@@ -35,7 +35,7 @@ public function addBlock($BlockHeight, $prevBlockHash) {
 $timestamp = time();
 $coinbaseInstance = new Coinbase($BlockHeight);
 $coinbaseTx = $coinbaseInstance->coinbaseTransaction();
-$merkleRoot = ' ';
+$merkleRoot = $coinbaseTx->TxId;
 $bits = 'ffff001f';
 $blockheader = new BlockHeader($GLOBALS['VERSION'], $prevBlockHash, $merkleRoot, $timestamp, $bits);
 $blockheader->mine();

@@ -31,7 +31,10 @@ public function coinbaseTransaction() {
 $targetScript = Script::p2pkhScript($targetH160);
 $txOuts[] = new TxOut($targetAmount, $targetScript);
 
-return new Tx(1, $txIns, $txOuts, 0);
+$coinBaseTx = new Tx(1, $txIns, $txOuts, 0);
+$coinBaseTx->TxId = $coinBaseTx->id();
+
+return $coinBaseTx;
 }
 
 public function decodeBase58API($value)

@@ -1,5 +1,5 @@
 <?php
-
+require_once 'Blockchain/Backend/util/util.php';
 class Tx
 {
 public $locktime;
@@ -14,15 +14,52 @@ public function __construct($version, $txIns, $txOuts, $locktime) {
 $this->locktime = $locktime;
 }
 
+/**
+* @throws Exception
+*/
 public function serialize() {
-$result = intToLittleEndian($this->version, 4);
-$result .= count($this->txIns);
+// Initialize an empty result string
+$result = "";
+
+// Serialize the version as a little-endian 4-byte integer
+$result .= intToLittleEndian($this->version, 4);
+
+// Serialize the number of transaction inputs as a variable-length integer
+$result .= encode_varint(count($this->tx_ins));
+
+// Serialize each transaction input
+foreach ($this->tx_ins as $tx_in) {
+$result .= $tx_in->serialize();
+}
+
+// Serialize the number of transaction outputs as a variable-length integer
+$result .= encode_varint(count($this->tx_outs));
 
-// Add serialization logic here
+// Serialize each transaction output
+foreach ($this->tx_outs as $tx_out) {
+$result .= $tx_out->serialize();
+}
+
+// Serialize the locktime as a little-endian 4-byte integer
+$result .= intToLittleEndian($this->locktime, 4);
 
+// Return the serialized result
 return $result;
 }
 
+public function id() {
+// Human-readable Tx id
+return $this->hash()->hex();
+}
+
+/**
+* @throws Exception
+*/
+public function hash() {
+// Binary Hash of serialization
+return strrev(hash256($this->serialize()));
+}
+
 public function isCoinbase() {
 if (count($this->txIns) !== 1) {
 return false;

@@ -14,4 +14,13 @@ public function __construct($prevTx, $prevIndex, $scriptSig = null, $sequence =
 $this->scriptSig = $scriptSig ?? new Script();
 $this->sequence = $sequence;
 }
+
+public function serialize()
+{
+$result = strrev($this->prev_tx);
+$result .= intToLittleEndian($this->prev_index, 4);
+$result .= $this->script_sig->serialize();
+$result .= intToLittleEndian($this->sequence, 4);
+return $result;
+}
 }

@@ -1,5 +1,5 @@
 <?php
-
+require_once 'Blockchain/Backend/util/util.php';
 class TxOut
 {
 public $amount;
@@ -9,4 +9,11 @@ public function __construct($amount, $scriptPubkey) {
 $this->amount = $amount;
 $this->scriptPubkey = $scriptPubkey;
 }
+
+public function serialize()
+{
+$result = intToLittleEndian($this->amount, 8);
+$result .= $this->script_pubkey->serialize();
+return $result;
+}
 }

@@ -10,11 +10,15 @@ function hash160($data) {
 return hash('ripemd160', $sha256Hash, true);
 }
 
-function intToLittleEndian($number, $length)
-{
-// Use 'V' format for little-endian and unsigned long
-$value = pack('V', $number);
-return bin2hex($value);
+function intToLittleEndian($n, $length) {
+// Convert an integer to a little-endian byte string of a specified length
+$result = '';
+for ($i = 0; $i < $length; $i++) {
+$byte = $n & 0xFF; // Get the least significant byte
+$result .= chr($byte); // Convert to a character and append to the result
+$n >>= 8; // Shift the integer right by 8 bits
+}
+return $result;
 }
 
 function bytesNeeded($n)
@@ -33,6 +37,27 @@ function littleEndianToInt($b)
 return hexdec(bin2hex($littleEndian));
 }
 
+
+function encode_varint($i) {
+if ($i < 0xFD) {
+return chr($i);
+} elseif ($i < 0x10000) {
+return "\xFD" . intToLittleEndian($i, 2);
+} elseif ($i < 0x100000000) {
+return "\xFE" . intToLittleEndian($i, 4);
+} elseif ($i < 0x10000000000000000) {
+return "\xFF" . intToLittleEndian($i, 8);
+} else {
+throw new Exception("integer too large: $i");
+}
+}
+
+//try {
+// $encoded = encode_varint(500);
+//} catch (Exception $e) {
+//}
+//echo bin2hex($encoded);
+
 // Example usage
 //$input = 'some data to hash';
 //$hashed256 = hash256($input);