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

var BUF_LENGTH = 64 * 1024
var _buff = new Buffer(BUF_LENGTH)

var copyFileSync = function (srcFile, destFile, clobber) {
  if (fs.existsSync(destFile) && !clobber) {
    throw Error('EEXIST')
  }

  var fdr = fs.openSync(srcFile, 'r')
  var stat = fs.fstatSync(fdr)
  var fdw = fs.openSync(destFile, 'w', stat.mode)
  var bytesRead = 1
  var pos = 0

  while (bytesRead > 0) {
    bytesRead = fs.readSync(fdr, _buff, 0, BUF_LENGTH, pos)
    fs.writeSync(fdw, _buff, 0, bytesRead)
    pos += bytesRead
  }

  fs.closeSync(fdr)
  fs.closeSync(fdw)
}

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 () {}

  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)
      })
    })
  })
}

function copySync (src, dest, options) {
  if (typeof options === 'function' || options instanceof RegExp) {
    options = {filter: options}
  }

  options = options || {}
  options.recursive = !!options.recursive

  // default to true for now
  options.clobber = 'clobber' in options ? !!options.clobber : true

  options.filter = options.filter || function () { return true }

  var stats = options.recursive ? fs.lstatSync(src) : fs.statSync(src)
  var destFolder = path.dirname(dest)
  var destFolderExists = fs.existsSync(destFolder)
  var performCopy = false

  if (stats.isFile()) {
    if (options.filter instanceof RegExp) performCopy = options.filter.test(src)
    else if (typeof options.filter === 'function') performCopy = options.filter(src)

    if (performCopy) {
      if (!destFolderExists) mkdir.mkdirsSync(destFolder)
      copyFileSync(src, dest, options.clobber)
    }
  } else if (stats.isDirectory()) {
    if (!fs.existsSync(dest)) mkdir.mkdirsSync(dest)
    var contents = fs.readdirSync(src)
    contents.forEach(function (content) {
      copySync(path.join(src, content), path.join(dest, content), {filter: options.filter, recursive: true})
    })
  } else if (options.recursive && stats.isSymbolicLink()) {
    var srcPath = fs.readlinkSync(src)
    fs.symlinkSync(srcPath, dest)
  }
}

module.exports = {
  copy: copy,
  copySync: copySync
}
