//
//  File.swift
//
//
//  Created by Victor BODINAUD on 31/03/2021.
//

import Foundation

public class Transaction: Codable {
    public let sender: String
    public let receiver: String
    public let amount: Int
    public let type: String
    public var signature: Data?
    public var senderPublicKey: Data?

    public init(sender: String, receiver: String, amount: Int, type: String) {
        self.sender = sender
        self.receiver = receiver
        self.amount = amount
        self.type = type
    }

    // Pour encoder/décoder les Data optionnels
    enum CodingKeys: String, CodingKey {
        case sender, receiver, amount, type, signature, senderPublicKey
    }

    func messageToSign() -> Data {
        return "\(sender)\(receiver)\(amount)\(type)".data(using: .utf8)!
    }

    func isSignatureValid() -> Bool {
        guard let signature = signature,
              let publicKeyData = senderPublicKey
        else {
            return false
        }

        if type == "MINING_REWARD" {
            return true
        }

        return Wallet.verifySignature(
            for: self,
            signature: signature,
            publicKeyData: publicKeyData
        )
    }

    func isValid() -> Bool {
        // Vérifications de base
        if amount <= 0 {
            print("Transaction: Amount must be positive")
            return false
        }

        if sender.isEmpty || receiver.isEmpty {
            print("Transaction: Invalid addresses")
            return false
        }

        // Vérification du type
        if !["TRANSFER", "MINING_REWARD"].contains(type) {
            print("Transaction: Invalid type")
            return false
        }

        // Vérifications spécifiques selon le type
        if type == "MINING_REWARD" {
            if sender != "SYSTEM" {
                print("Transaction: Mining reward must come from SYSTEM")
                return false
            }
            if amount != 50 { // La récompense doit être exactement 50
                print("Transaction: Invalid mining reward amount")
                return false
            }
            return true // Pas besoin de vérifier la signature pour les récompenses
        }

        // Pour les transactions normales
        if !isSignatureValid() {
            print("Transaction: Invalid signature")
            return false
        }

        if sender == receiver {
            print("Transaction: Sender cannot be receiver")
            return false
        }

        return true
    }
}