const possibleChars = "ABCDESFHIJKLMNOPQRSTUVWXYZ1234567890";
const possibleCharsLength = possibleChars.length;

function randomId(length) {
   let ans = "";
   for (; length > 0; length--) {
      let idx = Math.floor(Math.random() * possibleCharsLength);
      ans += possibleChars[idx];
   }
   return ans;
}

//Generating random preset, to identify possible doubles
const preset = randomId(3);

console.log("The radnom preset for this set is:", preset);
console.log("Make shure this was not used before and if so, retry")
var etk = {};

for (var i = 0; i < 12 * 100; i++) {
   let id = preset + randomId(6);
   if (etk[id] !== undefined) i--;
   else etk[id] = 1;
}

var ets = Object.keys(etk);

const bluebird = require("bluebird");
const PDFDocument = require("pdfkit");
const doc = new PDFDocument({ size: "A4", autoFirstPage: false });
const fs = require("fs");
//const barcode = require("barcode");
const bwipjs = require('bwip-js');
const ewidth = 277;
const eheight = 119;
const mgap = 8.49;

doc.pipe(fs.createWriteStream(__dirname + "/etiketten.pdf"));

//A4 2480 x 3508
//doc.addPage({margin: 0});
//S = 1134

//A4: [595.28, 841.89],
// 28.29
//o w:14,15
//o h: 62,24
// <------------> (277)
// |
// | (119)
// |

function print(xo, yo, bc) {
   //doc.rect(xo, yo, ewidth, eheight);
   //doc.stroke();

   //Name Field
   doc.fontSize(16);
   var h = yo + (eheight / 4) * 3;
   doc.text("Name", xo + 5, h + 6);
   doc.moveTo(xo + 5, h).lineTo(xo + (ewidth / 4) * 2.2, h);
   doc.stroke();
   //Price Field;
   doc.text("Preis", xo + (ewidth / 4) * 2.4 + 5, h + 6);
   doc.moveTo(xo + (ewidth / 4) * 2.4 + 5, h).lineTo(xo + ewidth - 10, h);
   doc.stroke();
   //Sid Field:
   var h = yo + (eheight / 4) + 10;

   doc.text("SchülerId", xo + (ewidth / 4) * 2.4 + 5, h + 6);
   doc.moveTo(xo + (ewidth / 4) * 2.4 + 5, h).lineTo(xo + ewidth - 10, h);
   doc.stroke();
   //Barcode:

   var imagewidth = (ewidth / 4) * 2.2;
   var imageheight = 20;
   return new Promise((resolve, reject) => {
      bwipjs.toBuffer({
         bcid: "code128",
         text: bc,
         scale: 1,
         height: imageheight,
         width: imagewidth,
         includetext: true,
         textxalign: "center",
         textsize: 15
      }, (err, png) => {
         if (err) return console.log(err);
         doc.image(png, xo + 5, yo + 5, { height: 50, width: imagewidth });
         resolve();
      });
   });
}

function page(items, callback, index) { //bekommt ein array mit 12 ids
   doc.addPage({ margin: 0 });
   var j = 0;
   var proms = [];
   for (var i = 0; i < 6; i++) {
      if (j >= items.length) break;;
      proms.push(print(14.15, 62.24 + i * eheight, items[j]));
      j++;
   }

   for (var i = 0; i < 6; i++) {
      if (j >= items.length) break;
      proms.push(print(14.15 + ewidth + mgap, 62.24 + i * eheight, items[j]));
      j++;
   }
   Promise.all(proms).then(() => {
      callback(index + 12);
   });
}

function printpack(index) {
   if (index >= ets.length) {
      doc.end();
      return;
   }
   var i = [];
   for (var g = 0; g < 12; g++) {
      if (index + g >= ets.length) break;
      i.push(ets[index + g]);
   }
   page(i, printpack, index);
}
printpack(0);