✨Add mempool & transactions

SwiftChain/Models/AccountManager.swift

@@ -0,0 +1,72 @@
+//
+//  AccountManager.swift
+//  SwiftChain
+//
+//  Created by Victor on 27/11/2024.
+//
+
+class AccountManager {
+    private var accounts: [String: Account] = [:]
+
+    // Mining reward amount
+    private let miningReward = 50
+
+    func getAccount(_ address: String) -> Account {
+        if let account = accounts[address] {
+            return account
+        }
+        let newAccount = Account(id: address, balance: 0)
+        accounts[address] = newAccount
+        return newAccount
+    }
+
+    func canProcessTransaction(_ transaction: Transaction) -> Bool {
+        // Mining rewards are always valid
+        if transaction.type == "MINING_REWARD" {
+            return true
+        }
+
+        let senderAccount = getAccount(transaction.sender)
+        return senderAccount.balance >= transaction.amount
+    }
+
+    func processTransaction(_ transaction: Transaction) -> Bool {
+        if !canProcessTransaction(transaction) {
+            return false
+        }
+
+        if transaction.type == "MINING_REWARD" {
+            let minerAccount = getAccount(transaction.receiver)
+            minerAccount.balance += miningReward
+            return true
+        }
+
+        let senderAccount = getAccount(transaction.sender)
+        let receiverAccount = getAccount(transaction.receiver)
+
+        senderAccount.balance -= transaction.amount
+        receiverAccount.balance += transaction.amount
+
+        return true
+    }
+
+    func getBalance(_ address: String) -> Int {
+        return getAccount(address).balance
+    }
+
+    func processBlock(_ block: Block) -> Bool {
+        // Create temporary state to validate all transactions
+        let tempAccounts = accounts
+
+        // Try to process all transactions
+        for transaction in block.transactions {
+            if !processTransaction(transaction) {
+                // Restore previous state if any transaction fails
+                accounts = tempAccounts
+                return false
+            }
+        }
+
+        return true
+    }
+}

SwiftChain/Models/Block.swift

@@ -11,49 +11,71 @@ import CryptoSwift
 
 class Block {
     var hash: String
-    var data: String
+    var transactions: [Transaction]
     var previousHash: String
     var index: Int
     var nonce: Int
     var timestamp: Int
+    var difficulty: Int
+    var miner: String? // Adresse qui recevra la récompense
 
-    /**
-        Initialize a block with the provided parts and specifications.
-     
-        - parameters:
-            - hash: The hash of the block
-            - data: The data of the block
-            - previousHash: The hash of the previous block
-            - index: The index of the block
-            - nonce: The nonce of the block
-            - timestamp: The timestamp of the block
-     
-        - returns: A beautiful new block for the blockchain.
-     */
-    init(hash: String = "", data: String = "", previousHash: String = "", index: Int = 0, nonce: Int = 0, timestamp: Int = 0) {
-        self.data = data
+    init(hash: String = "", transactions: [Transaction] = [], previousHash: String = "",
+         index: Int = 0, nonce: Int = 0, timestamp: Int = 0, difficulty: Int = 4) {
+        self.hash = hash
+        self.transactions = transactions
         self.previousHash = previousHash
         self.index = index
         self.nonce = nonce
         self.timestamp = timestamp
-        self.hash = hash
+        self.difficulty = difficulty
+    }
+
+    func mineBlock() -> Double {
+        let startTime = Date()
+        let target = String(repeating: "0", count: difficulty)
+
+        print("Mining block \(index) with difficulty \(difficulty)...")
+
+        repeat {
+            nonce += 1
+            hash = generateHash()
+        } while !hash.hasPrefix(target)
+
+        let timeElapsed = Date().timeIntervalSince(startTime)
+        print("Block mined! Nonce: \(nonce), Hash: \(hash)")
+
+        return timeElapsed
+    }
+
+    func isValid() -> Bool {
+        let target = String(repeating: "0", count: difficulty)
+        return hash == generateHash() && hash.hasPrefix(target)
     }
 
