export function hightlight(table) {
  var isMouseDown = false;
  var startRowIndex = null;
  var startCellIndex = null;

  function selectTo(cell) {
    var row = cell.parent();
    var cellIndex = cell.index();
    var rowIndex = row.index();

    var rowStart, rowEnd, cellStart, cellEnd;

    if (rowIndex < startRowIndex) {
      rowStart = rowIndex;
      rowEnd = startRowIndex;
    } else {
      rowStart = startRowIndex;
      rowEnd = rowIndex;
    }

    if (cellIndex < startCellIndex) {
      cellStart = cellIndex;
      cellEnd = startCellIndex;
    } else {
      cellStart = startCellIndex;
      cellEnd = cellIndex;
    }

    for (var i = rowStart; i <= rowEnd; i++) {
      var rowCells = table
        .find('tr')
        .eq(i)
        .find('td');
      for (var j = cellStart; j <= cellEnd; j++) {
        rowCells.eq(j - 1).addClass('selected');
      }
    }
  }

  table
    .find('td')
    .mousedown(function(e) {
      isMouseDown = true;
      var cell = $(this);

      table.find('.selected').removeClass('selected'); // deselect everything

      if (e.shiftKey) {
        selectTo(cell);
      } else {
        cell.addClass('selected');
        startCellIndex = cell.index();
        startRowIndex = cell.parent().index();
      }

      return false; // prevent text selection
    })
    .mouseover(function() {
      if (!isMouseDown) return;
      table.find('.selected').removeClass('selected');
      selectTo($(this));
    })
    .bind('selectstart', function() {
      return false;
    });

  $(document).mouseup(function() {
    isMouseDown = false;
  });
}