Feat/fee handling

main.py

@@ -27,11 +27,11 @@
 
 from minichain import Transaction, Blockchain, Block, State, Mempool, P2PNetwork, mine_block
 from minichain.validators import is_valid_receiver
+from minichain.block import calculate_receipt_root
 
 
 logger = logging.getLogger(__name__)
 
-BURN_ADDRESS = "0" * 40
 TRUSTED_PEERS = set()
 LOCALHOST_PEERS = {"127.0.0.1", "::1", "localhost", "0:0:0:0:0:0:0:1"}
 
@@ -61,13 +61,17 @@ def mine_and_process_block(chain, mempool, miner_pk):
     temp_state = chain.state.copy()
     mineable_txs = []
     stale_txs = []
+    receipts = []
     for tx in pending_txs:
         expected_nonce = temp_state.get_account(tx.sender).get("nonce", 0)
         if tx.nonce < expected_nonce:
             stale_txs.append(tx)
             continue
-        if temp_state.validate_and_apply(tx):
+
+        receipt = temp_state.validate_and_apply(tx)
+        if receipt is not None:
             mineable_txs.append(tx)
+            receipts.append(receipt)
 
     if stale_txs:
         mempool.remove_transactions(stale_txs)
@@ -76,12 +80,16 @@ def mine_and_process_block(chain, mempool, miner_pk):
         logger.info("No mineable transactions in current queue window.")
         return None
 
-    temp_state.credit_mining_reward(miner_pk)
+    total_fees = sum(getattr(tx, 'fee', 0) for tx in mineable_txs)
+    temp_state.credit_mining_reward(miner_pk, reward=temp_state.DEFAULT_MINING_REWARD + total_fees)
 
     block = Block(
         index=chain.last_block.index + 1,
         previous_hash=chain.last_block.hash,
         transactions=mineable_txs,
+        state_root=temp_state.state_root(),
+        receipt_root=calculate_receipt_root(receipts),
+        receipts=receipts,
         miner=miner_pk,
     )
 
@@ -206,23 +214,27 @@ async def cli_loop(sk, pk, chain, mempool, network):
         # ── send ──
         elif cmd == "send":
             if len(parts) < 3:
-                print("  Usage: send <receiver_address> <amount>")
+                print("  Usage: send <receiver_address> <amount> [fee]")
                 continue
             receiver = parts[1]
             if not is_valid_receiver(receiver):
                 print("  Invalid receiver format. Expected 40 or 64 hex characters.")
                 continue
             try:
                 amount = int(parts[2])
+                fee = int(parts[3]) if len(parts) > 3 else 0
             except ValueError:
-                print("  Amount must be an integer.")
+                print("  Amount and fee must be integers.")
                 continue
             if amount <= 0:
                 print("  Amount must be greater than 0.")
                 continue
+            if fee < 0:
+                print("  Fee cannot be negative.")
+                continue
 
             nonce = chain.state.get_account(pk).get("nonce", 0)
-            tx = Transaction(sender=pk, receiver=receiver, amount=amount, nonce=nonce)
+            tx = Transaction(sender=pk, receiver=receiver, amount=amount, nonce=nonce, fee=fee)
             tx.sign(sk)
 
             if mempool.add_transaction(tx):

minichain/block.py

@@ -4,36 +4,36 @@
 from collections.abc import Sequence
 
 from .transaction import Transaction
+from .receipt import Receipt
 from .serialization import canonical_json_hash, canonical_json_bytes
 
-
 def _sha256(data: str) -> str:
     return hashlib.sha256(data.encode()).hexdigest()
 
-# <-- Updated to Sequence to accept the frozen tuple
-def _calculate_merkle_root(transactions: Sequence[Transaction]) -> Optional[str]:
-    if not transactions:
+def _calculate_merkle_tree(hashes: Sequence[str]) -> Optional[str]:
+    if not hashes:
         return None
-
-    # Hash each transaction deterministically
-    tx_hashes = [
-        tx.tx_id
-        for tx in transactions
-    ]
-
-    # Build Merkle tree
-    while len(tx_hashes) > 1:
-        if len(tx_hashes) % 2 != 0:
-            tx_hashes.append(tx_hashes[-1])  # duplicate last if odd
-
+    hashes_list = list(hashes)
+    while len(hashes_list) > 1:
+        if len(hashes_list) % 2 != 0:
+            hashes_list.append(hashes_list[-1])
         new_level = []
-        for i in range(0, len(tx_hashes), 2):
-            combined = tx_hashes[i] + tx_hashes[i + 1]
+        for i in range(0, len(hashes_list), 2):
+            combined = hashes_list[i] + hashes_list[i + 1]
             new_level.append(_sha256(combined))
+        hashes_list = new_level
+    return hashes_list[0]
 
