function addMonths(date, months) {
  date.setMonth(date.getMonth() + months);
  return date;
}

class Calendar {
  constructor(model, options, date) {
    this.Options = {
      Color: '',
      LinkColor: '',
      NavShow: true,
      NavVertical: false,
      NavLocation: '',
      DateTimeShow: true,
      DateTimeFormat: 'mmm, yyyy',
      DatetimeLocation: '',
      EventClick: '',
      EventTargetWholeDay: false,
      DisabledDays: [],
      ModelChange: model
    };
    for (var key in options) {
      this.Options[key] = typeof options[key] == 'string' ? options[key].toLowerCase() : options[key];
    }

    model ? this.Model = model : this.Model = {};
    this.Today = new Date();

    this.Selected = this.Today;
    this.Today.Month = this.Today.getMonth();
    this.Today.Year = this.Today.getFullYear();
    if (date) { this.Selected = date; }
    this.Selected.Month = this.Selected.getMonth();
    this.Selected.Year = this.Selected.getFullYear();

    this.Selected.Days = new Date(this.Selected.Year, (this.Selected.Month + 1), 0).getDate();
    this.Selected.FirstDay = new Date(this.Selected.Year, (this.Selected.Month), 1).getDay();
    this.Selected.LastDay = new Date(this.Selected.Year, (this.Selected.Month + 1), 0).getDay();

    this.Prev = new Date(this.Selected.Year, (this.Selected.Month - 1), 1);
    if (this.Selected.Month == 0) { this.Prev = new Date(this.Selected.Year - 1, 1, 1); }
    this.Prev.Days = new Date(this.Prev.getFullYear(), (this.Prev.getMonth() + 1), 0).getDate();
  }
}

function createCalendar(calendar, element, adjuster) {
  if (typeof adjuster !== 'undefined') {
    var newDate = new Date(calendar.Selected.Year, calendar.Selected.Month + adjuster, 1);
    calendar = new Calendar(calendar.Model, calendar.Options, newDate);
    element.innerHTML = '';
  } else {
    for (var key in calendar.Options) {
      typeof calendar.Options[key] != 'function' && typeof calendar.Options[key] != 'object' && calendar.Options[key] ? element.className += " " + key + "-" + calendar.Options[key] : 0;
    }
  }
    var g = ["Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"];
    var months = [
    "January",
    "February",
    "March",
    "April",
    "May",
    "June",
    "July",
    "August",
    "September",
    "October",
    "November",
    "December",
  ];

  function AddSidebar() {
    var sidebar = document.createElement('div');
    sidebar.className += 'cld-sidebar';

    var monthList = document.createElement('ul');
    monthList.className += 'cld-monthList';

    for (var i = 0; i < months.length - 3; i++) {
      var x = document.createElement('li');
      x.className += 'cld-month';
      var n = i - (4 - calendar.Selected.Month);
      if (n < 0) { n += 12; }
      else if (n > 11) { n -= 12; }
      if (i == 0) {
        x.className += ' cld-rwd cld-nav';
        x.addEventListener('click', function () {
          typeof calendar.Options.ModelChange == 'function' ? calendar.Model = calendar.Options.ModelChange() : calendar.Model = calendar.Options.ModelChange;
          createCalendar(calendar, element, -1);
        });
        x.innerHTML += '<svg height="15" width="15" viewBox="0 0 100 75" fill="rgba(255,255,255,0.5)"><polyline points="0,75 100,75 50,0"></polyline></svg>';
      }
      else if (i == months.length - 4) {
        x.className += ' cld-fwd cld-nav';
        x.addEventListener('click', function () {
          typeof calendar.Options.ModelChange == 'function' ? calendar.Model = calendar.Options.ModelChange() : calendar.Model = calendar.Options.ModelChange;
          createCalendar(calendar, element, 1);
        });
        x.innerHTML += '<svg height="15" width="15" viewBox="0 0 100 75" fill="rgba(255,255,255,0.5)"><polyline points="0,0 100,0 50,75"></polyline></svg>';
      }
      else {
        if (i < 4) { x.className += ' cld-pre'; }
        else if (i > 4) { x.className += ' cld-post'; }
        else { x.className += ' cld-curr'; }

