs';
import { dirname, join } from 'path';
import * as resolve from 'resolve';
import { promisify } from 'util';
import { NgAddSaveDepedency } from './package-metadata';

const readFile = promisify(fs.readFile);

interface PackageJson {
  name: string;
  version: string;
  dependencies?: Record<string, string>;
  devDependencies?: Record<string, string>;
  peerDependencies?: Record<string, string>;
  optionalDependencies?: Record<string, string>;
  'ng-update'?: {
    migrations?: string;
  };
  'ng-add'?: {
    save?: NgAddSaveDepedency;
  };
}

function getAllDependencies(pkg: PackageJson): Set<[string, string]> {
  return new Set([
    ...Object.entries(pkg.dependencies || []),
    ...Object.entries(pkg.devDependencies || []),
    ...Object.entries(pkg.peerDependencies || []),
    ...Object.entries(pkg.optionalDependencies || []),
  ]);
}

export interface PackageTreeNode {
  name: string;
  version: string;
  path: string;
  package: PackageJson | undefined;
}

export async function readPackageJson(packageJsonPath: string): Promise<PackageJson | undefined> {
  try {
    return JSON.parse((await readFile(packageJsonPath)).toString());
  } catch {
    return undefined;
  }
}

export function findPackageJson(workspaceDir: string, packageName: string): string | undefined {
  try {
    // avoid require.resolve here, see: https://github.com/angular/angular-cli/pull/18610#issuecomment-681980185
    const packageJsonPath = resolve.sync(`${packageName}/package.json`, { basedir: workspaceDir });

    return packageJsonPath;
  } catch {
    return undefined;
  }
}

export async function getProjectDependencies(dir: string): Promise<Map<string, PackageTreeNode>> {
  const pkg = await readPackageJson(join(dir, 'package.json'));
  if (!pkg) {
    throw new Error('Could not find package.json');
  }

  const results = new Map<string, PackageTreeNode> ();
  for (const [name, version] of getAllDependencies(pkg)) {
    const packageJsonPath = findPackageJson(dir, name);
    if (!packageJsonPath) {
      continue;
    }

    results.set(name, {
      name,
      version,
      path: dirname(packageJsonPath),
      package: await readPackageJson(packageJsonPath),
    });
  }

  return results;
}
