"use strict";

const readCmdShim = require("read-cmd-shim");
const fs = require("fs-extra");
const log = require("npmlog");
const path = require("path");

module.exports.resolveSymlink = resolveSymlink;

function resolveSymlink(filePath) {
  log.silly("resolveSymlink", filePath);

  let result;

  if (process.platform === "win32") {
    result = resolveWindowsSymlink(filePath);
  } else {
    result = resolvePosixSymlink(filePath);
  }

  log.verbose("resolveSymlink", [filePath, result]);

  return result;
}

function resolveSymbolicLink(filePath) {
  const lstat = fs.lstatSync(filePath);
  const resolvedPath = lstat.isSymbolicLink()
    ? path.resolve(path.dirname(filePath), fs.readlinkSync(filePath))
    : false;

  return {
    resolvedPath,
    lstat,
  };
}

function resolvePosixSymlink(filePath) {
  return resolveSymbolicLink(filePath).resolvedPath;
}

function resolveWindowsSymlink(filePath) {
  const { resolvedPath, lstat } = resolveSymbolicLink(filePath);

  if (lstat.isFile() && !resolvedPath) {
    try {
      return path.resolve(path.dirname(filePath), readCmdShim.sync(filePath));
    } catch (e) {
      return false;
    }
  }

  return resolvedPath && path.resolve(resolvedPath);
}