/*
  Backform
  http://github.com/amiliaapp/backform

  Copyright (c) 2014 Amilia Inc.
  Written by Martin Drapeau
  Licensed under the MIT @license
 */
(function(root, factory) {

  // Set up Backform appropriately for the environment. Start with AMD.
  if (typeof define === 'function' && define.amd) {
    define(['underscore', 'jquery', 'backbone', 'backform', 'backgrid', 'codemirror', 'pgadmin.backgrid', 'codemirror.sql'],
     function(_, $, Backbone, Backform, Backgrid, CodeMirror) {
      // Export global even in AMD case in case this script is loaded with
      // others that may still expect a global Backform.
      return factory(root, _, $, Backbone, Backform, Backgrid, CodeMirror);
    });

  // Next for Node.js or CommonJS. jQuery may not be needed as a module.
  } else if (typeof exports !== 'undefined') {
    var _ = require('underscore') || root._,
      $ = root.jQuery || root.$ || root.Zepto || root.ender,
      Backbone = require('backbone') || root.Backbone,
      Backform = require('backform') || root.Backform,
      Backgrid = require('backgrid') || root.Backgrid;
      CodeMirror = require('codemirror') || root.CodeMirror;
      pgAdminBackgrid = require('pgadmin.backgrid');
    factory(root, _, $, Backbone, Backform, Backgrid, CodeMirror);

  // Finally, as a browser global.
  } else {
    factory(root, root._, (root.jQuery || root.Zepto || root.ender || root.$), root.Backbone, root.Backform, root.Backgrid, root.CodeMirror);
  }
}(this, function(root, _, $, Backbone, Backform, Backgrid, CodeMirror) {

  var pgAdmin = (window.pgAdmin = window.pgAdmin || {});

  pgAdmin.editableCell = function() {
    if (this.attributes && !_.isUndefined(this.attributes.disabled) &&
        !_.isNull(this.attributes.disabled)) {
      if(_.isFunction(this.attributes.disabled)) {
        return !(this.attributes.disabled.apply(this, arguments));
      }
      if (_.isBoolean(this.attributes.disabled)) {
        return !this.attributes.disabled;
      }
    }
  };

  // HTML markup global class names. More can be added by individual controls
  // using _.extend. Look at RadioControl as an example.
  _.extend(Backform, {
    controlLabelClassName: "control-label col-sm-4",
    controlsClassName: "pgadmin-controls col-sm-8",
    groupClassName: "pgadmin-control-group form-group col-xs-12",
    setGroupClassName: "set-group col-xs-12",
    tabClassName: "backform-tab col-xs-12",
    setGroupContentClassName: "fieldset-content col-xs-12"
    });

  var controlMapper = Backform.controlMapper = {
    'int': ['uneditable-input', 'input', 'integer'],
    'text': ['uneditable-input', 'input', 'string'],
    'numeric': ['uneditable-input', 'input', 'number'],
    'date': 'datepicker',
    'boolean': 'boolean',
    'options': ['readonly-option', 'select', Backgrid.Extension.PGSelectCell],
    'multiline': ['textarea', 'textarea', 'string'],
    'collection': ['sub-node-collection', 'sub-node-collection', 'string'],
    'uniqueColCollection': ['unique-col-collection', 'unique-col-collection', 'string'],
    'switch' : 'switch'
  };

  var getMappedControl = Backform.getMappedControl = function(type, mode) {
    if (type in Backform.controlMapper) {
      var m = Backform.controlMapper[type];

      if (!_.isArray(m)) {
        return m;
      }

      var idx = 1, len = _.size(m);

      switch (mode) {
        case 'properties':
          idx = 0;
          break;
        case 'edit':
        case 'create':
        case 'control':
          idx = 1;
          break;
        case 'cell':
          idx = 2;
          break;
        default:
          idx = 0;
          break;
      }

      return m[idx > len ? 0 : idx];
    }
    alert ("Developer: did you forget to put/implement the control type - '" + type + "' in mapper");
    return null;
  }


  // Override the Backform.Control to allow to track changes in dependencies,
  // and rerender the View element
  var BackformControlInit = Backform.Control.prototype.initialize;
  Backform.Control.prototype.initialize = function() {
    BackformControlInit.apply(this, arguments);

