function toggle_grid(whichDay) {
  var vclasses= [['in-list'], ['in-calendar', 'onlyday1'], ['in-calendar', 'onlyday2'], ['in-calendar', 'onlyday3'],
                 ['in-calendar', 'onlyday4'], ['in-calendar', 'alldays']];
  document.body.classList.remove( 'alldays', 'onlyday1', 'onlyday2', 'onlyday3', 'onlyday4', 'in-list', 'in-calendar');
  if( whichDay < 0 || whichDay > 5 ) return;
  document.body.classList.add(...vclasses[whichDay]);
  document.getElementById('qrcode').classList.toggle('limit', whichDay == 0);
}

function toggle_corr_mode() {
  if (!document.body.classList.contains('correlate')) {
    document.body.classList.remove('all-tracks', 'languages', 'classifiers');
    document.querySelectorAll('.event').forEach(elem => elem.setAttribute('corr', ''));
  }
  document.body.classList.toggle('correlate');
}

function toggle_classifier(classifier, is_track, is_range) {
  if (document.body.classList.contains('classifiers') && document.body.getAttribute('classifiers') == classifier) {
    document.body.classList.remove('classifiers');
    return;
  }
  var default_intensity = 0, prefix = '';
  if (is_range) {
    default_intensity = 5;
    prefix = '+';
  }
  is_range = is_range ? '+' : '';
  for (ev of window.top.all_events) {
    if (ev.event_classifiers) {
      var intensity = default_intensity;
      // if track selector and empty, set to 80%
      if (ev.event_classifiers[classifier])
          intensity = Math.round(ev.event_classifiers[classifier] / 10);
      $('#event_'+ev.event_id).attr('intensity', prefix + intensity);
    }
  }
  document.body.classList.add('classifiers');
  document.body.classList.remove('all-tracks', 'languages', 'correlate');
  document.body.setAttribute('classifier', classifier);
}

function set_random_event() {
    var keys = Object.keys(all_events).filter(function(event_id) {
        return $('#event_'+event_id+'.selected').length == 0 &&
        $('#event_'+event_id+'.rejected').length == 0;
    });

    if (keys.length == 0) {
        $('.narpr').toggleClass('hidden');
        return;
    }

    item = all_events[keys[ keys.length * Math.random() << 0]];
    $('.narpr_title').text(item.title || '');
    $('.narpr_track').text(item.track_name || '');
    $('.narpr_subtitle').text(item.subtitle || '');
    $('.narpr_speakers').text(item.speaker_names || '');
    $('.narpr_abstract').html(item.abstract || '');
    window.narpr_event = item.event_id;
}

function redraw_qrcode(ids) {
    if (!ids)
       ids = $('.selected').map( function() { return $(this).attr('event_id'); }).get();
    if ($('#qrcode').hasClass('hidden') && ids.length == 0 )
       return;
    var request = JSON.stringify({'talk_ids': ids});
    var size = 68;
    if($('body').hasClass('qrcode-huge')) {
      size = 400;
    }

    $('#qrcode').empty();
    $('#qrcode').qrcode({width: size, height: size, text: request});
    $('#qrcode').removeClass('hidden');
}

function redraw_calendar(myuid, ids) {
    if (!ids)
       ids = $('.selected').map( function() { return $(this).attr('event_id'); }).get();

    var now = new Date();
    var calendar = 'BEGIN:VCALENDAR\r\nVERSION:2.0\r\nPRODID:-//events.ccc.de//halfnarp//EN\r\nX-WR-TIMEZONE:Europe/Berlin\r\n';
    ids.forEach( function(id) {
      var item = all_events[id];
      if ('start_time' in item) {