     /**
-        Generate the hash of the block.
-     
-        - returns: The hash of the block
+     Génère le hash en incluant toutes les transactions
      */
     func generateHash() -> String {
-        return data.sha256()
+        let txData = transactions.map {
+            "\($0.sender)\($0.receiver)\($0.amount)\($0.type)"
+        }.joined()
+
+        return "\(previousHash)\(txData)\(String(timestamp))\(String(index))\(String(nonce))".sha256()
     }
 
     /**
-        Generate the timestamp of the block
-     
-        - returns: The timestamp of the block
+     Calcule le montant total des transactions dans le bloc
      */
-    func generateTimestamp() -> Int {
-        return Int(Date().timeIntervalSince1970)
+    func getTotalAmount() -> Int {
+        return transactions.reduce(0) { $0 + $1.amount }
+    }
+
+    /**
+     Vérifie si le bloc contient une transaction spécifique
+     */
+    func containsTransaction(_ txId: String) -> Bool {
+        return transactions.contains { tx in
+            "\(tx.sender)\(tx.receiver)\(tx.amount)".sha256() == txId
+        }
     }
 }

SwiftChain/Models/Blockchain.swift

@@ -10,6 +10,16 @@ import Foundation
 
 class Blockchain {
     var chain = [Block]()
+    let memPool: MemPool
+    let accountManager: AccountManager
+    let minDifficulty = 2
+    let maxDifficulty = 6
+    let targetBlockTime = 10.0 // en secondes
+
+    init() {
+        self.accountManager = AccountManager()
+        self.memPool = MemPool(accountManager: accountManager)
+    }
 
     /**
         Initialize the first block of the blockchain.
@@ -17,14 +27,12 @@ class Blockchain {
         - Parameters:
             - data: The datas of the block
      */
-    func createGenesisBlock(data: String) {
+    func createGenesisBlock() {
         let genesisBlock = Block()
-        genesisBlock.data = data
         genesisBlock.previousHash = "0000"
         genesisBlock.index = 0
-        genesisBlock.nonce = 0
-        genesisBlock.timestamp = genesisBlock.generateTimestamp()
-        genesisBlock.hash = genesisBlock.generateHash()
+        genesisBlock.timestamp = Int(Date().timeIntervalSince1970)
+        genesisBlock.mineBlock()
         chain.append(genesisBlock)
         print("Genesis block created -- hash: \(genesisBlock.hash)")
     }
@@ -35,54 +43,77 @@ class Blockchain {
         - Parameters:
             - data: The datas of the block
      */
-    func createBlock(data: String) {
-        let newBlock = Block()
-        newBlock.data = data
-        newBlock.previousHash = chain.last!.hash
-        newBlock.index = chain.count
-        newBlock.nonce = 0
-        newBlock.timestamp = newBlock.generateTimestamp()
-        newBlock.hash = newBlock.generateHash()
+    func createBlock(minerAddress: String) -> Block? {
+        guard let lastBlock = chain.last else { return nil }
+
+        // Récupérer les transactions en attente
+        var transactions = memPool.getTransactionsForBlock()
+
+        // Ajouter la récompense de minage
+        let miningReward = Transaction(sender: "SYSTEM", receiver: minerAddress, amount: 50, type: "MINING_REWARD")
+        transactions.append(miningReward)
+
+        let newBlock = Block(
+            transactions: transactions,
+            previousHash: lastBlock.hash,
+            index: chain.count,
+            difficulty: calculateNewDifficulty()
+        )
+
+        newBlock.miner = minerAddress
+        newBlock.timestamp = Int(Date().timeIntervalSince1970)
+        let miningTime = newBlock.mineBlock()
+
+        // Valider et traiter les transactions
+        if accountManager.processBlock(newBlock) {
             chain.append(newBlock)
-        
-        print("-- Block \(newBlock.index) created --\n hash: \(newBlock.hash)\n previous hash: \(newBlock.previousHash)\n data: \(newBlock.data)")
+            print("""
+                Block \(newBlock.index) created:
+                Hash: \(newBlock.hash)
+                Previous hash: \(newBlock.previousHash)
+                Transactions: \(newBlock.transactions.count)
+                Mining time: \(String(format: "%.2f", miningTime)) seconds
+                """)
+            return newBlock
         }
 
