var fs = require('fs');
var cp = require('child_process');
var glob = require('glob');
var ini = require('ini');

/**
 * Load a JSON file
 *
 * @param filePath The path of the json file
 * @return Promise
 */
exports.loadJSONFile = function(filePath) {
  return new Promise(function(resolve, reject) {
    fs.readFile(filePath, 'utf8', function(err, fileContent) {
      if(err) return reject(err);
      try {
        var json = JSON.parse(fileContent);
        return resolve(json);
      } catch(err) {
        return reject(err);
      }
    });
  });
};

/**
 * Load a INI file
 *
 * @param filePath The path of the json file
 * @return Promise
 */
exports.loadINIFile = function(filePath) {
  return new Promise(function(resolve, reject) {
    fs.readFile(filePath, 'utf8', function(err, content) {
      if(err) return reject(err);
      try {
        var decoded = ini.decode(content);
        return resolve(decoded);
      } catch(err) {
        return reject(err);
      }
    });
  });
};

exports.runApp = function(execPath) {
  return new Promise(function(resolve, reject) {
    cp.exec(execPath, function(err) {
      if(err) return reject(err);
      return resolve();
    });
  });
};


var _globCache = {
  statCache: {},
  cache: {},
  realpathCache: {},
  symlinks: {}
};

exports.findFiles = function(pattern, opts) {
  return new Promise(function(resolve, reject) {

    opts = opts || {};
    opts.cache = _globCache.cache;
    opts.statCache = _globCache.statCache;
    opts.realpathCache = _globCache.realpathCache;
    opts.symlinks = _globCache.symlinks;

    glob(pattern, opts, function(err, files) {
      if(err) return reject(err);
      return resolve(files);
    });

  });
};

exports.exists = function(filePath) {
  return new Promise(function(resolve) {
    fs.exists(filePath, resolve);
  });
};