/**
   * @fileoverview Utility for executing npm commands.
   * @author Ian VanSchooten
   */
  
  "use strict";
  
  //------------------------------------------------------------------------------
  // Requirements
  //------------------------------------------------------------------------------
  
  const fs = require("fs"),
      path = require("path"),
      shell = require("shelljs"),
      log = require("../logging");
  
  //------------------------------------------------------------------------------
  // Helpers
  //------------------------------------------------------------------------------
  
  /**
   * Find the closest package.json file, starting at process.cwd (by default),
   * and working up to root.
   *
   * @param   {string} [startDir=process.cwd()] Starting directory
   * @returns {string}                          Absolute path to closest package.json file
   */
  function findPackageJson(startDir) {
      let dir = path.resolve(startDir || process.cwd());
  
      do {
          const pkgfile = path.join(dir, "package.json");
  
          if (!shell.test("-f", pkgfile)) {
              dir = path.join(dir, "..");
              continue;
          }
          return pkgfile;
      } while (dir !== path.resolve(dir, ".."));
      return null;
  }
  
  //------------------------------------------------------------------------------
  // Private
  //------------------------------------------------------------------------------
  
  /**
   * Install node modules synchronously and save to devDependencies in package.json
   * @param   {string|string[]} packages Node module or modules to install
   * @returns {void}
   */
  function installSyncSaveDev(packages) {
      if (Array.isArray(packages)) {
          packages = packages.join(" ");
      }
      shell.exec(`npm i --save-dev ${packages}`, { stdio: "inherit" });
  }
  
  /**
   * Check whether node modules are include in a project's package.json.
   *
   * @param   {string[]} packages           Array of node module names
   * @param   {Object}  opt                 Options Object
   * @param   {boolean} opt.dependencies    Set to true to check for direct dependencies
   * @param   {boolean} opt.devDependencies Set to true to check for development dependencies
   * @param   {boolean} opt.startdir        Directory to begin searching from
   * @returns {Object}                      An object whose keys are the module names
   *                                        and values are booleans indicating installation.
   */
  function check(packages, opt) {
      let deps = [];
      const pkgJson = (opt) ? findPackageJson(opt.startDir) : findPackageJson();
      let fileJson;
  
      if (!pkgJson) {
          throw new Error("Could not find a package.json file. Run 'npm init' to create one.");
      }
  
      try {
          fileJson = JSON.parse(fs.readFileSync(pkgJson, "utf8"));
      } catch (e) {
          log.info("Could not read package.json file. Please check that the file contains valid JSON.");
          throw new Error(e);
      }
  
      if (opt.devDependencies && typeof fileJson.devDependencies === "object") {
          deps = deps.concat(Object.keys(fileJson.devDependencies));
      }
      if (opt.dependencies && typeof fileJson.dependencies === "object") {
          deps = deps.concat(Object.keys(fileJson.dependencies));
      }
      return packages.reduce((status, pkg) => {
          status[pkg] = deps.indexOf(pkg) !== -1;
          return status;
      }, {});
  }
  
  /**
   * Check whether node modules are included in the dependencies of a project's
   * package.json.
   *
   * Convienience wrapper around check().
   *
   * @param   {string[]} packages  Array of node modules to check.
   * @param   {string}   rootDir   The directory contianing a package.json
   * @returns {Object}             An object whose keys are the module names
   *                               and values are booleans indicating installation.
   */
  function checkDeps(packages, rootDir) {
      return check(packages, { dependencies: true, startDir: rootDir });
  }
  
  /**
   * Check whether node modules are included in the devDependencies of a project's
   * package.json.
   *
   * Convienience wrapper around check().
   *
   * @param   {string[]} packages  Array of node modules to check.
   * @returns {Object}             An object whose keys are the module names
   *                               and values are booleans indicating installation.
   */
  function checkDevDeps(packages) {
      return check(packages, { devDependencies: true });
  }
  
  /**
   * Check whether package.json is found in current path.
   *
   * @param   {string=} startDir Starting directory
   * @returns {boolean} Whether a package.json is found in current path.
   */
  function checkPackageJson(startDir) {
      return !!findPackageJson(startDir);
  }
  
  //------------------------------------------------------------------------------
  // Public Interface
  //------------------------------------------------------------------------------
  
  module.exports = {
      installSyncSaveDev,
      checkDeps,
      checkDevDeps,
      checkPackageJson
  };