// ==UserScript==
// @name         IEEE Xplore → KU OA Quick Switch (+ PDF)
// @namespace    https://github.com/coolmoon327/ieeexplore-ku-oa
// @version      1.1.0
// @description  Adds a floating button on ieeexplore.ieee.org to reopen the current path via Khalifa University EZproxy; shows a second button on /document/<id> pages to open the PDF directly.
// @author       coolmoon327
// @match        https://ieeexplore.ieee.org/*
// @run-at       document-idle
// @grant        GM_openInTab
// @license      MIT
// @homepageURL  https://github.com/coolmoon327/ieeexplore-ku-oa
// @supportURL   https://github.com/coolmoon327/ieeexplore-ku-oa/issues
// @downloadURL  https://raw.githubusercontent.com/coolmoon327/ieeexplore-ku-oa/main/userscripts/ieee-ku-oa.user.js
// @updateURL    https://raw.githubusercontent.com/coolmoon327/ieeexplore-ku-oa/main/userscripts/ieee-ku-oa.user.js
// ==/UserScript==

(function () {
  'use strict';

  const PROXY_ROOT = 'https://ieeexplore-ieee-org.khalifa.idm.oclc.org';
  const WRAP_ID = 'ku-oa-fab';

  if (document.getElementById(WRAP_ID)) return;

  // --- UI helpers -----------------------------------------------------------
  function makeBtn(text, title) {
    const b = document.createElement('button');
    b.type = 'button';
    b.setAttribute('aria-label', text);
    b.textContent = text;
    b.title = title || '';
    Object.assign(b.style, {
      padding: '8px 12px',
      borderRadius: '9999px',
      border: 'none',
      cursor: 'pointer',
      fontSize: '12px',
      lineHeight: '1',
      background: '#00629b', // IEEE blue
      color: '#fff',
      boxShadow: '0 2px 10px rgba(0,0,0,.15)',
      opacity: '0.92'
    });
    b.addEventListener('mouseenter', () => (b.style.opacity = '1'));
    b.addEventListener('mouseleave', () => (b.style.opacity = '0.92'));
    return b;
  }

  // Floating wrapper (top-right)
  const wrap = document.createElement('div');
  wrap.id = WRAP_ID;
  Object.assign(wrap.style, {
    position: 'fixed',
    top: '14px',
    right: '14px',
    zIndex: '99999',
    display: 'flex',
    flexDirection: 'column',
    gap: '8px'
  });

  // Main button: open same path via KU proxy
  const btnMain = makeBtn('KU OA', 'Open this page via Khalifa University\'s EZproxy in a new tab');
  btnMain.addEventListener('click', () => {
    const path = location.pathname + location.search + location.hash;
    const target = PROXY_ROOT + path;
    try {
      GM_openInTab(target, { active: true });
    } catch (e) {
      // Fallback in case GM_openInTab is unavailable
      window.open(target, '_blank');
    }
  });

  // Secondary button: PDF (only on /document/<id>)
  const btnPdf = makeBtn('KU PDF', 'Open the proxied PDF view for this document in a new tab');

  function getArnumber() {
    const m = location.pathname.match(/\/document\/(\d+)/);
    return m ? m[1] : null;
  }

  function updatePdfBtn() {
    const ar = getArnumber();
    if (ar) {
      if (!btnPdf.isConnected) wrap.appendChild(btnPdf);
      btnPdf.onclick = () => {
        // Stable PDF viewer route on IEEE Xplore
        const url = `${PROXY_ROOT}/stamp/stamp.jsp?tp=&arnumber=${ar}`;
        try {
          GM_openInTab(url, { active: true });
        } catch (e) {
          window.open(url, '_blank');
        }
      };
    } else if (btnPdf.isConnected) {
      btnPdf.remove();
    }
  }

  // Mount UI
  wrap.appendChild(btnMain);
  document.documentElement.appendChild(wrap);
  updatePdfBtn();

  // Handle SPA navigation on IEEE Xplore
  function onUrlChange() {
    updatePdfBtn();
  }

  const origPush = history.pushState;
  history.pushState = function () {
    const r = origPush.apply(this, arguments);
    onUrlChange();
    return r;
  };
  const origReplace = history.replaceState;
  history.replaceState = function () {
    const r = origReplace.apply(this, arguments);
    onUrlChange();
    return r;
  };
  window.addEventListener('popstate', onUrlChange);
})();