#!/usr/bin/env node

var readlineSync = require('readline-sync');
var items = [];

var ranlength = Math.floor(Math.random() * 65 ) + 35
console.log( "ranlength=" , ranlength )
for (var i = 0; i < ranlength ; i = i + 1) {
  items.push("array-item" + i);
}


var index = "null"
var selection = "";
var size = 20;
var pagecounter = 0;
for (var i = 0; i < items.length; i += size) {
  var smallarray = items.slice(i, i + size);
  index = readlineSync.keyInSelect(smallarray, null, {
    cancel: 'Next page'
  });
  if (index === -1) {
    pagecounter = pagecounter + size
  } else {
    //console.log("BREAK")
    pagecounter = pagecounter + index
    break;
  }
}
selection = items[pagecounter]
console.log("Your selection is:",  selection  )

var slection = "";

var selection = "";

const readlineSync = require('readline-sync');

function selectItem(items) {
  if (!items || !items.length) { return -1; }

  const MAX_ITEMS = 8,
    MAX_PAGE_INDEX = Math.ceil(items.length / MAX_ITEMS) - 1;

  let pageIndex = 0;
  while (true) {
    const PAGE_ITEMS = [];
    let indexPrev = -1, indexNext = -1;
    if (pageIndex > 0) {
      PAGE_ITEMS.push(`(PREVIOUS ${MAX_ITEMS} items)`);
      indexPrev = PAGE_ITEMS.length - 1;
    }
    Array.prototype.push.apply(PAGE_ITEMS,
      items.slice(pageIndex * MAX_ITEMS, (pageIndex + 1) * MAX_ITEMS));
    if (pageIndex < MAX_PAGE_INDEX) {
      PAGE_ITEMS.push(`(NEXT ${pageIndex < MAX_PAGE_INDEX - 1 ? MAX_ITEMS :
        items.length - MAX_ITEMS * (pageIndex + 1)} item(s))`);
      indexNext = PAGE_ITEMS.length - 1;
    }

    console.log('\x1B[2J');
    const index = readlineSync.keyInSelect(PAGE_ITEMS);
    if (indexPrev !== -1 && index === indexPrev) {
      pageIndex--;
    } else if (indexNext !== -1 && index === indexNext) {
      pageIndex++;
    } else {
      return index === -1 ? index :
        (index + pageIndex * MAX_ITEMS - (indexPrev === -1 ? 0 : 1));
    }
  }
}

const items = ['ITEM 1', 'ITEM 2', 'ITEM 3', 'ITEM 4', 'ITEM 5', 'ITEM 6', 'ITEM 7',
    'ITEM 8', 'ITEM 9', 'ITEM 10', 'ITEM 11', 'ITEM 12', 'ITEM 13', 'ITEM 14', 'ITEM 15',
    'ITEM 16', 'ITEM 17', 'ITEM 18', 'ITEM 19', 'ITEM 20'
  ],
  index = selectItem(items);
console.log(index === -1 ? '\nYou canceled.' : `\nYou chose ${items[index]}`);