          var start = new Date(item.start_time);
          calendar += 'BEGIN:VEVENT\r\n';
          calendar += 'UID:'+myuid+item.event_id+'\r\n';
          calendar += 'DTSTAMP:' + now.toISOString().replace(/-|;|:|\./g, '').replace(/...Z$/, 'Z') + '\r\n';
          calendar += 'DTSTART:' + start.toISOString().replace(/-|;|:|\./g, '').replace(/...Z$/, 'Z') + '\r\n';
          calendar += 'DURATION:PT' + item.duration + 'S\r\n';
          calendar += 'LOCATION:' + item.room_name + '\r\n';
          calendar += 'URL:http://events.ccc.de/congress/2023/Fahrplan/events/' + item.event_id + '.html\r\n';
          calendar += 'SUMMARY:' + item.title + '\r\n';
          calendar += 'DESCRIPTION:' + item.abstract.replace(/\n|\r/g, ' ') + '\r\n';
    //      console.log( 'id:' + id + ' ' + all_events[id] );
    //      console.log( all_events[id].title );
          calendar += 'END:VEVENT\r\n';
        }
    });
    calendar += 'END:VCALENDAR\r\n';
    $('.export-url-a').attr( 'href', "data:text/calendar;filename=38C3.ics," + encodeURIComponent(calendar) );
    $('.export-url').removeClass( 'hidden' );
}

function do_the_halfnarp() {
//  var halfnarpAPI      = 'talks_36C3.json';
  var halfnarpAPI     = '/-/talkpreferences';
  var halfnarpCorrs   = 'corr_array_38c3.json';
  var halfnarpPubAPI  = halfnarpAPI + '/public/';
  var isTouch = (('ontouchstart' in window) || (navigator.msMaxTouchPoints > 0));
  window.top.all_events = new Object();
  window.top.narpr_rejected = new Array();
  var myuid, mypid, newfriend = new Object();
  var allhours        = ['10', '11','12','13','14','15','16','17','18','19','20','21','22','23','00','01','02','03'];

  $('.narpr_done').click( function(ev) {
      $('.narpr').toggleClass('hidden', true);
      if (!window.narpr_alerted) {
          window.narpr_alerted = true;
          alert("Thank you for using narpr(β). Don't forget to SUBMIT!");
      }
  });

  $('.narpr').on({ 'touchstart' : function(ev) {
     // alert("foo: " + ev.originalEvent.touches[0].clientX );
     window.touch_startX = ev.originalEvent.touches[0].clientX;
     window.touch_curX = ev.originalEvent.touches[0].clientX;
     window.touch_valid = true;
     $('.narpr').css('background', '#ddd');
  } });

  $('.narpr').on({ 'touchmove' : function(ev) {
    var narp_view = $('.narpr');
     if (ev.originalEvent.touches.length > 1) {
         narp_view.css('background', 'white');
         window.touch_valid = false;
     }
    if (!window.touch_valid)
        return;
     if (ev.originalEvent.touches[0].clientX > window.touch_startX + 100)
        narp_view.css('background', 'green');
     else if (ev.originalEvent.touches[0].clientX < window.touch_startX - 100)
        narp_view.css('background', 'red');
     else
        narp_view.css('background', '#ddd');
     window.touch_curX = ev.originalEvent.touches[0].clientX;

    // console.log(narp_view[0].clientHeight + ':' + narp_view[0].scrollHeight);
    if( narp_view[0].clientHeight >= narp_view[0].scrollHeight)
        ev.preventDefault();
  } });

  $('.narpr').on({ 'touchend' : function(ev) {
    if (!window.touch_valid)
        return;
     if (window.touch_curX > window.touch_startX + 100) {
        $('#event_'+window.narpr_event).toggleClass('selected', true);
        set_random_event();
    }
    if (window.touch_curX < window.touch_startX - 100) {
        $('#event_'+window.narpr_event).toggleClass('selected', false);
        $('#event_'+window.narpr_event).toggleClass('rejected', true);
        set_random_event();
    }

    $('.narpr').css('background', 'white');
  } });

  /* Add callback for submit click */
  $('.submit').click( function() {
    var myapi;

