// called to load model with server data 
Gradebook.GridModel.prototype.requestLoadData = function( forceFlush ) {
  GradebookUtil.debug('GridModel requestLoadData called');
  this.lastUpdateTS = new Date().getTime();
  this.gradebookService.requestLoadData(
      (this._loadDataFromJSON).bind(this),
      (this._reportError).bind(this),
      (this._reportException).bind(this), forceFlush );
}

// called to update model with server data 
Gradebook.GridModel.prototype.requestUpdateData = function() {
  var timeSinceLastUpdate = new Date().getTime() - this.lastUpdateTS;
  // don't update if window is resizing and we've reloaded in the last 5
  // minutes
  if (!this.usingCachedBook && this.resizingWindow && ( timeSinceLastUpdate < 5*60*1000) ){
    this.fireModelChanged();
    return; 
  }
  this.lastUpdateTS = new Date().getTime();
  GradebookUtil.debug('GridModel requestUpdateData called');
  var customViewId = null;
  if (this.currentCustomView && this.currentCustomView.usesGroups()){
    customViewId = this.currentCustomView.id;
  }
  this.gradebookService.requestUpdateData(this.version, this.lastUserChangeTS, this.usersHash, customViewId,
      (this._updateDataFromJSON).bind(this),
      (this._reportError).bind(this),
      (this._reportException).bind(this));
}


// callback when initializing this gradebook model with server data
Gradebook.GridModel.prototype._loadDataFromJSON = function(reply) {
  GradebookUtil.debug('GridModel _loadDataFromJSON called');
  try {
    var jsonBook;
  if (typeof(JSON) === 'object' && typeof(JSON.parse) === 'function') 
    {
      jsonBook = JSON.parse(reply.responseText);
    }
    else
    {
      jsonBook = eval('(' + reply.responseText + ')');
    }
  } catch (e) {
    this.fireModelError(e, reply.responseText);
    return;
  }
  if ( jsonBook.cachedBook )
  {
    jsonBook = jsonBook.cachedBook;
    this.usingCachedBook = true;
  }
  try {
    this.schemaMap = new Array();
    for (var i = 0; i < jsonBook.schemas.length; i++){
      jsonBook.schemas[i] = this._createSchema(jsonBook.schemas[i].type, jsonBook.schemas[i]);
      this.schemaMap[jsonBook.schemas[i].id] = jsonBook.schemas[i];
    }
    this.colDefMap = new Array();
    for (var i = 0; i < jsonBook.colDefs.length; i++){
      jsonBook.colDefs[i] = this._createColDef( jsonBook.colDefs[i], this, this.schemaMap );
      this.colDefMap[jsonBook.colDefs[i].id] = i;
    }

  // embelish 1st cell of each row with some flags
    this.rowUserIdMap = new Array();
    if (jsonBook.rows){
      for (var i = 0,len = jsonBook.rows.length; i < len; i++){
        var c = jsonBook.rows[i][0];
        c.isRowChecked = false;
        c.isHidden = false;
        c.isAvailable = true;
        c.comput_err = false;
        this.rowUserIdMap[c.uid] = i;
      }
    }

    this.customViewMap = new Array();
    if (jsonBook.customViews){
      for (var i = 0; i < jsonBook.customViews.length; i++){
        jsonBook.customViews[i] = new Gradebook.CustomView( jsonBook.customViews[i], this );
        this.customViewMap[jsonBook.customViews[i].id] = i;
      }
    }
    this.groupsMap = new Array();
    if (jsonBook.groups){
      for (var i = 0; i < jsonBook.groups.length; i++){
        this.groupsMap[jsonBook.groups[i].id] = i;
      }
    }
    this.scoreProvidersMap = new Array();
    if (jsonBook.scoreProviders){
      for (var i = 0; i < jsonBook.scoreProviders.length; i++){
        this.scoreProvidersMap[jsonBook.scoreProviders[i].handle] = jsonBook.scoreProviders[i];
      }
    }

    this._buildCategoryNameMap( jsonBook );
    Object.extend(this, jsonBook); // assign json properties to this object
    this._buildGradingPeriodMap();
    this._setStudentInfoLayout();
    this.setCurrentView( this.initialView );
    this._updateVisibleRows(jsonBook);
    this.sortColumns();
    if (this.colDefMap['LN'] != undefined){
      this.sortColumnId = 'LN';
      this.sortDir = 'ASC';
      this.reSort();
    }
    this.lastLogEntryTS = jsonBook.lastLogEntryTS;
    
    if ( !this.usingCachedBook ) {
      this.initialView = null;
      this.fireModelChanged();
    } else {
      this.requestUpdateData();
    }
  } catch (e) {
    this.fireModelError(e);
  }
}

