Block.cr

def generate(last_block, data)
  new_block = self.create(
    last_block[:index] + 1,
    Time.now.to_s,
    data,
    last_block[:hash]
  )

  i = 0

  loop do
    hex = i.to_s(16)
    new_block = new_block.merge({ nonce: hex })

    if !self.is_hash_valid?(self.calculate_hash(new_block), new_block[:difficulty])
      puts "Mining: trying another nonce... #{self.calculate_hash(new_block)}"
      i += 1
      # sleep 25.milliseconds
      next
    else
      puts "\nMining complete! Nonce for this block is #{new_block[:nonce]}."
      new_block = new_block.merge({ hash: self.calculate_hash(new_block) })
      break
    end
  end

  new_block
end