function DataTableColumnHeaderUI(dataTableView, column, columnIndex, td) {
    this._dataTableView = dataTableView;
    this._column = column;
    this._columnIndex = columnIndex;
    this._td = td;
    
    this._render();
}

DataTableColumnHeaderUI.prototype._render = function() {
    var self = this;
    var td = this._td;
    
    var headerTable = document.createElement("table");
    $(headerTable).addClass("column-header-layout").attr("cellspacing", "0").attr("cellpadding", "0").attr("width", "100%").appendTo(td);
    
    var headerTableRow = headerTable.insertRow(0);
    var headerLeft = headerTableRow.insertCell(0);
    var headerRight = headerTableRow.insertCell(1);
    
    $('<span></span>').html(this._column.headerLabel).appendTo(headerLeft);
    
    $(headerRight).attr("width", "1%");
    $('<img src="/images/menu-dropdown.png" />').addClass("column-header-menu").appendTo(headerRight).click(function() {
        self._createMenuForColumnHeader(this);
    });
    
    if ("reconStats" in this._column) {
        var stats = this._column.reconStats;
        if (stats.nonBlanks > 0) {
            var newPercent = Math.ceil(100 * stats.newTopics / stats.nonBlanks);
            var matchPercent = Math.ceil(100 * stats.matchedTopics / stats.nonBlanks);
            var unreconciledPercent = Math.ceil(100 * (stats.nonBlanks - stats.matchedTopics - stats.newTopics) / stats.nonBlanks);
            
            var whole = $('<div>')
                .height("3px")
                .css("background", "#333")
                .css("position", "relative")
                .attr("title", matchPercent + "% matched, " + newPercent + "% new, " + unreconciledPercent + "% to be reconciled")
                .width("100%")
                .appendTo(td);
            
            $('<div>').height("100%").css("background", "white").css("position", "absolute")
                .width(Math.round((stats.newTopics + stats.matchedTopics) * 100 / stats.nonBlanks) + "%")
                .appendTo(whole);
                
            $('<div>').height("100%").css("background", "#6d6").css("position", "absolute")
                .width(Math.round(stats.matchedTopics * 100 / stats.nonBlanks) + "%")
                .appendTo(whole);
        }
    }
};