    /* Get user's preferences and try to save them locally */
    var ids = $('.selected').map( function() {
        return $(this).attr('event_id');
      }).get();
    try {
      localStorage['38C3-halfnarp'] = ids;
      myapi = localStorage.getItem('38C3-halfnarp-api');
      if (myapi) {
        myapi = myapi.replace(/.*?:\//g, "");
        myapi = 'https:/' + myapi.replace(/.*?:\//g, "");
      }
    } catch(err) {
      alert('Storing your choices locally is forbidden.');
    }

    /* Convert preferences to JSON and post them to backend */
    var request = JSON.stringify({'talk_ids': ids});
    if( !myapi || !myapi.length ) {
      /* If we do not have resource URL, post data and get resource */
      $.ajax({
        type: 'POST',
        url: halfnarpAPI + '/',
        data: request,
        headers: {
            'Accept': 'application/json',
            'Content-Type': 'application/json'
        },
        contentType: "text/plain",
        dataType: 'json',
      }).done(function(data) {
        $('.info').text('submitted');
        $('.info').removeClass('hidden');
        try {
          localStorage['38C3-halfnarp-api'] = data['update_url'];
          localStorage['38C3-halfnarp-pid'] = mypid = data['hashed_uid'];
          localStorage['38C3-halfnarp-uid'] = myuid = data['uid'];
          window.location.hash = mypid;
        } catch(err) {}
      }, 'json' ).fail(function() {
        $('.info').text('failed :(');
        $('.info').removeClass('hidden');
      });
    } else {
      /* If we do have a resource URL, update resource */
      $.ajax({
        type: 'PUT',
        url: myapi,
        data: request,
        contentType: "application/json",
        dataType: 'json',
      }).done(function(data) {
        localStorage['38C3-halfnarp-uid'] = myuid = data['uid'];
        if( localStorage['38C3-halfnarp-pid'] ) {
            window.location.hash = localStorage['38C3-halfnarp-pid'];
        }
        $('.info').text('updated');
        $('.info').removeClass('hidden');
      }).fail(function(msg) {
        $('.info').text('failed :(');
        $('.info').removeClass('hidden');
      });
    }

    /* Tell QRCode library to update and/or display preferences for Apps */
    redraw_qrcode(ids);

    if (myuid)
        redraw_calendar(myuid, ids);
  });

  /* Add handler for type ahead search input field */
  var filter = document.getElementById('filter');
  filter.onpaste = filter.oncut = filter.onkeypress = filter.onkeydown = filter.onkeyup = function() {
    var cnt = this.value.toLowerCase();
    if( cnt.length )
      document.querySelectorAll('.event').forEach(elem => elem.style.display = (elem.textContent || elem.innerText || '').toLowerCase().includes(cnt) ? "initial" : "none" );
   else
      document.querySelectorAll('.event').forEach(elem => elem.style.display = "initial");
  };

  /* Add click handlers for event div sizers */
  document.querySelector('.vsmallboxes').onclick = function() {
    document.body.classList.remove('size-medium', 'size-large');
    document.body.classList.add('size-small');
  };

  document.querySelector('.vmediumboxes').onclick = function() {
    document.body.classList.remove('size-small', 'size-large');
    document.body.classList.add('size-medium');
  };

  document.querySelector('.vlargeboxes').onclick = function() {
    document.body.classList.remove('size-small', 'size-medium');
    document.body.classList.add('size-large');
  };

  /* Add de-highlighter on touch interface devices */
  if( isTouch ) {
    document.body.onclick = function() {
        document.querySelector('.highlighted').forEach(elem => elem.classList.remove('highlighted'));
    };
    document.querySelector('.touch-only').forEach(elem => elem.classList.remove('hidden'));
  }