-        tx_hashes = new_level
+# <-- Updated to Sequence to accept the frozen tuple
+def _calculate_merkle_root(transactions: Sequence[Transaction]) -> Optional[str]:
+    if not transactions:
+        return None
+    return _calculate_merkle_tree([tx.tx_id for tx in transactions])
 
-    return tx_hashes[0]
+def calculate_receipt_root(receipts: Sequence[Receipt]) -> Optional[str]:
+    if not receipts:
+        return None
+    return _calculate_merkle_tree([canonical_json_hash(r.to_dict()) for r in receipts])
 
 class Block:
     def __init__(
@@ -43,12 +43,16 @@ def __init__(
         transactions: Optional[Sequence[Transaction]] = None,
         timestamp: Optional[float] = None,
         difficulty: Optional[int] = None,
-        miner: Optional[str] = None
+        state_root: Optional[str] = None,
+        receipt_root: Optional[str] = None,
+        receipts: Optional[Sequence[Receipt]] = None,
+        miner: Optional[str] = None,
     ):
         self.index = index
         self.previous_hash = previous_hash
         # Freeze transactions into an immutable tuple to prevent header/body mismatch
         self.transactions = tuple(transactions) if transactions else ()
+        self.receipts = tuple(receipts) if receipts else ()
         self.miner = miner
         # Deterministic timestamp (ms)
         self.timestamp: int = (
@@ -60,10 +64,15 @@ def __init__(
         self.nonce: int = 0
         self.hash: Optional[str] = None
         self.state_root: Optional[str] = state_root
+        self.receipt_root: Optional[str] = receipt_root
         self.miner: Optional[str] = miner
 
-        # NEW: compute merkle root once
+        # NEW: compute merkle roots once
         self.merkle_root: Optional[str] = _calculate_merkle_root(self.transactions)
+
+        # If receipt_root is missing but we have receipts, calculate it.
+        if self.receipt_root is None and self.receipts:
+            self.receipt_root = calculate_receipt_root(self.receipts)
 
     # -------------------------
     # HEADER (used for mining)
@@ -74,10 +83,10 @@ def to_header_dict(self):
             "previous_hash": self.previous_hash,
             "merkle_root": self.merkle_root,
             "state_root": self.state_root,
+            "receipt_root": self.receipt_root,
             "timestamp": self.timestamp,
             "difficulty": self.difficulty,
             "nonce": self.nonce,
-            "miner": self.miner,
         }
         # Include miner in header only when present (optional field)  <-- Reworded comment
         if self.miner is not None:
@@ -91,6 +100,9 @@ def to_body_dict(self):
         return {
             "transactions": [
                 tx.to_dict() for tx in self.transactions
+            ],
+            "receipts": [
+                r.to_dict() for r in self.receipts
             ]
         }
 
@@ -115,6 +127,10 @@ def from_dict(cls, payload: dict):
             Transaction.from_dict(tx_payload)
             for tx_payload in payload.get("transactions", [])
         ]
+        receipts = [
+            Receipt.from_dict(r_payload)
+            for r_payload in payload.get("receipts", [])
+        ]
 
         # Safely extract and cast difficulty if it exists
         raw_diff = payload.get("difficulty")
@@ -123,13 +139,15 @@ def from_dict(cls, payload: dict):
         # Safely extract and cast timestamp if it exists <-- Added explicit timestamp casting
         raw_ts = payload.get("timestamp")
         parsed_ts = int(raw_ts) if raw_ts is not None else None
-
         block = cls(
             index=int(payload["index"]),  
             previous_hash=payload["previous_hash"],
             transactions=transactions,
             timestamp=parsed_ts,          # <-- Passed the casted timestamp
             difficulty=parsed_diff,       
+            state_root=payload.get("state_root"),
+            receipt_root=payload.get("receipt_root"),
+            receipts=receipts,
             miner=payload.get("miner"),
         )
         block.nonce = int(payload.get("nonce", 0))  
@@ -143,6 +161,12 @@ def from_dict(cls, payload: dict):
         # Recalculate and verify the Merkle root!
         if "merkle_root" in payload and payload["merkle_root"] != block.merkle_root:
             raise ValueError("merkle_root does not match transactions")
+
+        if "receipt_root" in payload:
+            expected_receipt_root = calculate_receipt_root(block.receipts)
+            if payload["receipt_root"] != expected_receipt_root:
+                raise ValueError("receipt_root does not match receipts")
+
         return block
 
