block.rb

require 'digest/sha2'
require 'time'

require_relative 'transaction'
require_relative 'proof_of_work'

class Block
  attr_reader :hash, :height, :transactions, :timestamp, :nonce, :previous_hash

  def initialize args
    @hash = args[:hash]
    @height = args[:height]
    @transactions = args[:transactions]
    @timestamp = args[:timestamp]
    @nonce = args[:nonce]
    @previous_hash = args[:previous_hash]
  end

  private
  def calculate_hash args
      Digest::SHA256.hexdigest({
          height: args[:height],
          previous_hash: args[:previous_hash],
          timestamp: args[:timestamp],
          transactions: args[:transactions]
      }.to_json)
  end

  class << self
      # ジェネシス・ブロックを生成する
      def create_genesis_block
          address = "62e907b15cbf27d5425399ebf6f0fb50ebb88f18"
          timestamp = Time.parse("2009/1/3").to_i
          previous_hash = '0'
          genesis_coinbase_data = "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks"
          transactions = [Transaction.new_coinbase_transaction(address, genesis_coinbase_data)]

          pow = ProofOfWork.new(
              timestamp: timestamp,
              previous_hash: previous_hash,
              transactions: transactions
          )

          nonce, hash = pow.do_proof_of_work
          Block.new(
              hash: hash,
              height: 0,
              transactions: transactions,
              timestamp: timestamp,
              nonce: nonce,
              previous_hash: previous_hash
          )
      end
  end
end