  /* Add callbacks for view selector */
  document.querySelector('.vlist').onclick = function() { toggle_grid(0); };
  document.querySelector('.vday1').onclick = function() { toggle_grid(1); };
  document.querySelector('.vday2').onclick = function() { toggle_grid(2); };
  document.querySelector('.vday3').onclick = function() { toggle_grid(3); };
  document.querySelector('.vday4').onclick = function() { toggle_grid(4); };
  document.querySelector('.vdays').onclick = function() { toggle_grid(5); };

  document.querySelector('.vlang').onclick = function() { document.body.classList.toggle('languages'); };
  document.querySelector('.vtrack').onclick = function() { document.body.classList.toggle('all-tracks'); };
  document.querySelector('.vnarpr').onclick = function() { $('.narpr').toggleClass('hidden'); set_random_event(); };

  document.querySelector('.vcorr').onclick = toggle_corr_mode;

  $('.vclass').click( function() { toggle_classifier( $(this).attr('classifier'), $(this).hasClass('track'), $(this).hasClass('two_poles')); });

  /* Create hour guides */
  for (hour of allhours) {
    var elem = document.createElement('hr');
    elem.classList.add('guide', 'time_' + hour + '00');
    document.body.append(elem);
    elem = document.createElement('div');
    elem.textContent = hour + '00';
    elem.classList.add('guide', 'time_' + hour + '00');
    document.body.append(elem);
  }

  /* If we've been here before, try to get local preferences. They are authoratative */
  var selection = [], friends = { };
  try {
    selection = localStorage['38C3-halfnarp'] || [];
    friends   = localStorage['38C3-halfnarp-friends'] || { };
    myuid     = localStorage['38C3-halfnarp-uid'] || '';
    mypid     = localStorage['38C3-halfnarp-pid'] || '';
  } catch(err) {
  }

  /* Fetch list of lectures to display */
  $.getJSON( halfnarpAPI, { format: 'json' })
    .done(function( data ) {
      $.each( data, function( i, item ) {
          /* Save event to all_events hash */
          all_events[item.event_id] = item;

          /* Take copy of hidden event template div and select them, if they're in
             list of previous prereferences */
          var t = $( '#template' ).clone(true);
          var event_id = item.event_id.toString();
          t.addClass('event ' + ' lang_' + (item.language || 'en'));
          t.attr('event_id', item.event_id.toString());
          t.attr('id', 'event_' + item.event_id.toString());
          if( selection && selection.indexOf(item.event_id) != -1 ) {
            t.addClass( 'selected' );
          }

          /* Sort textual info into event div */
          t.find('.title').text(item.title);
          t.find('.speakers').text(item.speaker_names);
          t.find('.abstract').append(item.abstract);

          if (item.event_classifiers && item.event_classifiers['Foundations'] && item.event_classifiers['Foundations'] > 40.0)
                t.addClass('foundation');

          /* start_time: 2014-12-29T21:15:00+01:00" */
          var start_time = new Date(item.start_time);

          var day  = start_time.getUTCDate() - 26;
          var hour = start_time.getUTCHours() + 1;
          var mins = start_time.getUTCMinutes();

          /* After midnight: sort into yesterday */
          if( hour < 9 )
            day--;
          if( hour > 23)
              hour -= 24;

          /* Fix up room for 38C3 */
          room = (item.room_id || '').toString().replace('1','room1').replace('2','room2').replace('3','room3');

          /* Apply attributes to sort events into calendar */
          t.addClass(room + ' duration_' + item.duration + ' day_'+day + ' time_' + (hour<10?'0':'') + hour + '' + (mins<10?'0':'') + mins);

          t.click( function(event) {
            if ($('body').hasClass('correlate')) {
              mark_corr($(this).attr('event_id'));
              event.stopPropagation();
              return;
            }
            /* Transition for touch devices is highlighted => selected => highlighted ... */
            if( isTouch ) {
              if ( $( this ).hasClass('highlighted') ) {
                $( this ).toggleClass('selected');
                $('.info').addClass('hidden');
              } else {
                $('.highlighted').removeClass('highlighted');
                $( this ).addClass('highlighted');
              }
            } else {
              $( this ).toggleClass('selected');
              $('.info').addClass('hidden');
            }
            event.stopPropagation();
          });
          /* Put new event into DOM tree. Track defaults to 'Other' */
          try {
            var track = item.track_id.toString();
          } catch(e) {
            var track = "Other";
          }
          var d = $( '#' + track );
          t.addClass('track_' + track );
          if( !d.length ) {
            d = $( '#Other' );
          }
          d.append(t);
          if( newfriend.pid ) {
            newfriend.prefs.forEach( function( eventid ) {
              $( '#event_' + eventid ).addClass( 'friend' );
            });
          }
      });