-    /**
-        Insert a corrupted block in the blockhain.
-        (for testing purpose)
-     */
-    func insertCorruptedBlock() {
-        let newCorruptedBlock = Block()
-        newCorruptedBlock.data = "Corrupted block"
-        newCorruptedBlock.previousHash = "1234567890"
-        newCorruptedBlock.index = chain.count
-        newCorruptedBlock.nonce = 0
-        newCorruptedBlock.timestamp = newCorruptedBlock.generateTimestamp()
-        newCorruptedBlock.hash = newCorruptedBlock.generateHash()
-        chain.append(newCorruptedBlock)
-        
-        print("-- Corrupted block \(newCorruptedBlock.index) created --\n hash: \(newCorruptedBlock.hash)\n previous hash: \(newCorruptedBlock.previousHash)\n data: \(newCorruptedBlock.data)")
+        return nil
     }
 
-    /**
-        Check validity of the blockchain.
-     */
-    func chainValidity() {
-        var isChainValid = true
-        var corruptedBlock = Block()
+    private func calculateNewDifficulty() -> Int {
+        guard chain.count >= 2 else { return minDifficulty }
 
-        for i in 1...chain.count-1 {
-            if chain[i].previousHash != chain[i-1].hash {
-                isChainValid = false
-                corruptedBlock = chain[i]
-            }
+        let lastBlock = chain.last!
+        let previousBlock = chain[chain.count - 2]
+        let timeSpent = Double(lastBlock.timestamp - previousBlock.timestamp)
+
+        if timeSpent < targetBlockTime / 2 {
+            return min(lastBlock.difficulty + 1, maxDifficulty)
+        } else if timeSpent > targetBlockTime * 2 {
+            return max(lastBlock.difficulty - 1, minDifficulty)
         }
 
-        print("Chain is valid : \(isChainValid)")
-        
-        if !isChainValid {
-            print("Corrupted block is : \(corruptedBlock.index)")
+        return lastBlock.difficulty
     }
+
+    func submitTransaction(_ transaction: Transaction) -> Bool {
+        return memPool.addTransaction(transaction)
+    }
+
+    func getBalance(address: String) -> Int {
+        return accountManager.getBalance(address)
+    }
+
+    func chainValidity() -> Bool {
+        for i in 1..<chain.count {
+            let currentBlock = chain[i]
+            let previousBlock = chain[i-1]
+
+            if !currentBlock.isValid() || currentBlock.previousHash != previousBlock.hash {
+                print("Chain invalid at block \(i)")
+                return false
+            }
+        }
+        return true
     }
 }

SwiftChain/Models/MemPool.swift

@@ -0,0 +1,84 @@
+//
+//  MemPool.swift
+//  SwiftChain
+//
+//  Created by Victor on 27/11/2024.
+//
+
+class MemPool {
+    private var pendingTransactions: [Transaction] = []
+    private let maxTransactionsPerBlock: Int = 10
+    private let accountManager: AccountManager
+
+    init(accountManager: AccountManager) {
+        self.accountManager = accountManager
+    }
+
+    /**
+     Ajoute une transaction au mempool après validation
+     */
+    func addTransaction(_ transaction: Transaction) -> Bool {
+        if validateTransaction(transaction) {
+            pendingTransactions.append(transaction)
+            return true
+        }
+        return false
+    }
+
+    /**
+     Valide une transaction avant de l'ajouter au pool
+     */
+    private func validateTransaction(_ transaction: Transaction) -> Bool {
+        // Basic validations
+        if transaction.amount <= 0 {
+            return false
+        }
+
+        // Skip balance check for mining rewards
+        if transaction.type == "MINING_REWARD" {
+            return true
+        }
+
+        // Check if sender has enough balance
+        return accountManager.canProcessTransaction(transaction)
+    }
+
+    /**
+     Récupère un lot de transactions prêtes pour le prochain bloc
+     */
+    func getTransactionsForBlock() -> [Transaction] {
+        var validTransactions: [Transaction] = []
+        var remainingTransactions: [Transaction] = []
+
+        for transaction in pendingTransactions {
+            if validTransactions.count >= maxTransactionsPerBlock {
+                break
+            }
+
+            if validateTransaction(transaction) {
+                validTransactions.append(transaction)
+            } else {
+                remainingTransactions.append(transaction)
+            }
+        }
+
+        // Update pending transactions, removing the selected ones
+        pendingTransactions = remainingTransactions + pendingTransactions.dropFirst(validTransactions.count)
+
+        return validTransactions
+    }
+
+    /**
+     Vérifie si il y a des transactions en attente
+     */
+    var hasPendingTransactions: Bool {
+        return !pendingTransactions.isEmpty
+    }
+
+    /**
+     Retourne toutes les transactions en attente sans les retirer
+     */
+    func getAllPendingTransactions() -> [Transaction] {
+        return pendingTransactions
+    }
+}

