/**
   * @fileoverview Utilities for working with globs and the filesystem.
   * @author Ian VanSchooten
   * @copyright 2015 Ian VanSchooten. All rights reserved.
   * See LICENSE in root directory for full license.
   */
  "use strict";
  
  //------------------------------------------------------------------------------
  // Requirements
  //------------------------------------------------------------------------------
  
  var debug = require("debug"),
      fs = require("fs"),
      glob = require("glob"),
      shell = require("shelljs"),
  
      IgnoredPaths = require("../ignored-paths");
  
  debug = debug("eslint:glob-util");
  
  //------------------------------------------------------------------------------
  // Helpers
  //------------------------------------------------------------------------------
  
  /**
   * Checks if a provided path is a directory and returns a glob string matching
   * all files under that directory if so, the path itself otherwise.
   *
   * Reason for this is that `glob` needs `/**` to collect all the files under a
   * directory where as our previous implementation without `glob` simply walked
   * a directory that is passed. So this is to maintain backwards compatibility.
   *
   * Also makes sure all path separators are POSIX style for `glob` compatibility.
   *
   * @param {string[]} [extensions] An array of accepted extensions
   * @returns {Function} A function that takes a pathname and returns a glob that
   *                     matches all files with the provided extensions if
   *                     pathname is a directory.
   */
  function processPath(extensions) {
      var suffix = "/**";
  
      if (extensions) {
          if (extensions.length === 1) {
              suffix += "/*." + extensions[0];
          } else {
              suffix += "/*.{" + extensions.join(",") + "}";
          }
      }
  
      /**
       * A function that converts a directory name to a glob pattern
       *
       * @param {string} pathname The directory path to be modified
       * @returns {string} The glob path or the file path itself
       * @private
       */
      return function(pathname) {
          var newPath = pathname;
  
          if (shell.test("-d", pathname)) {
              newPath = pathname.replace(/[\/\\]$/, "") + suffix;
          }
  
          return newPath.replace(/\\/g, "/").replace(/^\.\//, "");
      };
  }
  
  //------------------------------------------------------------------------------
  // Public Interface
  //------------------------------------------------------------------------------
  
  /**
   * Resolves the patterns into glob-based patterns for easier handling.
   * @param   {string[]} patterns    File patterns (such as passed on the command line).
   * @param   {string[]} extensions  List of valid file extensions.
   * @returns {string[]} The equivalent glob patterns.
   */
  function resolveFileGlobPatterns(patterns, extensions) {
      extensions = extensions || [".js"];
  
      extensions = extensions.map(function(ext) {
          return ext.charAt(0) === "." ? ext.substr(1) : ext;
      });
  
      return patterns.map(processPath(extensions));
  }
  
  /**
   * Build a list of absolute filesnames on which ESLint will act.
   * Ignored files are excluded from the results, as are duplicates.
   *
   * @param   {string[]} globPatterns            Glob patterns.
   * @param   {Object}   [options]               An options object.
   * @param   {boolean}  [options.ignore]        False disables use of .eslintignore.
   * @param   {string}   [options.ignorePath]    The ignore file to use instead of .eslintignore.
   * @param   {string}   [options.ignorePattern] A pattern of files to ignore.
   * @returns {string[]} Resolved absolute filenames.
   */
  function listFilesToProcess(globPatterns, options) {
      var ignoredPaths,
          ignoredPathsList,
          files = [],
          added = {},
          globOptions;
  
      /**
       * Executes the linter on a file defined by the `filename`. Skips
       * unsupported file extensions and any files that are already linted.
       * @param {string} filename The file to be processed
       * @returns {void}
       */
      function addFile(filename) {
          if (ignoredPaths.contains(filename)) {
              return;
          }
          filename = fs.realpathSync(filename);
          if (added[filename]) {
              return;
          }
          files.push(filename);
          added[filename] = true;
      }
  
      options = options || { ignore: true };
      ignoredPaths = IgnoredPaths.load(options);
      ignoredPathsList = ignoredPaths.patterns || [];
      globOptions = {
          nodir: true,
          ignore: ignoredPathsList
      };
  
      debug("Creating list of files to process.");
      globPatterns.forEach(function(pattern) {
          if (shell.test("-f", pattern)) {
              addFile(pattern);
          } else {
              glob.sync(pattern, globOptions).forEach(addFile);
          }
      });
  
      return files;
  }
  
  module.exports = {
      resolveFileGlobPatterns: resolveFileGlobPatterns,
      listFilesToProcess: listFilesToProcess
  };