//callback when updating this gradebook model with server data
Gradebook.GridModel.prototype._updateDataFromJSON = function(reply) {
  GradebookUtil.debug('GridModel _updateDataFromJSON called');
  try {
    var jsonBook;
  if (typeof(JSON) === 'object' && typeof(JSON.parse) === 'function') 
    {
      jsonBook = JSON.parse(reply.responseText);
    }
    else
    {
      jsonBook = eval('(' + reply.responseText + ')');
    }
  } catch (e) {
    this.fireModelError(e, reply.responseText);
    return;
  }
  try {
    // need to reinitialize if new users added to pick up existing grades
    // when a user is re-enabled
    if (this._hasNewUsers(jsonBook)) {
      this.requestLoadData( true /* force flush since extra users cannot be loaded by delta */ );
      return;
    }
    this.version = jsonBook.version;
    this.lastUserChangeTS = jsonBook.lastUserChangeTS;
    this.usersHash = jsonBook.usersHash;
    this.numFrozenColumns = jsonBook.numFrozenColumns;
    this.gradingPeriods = jsonBook.gradingPeriods;
    this.categories = jsonBook.categories;
    this._buildCategoryNameMap( jsonBook );
    this.studentInfoLayouts = jsonBook.studentInfoLayouts;
    this.pubColID = jsonBook.pubColID;
    this.defView = jsonBook.defView;

    if (jsonBook.schemas){
      for (var i = 0; i < jsonBook.schemas.length; i++){
        // create a new schema if one with same id does not already exists
        var schema = this.schemaMap[jsonBook.schemas[i].id]; 
        if (schema === undefined){
          schema = this._createSchema(jsonBook.schemas[i].type, jsonBook.schemas[i]);
          this.schemaMap[jsonBook.schemas[i].id] = schema;
        } else {
          Object.extend(schema, jsonBook.schemas[i]);
        }
      }
    }
    if (jsonBook.groups){
      if (!this.groupsMap || !this.groups || this.groups.length == 0){
        this.groupsMap = new Array();
        this.groups = jsonBook.groups;
        for (var i = 0; i < jsonBook.groups.length; i++){
          this.groupsMap[jsonBook.groups[i].id] = i;
        }
      } else {
        for (var i = 0; i < jsonBook.groups.length; i++){
          var group = this.groupsMap[jsonBook.groups[i].id]; 
          if (group === undefined){
            this.groupsMap[jsonBook.groups[i].id] = this.groups.length;
            this.groups.push( jsonBook.groups[i] );
          } else {
            this.groups[group] = jsonBook.groups[i];
          }
        }
      }
    }

