//PROTOTYPE for an object that
/*
    is constructed from 2d array
    pulls headers from first row
    has getters and filters as needed
    has setter for sheet update at row level
    ...

*/
function SheetInterface(ss,sheetName) {
  this.sheet = ss.getSheetByName(sheetName);
  this.data = this.sheet.getDataRange().getValues();
  this.headers = this.data.shift();

}

SheetInterface.prototype = {
  constructor: SheetInterface,

  filtered: function(filterObject, colsArray){
    this.data = this.getFiltered(filterObject, colsArray);
  }, //rewrites this object's data

  getFiltered: function(filterObject,colsArray) {
    var that = this;
    var keys = Object.keys(filterObject);
    var filtered = this.data.filter(function(thisRow){
      return keys.every(function(thisKey){
        var comparison = that.headers.indexOf(thisKey);
        return thisRow[comparison] === filterObject[thisKey];
      })
    })
    if (filtered.length === 0 ) return false; //EARLY return if no matches
    if (!colsArray) return filtered; //EARLY RETURN if no 2nd argument

    var result = [];
    var headerIndices = [];
    for (var i in colsArray) {
      headerIndices.push(this.getIndexOf(colsArray[i]))
//      Logger.log(this.getIndexOf(colsArray[i]) + ' ' + colsArray[i]);
    }
    for (var j in filtered) {
      var row = [];
      for (var i in headerIndices) {
        var thisSubset = filtered[j][headerIndices[i]];
        row.push(thisSubset);
      }
      result.push(row);
    }
    Logger.log(result);
    return result;
  }, //subset of columns in rows that match every key/value pair in filterObject

  getMatchingIndices: function(filterArray) {
    var data = this.data;
    var indices = [];
    for (var row in data) {
      var truthy = filterArray.every(function(thisCriteria){
          return data[row].indexOf(thisCriteria) > -1;
      })
      if (truthy) indices.push(row);
    }
    return indices;
  }, //array of index values for rows that match filterArray

  getMatching: function(filterArray) {
    var data = this.data;
    var rows = [];
    for (var row in data) {
      var truthy = filterArray.every(function(thisCriteria){
          return data[row].indexOf(thisCriteria) > -1;
      })
      if (truthy) rows.push(data[row]);
    }
    return rows;
  }, //array of data rows that match filterArray

  getFirstMatch: function(filterArray) {
    var result;
    var truthy =  this.data.some(function(row){
      result = row;
      return filterArray.every(function(criteria){
        return row.indexOf(criteria) > -1;
      })
    })
    return (truthy ? result : -1);
  }, //more efficient when you are sure there's just one or none

  getArrayOfUnique: function(keys){ //String []
    var that = this;
    var result = [];
    this.data.forEach(function(value){
      var temp = [];
      keys.forEach(function(key){
        temp.push(value[that.getIndexOf(key)]);
      })
      if (!result.some(function(added){ return temp.every(function(v,i) { return v === added[i] }) }) ) { //if not exist some row in added[] that matches
        result.push(temp);
      }

    })
    return result;
  }, //returns array of first occurence of each unique match

  getUniqueValuesByKey: function(key) { //String
    var index = this.headers.indexOf(key);
    var result = [];
    for (var i in this.data) {
      if (result.indexOf(this.data[i][index]) === -1) {
        result.push(this.data[i][index]);
      }
    }
    return result;
  }, //returns array of unique answers to header (single) key

  getGroupedSheetRows: function(config) {
    //config is subset of headers, method returns array of arrays of grouped data arrays
    var that = this;
    var a = this.getArrayOfUnique(config);
    var b = [];
    a.forEach(function(unique){ //iterate the data
      var thisSpec = {}; //constructing a match object for this one
      config.forEach(function(v,i){ //iterate the subset of headers
        thisSpec[v] = unique[i]; //set key (header item) to this evaluee value
      })
      var c = that.getFiltered(thisSpec); //use spec to get full data
      if (c!== []) b.push([thisSpec, c]);
    });

    return b;
  }, //b = [[[data]]]; b.length = number of unique combinations of config column values

};
//  USAGE

// 1. build object from spreadsheet ID and actual tab name
//  var ss = SpreadsheetApp.openById("1MlRNNCjl2qg83FAwLEpgMsiaXGkrhPXCIJTe6QkvQtY");
//  var contestants = new SheetInterface(ss,"Boilerplate");

// 2. use methods to get subsets of data
//  var a = contestants.getFiltered(["Reading Freud I", "2017 Fall"]);
//  var b = contestants.getMatchingIndices(["Case Conference", "2017 Fall", "Mixed"]);
//  var c = contestants.getFirstMatch(["Reading Freud I", "2017 Fall"]);
//  var d = contestants.getUniqueArray("Candidate");
//
SheetInterface.prototype.updateRow = function(index) {
  var numCols = this.sheet.getLastColumn();
  var values = [this.data[index]];
  this.sheet
    .getRange(+index+2,1,1,numCols)
    .setValues(values);
} //writes current state of data back to sheet at row corresponding to data index

SheetInterface.prototype.getIndexOf = function(headerItem) {
  return this.headers.indexOf(headerItem);
} //returns column index or -1