From e1b5ea1bd6933429b322657b1d1614d7883e6bce Mon Sep 17 00:00:00 2001
From: KOSASIH <kosasihg88@gmail.com>
Date: Tue, 26 Nov 2024 13:50:56 +0700
Subject: [PATCH] Create blockchain.py

---
 QuantumNexusProtocol/src/core/blockchain.py | 96 +++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 QuantumNexusProtocol/src/core/blockchain.py

diff --git a/QuantumNexusProtocol/src/core/blockchain.py b/QuantumNexusProtocol/src/core/blockchain.py
new file mode 100644
index 000000000..051cf3606
--- /dev/null
+++ b/QuantumNexusProtocol/src/core/blockchain.py
@@ -0,0 +1,96 @@
+import hashlib
+import json
+from time import time
+
+class Block:
+    def __init__(self, index, previous_hash, transactions, timestamp=None):
+        self.index = index
+        self.previous_hash = previous_hash
+        self.transactions = transactions
+        self.timestamp = timestamp or time()
+        self.hash = self.calculate_hash()
+
+    def calculate_hash(self):
+        block_string = json.dumps(self.__dict__, sort_keys=True).encode()
+        return hashlib.sha256(block_string).hexdigest()
+
+class Blockchain:
+    def __init__(self):
+        self.chain = []
+        self.current_transactions = []
+        self.difficulty = 4  # Difficulty for mining new blocks
+        self.max_block_size = 1024  # Maximum block size in bytes
+
+        # Create the genesis block
+        self.create_block(previous_hash='1', transactions=[])
+
+    def create_block(self, previous_hash, transactions):
+        block = Block(
+            index=len(self.chain) + 1,
+            previous_hash=previous_hash,
+            transactions=transactions
+        )
+        self.chain.append(block)
+        self.current_transactions = []  # Reset current transactions
+        return block
+
+    def add_transaction(self, sender, recipient, amount):
+        transaction = {
+            'sender': sender,
+            'recipient': recipient,
+            'amount': amount
+        }
+        transaction_size = len(json.dumps(transaction).encode())
+        
+        if self.get_current_block_size() + transaction_size > self.max_block_size:
+            raise Exception("Transaction exceeds maximum block size.")
+        
+        self.current_transactions.append(transaction)
+        return self.get_last_block().index + 1  # Return the index of the block that will hold this transaction
+
+    def get_last_block(self):
+        return self.chain[-1] if self.chain else None
+
+    def validate_chain(self):
+        for i in range(1, len(self.chain)):
+            current = self.chain[i]
+            previous = self.chain[i - 1]
+
+            # Check if the hash of the block is correct
+            if current.hash != current.calculate_hash():
+                return False
+
+            # Check if the previous block's hash is correct
+            if current.previous_hash != previous.hash:
+                return False
+
+        return True
+
+    def get_current_block_size(self):
+        return sum(len(json.dumps(tx).encode()) for tx in self.current_transactions)
+
+    def mine_block(self, miner_address):
+        if not self.current_transactions:
+            raise Exception("No transactions to mine.")
+
+        previous_block = self.get_last_block()
+        previous_hash = previous_block.hash
+
+        # Create a new block with the current transactions
+        block = self.create_block(previous_hash, self.current_transactions)
+
+        # Reward the miner
+        self.add_transaction(sender="system", recipient=miner_address, amount=1)  # Reward for mining
+
+        return block
+
+    def get_chain(self):
+        return [block.__dict__ for block in self.chain]
+
+    def get_transaction_history(self):
+        return self.current_transactions
+
+    def get_block_by_index(self, index):
+        if index < 0 or index >= len(self.chain):
+            raise Exception("Block index out of range.")
+        return self.chain[index]