var cc = require('./lib/utils');
var join = require('path').join;
var deepExtend = require('deep-extend');
var etc = '/etc';
var win = process.platform === 'win32';
var home = win ? process.env.USERPROFILE : process.env.HOME;

module.exports = function (name, defaults, argv, parse) {
  if ('string' !== typeof name)
    throw new Error('rc(name): name *must* be string');
  if (!argv) argv = require('minimist')(process.argv.slice(2));
  defaults =
    ('string' === typeof defaults ? cc.json(defaults) : defaults) || {};

  parse = parse || cc.parse;

  var env = cc.env(name + '_');

  var configs = [defaults];
  var configFiles = [];
  function addConfigFile(file) {
    if (configFiles.indexOf(file) >= 0) return;
    var fileConfig = cc.file(file);
    if (fileConfig) {
      configs.push(parse(fileConfig));
      configFiles.push(file);
    }
  }

  // which files do we look at?
  if (!win)
    [join(etc, name, 'config'), join(etc, name + 'rc')].forEach(addConfigFile);
  if (home)
    [
      join(home, '.config', name, 'config'),
      join(home, '.config', name),
      join(home, '.' + name, 'config'),
      join(home, '.' + name + 'rc'),
    ].forEach(addConfigFile);
  addConfigFile(cc.find('.' + name + 'rc'));
  if (env.config) addConfigFile(env.config);
  if (argv.config) addConfigFile(argv.config);

  return deepExtend.apply(
    null,
    configs.concat([
      env,
      argv,
      configFiles.length ?
        { configs: configFiles, config: configFiles[configFiles.length - 1] }
      : undefined,
    ])
  );
};