// ==UserScript==
// @name    Publication Auto PDF
// @name:zh-CN  SCI文献PDF直达
// @version 0.2.1
// @author  sincostandx
// @description Automatically jumps to PDF when you visit a journal article abstract page. Also includes a utility to copy or download citation info.
// @description:zh-CN  访问SCI文献摘要页时自动跳转至PDF，附带文献摘录工具
// @include http*://www.sciencedirect.com/science/article/*
// @include http*://pubs.acs.org/doi/*
// @include http*://www.tandfonline.com/doi/abs/*
// @include http*://www.beilstein-journals.org/*
// @include http*://onlinelibrary.wiley.com/doi/*
// @include http*://www.eurekaselect.com/*/article*
// @include http*://pubs.rsc.org/en/Content/*
// @include http*://link.springer.com/article*
// @include http*://aip.scitation.org/doi/10*
// @include http*://aip.scitation.org/doi/abs/10*
// @include http*://www.nature.com/articles*
// @include http*://science.sciencemag.org/content*
// @include http*://journals.aps.org/*/abstract/10*
// @exclude *.pdf
// @grant   GM.xmlHttpRequest
// @grant   GM.getValue
// @grant   GM.setValue
// @run-at  document-start
// @namespace https://greasyfork.org/users/171198
// @downloadURL none
// ==/UserScript==

var tit=null; //title
var doi=null;
var pdf=null; //pdf url

var sty=''; // citation text style

if (location.href.includes('pubs.acs.org/doi/abs/'))
  pdf=location.href.replace('/abs/','/pdf/'); // Works for ACS journals
else if (location.href.includes('pubs.acs.org/doi/10.'))
  pdf=location.href.replace('/doi/','/doi/pdf/');
else if (location.href.includes('journals.aps.org/') && location.href.includes('abstract/10.'))
  pdf=location.href.replace('/abstract/','/pdf/');


var jump = window.history.length<=1 || sessionStorage.getItem(location.pathname) === null;
sessionStorage.setItem(location.pathname,'1');

if (jump && pdf !== null && location.href !== pdf) {
  window.stop();
  location.href=pdf;
} else {
  checkLoaded();
}

function checkLoaded() {
  if (document.body !== null && document.body.innerHTML.length !== 0)
    loadMeta();
  else
    setTimeout(checkLoaded,100);
}

function loadMeta() {
  var titmeta=['dc.title','citation_title'];
  var doimeta=['citation_doi','dc.identifier','dc.source'];
  var l=document.getElementsByTagName('meta');
  for(var i=0; i<l.length; ++i) {
    var n=l[i].getAttribute("name");
    if (n===null)
      continue;
  	n=n.toLowerCase();
    if (tit===null && titmeta.includes(n)) {
      tit = l[i].getAttribute("content");
      continue;
    }
    if (doi===null && doimeta.includes(n)) {
      var d = l[i].getAttribute("content");
      if (d.includes('10.')) {
        if (d.includes('doi')) {
          doi=d.slice(d.indexOf('10.'));
        } else {
          doi=d;
        }
        continue;
      }
    }
    if (pdf===null && n === 'citation_pdf_url')
      pdf = l[i].getAttribute("content");
  }
  if (jump && pdf !== null && location.href !== pdf) {
    window.stop();
    location.href=pdf;
  } else {
    if (doi===null) return;
    if (tit===null) tit='Unknown Title';
    toolbox(tit,doi,pdf);
  }
}

// newbr, newinput, newtag are util functions to create toolbox elements.
function newbr(parent) {
  parent.appendChild(document.createElement('br'));
}

function newinput(parent,type,value,onclick) {
  var i = document.createElement('input');
  i.type = type;
  i.value = value;
  if (onclick!==null)
    i.addEventListener("click", onclick, false);
  i.className = 'toolbox';
  parent.appendChild(i);
  return i;
}

function newtag(parent,tag,text) {
  var i = document.createElement(tag);
  if (text !== null)
    i.innerHTML = text;
  i.className = 'toolbox';
  parent.appendChild(i);
  return i;
}

function toolbox(tit,doi,pdf) {
  var div = document.createElement('div');
  div.style='z-index:2147483646;position:fixed;right:10px;top:50%;transform: translate(0, -50%);border:2px groove black;background:white;box-shadow:6px 6px 3px grey;';

  var sheet = document.createElement('style')
  sheet.innerHTML = '.toolbox{font-size: 10pt;font-family: sans-serif;margin:0;padding:0;margin-bottom:2px;display:initial;}input.toolbox,select.toolbox{background-image: none !important;width: auto;max-height:none}textarea.toolbox,input.toolbox[type=text]{-webkit-box-sizing: border-box;-moz-box-sizing: border-box;box-sizing: border-box;width: 11em;}input.toolbox[type=button]{padding: 2px 8px;}[tooltip]:before {position: absolute;opacity: 0;}[tooltip]:hover:before {content: attr(tooltip);opacity:1;color:black;background:white;padding:2px;border:1px groove black;white-space: nowrap;overflow: hidden;right:0;margin-top:-25pt;}'
  div.appendChild(sheet);
  
  // DOI textbox and copy button
  var txt_doi = newinput(div,'text',doi,null);
  newbr(div);
  newinput(div,'button','Copy',function(){txt_doi.select();document.execCommand("Copy");});
  newbr(div);newbr(div);
  
  // info textbox and copy button
  var info = tit+'\t'+doi;
  var txt_inf = newinput(div,'text',info,null);
  newbr(div);
  newinput(div,'button','Copy',function(){txt_inf.select();document.execCommand("Copy");});
  newbr(div);newbr(div);
  