    // Listen to the dependent fields in the model for any change
    var deps = this.field.get('deps');
    var that = this;
    if (deps && _.isArray(deps))
      _.each(deps, function(d) {
        attrArr = d.split('.');
        name = attrArr.shift();
        that.listenTo(that.model, "change:" + name, that.render);
    });
  };
  Backform.Control.prototype.template = _.template([
    '<label class="<%=Backform.controlLabelClassName%>"><%=label%></label>',
    '<div class="<%=Backform.controlsClassName%>">',
    '  <span class="<%=Backform.controlClassName%> uneditable-input" <%=disabled ? "disabled" : ""%>>',
    '    <%=value%>',
    '  </span>',
    '</div>'
  ].join("\n"));
  Backform.Control.prototype.clearInvalid = function() {
    this.$el.removeClass(Backform.errorClassName);
    this.$el.find(".pgadmin-control-error-message").remove();
    return this;
  };
  Backform.Control.prototype.updateInvalid = function() {
    var self = this;
    var errorModel = this.model.errorModel;
    if (!(errorModel instanceof Backbone.Model)) return this;

    this.clearInvalid();

    this.$el.find(':input').not('button').each(function(ix, el) {
      var attrArr = $(el).attr('name').split('.'),
          name = attrArr.shift(),
          path = attrArr.join('.'),
          error = self.keyPathAccessor(errorModel.toJSON(), $(el).attr('name'));

      if (_.isEmpty(error)) return;

      self.$el.addClass(Backform.errorClassName).append(
        $("<div></div>").addClass('pgadmin-control-error-message col-xs-12 help-block').text(error)
      );
    });
  };

  /*
   * Overriding the render function of the select control to allow us to use
   * options as function, which should return array in the format of
   * (label, value) pair.
   */
  Backform.SelectControl.prototype.render = function() {
    var field = _.defaults(this.field.toJSON(), this.defaults),
      attributes = this.model.toJSON(),
      attrArr = field.name.split('.'),
      name = attrArr.shift(),
      path = attrArr.join('.'),
      rawValue = this.keyPathAccessor(attributes[name], path),
      data = _.extend(field, {
        rawValue: rawValue,
        value: this.formatter.fromRaw(rawValue, this.model),
        attributes: attributes,
        formatter: this.formatter
      }),
      evalF = function(f, m) {
        return (_.isFunction(f) ? !!f(m) : !!f);
      };

    // Evaluate the disabled, visible, and required option
    _.extend(data, {
      disabled: evalF(data.disabled, this.model),
      visible:  evalF(data.visible, this.model),
      required: evalF(data.required, this.model)
    });
    // Evaluation the options
    if (_.isFunction(data.options)) {
      try {
        data.options = data.options.apply(this)
      } catch(e) {
        // Do nothing
        data = []
        this.model.trigger('pgadmin-view:transform:error', m, self.field, e);
      }
    }

    // Clean up first
    this.$el.removeClass(Backform.hiddenClassname);

    if (!data.visible)
      this.$el.addClass(Backform.hiddenClassname);

    this.$el.html(this.template(data)).addClass(field.name);
    this.updateInvalid();

    return this;
  };

  var ReadonlyOptionControl = Backform.ReadonlyOptionControl = Backform.SelectControl.extend({
    template: _.template([
      '<label class="<%=Backform.controlLabelClassName%>"><%=label%></label>',
      '<div class="<%=Backform.controlsClassName%>">',
      '<% for (var i=0; i < options.length; i++) { %>',
      ' <% var option = options[i]; %>',
      ' <% if (option.value === rawValue) { %>',
      ' <span class="<%=Backform.controlClassName%> uneditable-input" disabled><%-option.label%></span>',
      ' <% } %>',
      '<% } %>',
      '</div>'
    ].join("\n")),
    events: {},
    getValueFromDOM: function() {
      return this.formatter.toRaw(this.$el.find("span").text(), this.model);
    }
  });

  // Requires the Bootstrap Switch to work.
  var SwitchControl = Backform.SwitchControl = Backform.InputControl.extend({
    defaults: {
      label: "",
      options: {
        onText: 'True',
        offText: 'False',
        onColor: 'success',
        offColor: 'default',
        size: 'small'
      },
      extraClasses: []
    },
    template: _.template([
      '<label class="<%=Backform.controlLabelClassName%>"><%=label%></label>',
      '<div class="<%=Backform.controlsClassName%>">',
      '  <div class="checkbox">',
      '    <label>',
      '      <input type="checkbox" class="<%=extraClasses.join(\' \')%>" name="<%=name%>" <%=value ? "checked=\'checked\'" : ""%> <%=disabled ? "disabled" : ""%> <%=required ? "required" : ""%> />',
      '    </label>',
      '  </div>',
      '</div>'
    ].join("\n")),
    getValueFromDOM: function() {
      return this.formatter.toRaw(
          this.$input.prop('checked'),
          this.model
          );
    },
    events: {'switchChange.bootstrapSwitch': 'onChange'},
    render: function() {
      var field = _.defaults(this.field.toJSON(), this.defaults, {options: $.fn.bootstrapSwitch.defaults}),
          attributes = this.model.toJSON(),
          attrArr = field.name.split('.'),
          name = attrArr.shift(),
          path = attrArr.join('.'),
          rawValue = this.keyPathAccessor(attributes[name], path);

