// ==UserScript==
// @name        WordPress.com edit post redirects
// @namespace   tpenguinltg
// @description Redirects the new post page to the classic post page
// @include     https://wordpress.com/post*
// @include     https://wordpress.com/page*
// @version     1.2.2
// @homepageURL https://greasyfork.org/en/scripts/8581-wordpress-com-edit-post-redirects
// @homepageURL https://github.com/tpenguinltg/wpcom-edit-post-redirect.user.js
// @grant       none
// @license     MPLv2.0; http://mozilla.org/MPL/2.0/
// @copyright   2015, tPenguinLTG (http://tpenguinltg.wordpress.com/)
// @run-at      document-start
// @downloadURL none
// ==/UserScript==

// Based on function by dystroy. From http://stackoverflow.com/a/14388512
function fetchJSONFile(path, callback, fallback) {
    var httpRequest = new XMLHttpRequest();
    httpRequest.onreadystatechange = function() {
        if (httpRequest.readyState === 4) {
            if (httpRequest.status === 200) {
                var data = JSON.parse(httpRequest.responseText);
                if (callback) callback(data);
            }//if
            else {
                if(fallback) fallback();
            }//end if
        }//end if
    };//end onreadystatechange()
    httpRequest.open('GET', path);
    httpRequest.send(); 
}//end fetchJSONFile


/**
 * Scrapes the loaded page for the link to the classic editor.
 */
function scrapeClassicLink() {
  // scrape the edit URL from the page when the DOM has finished loading
  window.onload=function() {
    var classicLink=document.getElementsByClassName("switch-to-classic")[0].children[0].href;
    window.location.replace(classicLink);
  }; //end window.onload
}//end scrapeClassicLink


/**
 * Sets up a redirect using the given parsed API data.
 */
function apiRedirect(data) {
    // if not a private blog and is not Jetpack-enabled, redirect using API
    if(!data.error && !data.jetpack) {
      var postURL;

      //new post
      if(postid == "new") {
        postURL=data.URL+"/wp-admin/post-new.php?post_type="+postType;
      }//if

      //existing post
      else {
        postURL=data.URL+"/wp-admin/post.php?post="+postid+"&action=edit";
      }//end if

      //redirect
      window.location.replace(postURL);
    }//if

    // else this is a private blog or is Jetpack-enabled
    else {
      scrapeClassicLink();
    }//end if
}//end apiRedirect


// start

// gather information from URL
var parsedUrl=window.location.pathname.match(/(post|page)(\/(\d+)\/(\d+|new))?/);
var postType=parsedUrl[1];
var blogid=parsedUrl[3];
var postid=parsedUrl[4];

// if no blog given
if(!blogid) {
  scrapeClassicLink();
}// if
else {
  // Redirect to post URL based on API results
  // API docs: https://developer.wordpress.com/docs/api/
  fetchJSONFile("https://public-api.wordpress.com/rest/v1.1/sites/"+blogid, apiRedirect, scrapeClassicLink);
}//end if