update packages

add some docs

Sources/Blockchain/Models/Blockchain.swift

@@ -11,6 +11,12 @@ import Foundation
 class Blockchain {
     var chain = [Block]()
     
+    /**
+        Initialize the first block of the blockchain.
+        
+        - Parameters:
+            - data: The datas of the block
+     */
     func createGenesisBlock(data: String) {
         let genesisBlock = Block()
         genesisBlock.data = data
@@ -20,19 +26,63 @@ class Blockchain {
         genesisBlock.timestamp = genesisBlock.generateTimestamp()
         genesisBlock.hash = genesisBlock.generateHash()
         chain.append(genesisBlock)
-        print("Genesis block created -- hash: \(genesisBlock.hash ?? "")")
+        print("Genesis block created -- hash: \(genesisBlock.hash)")
     }
     
+    /**
+        Initialize a new block of the blockchain.
+     
+        - Parameters:
+            - data: The datas of the block
+     */
     func createBlock(data: String) {
         let newBlock = Block()
         newBlock.data = data
-        newBlock.previousHash = chain[chain.count-1].hash
+        newBlock.previousHash = chain.last!.hash
         newBlock.index = chain.count
         newBlock.nonce = 0
         newBlock.timestamp = newBlock.generateTimestamp()
         newBlock.hash = newBlock.generateHash()
         chain.append(newBlock)
         
-        print("Block \(newBlock.index ?? 0) created -- hash: \(newBlock.hash ?? "") previous hash: \(newBlock.previousHash ?? "") data: \(newBlock.data ?? "")")
+        print("-- Block \(newBlock.index) created --\n hash: \(newBlock.hash)\n previous hash: \(newBlock.previousHash)\n data: \(newBlock.data)")
+    }
+    
+    /**
+        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)")
+    }
+    
+    /**
+        Check validity of the blockchain.
+     */
+    func chainValidity() {
+        var isChainValid = true
+        var corruptedBlock = Block()
+        
+        for i in 1...chain.count-1 {
+            if chain[i].previousHash != chain[i-1].hash {
+                isChainValid = false
+                corruptedBlock = chain[i]
+            }
+        }
+        
+        print("Chain is valid : \(isChainValid)")
+        
+        if !isChainValid {
+            print("Corrupted block is : \(corruptedBlock.index)")
+        }
     }
 }