  // bibtex button
  var txt_bib = newtag(div,'textarea',null);
  txt_bib.style.display = 'none';
  txt_bib.style.resize = 'none';
  newbr(div);
  var btn_bib = newinput(div,'button','Copy BibTeX',loadBib);
  newbr(div);
  function loadBib() {
    btn_bib.disabled = true;
    btn_bib.value = 'Loading';
    GM.xmlHttpRequest({
      method: "GET",
      url: "https://dx.doi.org/" + doi,
      headers: {
        "Accept": 'application/x-bibtex'
      },
      onload: function(response) {
        if (response.readyState == 4 && response.status == 200) {
          var bib = response.responseText;
          txt_bib.value = bib;
          txt_bib.style.display = '';
					txt_bib.select();
          document.execCommand("Copy");
          btn_bib.value = 'Copy BibTeX';
        } else {
          btn_bib.value = 'Reload BibTeX';
        }
        btn_bib.disabled = false;
      },
      onerror: function(response) {
        btn_bib.value = 'Reload BibTeX';
        btn_bib.disabled = false;
      }
    });
  }
  // Text button
  var btn_txt = newinput(div,'button','Copy Text',loadTxt);
  function loadTxt() {
    if (sty==='') {
      setstyle();
      return;
    }
    btn_txt.disabled = true;
    btn_txt.value = 'Loading';
    GM.xmlHttpRequest({
      method: "GET",
      url: "https://dx.doi.org/" + doi,
      headers: {
        "Accept": 'text/x-bibliography; style='+sty
      },
      onload: function(response) {
        if (response.readyState == 4 && response.status == 200) {
          var bib = response.responseText;
          txt_bib.value = bib;
          txt_bib.style.display = '';
					txt_bib.select();
          document.execCommand("Copy");
          btn_txt.value = 'Copy Text';
        } else {
          btn_txt.value = 'Reload Text';
        }
        btn_txt.disabled = false;
      },
      onerror: function(response) {
        btn_txt.value = 'Reload Text';
        btn_txt.disabled = false;
      }
    });
  }
  // text style link
  var stylink = newtag(div,'a','Style');
  stylink.addEventListener('click',setstyle,false);
  stylink.style.cursor = 'pointer';
  newbr(div);
  
  function setstyle() {
    var div = document.createElement('div');
    div.style='z-index:2147483647;position:fixed;left:50%;top:50%;transform:translate(-50%, -50%);border:2px groove black;background:white;padding:20px;box-shadow:10px 10px 5px grey;';

    newtag(div,'h3','Choose a Citation Style:').style.fontSize="medium";
    var sel = newtag(div,'select',null);
    sel.size = 15;
    newbr(div);newbr(div);
    newtag(div,'p','This citation style will be saved as default.');

    var btns = newtag(div,'div',null);
    btns.style.textAlign = 'center';
    // OK button
    newinput(btns,'button','OK',function() {
      sty = sel.value;
      GM.setValue('sty',sty);
      document.body.removeChild(div);
      loadTxt();
    });
    // cancel button
    newinput(btns,'button','Cancel',function(){document.body.removeChild(div);}).style.marginLeft = '1em';

    // load styles
    GM.xmlHttpRequest({
      method: "GET",
      url: "https://citation.crosscite.org/styles",
      onload: function(response) {
        if (response.readyState == 4 && response.status == 200) {
          var l = JSON.parse(response.responseText);
          for (var i=0; i<l.length; i++) {
            var x = document.createElement("option");
            x.text = l[i];
            sel.add(x);
          }
          if (sty!=='')
            sel.value = sty;
          else
            sel.selectedIndex = 0;
        } else {
          alert('Cannot load style list.');
          document.body.removeChild(div);
        }
      },
      onerror: function(response) {
        alert('Cannot load style list.');
        document.body.removeChild(div);
      }
    });

    document.body.appendChild(div);
  }
  
  // RIS link
  var rislink = newtag(div,'a','Download RIS');
  rislink.addEventListener('click',loadris);
  rislink.style.cursor = 'pointer';
  function loadris() {
    rislink.removeEventListener('click',loadris);
    GM.xmlHttpRequest({
      method: "GET",
      url: "https://dx.doi.org/" + doi,
      headers: {
        "Accept": 'application/x-research-info-systems'
      },
      onload: function(response) {
        if (response.readyState == 4 && response.status == 200) {
          var ris = response.responseText;
          var blob = new Blob([ris], {type: "octet/stream"});
          var url  = URL.createObjectURL(blob);
          rislink.href = url;
          rislink.download = doi.replace('/','@')+'.ris';
          rislink.click();
        } else {
          alert('Unable to download RIS.');
          rislink.addEventListener('click',loadris);
        }
        btn_txt.disabled = false;
      },
      onerror: function(response) {
        alert('Unable to download RIS.');
        rislink.addEventListener('click',loadris);
      }
    });
  }

  newbr(div);newbr(div);
  
  // PDF link
  if (pdf !== null) {
    var pdflink = newtag(div,'a','PDF');
    pdflink.href = pdf;
    newbr(div);newbr(div);
  }
  
  // Sci-Hub link
  var scihubURL = 'https://sci-hub.tw/';
  var scihublink = newtag(div,'a','Sci-Hub');
  if (doi !== null)
  	scihublink.href = scihubURL + doi;
  else
    scihublink.href = scihubURL + location.href;
  newbr(div);newbr(div);
  
  document.body.appendChild(div);
  
  GM.getValue('sty','').then(function(v){sty=v;stylink.setAttribute('tooltip',v==='' ? 'You have not set a reference style' : 'Current style: '+v);});
}