define(["jquery"], function ($) {
  function SlickColumnPicker(columns, grid, options) {
    var $menu;
    var columnCheckboxes;

    var defaults = {
      fadeSpeed:250
    };

    function init() {
      grid.onHeaderContextMenu.subscribe(handleHeaderContextMenu);
      grid.onColumnsReordered.subscribe(updateColumnOrder);
      options = $.extend({}, defaults, options);

      $menu = $("<span class='bk-slick-columnpicker' style='display:none;position:absolute;z-index:20;' />").appendTo(document.body);

      $menu.bind("mouseleave", function (e) {
        $(this).fadeOut(options.fadeSpeed)
      });
      $menu.bind("click", updateColumn);

    }

    function destroy() {
      grid.onHeaderContextMenu.unsubscribe(handleHeaderContextMenu);
      grid.onColumnsReordered.unsubscribe(updateColumnOrder);
      $menu.remove();
    }

    function handleHeaderContextMenu(e, args) {
      e.preventDefault();
      $menu.empty();
      updateColumnOrder();
      columnCheckboxes = [];

      var $li, $input;
      for (var i = 0; i < columns.length; i++) {
        $li = $("<li />").appendTo($menu);
        $input = $("<input type='checkbox' />").data("column-id", columns[i].id);
        columnCheckboxes.push($input);

        if (grid.getColumnIndex(columns[i].id) != null) {
          $input.attr("checked", "checked");
        }

        $("<label />")
            .text(columns[i].name)
            .prepend($input)
            .appendTo($li);
      }

      $("<hr/>").appendTo($menu);
      $li = $("<li />").appendTo($menu);
      $input = $("<input type='checkbox' />").data("option", "autoresize");
      $("<label />")
          .text("Force fit columns")
          .prepend($input)
          .appendTo($li);
      if (grid.getOptions().forceFitColumns) {
        $input.attr("checked", "checked");
      }

      $li = $("<li />").appendTo($menu);
      $input = $("<input type='checkbox' />").data("option", "syncresize");
      $("<label />")
          .text("Synchronous resize")
          .prepend($input)
          .appendTo($li);
      if (grid.getOptions().syncColumnCellResize) {
        $input.attr("checked", "checked");
      }

      $menu
          .css("top", e.pageY - 10)
          .css("left", e.pageX - 10)
          .fadeIn(options.fadeSpeed);
    }

    function updateColumnOrder() {
      // Because columns can be reordered, we have to update the `columns`
      // to reflect the new order, however we can't just take `grid.getColumns()`,
      // as it does not include columns currently hidden by the picker.
      // We create a new `columns` structure by leaving currently-hidden
      // columns in their original ordinal position and interleaving the results
      // of the current column sort.
      var current = grid.getColumns().slice(0);
      var ordered = new Array(columns.length);
      for (var i = 0; i < ordered.length; i++) {
        if ( grid.getColumnIndex(columns[i].id) === undefined ) {
          // If the column doesn't return a value from getColumnIndex,
          // it is hidden. Leave it in this position.
          ordered[i] = columns[i];
        } else {
          // Otherwise, grab the next visible column.
          ordered[i] = current.shift();
        }
      }
      columns = ordered;
    }

    function updateColumn(e) {
      if ($(e.target).data("option") == "autoresize") {
        if (e.target.checked) {
          grid.setOptions({forceFitColumns:true});
          grid.autosizeColumns();
        } else {
          grid.setOptions({forceFitColumns:false});
        }
        return;
      }

      if ($(e.target).data("option") == "syncresize") {
        if (e.target.checked) {
          grid.setOptions({syncColumnCellResize:true});
        } else {
          grid.setOptions({syncColumnCellResize:false});
        }
        return;
      }

      if ($(e.target).is(":checkbox")) {
        var visibleColumns = [];
        $.each(columnCheckboxes, function (i, e) {
          if ($(this).is(":checked")) {
            visibleColumns.push(columns[i]);
          }
        });

        if (!visibleColumns.length) {
          $(e.target).attr("checked", "checked");
          return;
        }

        grid.setColumns(visibleColumns);
      }
    }

    function getAllColumns() {
      return columns;
    }

    init();

    return {
      "getAllColumns": getAllColumns,
      "destroy": destroy
    };
  }

  return SlickColumnPicker;
});