      Backform.InputControl.prototype.render.apply(this, arguments);
      this.$input = this.$el.find("input[type=checkbox]").first();

      //Check & set additional properties
      this.$input.bootstrapSwitch(
          _.extend(field.options, {'state': rawValue})
          );

      return this;
    }
  });

  // Backform Dialog view (in bootstrap tabbular form)
  // A collection of field models.
  var Dialog = Backform.Dialog = Backform.Form.extend({
    /* Array of objects having attributes [label, fields] */
    schema: undefined,
    tagName: "form",
    className: function() {
      return 'col-sm-12 col-md-12 col-lg-12 col-xs-12';
    },
    tabPanelClassName: function() {
      return Backform.tabClassName;
    },
    initialize: function(opts) {
      var s = opts.schema;
      if (s && _.isArray(s)) {
        this.schema = _.each(s, function(o) {
          if (o.fields && !(o.fields instanceof Backbone.Collection))
            o.fields = new Backform.Fields(o.fields);
          o.cId = o.cId || _.uniqueId('pgC_');
          o.hId = o.hId || _.uniqueId('pgH_');
          o.disabled = o.disabled || false;
        });
        if (opts.tabPanelClassName && _.isFunction(opts.tabPanelClassName)) {
          this.tabPanelClassName = opts.tabPanelClassName;
        }
      }
      this.model.errorModel = opts.errorModel || this.model.errorModel || new Backbone.Model();
      this.controls = [];
    },
    template: {
      'header': _.template([
        '<li role="presentation" <%=disabled ? "disabled" : ""%>>',
        ' <a data-toggle="tab" data-tab-index="<%=tabIndex%>" href="#<%=cId%>"',
        '  id="<%=hId%>" aria-controls="<%=cId%>">',
        '<%=label%></a></li>'].join(" ")),
      'panel': _.template(
        '<div role="tabpanel" class="tab-pane col-sm-12 col-md-12 col-lg-12 col-xs-12 fade" id="<%=cId%>" aria-labelledby="<%=hId%>"></div>'
      )},
    render: function() {
      this.cleanup();

      var c = this.$el
        .children().first().children('.active')
        .first().attr('id'),
        m = this.model,
        controls = this.controls,
        tmpls = this.template,
        self = this,
        idx=1;

      this.$el
          .empty()
          .attr('role', 'tabpanel')
          .attr('class', this.tabPanelClassName());
      m.panelEl = this.$el;

      var tabHead = $('<ul class="nav nav-tabs" role="tablist"></ul>')
        .appendTo(this.$el);
      var tabContent = $('<ul class="tab-content col-sm-12 col-md-12 col-lg-12 col-xs-12"></ul>')
        .appendTo(this.$el);

      _.each(this.schema, function(o) {
        var el = $((tmpls['panel'])(_.extend(o, {'tabIndex': idx})))
              .appendTo(tabContent)
              .removeClass('collapse').addClass('collapse'),
            h = $((tmpls['header'])(o)).appendTo(tabHead);

        o.fields.each(function(f) {
          var cntr = new (f.get("control")) ({
            field: f,
            model: m,
            dialog: self,
            tabIndex: idx
          });
          el.append(cntr.render().$el);
          controls.push(cntr);
        });
        idx++;
        tabHead.find('a[data-toggle="tab"]').off(
          'shown.bs.tab'
        ).off('hidden.bs.tab').on(
          'hidden.bs.tab', function() {
            self.hidden_tab = $(this).data('tabIndex');
            }).on('shown.bs.tab', function() {
              var that = this;
              self.shown_tab = $(that).data('tabIndex');
              m.trigger('pg-property-tab-changed', {
                'model': m, 'shown': self.shown_tab, 'hidden': self.hidden_tab,
                'tab': that
              });
            });
      });

      var makeActive = tabHead.find('[id="' + c + '"]').first();
      if (makeActive.length == 1) {
        makeActive.parent().addClass('active');
        tabContent.find('#' + makeActive.attr("aria-controls"))
          .addClass('in active');
      } else {
        tabHead.find('[role="presentation"]').first().addClass('active');
        tabContent.find('[role="tabpanel"]').first().addClass('in active');
      }