DataTableColumnHeaderUI.prototype._createMenuForColumnHeader = function(elmt) {
    self = this;
    MenuSystem.createAndShowStandardMenu([
        {
            label: "Edit Cells",
            submenu: [
                {
                    label: "To Titlecase",
                    click: function() { self._doTextTransform("toTitlecase(value)"); }
                },
                {
                    label: "To Uppercase",
                    click: function() { self._doTextTransform("toUppercase(value)"); }
                },
                {
                    label: "To Lowercase",
                    click: function() { self._doTextTransform("toLowercase(value)"); }
                },
                {
                    label: "Custom Transform ...",
                    click: function() { self._doTextTransformPrompt(); }
                },
                {},
                {
                    label: "Split Multi-Valued Cells ...",
                    click: function() { self._doSplitMultiValueCells(); }
                },
                {
                    label: "Join Multi-Valued Cells ...",
                    click: function() { self._doJoinMultiValueCells(); }
                }
            ]
        },
        {
            label: "Edit Column",
            submenu: [
                {
                    label: "Add Column Based on This Column ...",
                    click: function() { self._doAddColumn("value"); }
                },
                {
                    label: "Remove This Column",
                    click: function() { self._doRemoveColumn(); }
                },
            ]
        },
        {},
        {
            label: "Filter",
            tooltip: "Filter rows by this column's cell content or characteristics",
            submenu: [
                {
                    label: "Text Facet",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "list", 
                            {
                                "name" : self._column.headerLabel,
                                "columnName" : self._column.headerLabel, 
                                "expression" : "value"
                            }
                        );
                    }
                },
                {
                    label: "Custom Text Facet ...",
                    click: function() { self._doFilterByExpressionPrompt("value", "list"); }
                },
                {},
                {
                    label: "Numeric Facet",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "range", 
                            {
                                "name" : self._column.headerLabel,
                                "columnName" : self._column.headerLabel, 
                                "expression" : "value",
                                "mode" : "range",
                                "min" : 0,
                                "max" : 1
                            },
                            {
                            }
                        );
                    }
                },
                {
                    label: "Custom Numeric Facet ...",
                    click: function() { self._doFilterByExpressionPrompt("value", "range"); }
                },
                {},
                {
                    label: "Text Search",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "text", 
                            {
                                "name" : self._column.headerLabel,
                                "columnName" : self._column.headerLabel, 
                                "mode" : "text",
                                "caseSensitive" : false
                            }
                        );
                    }
                },
                {
                    label: "Regular Expression Search",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "text", 
                            {
                                "name" : self._column.headerLabel + " (regex)",
                                "columnName" : self._column.headerLabel, 
                                "mode" : "regex",
                                "caseSensitive" : true
                            }
                        );
                    }
                }
            ]
        },
        {
            label: "View",
            tooltip: "Collapse/expand columns to make viewing the data more convenient",
            submenu: [
                {
                    label: "Collapse This Column",
                    click: function() {
                        theProject.columnModel.columns[self._columnIndex].collapsed = true;
                        self._dataTableView.render();
                    }
                },
                {
                    label: "Collapse All Other Columns",
                    click: function() {
                        for (var i = 0; i < theProject.columnModel.columns.length; i++) {
                            if (i != self._columnIndex) {
                                theProject.columnModel.columns[i].collapsed = true;
                            }
                        }
                        self._dataTableView.render();
                    }
                },
                {
                    label: "Collapse All Columns To Right",
                    click: function() {
                        for (var i = self._columnIndex + 1; i < theProject.columnModel.columns.length; i++) {
                            theProject.columnModel.columns[i].collapsed = true;
                        }
                        self._dataTableView.render();
                    }
                }
            ]
        },
        {},
        {
            label: "Reconcile",
            tooltip: "Match this column's cells to topics on Freebase",
            submenu: [
                {
                    label: "Start Reconciling ...",
                    tooltip: "Reconcile text in this column with topics on Freebase",
                    click: function() {
                        self._doReconcile();
                    }
                },
                {},
                {
                    label: "Match Each Cell to Its Best Candidate",
                    tooltip: "Match each cell to its best candidate in this column for all current filtered rows",
                    click: function() {
                        self._doReconMatchBestCandidates();
                    }
                },
                {
                    label: "Create a New Topic for Each Cell",
                    tooltip: "Mark to create one new topic for each cell in this column for all current filtered rows",
                    click: function() {
                        self._doReconMarkNewTopics(false);
                    }
                },
                {
                    label: "Create One New Topic for Similar Cells",
                    tooltip: "Mark to create one new topic for each group of similar cells in this column for all current filtered rows",
                    click: function() {
                        self._doReconMarkNewTopics(true);
                    }
                },
                {
                    label: "Discard Reconciliation Judgments",
                    tooltip: "Discard reconciliaton results in this column for all current filtered rows",
                    click: function() {
                        self._doReconDiscardJudgments();
                    }
                },
                {},
                {
                    label: "Match Filtered Cells to ...",
                    tooltip: "Search for a topic to match all filtered cells to",
                    click: function() {
                        self._doSearchToMatch();
                    }
                }
            ]
        },
        {
            label: "Reconcile Filter",
            tooltip: "Match this column's cells to topics on Freebase",
            submenu: [
                {
                    label: "By Judgment",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "list", 
                            {
                                "name" : self._column.headerLabel + ": judgment",
                                "columnName" : self._column.headerLabel, 
                                "expression" : "cell.recon.judgment"
                            },
                            {
                                "scroll" : false
                            }
                        );
                    }
                },
                {},
                {
                    label: "Best Candidate's Relevance Score",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "range", 
                            {
                                "name" : self._column.headerLabel + ": best candidate's relevance score",
                                "columnName" : self._column.headerLabel, 
                                "expression" : "cell.recon.best.score",
                                "mode" : "range"
                            },
                            {
                            }
                        );
                    }
                },
                {
                    label: "Best Candidate's Type Match",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "list", 
                            {
                                "name" : self._column.headerLabel + ": best candidate's type match",
                                "columnName" : self._column.headerLabel, 
                                "expression" : "cell.recon.features.typeMatch"
                            },
                            {
                                "scroll" : false
                            }
                        );
                    }
                },
                {
                    label: "Best Candidate's Name Match",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "list", 
                            {
                                "name" : self._column.headerLabel + ": best candidate's name match",
                                "columnName" : self._column.headerLabel, 
                                "expression" : "cell.recon.features.nameMatch"
                            },
                            {
                                "scroll" : false
                            }
                        );
                    }
                },
                {},
                {
                    label: "Best Candidate's Name Edit Distance",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "range", 
                            {
                                "name" : self._column.headerLabel + ": best candidate's name edit distance",
                                "columnName" : self._column.headerLabel, 
                                "expression" : "cell.recon.features.nameLevenshtein",
                                "mode" : "range"
                            },
                            {
                            }
                        );
                    }
                },
                {
                    label: "Best Candidate's Name Word Similarity",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "range", 
                            {
                                "name" : self._column.headerLabel + ": best candidate's name word similarity",
                                "columnName" : self._column.headerLabel, 
                                "expression" : "cell.recon.features.nameWordDistance",
                                "mode" : "range"
                            },
                            {
                            }
                        );
                    }
                },
                {},
                {
                    label: "Best Candidate's Types",
                    click: function() {
                        ui.browsingEngine.addFacet(
                            "list", 
                            {
                                "name" : self._column.headerLabel + ": best candidate's types",
                                "columnName" : self._column.headerLabel, 
                                "expression" : "cell.recon.best.type"
                            }
                        );
                    }
                }
            ]
        }
    ], elmt, { width: "120px", horizontal: false });
};

