WalletManager.swift

//
//  WalletManager.swift
//  SLPWalletDemo
//
//  Created by Jean-Baptiste Dominguez on 2019/03/06.
//  Copyright © 2019 Bitcoin.com. All rights reserved.
//

import SLPWallet
import RxSwift
import RxCocoa

enum WalletManagerError: Error {
    case TOKEN_NOT_FOUND
}

class WalletManager {
    
    static let shared = WalletManager()
    
    var wallet: SLPWallet
    
    var observedToken: BehaviorRelay<SLPToken>?
    var observedTokens: PublishSubject<SLPToken>?
    
    init() {
        do {
            // For testnet -> Change as well in WalletManager -> .testnet
            wallet = try SLPWallet(.mainnet)
            setup()
        } catch {
            fatalError("It should be able to construct a wallet")
        }
    }
    
    func restore(_ mnemonic: String) -> Bool {
        guard let wallet = try? SLPWallet(mnemonic, network: .mainnet) else {
            return false
        }
        
        // Stop the scheduler of the previous wallet
        self.wallet.scheduler.cancel()
        
        // Replace the wallet
        self.wallet = wallet
        
        // Setup the wallet
        setup()
        
        return true
    }
    
    func observeToken(tokenId: String) throws -> Observable<SLPToken> {
        guard let token = wallet.tokens[tokenId] else {
            throw WalletManagerError.TOKEN_NOT_FOUND
        }
        
        let observedToken = BehaviorRelay<SLPToken>(value: token)
        self.observedToken = observedToken
        
        return observedToken.asObservable()
    }
    
    func observeTokens() -> Observable<SLPToken> {
        guard let observedTokens = self.observedTokens else {
            let observedTokens = PublishSubject<SLPToken>()
            self.observedTokens = observedTokens
            
            return observedTokens.asObservable()
        }
        
        return observedTokens.asObservable()
    }
    
    private func setup() {
        wallet.delegate = self
        wallet.scheduler.resume()
    }
}

extension WalletManager: SLPWalletDelegate {
    
    func onUpdatedToken(_ token: SLPToken) {
        
        // Notify
        if let observedToken = self.observedToken
            , observedToken.value.tokenId == token.tokenId {
            observedToken.accept(token)
        }
        
        // Notify
        if let observedTokens = self.observedTokens {
            observedTokens.onNext(token)
        }
        
    }
}