      return this;
    }
  });

  var Fieldset = Backform.Fieldset = Backform.Dialog.extend({
    template: {
      'header': _.template([
        '<fieldset class="<%=Backform.setGroupClassName%>"<%=disabled ? "disabled" : ""%>>',
        '  <legend class="badge" data-toggle="collapse" data-target="#<%=cId%>"><span class="caret"></span> <%=label%></legend>',
        '  ',
        '</fieldset>'
      ].join("\n")),
      'content': _.template(
        '  <div id="<%= cId %>" class="<%=Backform.setGroupContentClassName%> collapse in"></div>'
    )},
    render: function() {
      this.cleanup();

      var m = this.model,
          $el = this.$el,
          tmpl = this.template,
          controls = this.controls;

      this.$el.empty();

      _.each(this.schema, function(o) {
        if (!o.fields)
          return;

        var h = $((tmpl['header'])(o)).appendTo($el),
          el = $((tmpl['content'])(o))
              .appendTo(h);

        o.fields.each(function(f) {
          var cntr = new (f.get("control")) ({
            field: f,
            model: m
          });
          el.append(cntr.render().$el);
          controls.push(cntr);
        });
      });

      return this;
    },
    getValueFromDOM: function() {
      return "";
    },
    events: {}
  });

  var generateGridColumnsFromModel = Backform.generateGridColumnsFromModel =
    function(node_info, m, type, cols) {
      var groups = Backform.generateViewSchema(node_info, m, type),
      schema = [],
      columns = [],
      func,
      idx = 0;

      // Create another array if cols is of type object & store its keys in that array,
      // If cols is object then chances that we have custom width class attached with in.
      if (_.isNull(cols) || _.isUndefined(cols)) {
        func = function(f) {
          f.cell_priority = idx;
          idx = idx + 1;

          // We can also provide custom header cell class in schema itself,
          // But we will give priority to extraClass attached in cols
          // If headerCell property is already set by cols then skip extraClass property from schema
          if (!(f.headerCell) && f.cellHeaderClasses) {
            f.headerCell = Backgrid.Extension.CustomHeaderCell;
          }
        };
      } else if (_.isArray(cols)) {
        func = function(f) {
          f.cell_priority = _.indexOf(cols, f.name);

          // We can also provide custom header cell class in schema itself,
          // But we will give priority to extraClass attached in cols
          // If headerCell property is already set by cols then skip extraClass property from schema
          if ((!f.headerCell) && f.cellHeaderClasses) {
            f.headerCell = Backgrid.Extension.CustomHeaderCell;
          }
        };
      } else if(_.isObject(cols)) {
        var tblCols = Object.keys(cols);
        func = function(f) {
          var val = (f.name in cols) && cols[f.name];

          if (_.isNull(val) || _.isUndefined(val)) {
            f.cell_priority = -1;
            return;
          }
          if (_.isObject(val)) {
            if ('index' in val) {
              f.cell_priority = val['index'];
              idx = (idx > val['index']) ? idx + 1 : val['index'];
            } else {
              var i = _.indexOf(tblCols, f.name);
              f.cell_priority = idx = ((i > idx) ? i : idx);
              idx = idx + 1;
            }

            // We can also provide custom header cell class in schema itself,
            // But we will give priority to extraClass attached in cols
            // If headerCell property is already set by cols then skip extraClass property from schema
            if (!f.headerCell) {
              if (f.cellHeaderClasses) {
                f.headerCell = Backgrid.Extension.CustomHeaderCell;
              }
              if ('class' in val && _.isString(val['class'])) {
                f.headerCell = Backgrid.Extension.CustomHeaderCell;
                f.cellHeaderClasses = (f.cellHeaderClasses || '') + ' ' + val['class'];
              }
            }
          }
          if (_.isString(val)) {
            var i = _.indexOf(tblCols, f.name);

            f.cell_priority = idx = ((i > idx) ? i : idx);
            idx = idx + 1;

            if (!f.headerCell) {
              f.headerCell = Backgrid.Extension.CustomHeaderCell;
            }
            f.cellHeaderClasses = (f.cellHeaderClasses || '') + ' ' + val;
          }
        };
      }