      $.getJSON( halfnarpCorrs, { format: 'json' }).done(function(data) { window.top.all_votes = data; });
      toggle_grid(5);

      /* Check for a new friends public uid in location's #hash */
      var shared = window.location.hash;
      shared = shared ? shared.substr(1) : '';
      if( shared.length ) {
        if ( ( friends[shared] ) || ( shared === mypid ) ) {

        } else {
          $.getJSON( halfnarpPubAPI + shared, { format: 'json' })
            .done(function( data ) {
              newfriend.pid      = shared;
              newfriend.prefs    = data.talk_ids;
              newfriend.prefs.forEach( function( eventid ) {
                $( '#event_' + eventid ).addClass( 'friend' );
              });
            });
        }
      }
      // window.location.hash = '';

      ids = $('.selected').map( function() { return $(this).attr('event_id'); }).get();
      if (ids.length) {
           redraw_qrcode(ids);
           if (myuid)
               redraw_calendar(myuid, ids);
      }

      $('#qrcode').click( function() {
          $('body').toggleClass('qrcode-huge');
          redraw_qrcode();
      });

      /* Update friends cache */
      for( var friend in friends ) {
        $.getJSON( halfnarpPubAPI + friends.pid, { format: 'json' })
          .done(function( data ) {
            friend.prefs = data.talk_ids;
            localStorage['38C3-halfnarp-friends'] = friends;
            update_friends();
          });
      }

    });
  document.onkeypress = function(e) {
    if( document.activeElement.tagName == 'INPUT' || document.activeElement.tagName == 'TEXTAREA' )
      return;
    switch( e.keyCode ) {
      case 48: case 94: /* 0 */
        toggle_grid(5);
        break;
      case 49: case 50: case 51: case 52: /* 1-4 */
/*        toggle_grid(e.keyCode-48); */
        break;
      case 76: case 108: /* l */
        toggle_grid(0);
        break;
      case 68: case 100: /* d */
/*          toggle_grid(5); */
        break;
      case 73: case 105: /* i */
        document.body.classList.remove('all-tracks');
        document.body.classList.toggle('languages');
        break;
      case 84: case 116: /* t */
        document.body.classList.remove('languages');
        document.body.classList.toggle('all-tracks');
        break;
      case 67: case 99: /* c */
/*          toggle_corr_mode(); */
        break;
      }
  };
}

function mark_corr(eid) {
  /* If JSON with votes is not there, bail */
  if (!all_votes) return;

  /* Reset correlation markers */
  document.querySelectorAll('.event').forEach(elem => elem.setAttribute('corr', ''));

  /* Get index of reference event id */
  var eoff = all_votes.event_ids.indexOf(eid);
  if (eoff==-1) return;

  document.querySelectorAll('.event').forEach( function(dest) {
    var destid = dest.getAttribute('event_id');
    /* mark reference event at another place */
    if (destid == eid) {
      dest.setAttribute('corr', 'x');
      return;
    }

    var destoff = all_votes.event_ids.indexOf(destid);
    if (destoff==-1) {
      dest.setAttribute('corr', '0');
      return;
    }

    /* Only the smaller event-id's string has the info */
    if (eoff < destoff)
      dest.setAttribute('corr', all_votes.event_corrs[eoff].charAt(destoff-eoff-1));
    else
      dest.setAttribute('corr', all_votes.event_corrs[destoff].charAt(eoff-destoff-1));
  });
}