Add Bitcoin::Block#create_genesis

lib/bitcoin/block.rb

@@ -15,6 +15,27 @@ def initialize(header, transactions = [])
       @transactions = transactions
     end
 
+    # Create genesis block.
+    # @param [String] msg Message embedded in coinbase transaction.
+    # @param [Bitcoin::Script] script Coinbase transaction scriptPubkey.
+    # @param [Integer] time Block time.
+    # @param [Integer] nonce nonce.
+    # @param [Integer] bits nBits
+    # @param [Integer] version nVersion.
+    # @param [Integer] rewards Block rewards(satoshi).
+    def self.create_genesis(msg, script, time, nonce, bits, version, rewards = 50 * 100000000)
+      coinbase = Bitcoin::Tx.create_coinbase(msg, script, rewards)
+      header = BlockHeader.new(
+        version,
+        '00' * 32,
+        MerkleTree.build_from_leaf([coinbase.txid]).merkle_root.rhex,
+        time,
+        bits,
+        nonce
+      )
+      Block.new(header, [coinbase])
+    end
+
     def self.parse_from_payload(payload)
       Bitcoin::Message::Block.parse_from_payload(payload).to_block
     end

lib/bitcoin/tx.rb

@@ -33,6 +33,19 @@ def initialize
     alias_method :in, :inputs
     alias_method :out, :outputs
 
+    # Create coinbase transaction.
+    # @param [String] msg Message embedded in coinbase transaction.
+    # @param [Bitcoin::Script] script Coinbase transaction scriptPubkey.
+    # @param [Integer] rewards Coinbase Transaction Rewards
+    # @return [Bitcoin::Tx] Coinbase transaction.
+    def self.create_coinbase(msg, script, rewards = 50 * 100000000)
+      coinbase = Tx.new
+      script_sig = Bitcoin::Script.new << 486604799 << "04" << msg.bth
+      coinbase.in << TxIn.new(out_point: OutPoint.create_coinbase_outpoint, script_sig: script_sig)
+      coinbase.out << TxOut.new(value: rewards, script_pubkey: script)
+      coinbase
+    end
+
     def self.parse_from_payload(payload, non_witness: false, strict: false)
       buf = payload.is_a?(String) ? StringIO.new(payload) : payload
       tx = new

spec/bitcoin/block_spec.rb

@@ -86,4 +86,19 @@
     end
   end
 
+  describe "create_genesis" do
+    it do
+      testnet4 = described_class.create_genesis(
+        "03/May/2024 000000000000000000001ebd58c244970b3aa9d783bb001011fbe8ea8e98e00e",
+        Bitcoin::Script.new << "000000000000000000000000000000000000000000000000000000000000000000" << Bitcoin::Opcodes::OP_CHECKSIG,
+        1714777860,
+        393743547,
+        0x1d00ffff,
+        1
+      )
+      expect(testnet4.header.merkle_root.rhex).to eq('7aa0a7ae1e223414cb807e40cd57e667b718e42aaf9306db9102fe28912b7b4e')
+      expect(testnet4.block_hash.rhex).to eq('00000000da84f2bafbbc53dee25a72ae507ff4914b867c565be350b0da8bf043')
+    end
+  end
+
 end