DataTableColumnHeaderUI.prototype._doFilterByExpressionPrompt = function(expression, type) {
    var self = this;
    DataTableView.promptExpressionOnVisibleRows(
        this._column,
        (type == "list" ? "Custom Facet on column " : "Custom Numeric Facet on column") + this._column.headerLabel, 
        expression,
        function(expression) {
            var config = {
                "name" : self._column.headerLabel + ": " + expression,
                "columnName" : self._column.headerLabel, 
                "expression" : expression
            };
            if (type == "range") {
                config.mode = "range";
            }

            ui.browsingEngine.addFacet(type, config);
        }
    );
};

DataTableColumnHeaderUI.prototype._doTextTransform = function(expression) {
    Gridworks.postProcess(
        "do-text-transform",
        { columnName: this._column.headerLabel, expression: expression },
        null,
        { cellsChanged: true }
    );
};

DataTableColumnHeaderUI.prototype._doTextTransformPrompt = function() {
    var self = this;
    DataTableView.promptExpressionOnVisibleRows(
        this._column,
        "Custom Transform on " + this._column.headerLabel, 
        "value",
        function(expression) {
            self._doTextTransform(expression);
        }
    );
};

DataTableColumnHeaderUI.prototype._doReconcile = function() {
    var self = this;
    var dismissBusy = DialogSystem.showBusy();
    $.post(
        "/command/guess-types-of-column?" + $.param({ project: theProject.id, columnName: this._column.headerLabel }), 
        null,
        function(data) {
            if (data.code != "ok") {
                dismissBusy();
                new ReconDialog(self._column, []);
            } else {
                data.types = data.types.slice(0, 20);
                
                var ids = $.map(data.types, function(elmt) { return elmt.id; });
                if (ids.length == 0) {
                    dismissBusy();
                    new ReconDialog(self._column, []);
                } else {
                    var query = [{
                        "id|=" : ids,
                        "id" : null,
                        "/freebase/type_profile/kind" : []
                    }];
                    $.getJSON(
                        "http://api.freebase.com/api/service/mqlread?" + $.param({ "query" : JSON.stringify({ "query" : query }) }) + "&callback=?",
                        null,
                        function(o) {
                            dismissBusy();
                            
                            var kindMap = {};
                            $.each(o.result, function() {
                                var m = kindMap[this.id] = {};
                                $.each(this["/freebase/type_profile/kind"], function() {
                                    m[this] = true;
                                });
                            });
                            
                            new ReconDialog(self._column, $.map(data.types, function(type) {
                                if (type.id in kindMap) {
                                    var m = kindMap[type.id];
                                    if (!("Role" in m) && !("Annotation" in m)) {
                                        return type;
                                    }
                                }
                                return null;
                            }));
                        },
                        "jsonp"
                    );
                }
            }
        },
        "json"
    );