        (function () {
          var adj = (i - 4);
          x.addEventListener('click', function () {
            typeof calendar.Options.ModelChange == 'function' ? calendar.Model = calendar.Options.ModelChange() : calendar.Model = calendar.Options.ModelChange;
            createCalendar(calendar, element, adj);
          });
          x.setAttribute('style', 'opacity:' + (1 - Math.abs(adj) / 4));
          x.innerHTML += months[n].substr(0, 3);
        }());

        if (n == 0) {
          var y = document.createElement('li');
          y.className += 'cld-year';
          if (i < 5) {
            y.innerHTML += calendar.Selected.Year;
          } else {
            y.innerHTML += calendar.Selected.Year + 1;
          }
          monthList.appendChild(y);
        }
      }
      monthList.appendChild(x);
    }
    sidebar.appendChild(monthList);
    if (calendar.Options.NavLocation) {
      document.getElementById(calendar.Options.NavLocation).innerHTML = "";
      document.getElementById(calendar.Options.NavLocation).appendChild(sidebar);
    }
    else { element.appendChild(sidebar); }
  }

  var mainSection = document.createElement('div');
  mainSection.className += "cld-main";

  function AddDateTime() {
    var datetime = document.createElement('div');
    datetime.className += "cld-datetime";
    if (calendar.Options.NavShow && !calendar.Options.NavVertical) {
      var rwd = document.createElement('div');
      rwd.className += " cld-rwd cld-nav";
      rwd.addEventListener('click', function () { createCalendar(calendar, element, -1); });
      rwd.innerHTML = '<svg height="15" width="15" viewBox="0 0 75 100" fill="rgba(0,0,0,0.5)"><polyline points="0,50 75,0 75,100"></polyline></svg>';
      datetime.appendChild(rwd);
    }
    var today = document.createElement('div');
    today.className += ' today';
    today.innerHTML = months[calendar.Selected.Month] + ", " + calendar.Selected.Year;
    datetime.appendChild(today);
    if (calendar.Options.NavShow && !calendar.Options.NavVertical) {
      var fwd = document.createElement('div');
      fwd.className += " cld-fwd cld-nav";
      fwd.addEventListener('click', function () { createCalendar(calendar, element, 1); });
      fwd.innerHTML = '<svg height="15" width="15" viewBox="0 0 75 100" fill="rgba(0,0,0,0.5)"><polyline points="0,0 75,50 0,100"></polyline></svg>';
      datetime.appendChild(fwd);
    }
    if (calendar.Options.DatetimeLocation) {
      document.getElementById(calendar.Options.DatetimeLocation).innerHTML = "";
      document.getElementById(calendar.Options.DatetimeLocation).appendChild(datetime);
    }
    else { mainSection.appendChild(datetime); }
  }

  // function AddLabels() {
  //   var labels = document.createElement('ul');
  //   labels.className = 'cld-labels';
  //   var labelsList = ["P", "S", "Ç", "P", "C", "C", "P", "PZ", "S", "Ç", "P", "C", "C", "PZ", "P", "S", "Ç", "P", "C", "C", "PZ", "P", "S", "Ç", "P", "C", "C", "PZ", "P", "S", "Ç"];
  //   for (var i = 0; i < labelsList.length; i++) { 
  //     var label = document.createElement('li'); 
  //     label.className += "cld-label";
  //     label.innerHTML = labelsList[i ++]; 
  //     labels.appendChild(label); 
  //     console.log(i);
  //   }
    
  //   mainSection.appendChild(labels);
  // }

  

