Google Sheet Script to distribute projects to groups

script.js

var CHOICES_SHEETS  = 'Choix',
    PROJECTS_SHEETS = 'Sujets',
    RESULTS_SHEETS  = 'Résultat';

/**
 * randomInt
 * @return {Number}   An int in [0; max[
 */
var randomInt = function (max) {
  var max = Math.floor(max);
  return Math.floor(Math.random() * (max));
};

var _d = (function () {
  var data = {
    _groups: {},
    _projects: {},

    init: function (projects, groups, choices) {
      data._projects = projects;
      data._groups  = groups;
    },
    
    assign: function (group, project) {
      data._groups[group] = project;
      data._projects[project].taken = group;
      Logger.log('Assign '+ group + ' to ' + project);
    },
    
    isGroupDone: function (group) {
      return !!data._groups[group];
    },
    
    isProjectTaken: function (project) {
      return !!data._projects[project].taken;
    },
    
    getFreeProjects: function () {
      var arr = []; //we return an array it's better here
      
      for (var k in data._projects) {
        var p = data._projects[k];
        if (!p.taken) {
          arr.push({
            name:    k,
            choices: p.choices,
          });
        }
      }
      
      return arr;
    },
    
    getFreeGroups: function () {
      var arr = []; //we return an array it's better here
      
      for (var k in data._groups) {
        if (!data.isGroupDone(k)) {
          arr.push(k);
        }
      }
      
      return arr;
    },
    
  };

  /**
   * getRowProjects
   * Get projects from the sheet
   */
  var getRowProjects = function (spreadsheet) {
    var projectsSheet = spreadsheet.getSheetByName(PROJECTS_SHEETS);
    var maxRow = projectsSheet.getLastRow();
    var projects = projectsSheet.getRange(2, 1, maxRow, 1);
    
    var o = {};
    
    projects.getValues()
    .map(function (e) {
      return e[0]
    })
    .forEach(function (p) {
      o[p] = {
        choices: [[], [], [], [], []],
        taken: false,
      }; 
    });
    
    return o;
  };
  
  /**
   * getChoices
   * Get choices from the sheet
   */
  var getChoices = function (spreadsheet) {
    var choiceSheet = spreadsheet.getSheetByName(CHOICES_SHEETS);
    var maxRow = choiceSheet.getLastRow();
    
    var choices = choiceSheet.getRange(2, 1, maxRow, 6);
       
    return choices.getValues()
    .filter(function (e) {
      return e[0] !== '';  
    });    
  };
   
  /**
   * getGroups
   * Get groups from the sheet
   */ 
  var getGroups = function (spreadsheet) {
    var choiceSheet = spreadsheet.getSheetByName(CHOICES_SHEETS);
    var maxRow = choiceSheet.getLastRow();
    
    var groups = choiceSheet.getRange(2, 1, maxRow, 1);
    
    var o = {};
  
    groups.getValues()
    .filter(function (e) {
      return e[0] !== '';  
    })
    .forEach(function (g) {
      o[g] = null; 
    });
    
    return o;    
  };
  
  /**
   * buildProjects
   *
   * Build the projects object 
   * @example
   * {
   *    'my-project': {
   *         choices: [        // array length is 5 (because 5 choices)
   *             ['Group X', 'Group M'], // first choice groups
   *             ['Group A'],            // second choice groups
   *         ],
   *     },
   *     ...
   * }
   *
   * @return {Object}  All the projects with their choices
   */
  var buildProjects = function (projects, choices) {
    choices.forEach(function (row) {
      var group = row.shift();
      
      row.forEach(function (project, i) {
        Logger.log('Register ' + group + ' to '
                   + project + ' for choice ' + i);
        projects[project].choices[i].push(group);
      });
    });
    
    return projects;
  };
  
  /**
   * assignByPref
   * 
   * Assign projects according to choice number `pref`
   */
  var assignByPref = function (data, pref) {
    data.getFreeProjects()
    .forEach(function (project) {  
      // groups that want this project and aren't already done
      var groups = project.choices[pref].filter(function (group) {
        return !data.isGroupDone(group);
      });
            
      if (groups.length === 0) { // no group for this project
        return; 
      }
      if (groups.length === 1) { 
        // just one group, perfect !
        data.assign(groups[0], project.name); 
      } else {
        // more than one group for this project
        // we compute a random number to decide wich group will get the
        // project
        var r = randomInt(groups.length);
        data.assign(groups[r], project.name);
      } 
    });
  };
  
  /**
   * assignLastProjectsAndGroups
   * 
   * Assign untaken projects with untaken groups
   * Must be run at the end of the distribution
   */
  var assignLastProjectsAndGroups = function (data) { 
    var freeProjects = data.getFreeProjects();
    var freeGroups = data.getFreeGroups();
    
    freeProjects.forEach(function (p, i) {
      if (freeGroups[i]) { //if only their is a free group
        data.assign(freeGroups[i], p.name);  
      }
    });
  };
  
  /**
   * writeResultToSheet
   */
  var writeResultToSheet = function (spreadsheet, data) {
    var confirm = Browser.msgBox(
      'Erase all previous results ?',
      Browser.Buttons.OK_CANCEL
    );
    
    Logger.log('Ask confirmation. Got ' + confirm);
    
    if (confirm !== 'ok') { // stop here
      return;
    }
    
    var resultSheet = spreadsheet.getSheetByName(RESULTS_SHEETS);
    var maxRow = resultSheet.getLastRow();
    resultSheet.deleteRows(2, maxRow);
    
    for (var k in data._groups) {
      Logger.log('Group ' + k + ' - Project ' + data._groups[k]);
      resultSheet.appendRow([k, data._groups[k]]);
    }
    
    data.getFreeProjects()
    .forEach(function (p) {
      Logger.log('Free Project ' + p.name);
      resultSheet.appendRow(['', p.name]);
    });
  };
  
  var init = function () {
    var spreadsheet = SpreadsheetApp.getActive();
    
    // INIT
    
    var projects = getRowProjects(spreadsheet),
        groups   = getGroups(spreadsheet),
        choices  = getChoices(spreadsheet);
    
    var builtProjects = buildProjects(projects, choices);
    
    data.init(builtProjects, groups, choices);
    
    // Distributing projects
    
    for (var i=0; i < 5; i++) {
      assignByPref(data, i);
    };
                             
    assignLastProjectsAndGroups(data);
    
    // Done, logging results
                             
    writeResultToSheet(spreadsheet, data);
  };
 
  return init;
  
}());

function distribute() {
  _d(); 
}

/**
* A special function that runs when the spreadsheet is open, used to add a
* custom menu to the spreadsheet.
*/
function onOpen() {
  var spreadsheet = SpreadsheetApp.getActive();
  var menuItems = [
    {name: 'Distribute projets', functionName: 'distribute'}
  ];
  spreadsheet.addMenu('Distribution', menuItems);
}