     @property

minichain/chain.py

@@ -1,4 +1,4 @@
-from .block import Block
+from .block import Block, calculate_receipt_root
 from .state import State
 from .pow import calculate_hash
 import logging
@@ -47,18 +47,18 @@ def _create_genesis_block(self, genesis_path):
                 with open(genesis_path, "r") as f:
                     config = json.load(f)
             except Exception as e:
-                logger.error(f"Failed to load genesis config: {e}")
+                logger.error("Failed to load genesis config: %s", e)
                 sys.exit(1)
         else:
-            logger.error(f"Failed to load genesis config: file {genesis_path} does not exist.")
+            logger.error("Failed to load genesis config: file %s does not exist.", genesis_path)
             sys.exit(1)
 
         # Apply genesis allocations
         alloc = config.get("alloc", {})
         for address, data in alloc.items():
             balance = data.get("balance", 0)
             if not isinstance(balance, int) or balance < 0:
-                logger.error(f"Invalid genesis balance for {address}: {balance}. Must be a non-negative integer.")
+                logger.error("Invalid genesis balance for %s: %s. Must be a non-negative integer.", address, balance)
                 sys.exit(1)
             account = self.state.get_account(address)
             account['balance'] = balance
@@ -72,15 +72,17 @@ def _create_genesis_block(self, genesis_path):
             transactions=[],
             timestamp=timestamp,
             difficulty=difficulty,
-            state_root=self.state.state_root()
+            state_root=self.state.state_root(),
+            receipt_root=None,
+            receipts=[]
         )
 
         computed_hash = calculate_hash(genesis_block.to_header_dict())
         config_hash = config.get("hash")
 
         if config_hash:
             if config_hash != computed_hash:
-                logger.error(f"Genesis hash mismatch. Config hash: {config_hash}, Computed hash: {computed_hash}")
+                logger.error("Genesis hash mismatch. Config hash: %s, Computed hash: %s", config_hash, computed_hash)
                 sys.exit(1)
             genesis_block.hash = config_hash
         else:
@@ -111,17 +113,30 @@ def add_block(self, block):
 
             # Validate transactions on a temporary state copy
             temp_state = self.state.copy()
+            receipts = []
 
             for tx in block.transactions:
-                result = temp_state.validate_and_apply(tx)
+                receipt = temp_state.validate_and_apply(tx)
 
-                # Reject block if any transaction fails
-                if not result:
+                # Reject block if any transaction fails mathematical validation (None)
+                if receipt is None:
                     logger.warning("Block %s rejected: Transaction failed validation", block.index)
                     return False
+
+                receipts.append(receipt)
 
+            total_fees = sum(getattr(tx, 'fee', 0) for tx in block.transactions)
             if block.miner:
-                temp_state.credit_mining_reward(block.miner)
+                temp_state.credit_mining_reward(block.miner, reward=temp_state.DEFAULT_MINING_REWARD + total_fees)
+
+            computed_receipt_root = calculate_receipt_root(receipts)
+            if block.receipt_root != computed_receipt_root:
+                logger.warning("Block %s rejected: Invalid receipt root. Expected %s, got %s", block.index, computed_receipt_root, block.receipt_root)
+                return False
+
+            if [r.to_dict() for r in block.receipts] != [r.to_dict() for r in receipts]:
+                logger.warning("Block %s rejected: Receipts payload mismatch", block.index)
+                return False
 
             # Verify state root
             if block.state_root != temp_state.state_root():

minichain/contract.py

@@ -114,7 +114,7 @@ def execute(self, contract_address, sender_address, payload, amount):
                 logger.error("Contract execution crashed without result")
                 return False
             if result["status"] != "success":
-                logger.error(f"Contract Execution Failed: {result.get('error')}")
+                logger.error("Contract Execution Failed: %s", result.get('error'))
                 return False
 
             # Validate storage is JSON serializable
@@ -155,7 +155,7 @@ def _validate_code_ast(self, code):
                         logger.warning("Rejected type() call.")
                         return False
                 if isinstance(node, ast.Call) and isinstance(node.func, ast.Name) and node.func.id in {"getattr", "setattr", "delattr"}:
-                    logger.warning(f"Rejected direct call to {node.func.id}.")
+                    logger.warning("Rejected direct call to %s.", node.func.id)
                     return False
                 if isinstance(node, ast.Constant) and isinstance(node.value, str):
                     if "__" in node.value:

minichain/mempool.py

@@ -51,7 +51,9 @@ def get_transactions_for_block(self):
 
             for sender, txs in snapshot.items():
                 if txs:
-                    if best_tx is None or (txs[0].timestamp, sender, txs[0].nonce) < (best_tx.timestamp, best_sender, best_tx.nonce):
+                    current_criteria = (-getattr(txs[0], 'fee', 0), txs[0].timestamp, sender, txs[0].nonce)
+                    best_criteria = (-getattr(best_tx, 'fee', 0), best_tx.timestamp, best_sender, best_tx.nonce) if best_tx else None
+                    if best_tx is None or current_criteria < best_criteria:
                         best_tx = txs[0]
                         best_sender = sender