      // Prepare columns for backgrid
      _.each(groups, function(fields, key) {
        _.each(fields, function(f) {
          if (!f.control && !f.cell) {
            return;
          }
          // Check custom property in cols & if it is present then attach it to current cell
          func(f);
          if (f.cell_priority != -1) {
            columns.push(f);
          }
        });
        schema.push({label: key, fields: fields});
      });
      return {
        'columns': _.sortBy(columns, function(c) {
          return c.cell_priority;
        }),
        'schema': schema
      };
    };

  var UniqueColCollectionControl = Backform.UniqueColCollectionControl = Backform.Control.extend({
    initialize: function() {
        Backform.Control.prototype.initialize.apply(this, arguments);

        var uniqueCol = this.field.get('uniqueCol') || [],
            m = this.field.get('model'),
            schema = m.prototype.schema || m.__super__.schema,
            columns = [];

        _.each(schema, function(s) {
          columns.push(s.id);
        });

        // Check if unique columns provided are also in model attributes.
        if (uniqueCol.length > _.intersection(columns, uniqueCol).length){
            errorMsg = "Developer: Unique column/s [ "+_.difference(uniqueCol, columns)+" ] not found in collection model [ " + columns +" ]."
            alert (errorMsg);
        }

        var collection = this.model.get(this.field.get('name')),
            self = this;
        if (!collection) {
          collection = new (pgAdmin.Browser.Node.Collection)(null, {
            model: self.field.get('model'),
            silent: true,
            handler: self.model.handler || self.model
          });
          self.model.set(self.field.get('name'), collection, {silent: true});
        }
        self.listenTo(collection, "add", self.collectionChanged);
        self.listenTo(collection, "change", self.collectionChanged);
    },
    collectionChanged: function(newModel, coll, op) {
        var uniqueCol = this.field.get('uniqueCol') || [],
            uniqueChangedAttr = [],
            changedAttr = newModel.changedAttributes();
        // Check if changed model attributes are also in unique columns. And then only check for uniqueness.
        if (changedAttr) {
            _.each(uniqueCol, function(col) {
                if ( _.has(changedAttr,col))
                {
                   uniqueChangedAttr.push(col);
                }
            });
            if(uniqueChangedAttr.length == 0) {
                return;
            }
        } else {
            return;
        }

        var collection = this.model.get(this.field.get('name'));
        this.stopListening(collection, "change", this.collectionChanged);
        // Check if changed attribute's value of new/updated model also exist for another model in collection.
        // If duplicate value exists then set the attribute's value of new/updated model to it's previous values.
        collection.each(function(model) {
            if (newModel != model) {
                var duplicateAttrValues = []
                _.each(uniqueCol, function(attr) {
                    attrValue = newModel.get(attr);
                    if (!_.isUndefined(attrValue) && attrValue == model.get(attr)) {
                        duplicateAttrValues.push(attrValue)
                    }
                });
                if (duplicateAttrValues.length == uniqueCol.length){
                     newModel.set(uniqueChangedAttr[0], newModel.previous(uniqueChangedAttr[0]), {silent: true});
                     // TODO- Need to add notification in status bar for unique column.
                }
            }
        });
        this.listenTo(collection, "change", this.collectionChanged);
    },
    render: function() {
      var field = _.defaults(this.field.toJSON(), this.defaults),
          attributes = this.model.toJSON(),
          attrArr = field.name.split('.'),
          name = attrArr.shift(),
          path = attrArr.join('.'),
          rawValue = this.keyPathAccessor(attributes[name], path),
          data = _.extend(field, {
            rawValue: rawValue,
            value: this.formatter.fromRaw(rawValue, this.model),
            attributes: attributes,
            formatter: this.formatter
           }),
          evalF = function(f, m) {
            return (_.isFunction(f) ? !!f(m) : !!f);
          };

      // Evaluate the disabled, visible, required, canAdd, & canDelete option
      _.extend(data, {
        disabled: evalF(data.disabled, this.model),
        visible:  evalF(data.visible, this.model),
        required: evalF(data.required, this.model),
        canAdd: evalF(data.canAdd, this.model),
        canDelete: evalF(data.canDelete, this.model)
      });
      // Show Backgrid Control
      grid = (data.subnode == undefined) ? "" : this.showGridControl(data);

      this.$el.html(grid).addClass(field.name);
      this.updateInvalid();

      return this;
    },
    showGridControl: function(data) {
      var gridHeader = ["<div class='subnode-header'>",
          "  <label class='control-label col-sm-4'>" + data.label + "</label>" ,
          "  <button class='btn-sm btn-default add'>Add</buttton>",
          "</div>"].join("\n"),
        gridBody = $("<div class='pgadmin-control-group backgrid form-group col-xs-12 object subnode'></div>").append(gridHeader);

      var subnode = data.subnode.schema ? data.subnode : data.subnode.prototype,
          gridSchema = Backform.generateGridColumnsFromModel(
            data.node_info, subnode, this.field.get('mode'), data.columns
            ),
          self = this;

