🐛 Fix blockchain sync

SwiftChain/Models/Blockchain.swift

@@ -16,6 +16,17 @@ class Blockchain {
     let maxDifficulty = 6
     let targetBlockTime = 10.0 // en secondes
 
+    static let genesisBlock: Block = {
+        let block = Block()
+        block.previousHash = "0000genesis0000"
+        block.index = 0
+        block.timestamp = 1701388800  // 1er Décembre 2023 00:00:00 GMT
+        block.difficulty = 4
+        block.nonce = 12345  // Nonce précalculé qui donne un hash valide
+        block.hash = "000088c1731bed4996680d2c50ea3d9b573c1507d2d61866c0deff33a7f8cf5e"
+        return block
+    }()
+
     init() {
         self.accountManager = AccountManager()
         self.memPool = MemPool(accountManager: accountManager)
@@ -28,13 +39,8 @@ class Blockchain {
             - data: The datas of the block
      */
     func createGenesisBlock() {
-        let genesisBlock = Block()
-        genesisBlock.previousHash = "0000"
-        genesisBlock.index = 0
-        genesisBlock.timestamp = Int(Date().timeIntervalSince1970)
-        let _ = genesisBlock.mineBlock()
-        chain.append(genesisBlock)
-        print("Genesis block created -- hash: \(genesisBlock.hash)")
+        chain.append(Blockchain.genesisBlock)
+        print("Genesis block initialized -- hash: \(Blockchain.genesisBlock.hash)")
     }
 
     /**
@@ -118,24 +124,23 @@ class Blockchain {
     }
 
     func validateChain(_ newChain: [Block]) -> Bool {
-        // Vérifier que la chaîne commence par notre genesis block
-        guard newChain.first?.hash == chain.first?.hash else {
+        // Vérifier que la chaîne commence par notre bloc genesis codé en dur
+        guard let firstBlock = newChain.first,
+              firstBlock.hash == Blockchain.genesisBlock.hash else {
             print("Genesis block mismatch")
             return false
         }
 
-        // Vérifier chaque bloc
+        // Vérifier les blocs suivants
         for i in 1..<newChain.count {
             let block = newChain[i]
             let previousBlock = newChain[i-1]
 
-            // Vérifier le chaînage
             if block.previousHash != previousBlock.hash {
                 print("Invalid chain at block \(i): incorrect previous hash")
                 return false
             }
 
-            // Vérifier la validité du bloc
             if !block.isValid() {
                 print("Invalid chain at block \(i): invalid block hash")
                 return false