var Entries = Entries || function(head, body) {
  this.head_element = head;              // DOM element for head
  this.element = body;                   // DOM element for row

  this.entries_head = document.createElement('div');
  this.entries_head.className = 'row';
  this.head_element.appendChild(this.entries_head);

  this.entries_row = document.createElement('div');
  this.entries_row.className = 'row';

  this.last = document.createElement('div');
  this.last.className = 'cell';
  this.last.id = 'last';
  this.entries_row.appendChild(this.last);

  this.element.appendChild(this.entries_row);

  this.entries = []

  this.entry_count = 0;
};
Entries.prototype.clear = function() {
  for (var i = this.entries.length-1; i >= 0; i--) {
    this.entries[i].destroy();
  }
  this.entries = [];
};

Entries.prototype.addEntry = function(index) {
  index = this.entries.length;
  var entry = new EEntry(this, index);
  this.entries_row.insertBefore(entry.element, this.last);
  this.entries[index] = entry;
};
Entries.prototype.removeEntry = function(index) {
  if (index <= 1 || index > this.entries.length) return;
  var entry = this.entries[index];
  this.entries.splice(index, 1);
  for (var i = 0; i <= this.entries.lenth; i++) {
    this.entries[i].index = i;
  }
  entry.destroy();
};

var EEntry = EEntry || function(parent, index) {
  var self = this;
  this.parent = parent;
  this.index = index;

  this.element = document.createElement('div');
  this.element.className = 'cell';
  this.input = document.createElement('input');
  if (this.index == 0) this.input.placeholder = '01-12';
  this.input.addEventListener('input', function(e) {
    var event = document.createEvent('HTMLEvents');
    event.initEvent('headinput', true, true);
    event.entry_index = self.index;
    event.entry = self;
    self.parent.element.dispatchEvent(event);
  });
  this.element.appendChild(this.input);
};
EEntry.prototype.destroy = function() {
  this.element.parentNode.removeChild(this.element);
};