'use strict';

function datePicker(target) {
  if (!document.getElementById) {
    return;
  }

  if (!target || target.nodeName.toLowerCase() != 'input') {
    return;
  }

  this.target = target;
  this.oTable = document.createElement('table');
  this.oBody = document.createElement('tbody');
  this.oDates = [];
  this.oMonth = document.createElement('span');
  this.oYear = document.createElement('span');
  this.oHour = document.createElement('input');
  this.oMinute = document.createElement('input');
  this.oTable.id = 'dc_datepicker_' + target.id;
  this.oTable.className = 'date-picker';

  var cur = 1;
  var oRow, oHeading, oSpan;

  // Set title
  oRow = document.createElement('tr');

  // Month block
  oHeading = document.createElement('th');
  oHeading.colSpan = 4;
  oHeading.className = 'date-picker-month';

  var nav = document.createElement('span');
  nav.appendChild(document.createTextNode(String.fromCharCode(171)));
  nav.fn = this.changeMonth;
  nav.obj = this;
  nav.onclick = function() {
    this.fn.call(this.obj, -1);
  };
  nav.className = 'date-picker-control';
  oHeading.appendChild(nav);

  oHeading.appendChild(document.createTextNode(String.fromCharCode(160)));

  nav = document.createElement('span');
  nav.appendChild(document.createTextNode(String.fromCharCode(187)));
  nav.fn = this.changeMonth;
  nav.obj = this;
  nav.onclick = function() {
    this.fn.call(this.obj, +1);
  };
  nav.className = 'date-picker-control';
  oHeading.appendChild(nav);

  oHeading.appendChild(document.createTextNode(String.fromCharCode(160)));

  oHeading.appendChild(this.oMonth);

  oRow.appendChild(oHeading);

  // Year block
  oHeading = document.createElement('th');
  oHeading.colSpan = 3;
  oHeading.className = 'date-picker-year';

  oHeading.appendChild(this.oYear);

  oHeading.appendChild(document.createTextNode(String.fromCharCode(160)));

  nav = document.createElement('span');
  nav.appendChild(document.createTextNode(String.fromCharCode(171)));
  nav.fn = this.changeYear;
  nav.obj = this;
  nav.onclick = function() {
    this.fn.call(this.obj, -1);
  };
  nav.className = 'date-picker-control';
  oHeading.appendChild(nav);

  oHeading.appendChild(document.createTextNode(String.fromCharCode(160)));

  nav = document.createElement('span');
  nav.appendChild(document.createTextNode(String.fromCharCode(187)));
  nav.fn = this.changeYear;
  nav.obj = this;
  nav.onclick = function() {
    this.fn.call(this.obj, +1);
  };
  nav.className = 'date-picker-control';
  oHeading.appendChild(nav);

  oRow.appendChild(oHeading);

  this.oBody.appendChild(oRow);

  // Create legend
  oRow = document.createElement('tr');
  var cday;
  for (i = 0; i < this.days.length; i++) {
    cday = this.days[i].substring(0, 1).toUpperCase();
    oHeading = document.createElement('th');
    oHeading.appendChild(document.createTextNode(cday));
    oHeading.setAttribute('title', this.days[i]);
    oRow.appendChild(oHeading);
  }
  this.oBody.appendChild(oRow);

  // Create 6 rows of 7 cols for days
  for (var i = 0; i < 6; i++) {
    oRow = document.createElement('tr');

    for (var j = 0; j < 7; j++) {
      this.oDates[cur] = document.createElement('td');
      this.oDates[cur].appendChild(document.createTextNode(
        String.fromCharCode(160)));
      oRow.appendChild(this.oDates[cur]);
      cur++;
    }

    this.oBody.appendChild(oRow);
  }

  // Time controls
  oRow = document.createElement('tr');

  oHeading = document.createElement('th');
  oHeading.className = 'date-picker-control';
  oHeading.appendChild(document.createTextNode('!'));
  oHeading.setAttribute('title', this.now_msg);
  oHeading.fn = this.sendNow;
  oHeading.obj = this;
  oHeading.onclick = function() {
    this.fn.call(this.obj);
  };

  oRow.appendChild(oHeading);

  oHeading = document.createElement('th');
  oHeading.colSpan = 5;

  oSpan = document.createElement('span');
  oSpan.className = 'date-picker-control';
  oSpan.appendChild(document.createTextNode('-'));
  oSpan.fn = this.changeHour;
  oSpan.obj = this;
  oSpan.onclick = function() {
    this.fn.call(this.obj, -1);
  };
  oHeading.appendChild(oSpan);
  oHeading.appendChild(document.createTextNode(String.fromCharCode(160)));
  oSpan = document.createElement('span');
  oSpan.className = 'date-picker-control';
  oSpan.appendChild(document.createTextNode('+'));
  oSpan.fn = this.changeHour;
  oSpan.obj = this;
  oSpan.onclick = function() {
    this.fn.call(this.obj, +1);
  };
  oHeading.appendChild(oSpan);
  oHeading.appendChild(document.createTextNode(String.fromCharCode(160)));