      // Set visibility of Add button
      if (data.disabled || data.canAdd == false) {
        $(gridBody).find("button.add").remove();
      }

      // Insert Delete Cell into Grid
      if (data.disabled == false && data.canDelete) {
          gridSchema.columns.unshift({
            name: "pg-backform-delete", label: "",
            cell: Backgrid.Extension.DeleteCell,
            editable: false, cell_priority: -1
          });
      }

      var collection = this.model.get(data.name);
      // Initialize a new Grid instance
      var grid = new Backgrid.Grid({
          columns: gridSchema.columns,
          collection: collection,
          className: "backgrid table-bordered"
      });

      // Render subNode grid
      subNodeGrid = grid.render().$el;

      // Combine Edit and Delete Cell
      if (data.canDelete && data.canEdit) {
        $(subNodeGrid).find("th.pg-backform-delete").remove();
      }

      $dialog =  gridBody.append(subNodeGrid);

      // Add button callback
      if (!(data.disabled || data.canAdd == false)) {
        $dialog.find('button.add').first().click(function(e) {
            e.preventDefault();
            var allowMultipleEmptyRows = !!self.field.get('allowMultipleEmptyRows');

            // If allowMultipleEmptyRows is not set or is false then don't allow second new empty row.
            // There should be only one empty row.
            if (!allowMultipleEmptyRows && collection){
                var isEmpty = false;
                collection.each(function(model){
                    var modelValues = [];
                    _.each(model.attributes, function(val, key){
                        modelValues.push(val);
                    })
                    if(!_.some(modelValues, _.identity)){
                        isEmpty = true;
                    }
                });
                if(isEmpty){
                    return false;
                }
            }

            $(grid.body.$el.find($("tr.new"))).removeClass("new")
            var m = new (data.model)(null, {silent: true});
            collection.add(m);

            var idx = collection.indexOf(m);
            newRow = grid.body.rows[idx].$el;
            newRow.addClass("new");
            return false;
        });
      }

      return $dialog;
    }

  });

  var SubNodeCollectionControl =  Backform.SubNodeCollectionControl = Backform.Control.extend({
    render: function() {
      var field = _.defaults(this.field.toJSON(), this.defaults),
          attributes = this.model.toJSON(),
          attrArr = field.name.split('.'),
          name = attrArr.shift(),
          path = attrArr.join('.'),
          rawValue = this.keyPathAccessor(attributes[name], path),
          data = _.extend(field, {
            rawValue: rawValue,
            value: this.formatter.fromRaw(rawValue, this.model),
            attributes: attributes,
            formatter: this.formatter
           }),
          evalF = function(f, m) {
            return (_.isFunction(f) ? !!f(m) : !!f);
          };

      // Evaluate the disabled, visible, required, canAdd, cannEdit & canDelete option
      _.extend(data, {
        disabled: evalF(data.disabled, this.model),
        visible:  evalF(data.visible, this.model),
        required: evalF(data.required, this.model),
        canAdd: evalF(data.canAdd, this.model),
        canEdit: evalF(data.canEdit, this.model),
        canDelete: evalF(data.canDelete, this.model)
      });
      // Show Backgrid Control
      grid = (data.subnode == undefined) ? "" : this.showGridControl(data);

      this.$el.html(grid).addClass(field.name);
      this.updateInvalid();

      return this;
    },
    updateInvalid: function() {
      var self = this;
      var errorModel = this.model.errorModel;
      if (!(errorModel instanceof Backbone.Model)) return this;

      this.clearInvalid();

      var attrArr = self.field.get('name').split('.'),
        name = attrArr.shift(),
        path = attrArr.join('.'),
        error = self.keyPathAccessor(errorModel.toJSON(), path);

      if (_.isEmpty(error)) return;

      self.$el.addClass(Backform.errorClassName).append(
        $("<div></div>").addClass('pgadmin-control-error-message col-xs-12 help-block').text(error)
        );
    },
    showGridControl: function(data) {
      var gridHeader = ["<div class='subnode-header'>",
          "  <label class='control-label col-sm-4'>" + data.label + "</label>" ,
          "  <button class='btn-sm btn-default add'>Add</buttton>",
          "</div>"].join("\n");
        gridBody = $("<div class='pgadmin-control-group backgrid form-group col-xs-12 object subnode'></div>").append(gridHeader);

      var subnode = data.subnode.schema ? data.subnode : data.subnode.prototype,
          gridSchema = Backform.generateGridColumnsFromModel(
            data.node_info, subnode, this.field.get('mode'), data.columns
            ), self = this,
          pgBrowser = window.pgAdmin.Browser;