SwiftChain/main.swift

@@ -10,35 +10,90 @@ import Foundation
 
 let blockchain = Blockchain()
 var command: String?
+var currentMinerAddress = "MINER1" // Adresse par défaut du mineur
 
-blockchain.createGenesisBlock(data: "")
+print("""
+Blockchain CLI - Commandes disponibles:
+- mine : Miner un nouveau bloc
+- send : Envoyer des tokens
+- balance : Voir le solde d'une adresse
+- pending : Voir les transactions en attente
+- validity : Vérifier la validité de la chaîne
+- setminer : Changer l'adresse du mineur
+- exit : Quitter
+""")
+
+blockchain.createGenesisBlock()
 
 repeat {
-    print("Enter command:")
-    command = readLine()
+    print("\nEntrer une commande:")
+    command = readLine()?.lowercased()
 
-    // Create a new block
-    if command == "create" {
-        print("data for the new block:")
-        let data = readLine()
-        blockchain.createBlock(data: data ?? "")
+    switch command {
+    case "mine":
+        if let block = blockchain.createBlock(minerAddress: currentMinerAddress) {
+            print("Bloc miné avec succès. Récompense envoyée à \(currentMinerAddress)")
+            print("Nouveau solde: \(blockchain.getBalance(address: currentMinerAddress))")
+        } else {
+            print("Échec du minage")
         }
 
-    // Create a lot of blocks
-    if command == "spam" {
-        for _ in 1...1000 {
-            blockchain.createBlock(data: "\((blockchain.chain.last?.index ?? 0)+1)")
+    case "send":
+        print("Adresse de l'expéditeur:")
+        let sender = readLine() ?? ""
+        print("Adresse du destinataire:")
+        let receiver = readLine() ?? ""
+        print("Montant:")
+        if let amountStr = readLine(), let amount = Int(amountStr) {
+            let transaction = Transaction(
+                sender: sender,
+                receiver: receiver,
+                amount: amount,
+                type: "TRANSFER"
+            )
+
+            if blockchain.submitTransaction(transaction) {
+                print("Transaction ajoutée au mempool")
+            } else {
+                print("Transaction invalide")
             }
         }
 
-    // Check validity of the blockchain
-    if command == "validity" {
-        blockchain.chainValidity()
+    case "balance":
+        print("Entrer l'adresse:")
+        if let address = readLine() {
+            let balance = blockchain.getBalance(address: address)
+            print("Solde de \(address): \(balance)")
         }
 
-    // Insert a corrupted block
-    if command == "corrupt" {
-        blockchain.insertCorruptedBlock()
+    case "setminer":
+        print("Nouvelle adresse du mineur:")
+        if let address = readLine() {
+            currentMinerAddress = address
+            print("Adresse du mineur mise à jour: \(currentMinerAddress)")
+        }
+
+    case "pending":
+        let transactions = blockchain.memPool.getAllPendingTransactions()
+        print("Transactions en attente: \(transactions.count)")
+        for (index, tx) in transactions.enumerated() {
+            print("""
+                \(index + 1). De: \(tx.sender)
+                   À: \(tx.receiver)
+                   Montant: \(tx.amount)
+                   Type: \(tx.type)
+                """)
+        }
+
+    case "validity":
+        let isValid = blockchain.chainValidity()
+        print("Chaîne valide: \(isValid)")
+
+    case "exit":
+        print("Au revoir!")
+
+    default:
+        print("Commande inconnue")
     }
 
 } while command != "exit"