  this.oHour.size = 2;
  oHeading.appendChild(this.oHour);

  oHeading.appendChild(document.createTextNode(' : '));

  this.oMinute.size = 2;
  oHeading.appendChild(this.oMinute);

  oHeading.appendChild(document.createTextNode(String.fromCharCode(160)));
  oSpan = document.createElement('span');
  oSpan.className = 'date-picker-control';
  oSpan.appendChild(document.createTextNode('-'));
  oSpan.fn = this.changeMinute;
  oSpan.obj = this;
  oSpan.onclick = function() {
    this.fn.call(this.obj, -1);
  };
  oHeading.appendChild(oSpan);
  oHeading.appendChild(document.createTextNode(String.fromCharCode(160)));
  oSpan = document.createElement('span');
  oSpan.className = 'date-picker-control';
  oSpan.appendChild(document.createTextNode('+'));
  oSpan.fn = this.changeMinute;
  oSpan.obj = this;
  oSpan.onclick = function() {
    this.fn.call(this.obj, +1);
  };

  oHeading.appendChild(oSpan);

  oRow.appendChild(oHeading);

  // Close control
  oHeading = document.createElement('th');
  oHeading.className = 'date-picker-control';
  oHeading.appendChild(document.createTextNode('x'));
  oHeading.setAttribute('title', this.close_msg);
  oHeading.fn = this.close;
  oHeading.obj = this;
  oHeading.onclick = function() {
    this.fn.call(this.obj);
  };

  oRow.appendChild(oHeading);

  this.oBody.appendChild(oRow);
}

datePicker.prototype = {
  year: 0,
  month: 0,
  day: 0,
  hour: 0,
  minute: 0,

  img_src: '',
  img_top: '0.2em',
  now_msg: 'now',
  close_msg: 'close',

  days: new Array('Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday',
    'Saturday', 'Sunday'),

  months: new Array('January', 'February', 'March', 'April', 'May', 'June',
    'July', 'August', 'September', 'October', 'November', 'December'),

  setDate: function() {
    if (this.numberOfDays() < this.day) {
      this.day = this.numberOfDays();
    }

    while (this.oYear.hasChildNodes()) {
      this.oYear.removeChild(this.oYear.firstChild);
    }
    this.oYear.appendChild(document.createTextNode(this.year));

    while (this.oMonth.hasChildNodes()) {
      this.oMonth.removeChild(this.oMonth.firstChild);
    }
    this.oMonth.appendChild(document.createTextNode(
      this.months[this.month - 1]));

    var firstDay = this.firstDay();
    var nbDays = this.numberOfDays();

    // Empty days
    for (var i = 1; i <= 42; i++) {
      while (this.oDates[i].hasChildNodes()) {
        this.oDates[i].removeChild(this.oDates[i].firstChild);
      }
      this.oDates[i].appendChild(document.createTextNode('-'));
      this.oDates[i].className = '';
      this.oDates[i].onclick = function() {
        return;
      };
    }

    // Insert days from the first day to the last
    for (i = 1; i <= nbDays; i++) {
      var j = firstDay + i - 1;

      while (this.oDates[j].hasChildNodes()) {
        this.oDates[j].removeChild(this.oDates[j].firstChild);
      }

      this.oDates[j].appendChild(document.createTextNode(i));
      this.oDates[j].index = i;
      this.oDates[j].fn = this.sendDate;
      this.oDates[j].obj = this;
      this.oDates[j].onclick = function() {
        this.fn.call(this.obj, this.index);
      };
      if (i == this.day) {
        this.oDates[j].className = 'date-picker-today';
      } else {
        this.oDates[j].className = 'date-picker-day';
      }
    }

