randomSticker

// TokenID: Supply
const stickers = {
  '1012':	10,
  '1013':	11,
  '1014':	9,
  '1015':	20,
  '1016':	15,
  '1017':	5,
  '1018':	10,
  '1019':	17,
  '1031': 3
};

// Returns the total supply of stickers
const totalStickers = () => {
  let total = 0;
  Object.values(stickers).forEach(q => total += q);
  return total;
}

// Returns a random token ID using the supply as weigth 
const getRandomSticker = () => {
  const r = Math.random(); // 0 - 1
  const totalSupply = totalStickers(); // 100
  let sum = 0;
  for (i in stickers) {
    sum += stickers[i]/totalSupply; // 10/100
    if (r <= sum) return i;
  }
}

// Function to validate distribution
const stickersLog = {};
for(let i = 0; i<100; i++) {
  let sticker = getRandomSticker();
  if (!stickersLog[sticker]) {
    stickersLog[sticker] = 0;
  }
  stickersLog[sticker]++;
}

/* Claim the prize
 * @param albumHash (String) The list of stickers to claim the prize, all concatanated and sorted. 
 */
const claimPrize = (albumHash) => {
  // albumHash = 101031020410312 example, 3 stickers 10103, 10204, 10312
  const album = '101102103111112113'; // 3 types per country, 101, 102, 103, 111, 112, 113
  let hashToCheck = '';
  // we can do some length check already to avoid bad data
  for(let i = 0; i < albumHash.length; i+=5){
    // split into stickers
    let sticker = albumHash.substr(i, 5);
    console.log(sticker);
    // validate that the wallet is owner of the sticker, return error if user is not owner of any
    // add to hash
    hashToCheck += sticker.substr(0, 3); // we dont need the last 2 digits
  }
  if (album === hashToCheck) {
    // burn all stickers
    // send the wallet the cash prize
    return true;
  } else {
    // return error that hash is not valid
    return false;
  }
}