    if (jsonBook.colDefs){
      for (var i = 0; i < jsonBook.colDefs.length; i++){
        // create a new colDef if one with same id does not already exists
        var colIndex = this.colDefMap[jsonBook.colDefs[i].id];
        if (colIndex == undefined){
          if ( jsonBook.colDefs[i].deleted ) continue;
          this.colDefMap[jsonBook.colDefs[i].id] = this.colDefs.length;
          this.colDefs.push(this._createColDef( jsonBook.colDefs[i], this, this.schemaMap ));
        } else {
          // we should actually discard the previous version and replace it with the new one
          // however all cells hold a ref to the object making this
          // impractical. With incoming
          // refactoring that should not be an issue since col def will
          // always be looked up by
          // cell index in the row - right now only delete the src since it
          // is omitted from payload
          // when absent
          var colDef = this.colDefs[colIndex];
          colDef.comput_err = false;
          if ( colDef.src )
          {
            delete colDef.src;
          }
          Object.extend(colDef, jsonBook.colDefs[i]);
          // clear all grades in column if computation error for column
          if (jsonBook.colDefs[i].comput_err){
            var grades = this._getGradesForItemId(jsonBook.colDefs[i].id, true);
            for (var g = 0; g < grades.length; g++){
              grades[g].initialize( grades[g].colDef, grades[g].metaData);
            }
          }
          if (colDef.deleted){
            this.colDefMap[colDef.id] = null;
          }
          if (colDef.sid){
            colDef.primarySchema = this.schemaMap[colDef.sid];
          }
          if (colDef.ssid && colDef.ssid.length > 0){
            colDef.secondarySchema = this.schemaMap[colDef.ssid];
          } else {
            colDef.secondarySchema = null;
          }
        }
      }
    }
    // need to add any new row data?
    if (this.rows && this.rows.length > 0){
    	var numNewCols = this.colDefs.length - this.rows[0].length;
    	if (this.rows.length > 0 && numNewCols > 0){
      	for (var i = 0; i < this.rows.length; i++){
        	for (var c = 0; c < numNewCols; c++){
	          this.rows[i].push( {} );  // add empty cell for each new column
    	    }
	      }
		}	    
    }
    if (jsonBook.rows){
      // users changed, need to resync
      if (jsonBook.type == "delta_with_user"){
        // remove rows from model that are not in json data
        var tempArray = new Array();
        for (var i = 0; i < this.rows.length; i++){
          if (this._containsUser(jsonBook.rows, this.rows[i][0].uid)) {
            tempArray.push(this.rows[i]);
          }
        }
        this.rows = tempArray;
      }
      this.rowUserIdMap = new Array();
      for (var i = 0,len = this.rows.length; i < len; i++){
        this.rowUserIdMap[this.rows[i][0].uid] = i;
      }

      // update rows
      for (var i = 0; i < jsonBook.rows.length; i++){
        var row = this.getRowByUserId(jsonBook.rows[i][0].uid);
        if (row == null){
          GradebookUtil.error('Can not update non-existing row for user id: '+jsonBook.rows[i][0].uid);
        } else {
          this._updateRowDataFromJSON(row, jsonBook.rows[i], this.colDefs, this.colDefMap);
        }
      }
    }
    this._buildGradingPeriodMap();
    if (jsonBook.customViews){
      for (var i = 0; i < jsonBook.customViews.length; i++){
        // create a new custom view if one with same id does not already exists
        var idx = this.customViewMap[jsonBook.customViews[i].id]; 
        if (idx === undefined){
          this.customViewMap[jsonBook.customViews[i].id] = this.customViews.length;
          this.customViews.push(new Gradebook.CustomView( jsonBook.customViews[i], this ));
        } else {
          this.customViews[idx] = new Gradebook.CustomView( jsonBook.customViews[i], this );
        }
      }
    }
    // remove any custom views not in customViewIds
    if (this.customViews){
      var tempArray = new Array();
      this.customViewMap = new Array();
      for (var i = 0; i < this.customViews.length; i++){
        if ( jsonBook.customViewIds.indexOf( Number( this.customViews[i].id ) ) != -1 )  {
          this.customViewMap[this.customViews[i].id] = tempArray.length;
          tempArray.push(this.customViews[i]);
        }
      }
      this.customViews = tempArray;
    }
    this._setStudentInfoLayout();
    if (this.initialView || this.usingCachedBook){
      this.setCurrentView( this.initialView );
      this.initialView = null;
    }
    this.lastLogEntryTS = jsonBook.lastLogEntryTS;
    this._updateVisibleRows(jsonBook);
    this.sortColumns();
    this.reSort();
    this.usingCachedBook = false;
    this.checkedNoStudents(); // do this last, it will fireModelChanged
  } catch (e) {
    this.fireModelError(e);
  }
}

Gradebook.GridModel.prototype._updateRowDataFromJSON = function(thisRow, jsonRow, colDefs, colDefMap){

  for (var i = 0; i < jsonRow.length; i++){
    var colIndex = colDefMap[jsonRow[i].c];
    colDefs[colIndex].comput_err = false;
    var currentCell = thisRow[colIndex];
    // reset any property that is not always part of the cell data
    if ( currentCell.mp )       delete currentCell.mp;
    if ( currentCell.x )        delete currentCell.x;
    if ( currentCell.ax )       delete currentCell.ax;
    if ( currentCell.excluded ) delete currentCell.excluded;
    if ( currentCell.numAtt )   delete currentCell.numAtt;
    if ( currentCell.or )       delete currentCell.or; 
    if ( currentCell.ip )       delete currentCell.ip;    
    if ( currentCell.ng )       delete currentCell.ng;    
    if ( currentCell.na )       delete currentCell.na;    
    delete currentCell.attemptsInfo;
    Object.extend( currentCell, jsonRow[i] );
  }
  thisRow[0].isAvailable = thisRow[0].avail;
}

