var pdfjsLib = window['pdfjs-dist/build/pdf'];
var pdfcanvas = "the-canvas";
var cnt = 100;

function renderPage() {

  var el_title = document.getElementById('pdfprogress');


  el_title.innerHTML = 'Идет подготовка страницы ...';

  pageRendering = true;
  // Using promise to fetch the page
  pdfDoc.getPage(pageNum).then(function(page) {

  var canvas = document.getElementById('the-pdf');  
  var context = canvas.getContext('2d');
  //var viewport = page.getViewport({scale: scale});

  if (window.screen.width <= 560) {
    currscale = 1.5;  
  }
  else if (window.screen.width >= 560 && window.screen.width <= 1200) {
    currscale = 2;  
  }
  else{
    currscale = 2.5;  
  }

  var viewport = page.getViewport({scale: currscale});
 // var viewport = page.getViewport(canvas.width / page.getViewport(0.5).width)
  
 
    canvas.height = viewport.height;
    canvas.width = viewport.width;

    canvas.innerHTML = '';

    // Render PDF page into canvas context
    var renderContext = {
      canvasContext: context,
      viewport: viewport
    };
    var renderTask = page.render(renderContext);

    // Wait for rendering to finish
    renderTask.promise.then(function() {
      pageRendering = false;
      if (pageNumPending !== null) {
        // New page rendering is pending
        renderPage(pageNumPending);
        pageNumPending = null;
       
      }
        el_title.innerHTML = '';
    });
  });
  
  
 
}  



function prevclick(){
    prevurl = prevlink + '/'+ scale;
    location.href = prevurl;
    return;
}

function nextclick(){
    nexturl = nextlink + '/'+ scale;
    location.href = nexturl;
    return;
}


function pdfzoomin(){

    scale += 0.25;
    setzoom(scale);
    renderPage();


}

function pdfzoomout(){

    scale -= 0.25;
   setzoom(scale);
    renderPage();

}


function resize_plus(){
  if (window.screen.width >= 560) {
    cnt += 5;
  }
  else{
    cnt += 20;
  }
  newpdfzoom(cnt);
}


function resize_minus(){  
  if (window.screen.width >= 560) {
    cnt -= 5;
  }
  else{
    cnt -= 20;
  }
  newpdfzoom(cnt);
}

function newpdfzoom(czoom){
  
  var status = czoom+"%";
  
  document.getElementById(pdfcanvas).style.width = status;
  document.getElementById('zoomstatus_up').innerHTML = status;
  //document.getElementById('zoomstatus_down').innerHTML = status;

  setzoom('pdfscale', czoom);

}  

function getzoom( name ){

  
  var results = document.cookie.match ( '(^|;) ?' + name + '=([^;]*)(;|$)' );
 
  if ( results ){
    return parseFloat(unescape(results[2]));
  }  
  else {
    return null;
  }  

}

function setzoom( cname, cvalue, exdays = 30 ) {
    
    var d = new Date();
    d.setTime(d.getTime() + (exdays*24*60*60*1000));
    
   
    var expires = "expires="+ d.toUTCString();
    document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";

  }





function startpdfviewer(newcurr){

  var embed = false;

  pdcurr =  getzoom('pdcurr');
  
  if (pdcurr == newcurr){
    czoom = getzoom('pdfscale');
    if (czoom > 10) {
        cnt = czoom;
        newpdfzoom(czoom);
    }  
  }
  else {
     setzoom('pdcurr', newcurr);
     setzoom('pdfscale', 100);
  }

  var detect = new MobileDetect(window.navigator.userAgent);
  //var isOpera = window.opera | window.opr | ( navigator.userAgent.indexOf(' OPR/') > -1 ) | ( navigator.userAgent.indexOf(' Coast/') > -1 ) | ( navigator.userAgent.indexOf(' OPiOS/') > -1 );

  if (category == 1){
    embed = false;
  } 
  else if (category == 3){
    embed =  false; //true;
  } 

  //if(isOpera){
  //  embed = false;
  //}
  
  if (detect.phone()){
    embed = false;
  }  
  

  if (embed){    
    //document.getElementById(pdfcanvas).innerHTML = '<embed src="'+ url +'" width="100%" type="application/pdf" style="height: 100vh;">'; 
    document.getElementById(pdfcanvas).innerHTML = '<object data="'+ url +'" type="application/pdf" width="100%" height="100%" style="border: none;"><param name="toolbar" value="0"><param name="navpanes" value="0"><param name="view" value="FitH"></object>';
  }  

  else {

    var canv = document.createElement('canvas');
    canv.id = 'the-pdf';
    document.getElementById(pdfcanvas).appendChild(canv);

    pdfjsLib.getDocument(url).promise.then(function(pdfDoc_) {
      pdfDoc = pdfDoc_;
      renderPage();
    });
   
  }


      
}


function changepage(){

  var e = document.getElementById("pages");
  var currpage = e.options[e.selectedIndex].value;
  var newpage =  baseurl + currpage;

  location.href = newpage;

  return true;

}


function changeyear(){

  var e = document.getElementById("year_filter");
  var curryear = e.options[e.selectedIndex].value;

  yearurl = '/mybooks/gazeta/';

  if (curryear !== 'all')
    yearurl = yearurl + curryear + '/1';
  
  location.href = yearurl;

  return true;


}