'use strict';

const u = require('universalify').fromCallback;
const path = require('path');
const fs = require('graceful-fs');
const _mkdirs = require('../mkdirs');
const mkdirs = _mkdirs.mkdirs;
const mkdirsSync = _mkdirs.mkdirsSync;

const _symlinkPaths = require('./symlink-paths');
const symlinkPaths = _symlinkPaths.symlinkPaths;
const symlinkPathsSync = _symlinkPaths.symlinkPathsSync;

const _symlinkType = require('./symlink-type');
const symlinkType = _symlinkType.symlinkType;
const symlinkTypeSync = _symlinkType.symlinkTypeSync;

const pathExists = require('../path-exists').pathExists;

function createSymlink(srcpath, dstpath, type, callback) {
  callback = typeof type === 'function' ? type : callback;
  type = typeof type === 'function' ? false : type;

  pathExists(dstpath, (err, destinationExists) => {
    if (err) return callback(err);
    if (destinationExists) return callback(null);
    symlinkPaths(srcpath, dstpath, (err, relative) => {
      if (err) return callback(err);
      srcpath = relative.toDst;
      symlinkType(relative.toCwd, type, (err, type) => {
        if (err) return callback(err);
        const dir = path.dirname(dstpath);
        pathExists(dir, (err, dirExists) => {
          if (err) return callback(err);
          if (dirExists) return fs.symlink(srcpath, dstpath, type, callback);
          mkdirs(dir, (err) => {
            if (err) return callback(err);
            fs.symlink(srcpath, dstpath, type, callback);
          });
        });
      });
    });
  });
}

function createSymlinkSync(srcpath, dstpath, type) {
  const destinationExists = fs.existsSync(dstpath);
  if (destinationExists) return undefined;

  const relative = symlinkPathsSync(srcpath, dstpath);
  srcpath = relative.toDst;
  type = symlinkTypeSync(relative.toCwd, type);
  const dir = path.dirname(dstpath);
  const exists = fs.existsSync(dir);
  if (exists) return fs.symlinkSync(srcpath, dstpath, type);
  mkdirsSync(dir);
  return fs.symlinkSync(srcpath, dstpath, type);
}

module.exports = {
  createSymlink: u(createSymlink),
  createSymlinkSync,
};