      // Set visibility of Add button
      if (data.disabled || data.canAdd == false) {
        $(gridBody).find("button.add").remove();
      }

      // Insert Delete Cell into Grid
      if (data.disabled == false && data.canDelete) {
          gridSchema.columns.unshift({
            name: "pg-backform-delete", label: "",
            cell: Backgrid.Extension.DeleteCell,
            editable: false, cell_priority: -1
          });
      }

      // Insert Edit Cell into Grid
      if (data.disabled == false && data.canEdit) {
          var editCell = Backgrid.Extension.ObjectCell.extend({
            schema: gridSchema.schema
          });

          gridSchema.columns.unshift({
            name: "pg-backform-edit", label: "", cell : editCell,
            cell_priority: -2
          });
      }

      var collection = self.model.get(data.name);

      if (!collection) {
        collection = new (pgBrowser.Node.Collection)(null, {
          handler: self.model.handler || self,
          model: data.model,
          silent: true
        });
        self.model.set(data.name, collection, {silent: true});
      }

      // Initialize a new Grid instance
      var grid = new Backgrid.Grid({
          columns: gridSchema.columns,
          collection: collection,
          className: "backgrid table-bordered"
      });

      // Render subNode grid
      subNodeGrid = grid.render().$el;

      // Combine Edit and Delete Cell
      if (data.canDelete && data.canEdit) {
        $(subNodeGrid).find("th.pg-backform-delete").remove();
        $(subNodeGrid).find("th.pg-backform-edit").attr("colspan", "2");
      }

      $dialog =  gridBody.append(subNodeGrid);

      // Add button callback
      $dialog.find('button.add').click(function(e) {
        e.preventDefault();
        grid.insertRow({});
        newRow = $(grid.body.rows[collection.length - 1].$el);
        newRow.attr("class", "new").click(function(e) {
          $(this).attr("class", "");
        });
        return false;
      });

      return $dialog;
    }
  });

  /*
   * SQL Tab Control for showing the modified SQL for the node with the
   * property 'hasSQL' is set to true.
   *
   * When the user clicks on the SQL tab, we will send the modified data to the
   * server and fetch the SQL for it.
   */
  var SqlTabControl = Backform.SqlTabControl = Backform.Control.extend({
    defaults: {
      label: "",
      controlsClassName: "pgadmin-controls col-sm-12",
      extraClasses: [],
      helpMessage: null
    },
    template: _.template([
      '<div class="<%=controlsClassName%>">',
      '  <textarea class="<%=Backform.controlClassName%> <%=extraClasses.join(\' \')%>" name="<%=name%>" placeholder="<%-placeholder%>" <%=disabled ? "disabled" : ""%> <%=required ? "required" : ""%>><%-value%></textarea>',
      '  <% if (helpMessage && helpMessage.length) { %>',
      '    <span class="<%=Backform.helpMessageClassName%>"><%=helpMessage%></span>',
      '  <% } %>',
      '</div>'
    ].join("\n")),
    /*
     * Initialize the SQL Tab control properly
     */
    initialize: function(o) {
      Backform.Control.prototype.initialize.apply(this, arguments);

      // Save the required information for using it later.
      this.dialog = o.dialog;
      this.tabIndex = o.tabIndex;

      /*
       * We will listen to the tab change event to check, if the SQL tab has
       * been clicked or, not.
       */
      this.model.on('pg-property-tab-changed', this.onTabChange, this);
    },
    getValueFromDOM: function() {
        return this.formatter.toRaw(this.$el.find("textarea").val(), this.model);
    },
    render: function() {
      // Use the Backform Control's render function
      Backform.Control.prototype.render.apply(this, arguments);

      var sqlTab = CodeMirror.fromTextArea(
        (this.$el.find("textarea")[0]), {
        lineNumbers: true,
        mode: "text/x-sql",
        readOnly: true
      });
      this.sqlTab = sqlTab;
      return this;
    },
    onTabChange: function() {

      // Fetch the information only if the SQL tab is visible at the moment.
      if (this.dialog && this.dialog.shown_tab == this.tabIndex) {

        // We will send request to sever only if something is changed in model
        if(_.size(this.model.sessAttrs)) {

          var self = this,
            node = self.field.get('schema_node'),
            msql_url = node.generate_url.apply(
                node, [
                  null, 'msql', this.field.get('node_data'), true,
                  this.field.get('node_info')
                ]);


          // Fetching the modified SQL
          self.model.trigger('pgadmin-view:msql:fetching', self.method, node);