    // Set time
    this.setHour(this.hour);
    this.setMinute(this.minute);
  },

  setHour: function(h) {
    if (h < 0) {
      h = 23;
    }
    if (h > 23) {
      h = 0;
    }
    if (h < 10) {
      h = '0' + h;
    }

    this.hour = h * 1;
    this.oHour.value = h;
  },

  setMinute: function(m) {
    if (m < 0) {
      m = 59;
    }
    if (m > 59) {
      m = 0;
    }
    if (m < 10) {
      m = '0' + m;
    }

    this.minute = m * 1;
    this.oMinute.value = m;
  },

  changeMonth: function(dir) {
    var m = this.month;
    m = m + dir;

    if (m > 12) {
      this.month = 1;
      this.year++;
    } else if (m < 1) {
      this.month = 12;
      this.year--;
    } else {
      this.month = m;
    }

    this.setDate();
  },

  changeYear: function(dir) {
    this.year = this.year + dir;
    this.setDate();
  },

  changeHour: function(dir) {
    this.setHour(this.hour * 1 + dir);
  },

  changeMinute: function(dir) {
    this.setMinute(this.minute * 1 + dir);
  },

  sendDate: function(d) {
    var m = this.month;
    var hour = this.oHour.value * 1;
    var minute = this.oMinute.value * 1;

    if (hour < 0 || hour > 23 || isNaN(hour)) {
      hour = 0;
    }
    if (minute < 0 || minute > 59 || isNaN(minute)) {
      minute = 0;
    }

    if (m < 10) {
      m = '0' + m;
    }
    if (d < 10) {
      d = '0' + d;
    }
    if (hour < 10) {
      hour = '0' + hour;
    }
    if (minute < 10) {
      minute = '0' + minute;
    }

    this.target.value = this.year + '-' + m + '-' + d + ' ' + hour + ':' + minute;
    this.close();
  },

  sendNow: function() {
    var dt = new Date();
    var y = dt.getFullYear();
    var m = dt.getMonth() + 1;
    var d = dt.getDate();
    var h = dt.getHours();
    var i = dt.getMinutes();

    if (m < 10) {
      m = '0' + m;
    }
    if (d < 10) {
      d = '0' + d;
    }
    if (h < 10) {
      h = '0' + h;
    }
    if (i < 10) {
      i = '0' + i;
    }

    this.target.value = y + '-' + m + '-' + d + ' ' + h + ':' + i;
    this.close();
  },

  close: function() {
    document.body.removeChild(this.oTable);
  },

  numberOfDays: function() {
    var res = 31;
    if (this.month == 4 || this.month == 6 || this.month == 9 ||
      this.month == 11) {
      res = 30;
    } else if (this.month == 2) {
      res = 28;
      if (this.year % 4 == 0 && (this.year % 100 != 0 ||
          this.year % 400 == 0)) {
        res = 29;
      }
    }

    return res;
  },

  firstDay: function() {
    var dt = new Date(this.year, this.month - 1, 1);
    var res = dt.getDay();

    if (res == 0) {
      res = 7;
    }

    return res;
  },

  show: function() {
    // Parsing target value
    var re = /(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2})/;
    var match = re.exec(this.target.value);
    if (match) {
      this.year = match[1] * 1;
      this.month = match[2] * 1;
      this.day = match[3] * 1;
      this.hour = match[4] * 1;
      this.minute = match[5] * 1;
    } else {
      var dt = new Date();
      this.year = dt.getFullYear();
      this.month = dt.getMonth() + 1;
      this.day = dt.getDate();
      this.hour = dt.getHours();
      this.minute = dt.getMinutes();
    }

    this.oTable.appendChild(this.oBody);
    this.setDate();
    this.setPosition();
    document.body.appendChild(this.oTable);
    this.oHour.focus();
  },

  setPosition: function() {
    var t_x = this.findPosX(this.target);
    var t_y = this.findPosY(this.target);

    this.oTable.style.position = 'absolute';
    this.oTable.style.zIndex = '100';
    this.oTable.style.top = t_y + 'px';
    this.oTable.style.left = t_x + 'px';
  },

  findPosX: function(obj) {
    var curleft = 0;
    if (obj.offsetParent) {
      while (1) {
        curleft += obj.offsetLeft;
        if (!obj.offsetParent) {
          break;
        }
        obj = obj.offsetParent;
      }
    } else if (obj.x) {
      curleft += obj.x;
    }
    return curleft;
  },

  findPosY: function(obj) {
    var curtop = 0;
    if (obj.offsetParent) {
      while (1) {
        curtop += obj.offsetTop;
        if (!obj.offsetParent) {
          break;
        }
        obj = obj.offsetParent;
      }
    } else if (obj.y) {
      curtop += obj.y;
    }
    return curtop;
  },

  draw: function() {
    var imgE = document.createElement('img');
    imgE.src = this.img_src;
    imgE.alt = this.img_alt;
    imgE.style.position = 'absolute';
    imgE.style.top = this.img_top;
    imgE.style.left = (this.target.clientWidth + 4) + 'px';
    imgE.obj = this;
    imgE.fn = this.show;
    imgE.onclick = function() {
      this.fn.apply(this.obj);
    };

    this.target.parentNode.style.position = 'relative';
    this.target.parentNode.insertBefore(imgE, this.target.nextSibling);
  }
};