From 421c6f8343e64645d6eed3192b14f2e9303f52f2 Mon Sep 17 00:00:00 2001
From: davidchocholaty <david.chocholaty@seznam.cz>
Date: Thu, 7 Nov 2024 16:18:38 +0100
Subject: [PATCH] Add p2sh

---
 src/script.py      |  2 +-
 src/transaction.py | 44 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/script.py b/src/script.py
index b62cc79..683a34c 100644
--- a/src/script.py
+++ b/src/script.py
@@ -430,7 +430,7 @@ def op_checkmultisig(self) -> int:
         # 3. Handle proper error cases
         
         verified = True  # Replace with actual verification
-        
+
         self.stack.push(b'\x01' if verified else b'\x00')
         return 1
 
diff --git a/src/transaction.py b/src/transaction.py
index 661fedd..5a4ad3e 100644
--- a/src/transaction.py
+++ b/src/transaction.py
@@ -104,7 +104,7 @@ def valid_input(self, vin_idx, vin):
         if scriptpubkey_type == "p2pkh":
             return self.validate_p2pkh(vin_idx, vin)
         elif scriptpubkey_type == "p2sh":
-            pass
+            return self.validate_p2sh(vin_idx, vin)
         elif scriptpubkey_type == "v0_p2wsh":
             pass
         elif scriptpubkey_type == "v1_p2tr":
@@ -139,6 +139,47 @@ def validate_p2pkh(self, vin_idx, vin):
 
         return is_valid
 
+    def validate_p2sh(self, vin_idx, vin):
+        #################
+        # Pubkey script #
+        #################
+        scriptsig = decode_hex(vin.get("scriptsig", ""))
+        if not scriptsig:
+            return False
+        prevout = vin.get("prevout", {})
+        if not prevout:
+            return False
+        scriptpubkey = decode_hex(prevout.get("scriptpubkey", ""))
+
+        # Check if the scriptpubkey is a P2SH script
+        if scriptpubkey[:2] != b'\xa9\x14' or scriptpubkey[-1:] != b'\x87':
+            # Not a P2SH script, fallback to P2PKH validation
+            return self.validate_p2pkh(vin_idx, vin)
+
+        # Extract the script hash from the scriptpubkey        
+        script_hash = scriptpubkey[2:-1]
+
+        # Find the redeem script in the scriptsig
+        redeem_script_len = int.from_bytes(scriptsig[0:1], byteorder='little')
+        redeem_script = scriptsig[1:1+redeem_script_len]
+
+        # Create the combined script
+        script = Script.combine_scripts(redeem_script, json_transaction=self.json_transaction)
+
+        # Hash the redeem script and compare with the script hash
+        # Compute the HASH160 (RIPEMD-160 of SHA-256) of the redeem script
+        sha256_hash = hashlib.sha256(redeem_script).digest()
+        computed_script_hash = hashlib.new('ripemd160', sha256_hash).digest()
+
+        # Compare with the provided script hash
+        if computed_script_hash != script_hash:            
+            return False
+
+        # Execute the redeem script
+        is_valid = script.execute()
+
+        return is_valid
+
     def validate_p2wpkh(self, vin_idx, vin):
         """
         Validate a Pay-to-Witness-Public-Key-Hash (P2WPKH) transaction input
@@ -200,6 +241,7 @@ def validate_p2wpkh(self, vin_idx, vin):
         
         # Execute the script
         try:
+            #return script.execute()
             return script.execute()
         except Exception as e:
             print(f"P2WPKH validation error: {str(e)}")