120 lines
3.5 KiB
Swift
120 lines
3.5 KiB
Swift
//
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// Blockchain.swift
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// Blockchain
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//
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// Created by Victor BODINAUD on 27/02/2020.
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// Copyright © 2020 Victor BODINAUD. All rights reserved.
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//
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import Foundation
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class Blockchain {
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var chain = [Block]()
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let memPool: MemPool
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let accountManager: AccountManager
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let minDifficulty = 2
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let maxDifficulty = 6
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let targetBlockTime = 10.0 // en secondes
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init() {
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self.accountManager = AccountManager()
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self.memPool = MemPool(accountManager: accountManager)
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}
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/**
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Initialize the first block of the blockchain.
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- Parameters:
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- data: The datas of the block
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*/
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func createGenesisBlock() {
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let genesisBlock = Block()
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genesisBlock.previousHash = "0000"
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genesisBlock.index = 0
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genesisBlock.timestamp = Int(Date().timeIntervalSince1970)
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let _ = genesisBlock.mineBlock()
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chain.append(genesisBlock)
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print("Genesis block created -- hash: \(genesisBlock.hash)")
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}
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/**
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Initialize a new block of the blockchain.
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- Parameters:
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- data: The datas of the block
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*/
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func createBlock(minerAddress: String) -> Block? {
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guard let lastBlock = chain.last else { return nil }
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// Récupérer les transactions en attente
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var transactions = memPool.getTransactionsForBlock()
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// Ajouter la récompense de minage
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let miningReward = Transaction(sender: "SYSTEM", receiver: minerAddress, amount: 50, type: "MINING_REWARD")
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transactions.append(miningReward)
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let newBlock = Block(
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transactions: transactions,
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previousHash: lastBlock.hash,
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index: chain.count,
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difficulty: calculateNewDifficulty()
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)
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newBlock.miner = minerAddress
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newBlock.timestamp = Int(Date().timeIntervalSince1970)
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let miningTime = newBlock.mineBlock()
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// Valider et traiter les transactions
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if accountManager.processBlock(newBlock) {
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chain.append(newBlock)
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print("""
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Block \(newBlock.index) created:
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Hash: \(newBlock.hash)
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Previous hash: \(newBlock.previousHash)
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Transactions: \(newBlock.transactions.count)
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Mining time: \(String(format: "%.2f", miningTime)) seconds
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""")
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return newBlock
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}
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return nil
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}
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private func calculateNewDifficulty() -> Int {
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guard chain.count >= 2 else { return minDifficulty }
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let lastBlock = chain.last!
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let previousBlock = chain[chain.count - 2]
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let timeSpent = Double(lastBlock.timestamp - previousBlock.timestamp)
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if timeSpent < targetBlockTime / 2 {
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return min(lastBlock.difficulty + 1, maxDifficulty)
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} else if timeSpent > targetBlockTime * 2 {
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return max(lastBlock.difficulty - 1, minDifficulty)
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}
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return lastBlock.difficulty
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}
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func submitTransaction(_ transaction: Transaction) -> Bool {
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return memPool.addTransaction(transaction)
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}
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func getBalance(address: String) -> Int {
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return accountManager.getBalance(address)
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}
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func chainValidity() -> Bool {
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for i in 1..<chain.count {
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let currentBlock = chain[i]
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let previousBlock = chain[i-1]
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if !currentBlock.isValid() || currentBlock.previousHash != previousBlock.hash {
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print("Chain invalid at block \(i)")
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return false
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}
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}
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return true
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}
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}
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