          $.ajax({
            url: msql_url,
            type: 'GET',
            cache: false,
            data: self.model.toJSON(true)
          }).done(function(res) {
            self.sqlTab.clearHistory();
            self.sqlTab.setValue(res.data);
          }).fail(function() {
            self.model.trigger('pgadmin-view:msql:error', self.method, node, arguments);
          }).always(function() {
            self.model.trigger('pgadmin-view:msql:fetched', self.method, node, arguments);
          });
        } else {
          this.sqlTab.clearHistory();
          this.sqlTab.setValue(window.pgAdmin.Browser.messages.SQL_NO_CHANGE);
        }
      }
    },
    remove: function() {
      this.model.off('pg-property-tab-changed', this.onTabChange, this);
      Backform.Control.__super__.remove.apply(this, arguments);
    }
});

  ///////
  // Generate a schema (as group members) based on the model's schema
  //
  // It will be used by the grid, properties, and dialog view generation
  // functions.
  var generateViewSchema = Backform.generateViewSchema = function(node_info, Model, mode, node, treeData) {
    var proto = (Model && Model.prototype) || Model,
        schema = (proto && proto.schema),
        groups, pgBrowser = window.pgAdmin.Browser;

    // 'schema' has the information about how to generate the form.
    if (schema && _.isArray(schema)) {
      var evalASFunc = evalASFunc = function(prop) {
        return ((prop && proto[prop] &&
              typeof proto[prop] == "function") ? proto[prop] : prop);
      };
      groups = {},
      server_info = node_info && ('server' in node_info) &&
        pgBrowser.serverInfo && pgBrowser.serverInfo[node_info.server.id];

      _.each(schema, function(s) {
        // Do we understand - what control, we're creating
        // here?
        if (!s.mode || (s && s.mode && _.isObject(s.mode) &&
          _.indexOf(s.mode, mode) != -1)) {
          // Each field is kept in specified group, or in
          // 'General' category.
          var group = s.group || pgBrowser.messages.general_cateogty,
              control = s.control || Backform.getMappedControl(s.type, mode),
              cell =  s.cell || Backform.getMappedControl(s.type, 'cell');

          if (control == null) {
            return;
          }

          // Generate the empty group list (if not exists)
          groups[group] = (groups[group] || []);
          var ver_in_limit = (_.isUndefined(server_info) ? true :
                ((_.isUndefined(s.server_type) ? true :
                  (server_info.type in s.server_type)) &&
                (_.isUndefined(s.min_version) ? true :
                 (server_info.version >= s.min_version)) &&
                (_.isUndefined(s.max_version) ? true :
                 (server_info.version <= s.max_version)))),
              disabled = ((mode == 'properties') || !ver_in_limit),
              schema_node = (s.node && _.isString(s.node) &&
                  s.node in pgBrowser.Nodes &&  pgBrowser.Nodes[s.node]) || node;

          var o = _.extend(_.clone(s), {
            name: s.id,
            // Do we need to show this control in this mode?
            visible: evalASFunc(s.show),
            // This can be disabled in some cases (if not hidden)

            disabled: (disabled ? true : evalASFunc(s.disabled)),
            editable: (disabled ? false : (_.isUndefined(s.editable) ? pgAdmin.editableCell : !!(s.editable))),
            subnode: ((_.isString(s.model) && s.model in pgBrowser.Nodes) ?
                pgBrowser.Nodes[s.model].model : s.model),
            canAdd: (disabled ? false : evalASFunc(s.canAdd)),
            canEdit: (disabled ? false : evalASFunc(s.canEdit)),
            canDelete: (disabled ? false : evalASFunc(s.canDelete)),
            mode: mode,
            control: control,
            cell: cell,
            node_info: node_info,
            schema_node: schema_node,
            visible: (mode == 'properties'?
              (ver_in_limit ?
               (s.version || true) : false) : s.version || true)
          });
          delete o.id;

          // Temporarily store in dictionaly format for
          // utilizing it later.
          groups[group].push(o);
        }
      });

      // Do we have fields to genreate controls, which we
      // understand?
      if (_.isEmpty(groups)) {
        return null;
      }
      if (node && node.hasSQL && (mode == 'create' || mode == 'edit')) {
        groups[pgBrowser.messages.SQL_TAB] = [{
            name: 'sql',
            visible: true,
            disabled: false,
            type: 'text',
            control: 'sql-tab',
            node_info: node_info,
            schema_node: node,
            node_data: treeData
        }];
      }

    }
    return groups;
  }

  return Backform;
}));