Swift-Blockchain-Chain-1.swift

struct Block: Codable {
    var index: Int64
    var timestamp: Date
    var transactions: [Transaction]
    var proof: Int64
    var previous_hash: String
}

struct Transaction: Codable {
    var sender: String
    var recipient: String
    var amount: Int64
}

protocol Chain: class {

    var chain: [Block] {get}
    var current_transactions: [Transaction] {get}
    var nodes: Set<String> {get}
        
    /**
     # Creates a new block and adds it to the chain
     
     - Parameter proof: <int> The proof given by the Proof of Work algorithm
     - Parameter previous_hash: (Optional) <str> Hash of previous Block
     - returns: _dict_ New Block
     
     */
    func newBlock(previous_hash: String?, proof: Int64) -> Block
    
    /**
     Creates a new transaction to go into the next mined Block
     
     - Parameter sender: Address of the Sender
     - Parameter recipient: Address of the Recipient
     - Parameter amount: Amount
     - returns: The index of the Block that will hold this transaction
     */
    func newTransaction(sender: String, recipient: String, amount: Int64) -> Int64
    
    /**
     Returns the last Block in the chain
     */
    var last_block: Block {get}
    
    /**
     Creates a SHA-256 hash of a Block
     
     - Parameter block: <dict> Block
     - returns: String
     
     */
    func hash(block: Block) -> String
   
}