var fs = require('graceful-fs')
var path = require('path')
var ncp = require('./ncp')
var mkdir = require('../mkdirs')

function copy (src, dest, options, callback) {
  if (typeof options === 'function' && !callback) {
    callback = options
    options = {}
  } else if (typeof options === 'function' || options instanceof RegExp) {
    options = {filter: options}
  }
  callback = callback || function () {}
  options = options || {}

  // don't allow src and dest to be the same
  var basePath = process.cwd()
  var currentPath = path.resolve(basePath, src)
  var targetPath = path.resolve(basePath, dest)
  if (currentPath === targetPath) return callback(new Error('Source and destination must not be the same.'))

  fs.lstat(src, function (err, stats) {
    if (err) return callback(err)

    var dir = null
    if (stats.isDirectory()) {
      var parts = dest.split(path.sep)
      parts.pop()
      dir = parts.join(path.sep)
    } else {
      dir = path.dirname(dest)
    }

    fs.exists(dir, function (dirExists) {
      if (dirExists) return ncp(src, dest, options, callback)
      mkdir.mkdirs(dir, function (err) {
        if (err) return callback(err)
        ncp(src, dest, options, callback)
      })
    })
  })
}

module.exports = copy