};

DataTableColumnHeaderUI.prototype._doReconDiscardJudgments = function() {
    Gridworks.postProcess(
        "recon-discard-judgments",
        { columnName: this._column.headerLabel },
        null,
        { cellsChanged: true, columnStatsChanged: true }
    );
};

DataTableColumnHeaderUI.prototype._doReconMatchBestCandidates = function() {
    Gridworks.postProcess(
        "recon-match-best-candidates",
        { columnName: this._column.headerLabel },
        null,
        { cellsChanged: true, columnStatsChanged: true }
    );
};

DataTableColumnHeaderUI.prototype._doReconMarkNewTopics = function(shareNewTopics) {
    Gridworks.postProcess(
        "recon-mark-new-topics",
        { columnName: this._column.headerLabel, shareNewTopics: shareNewTopics },
        null,
        { cellsChanged: true, columnStatsChanged: true }
    );
};

DataTableColumnHeaderUI.prototype._doSearchToMatch = function() {
    var self = this;
    var frame = DialogSystem.createDialog();
    frame.width("400px");
    
    var header = $('<div></div>').addClass("dialog-header").text("Search for Match").appendTo(frame);
    var body = $('<div></div>').addClass("dialog-body").appendTo(frame);
    var footer = $('<div></div>').addClass("dialog-footer").appendTo(frame);
    
    $('<p></p>').text("Search Freebase for a topic to match all filtered cells:").appendTo(body);
    
    var input = $('<input />').appendTo($('<p></p>').appendTo(body));
    
    input.suggest({}).bind("fb-select", function(e, data) {
        Gridworks.postProcess(
            "recon-match-specific-topic-to-cells",
            {
                columnName: self._column.headerLabel,
                topicID: data.id,
                topicGUID: data.guid,
                topicName: data.name,
                types: $.map(data.type, function(elmt) { return elmt.id; }).join(",")
            },
            null,
            { cellsChanged: true, columnStatsChanged: true }
        );
        
        DialogSystem.dismissUntil(level - 1);
    });
    
    $('<button></button>').text("Cancel").click(function() {
        DialogSystem.dismissUntil(level - 1);
    }).appendTo(footer);
    
    var level = DialogSystem.showDialog(frame);
    input.focus().data("suggest").textchange();
};

DataTableColumnHeaderUI.prototype._doAddColumn = function(initialExpression) {
    var self = this;
    DataTableView.promptExpressionOnVisibleRows(
        this._column,
        "Add Column Based on Column " + this._column.headerLabel, 
        initialExpression,
        function(expression) {
            var headerLabel = window.prompt("Enter header label for new column:");
            if (headerLabel != null) {
                Gridworks.postProcess(
                    "add-column", 
                    {
                        baseColumnName: self._column.headerLabel, 
                        expression: expression, 
                        headerLabel: headerLabel, 
                        columnInsertIndex: self._columnIndex + 1 
                    },
                    null,
                    { modelsChanged: true }
                );
            }
        }
    );
};

DataTableColumnHeaderUI.prototype._doRemoveColumn = function() {
    Gridworks.postProcess(
        "remove-column", 
        {
            columnName: this._column.headerLabel
        },
        null,
        { modelsChanged: true }
    );
};

DataTableColumnHeaderUI.prototype._doJoinMultiValueCells = function() {
    var separator = window.prompt("Enter separator to use between values", ", ");
    if (separator != null) {
        Gridworks.postProcess(
            "join-multi-value-cells", 
            {
                columnName: this._column.headerLabel,
                keyColumnName: theProject.columnModel.keyColumnName,
                separator: separator
            },
            null,
            { rowsChanged: true }
        );
    }
};

DataTableColumnHeaderUI.prototype._doSplitMultiValueCells = function() {
    var separator = window.prompt("What separator currently separates the values?", ",");
    if (separator != null) {
        Gridworks.postProcess(
            "split-multi-value-cells", 
            {
                columnName: this._column.headerLabel,
                keyColumnName: theProject.columnModel.keyColumnName,
                separator: separator,
                mode: "plain"
            },
            null,
            { rowsChanged: true }
        );
    }
};