Gradebook.GridModel.prototype._createColDef = function(jsonColDef,model,schemaMap) {
  if (jsonColDef.type == "s"){
    return new Gradebook.StudentAttributeColDef( jsonColDef, model, schemaMap );
  } else {
    return new Gradebook.GradeColDef( jsonColDef, model, schemaMap );
  }
}

Gradebook.GridModel.prototype._createSchema = function(type,jsonSchema) {
  if (type == "S"){
    return new Gradebook.NumericSchema( jsonSchema, this );
  } else if (type == "X") {
    return new Gradebook.TextSchema( jsonSchema, this );
  } else if (type == "P") {
    return new Gradebook.PercentageSchema( jsonSchema, this );
  } else if (type == "C") {
    return new Gradebook.CompleteIncompleteSchema( jsonSchema, this );
  } else if (type == "T") {
    return new Gradebook.LetterSchema( jsonSchema, this );
  } else {
    GradebookUtil.debug('GridModel _createSchema invalid type: '+type);
    return null;
  }

}

Gradebook.GridModel.prototype._buildGradingPeriodMap = function() {
  this.gradingPeriodMap = new Array();
  if (this.gradingPeriods){
    for (var i = 0, len = this.gradingPeriods.length; i < len; i++){
      this.gradingPeriodMap[this.gradingPeriods[i].id] = this.gradingPeriods[i];    
    }
    this.gradingPeriods.sort(
        function(a,b){
          var aa = a.name.toLowerCase();
          var bb = b.name.toLowerCase();
          if (aa == bb) return 0;
          else if (aa < bb) return -1;
          else return 1;
        }
    );
  }
}

Gradebook.GridModel.prototype._setStudentInfoLayout = function(){
  // set pos & gbvis for student attribute columns from studentInfoLayouts
  for (var i = 0; i < this.studentInfoLayouts.length; i++){
    var colIndex = this.colDefMap[this.studentInfoLayouts[i].id]; 
    if (colIndex === undefined){
      continue;
    }
    var colDef = this.colDefs[colIndex];
    colDef.gbvis = this.studentInfoLayouts[i].gbvis;
    colDef.pos = this.studentInfoLayouts[i].pos;
  }
}

Gradebook.GridModel.prototype._updateVisibleRows = function(jsonBook) {
  var showAll = (!jsonBook.hiddenStudentIds || jsonBook.hiddenStudentIds.length == 0);
  this.visibleRows = new Array();
  var rows = this.rows;
  // loop through rows and set hidden flag for each row, add to visibleRows
  // if not hidden
  for (var i = 0, len = rows.length; i < len; i++){
    var row = rows[i];
    var isHidden = !showAll && ( jsonBook.hiddenStudentIds.indexOf( Number( row[0].uid ) ) != -1 );
    row[0].isHidden = isHidden;
    if ( !isHidden ) {
      this.visibleRows.push( row );
    }
  }
  this._applyCustomView();
  
}

Gradebook.GridModel.prototype._buildCategoryNameMap = function( jsonBook ) {
  this.catNameMap = new Array();
  if ( jsonBook.categories ) {
    for (var i = 0; i < jsonBook.categories.length; i++){
      this.catNameMap[jsonBook.categories[i].id] = jsonBook.categories[i].name;
    }
  }
}

Gradebook.GridModel.prototype._initMessages = function( ) {
  if ( this.messages ) return;
  this.loadingLocalizedMessages = true;
  this.gradebookService.requestLoadMessages(
      (this._onMessageLoaded).bind(this),
      (this._reportError).bind(this),
      (this._reportException).bind(this));
}

Gradebook.GridModel.prototype._onMessageLoaded = function( reply ) {
  var messagesJSON = eval('(' + reply.responseText + ')');
  this.messages = messagesJSON.gradebook2Messages;
  delete this.loadingLocalizedMessages;
}