  function AddDays() {

    function DayNumber(n,m=0,y=0) {
      const tnum = [];
      tnum[1]= "01"; tnum[2]= "02"; tnum[3]= "03"; tnum[4]= "04"; tnum[5]= "05"; tnum[6]= "06"; tnum[7]= "07"; tnum[8]= "08"; tnum[9]= "09"; tnum[10]= "10"; 
      tnum[11]= "11"; tnum[12]= "12"; tnum[13]= "13"; tnum[14]= "14"; tnum[15]= "15"; tnum[16]= "16"; tnum[17]= "17"; tnum[18]= "18"; tnum[19]= "19"; tnum[20]= "20"; 
      tnum[21]= "21"; tnum[22]= "22"; tnum[23]= "23"; tnum[24]= "24"; tnum[25]= "25"; tnum[26]= "26"; tnum[27]= "27"; tnum[28]= "28"; tnum[29]= "29"; tnum[30]= "30";
      tnum[31]= "31";
      var number = document.createElement('p');
      var mup=m+1;
      var tar=y+"-"+(tnum[mup])+"-"+tnum[n]+"T15:00";
      var tarih=date = new Date(tar);
      // var gun =new Date(tarih);
      var gunu =tarih.getDay();
      //var gn=tarih.substr(0,2);
      number.className += "cld-number";
      number.innerHTML += "<span>"+ g[gunu] +"<br><span>" + n + "</span></span>";
      return number;
    }
    var days = document.createElement('ul');
    days.className += "cld-days";
    for (var i = 0; i < calendar.Selected.Days; i++) {
      var day = document.createElement('li');
      day.className += "cld-day currMonth";
      var d = (i + calendar.Selected.FirstDay) % 7;
      for (var q = 0; q < calendar.Options.DisabledDays.length; q++) {
        if (d == calendar.Options.DisabledDays[q]) {
          day.className += " disableDay";
        }
      }
      var number = DayNumber((i + 1),calendar.Selected.Month,calendar.Selected.Year);
      for (var n = 0; n < calendar.Model.length; n++) {
        var evDate = calendar.Model[n].Date;
        var toDate = new Date(calendar.Selected.Year, calendar.Selected.Month, (i + 1));
        if (evDate.getTime() == toDate.getTime()) {
          number.className += " eventday";
          var title = document.createElement('p');
          title.className += "cld-title";
          if (typeof calendar.Model[n].Link == 'function' || calendar.Options.EventClick) {
            var a = document.createElement('a');
            a.setAttribute('href', '#');
            a.innerHTML += calendar.Model[n].Title;
            if (calendar.Options.EventClick) {
              var z = calendar.Model[n].Link;
              if (typeof calendar.Model[n].Link != 'string') {
                a.addEventListener('click', calendar.Options.EventClick.bind.apply(calendar.Options.EventClick, [null].concat(z)));
                if (calendar.Options.EventTargetWholeDay) {
                  day.className += " clickable";
                  day.addEventListener('click', calendar.Options.EventClick.bind.apply(calendar.Options.EventClick, [null].concat(z)));
                }
              } else {
                a.addEventListener('click', calendar.Options.EventClick.bind(null, z));
                if (calendar.Options.EventTargetWholeDay) {
                  day.className += " clickable";
                  day.addEventListener('click', calendar.Options.EventClick.bind(null, z));
                }
              }
            } else {
              a.addEventListener('click', calendar.Model[n].Link);
              if (calendar.Options.EventTargetWholeDay) {
                day.className += " clickable";
                day.addEventListener('click', calendar.Model[n].Link);
              }
            }
            title.appendChild(a);
          } else {
            title.innerHTML += '<a href="' + calendar.Model[n].Link + '">' + calendar.Model[n].Title + '</a>';
          }
          number.appendChild(title);
        }
      }
      day.appendChild(number);
      if ((i + 1) == calendar.Today.getDate() && calendar.Selected.Month == calendar.Today.Month && calendar.Selected.Year == calendar.Today.Year) {
        day.className += " today";
      }
      days.appendChild(day);
    }
    var extraDays = 0;
    if (days.children.length > 31) { extraDays = 0; }
    else if (days.children.length < 29) { extraDays = 0; }

    for (var i = 0; i < (extraDays - calendar.Selected.LastDay); i++) {
      var day = document.createElement('li');
      day.className += "cld-day ";
      var d = (i + calendar.Selected.LastDay + 1) % 7;
      for (var q = 0; q < calendar.Options.DisabledDays.length; q++) {
        if (d == calendar.Options.DisabledDays[q]) {
          day.className += " disableDay";
        }
      }

      var number = DayNumber(i + 1,calendar.Selected.Month,calendar.Selected.Year);
      day.appendChild(number);

      days.appendChild(day);
    }
    mainSection.appendChild(days);
  }
  if (calendar.Options.Color) {
    mainSection.innerHTML += '<style>.cld-main{color:' + calendar.Options.Color + ';}</style>';
  }
  if (calendar.Options.LinkColor) {
    mainSection.innerHTML += '<style>.cld-title a{color:' + calendar.Options.LinkColor + ';}</style>';
  }
  element.appendChild(mainSection);

  if (calendar.Options.NavShow && calendar.Options.NavVertical) {
    AddSidebar();
  }
  if (calendar.Options.DateTimeShow) {
    AddDateTime();
  }
  // AddLabels();
  AddDays();
}

function caleandar(el, data, settings) {
  var obj = new Calendar(data, settings);
  createCalendar(obj, el);
}