//
// Copyright 2021 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//

import Foundation
import MobileCoin
import SignalServiceKit

public class MobileCoinAPI: Dependencies {

    // MARK: - Passphrases & Entropy

    public static func passphrase(forPaymentsEntropy paymentsEntropy: Data) throws -> PaymentsPassphrase {
        guard paymentsEntropy.count == PaymentsConstants.paymentsEntropyLength else {
            throw PaymentsError.invalidEntropy
        }
        let result = MobileCoin.Mnemonic.mnemonic(fromEntropy: paymentsEntropy)
        switch result {
        case .success(let mnemonic):
            return try PaymentsPassphrase.parse(passphrase: mnemonic,
                                                validateWords: false)
        case .failure(let error):
            owsFailDebug("Error: \(error)")
            let error = Self.convertMCError(error: error)
            throw error
        }
    }

    public static func paymentsEntropy(forPassphrase passphrase: PaymentsPassphrase) throws -> Data {
        let mnemonic = passphrase.asPassphrase
        let result = MobileCoin.Mnemonic.entropy(fromMnemonic: mnemonic)
        switch result {
        case .success(let paymentsEntropy):
            guard paymentsEntropy.count == PaymentsConstants.paymentsEntropyLength else {
                throw PaymentsError.invalidEntropy
            }
            return paymentsEntropy
        case .failure(let error):
            owsFailDebug("Error: \(error)")
            let error = Self.convertMCError(error: error)
            throw error
        }
    }

    public static func isValidPassphraseWord(_ word: String?) -> Bool {
        guard let word = word?.strippedOrNil else {
            return false
        }
        return !MobileCoin.Mnemonic.words(matchingPrefix: word).isEmpty
    }

    // MARK: -

    private let paymentsEntropy: Data

    // PAYMENTS TODO: Finalize this value with the designers.
    private static let timeoutDuration: TimeInterval = 60

    let localAccount: MobileCoinAccount

    private let client: MobileCoinClient

    private init(paymentsEntropy: Data,
                 localAccount: MobileCoinAccount,
                 client: MobileCoinClient) throws {

        guard paymentsEntropy.count == PaymentsConstants.paymentsEntropyLength else {
            throw PaymentsError.invalidEntropy
        }

        owsAssertDebug(Self.paymentsHelper.arePaymentsEnabled)

        self.paymentsEntropy = paymentsEntropy
        self.localAccount = localAccount
        self.client = client
    }

    // MARK: -

    public static func configureSDKLogging() {
        if DebugFlags.internalLogging,
           !CurrentAppContext().isRunningTests {
            MobileCoinLogging.logSensitiveData = true
        }
    }

    // MARK: -

    static func buildLocalAccount(paymentsEntropy: Data) throws -> MobileCoinAccount {
        try Self.buildAccount(forPaymentsEntropy: paymentsEntropy)
    }

    private static func parseAuthorizationResponse(responseObject: Any?) throws -> OWSAuthorization {
        guard let params = ParamParser(responseObject: responseObject) else {
            throw OWSAssertionError("Invalid responseObject.")
        }
        let username: String = try params.required(key: "username")
        let password: String = try params.required(key: "password")
        return OWSAuthorization(username: username, password: password)
    }

    public static func buildPromise(paymentsEntropy: Data) -> Promise<MobileCoinAPI> {
        guard !CurrentAppContext().isNSE else {
            return Promise(error: OWSAssertionError("Payments disabled in NSE."))
        }
        return firstly(on: DispatchQueue.global()) { () -> Promise<SignalServiceKit.HTTPResponse> in
            let request = OWSRequestFactory.paymentsAuthenticationCredentialRequest()
            return Self.networkManager.makePromise(request: request)
        }.map(on: DispatchQueue.global()) { response -> OWSAuthorization in
            guard let json = response.responseBodyJson else {
                throw OWSAssertionError("Missing or invalid JSON")
            }
            return try Self.parseAuthorizationResponse(responseObject: json)
        }.map(on: DispatchQueue.global()) { (signalAuthorization: OWSAuthorization) -> MobileCoinAPI in
            let localAccount = try Self.buildAccount(forPaymentsEntropy: paymentsEntropy)
            let client = try localAccount.buildClient(signalAuthorization: signalAuthorization)
            return try MobileCoinAPI(paymentsEntropy: paymentsEntropy,
                                     localAccount: localAccount,
                                     client: client)
        }
    }

    // MARK: -

    class func isValidMobileCoinPublicAddress(_ publicAddressData: Data) -> Bool {
        MobileCoin.PublicAddress(serializedData: publicAddressData) != nil
    }

    // MARK: -

    func getLocalBalance() -> Promise<TSPaymentAmount> {
        Logger.verbose("")

        let client = self.client

        return firstly(on: DispatchQueue.global()) { () throws -> Promise<MobileCoin.Balance> in
            let (promise, future) = Promise<MobileCoin.Balance>.pending()
            if DebugFlags.paymentsNoRequestsComplete.get() {
                // Never resolve.
                return promise
            }
            client.updateBalances { (result: Swift.Result<Balances, BalanceUpdateError>) in
                switch result {
                case .success(let balances):
                    future.resolve(balances.mobBalance)
                case .failure(let error):
                    let error = Self.convertMCError(error: error)
                    future.reject(error)
                }
            }
            return promise
        }.map(on: DispatchQueue.global()) { (balance: MobileCoin.Balance) -> TSPaymentAmount in
            Logger.verbose("Success: \(balance)")
            // We do not need to support amountPicoMobHigh.
            guard let amountPicoMob = balance.amount() else {
                throw OWSAssertionError("Invalid balance.")
            }
            return TSPaymentAmount(currency: .mobileCoin, picoMob: amountPicoMob)
        }.recover(on: DispatchQueue.global()) { (error: Error) -> Promise<TSPaymentAmount> in
            owsFailDebugUnlessMCNetworkFailure(error)
            throw error
        }.timeout(seconds: Self.timeoutDuration, description: "getLocalBalance") { () -> Error in
            PaymentsError.timeout
        }
    }

    func getEstimatedFee(forPaymentAmount paymentAmount: TSPaymentAmount) throws -> Promise<TSPaymentAmount> {
        Logger.verbose("")

        guard paymentAmount.isValidAmount(canBeEmpty: false) else {
            throw OWSAssertionError("Invalid amount.")
        }

        let client = self.client

        // We don't need to support amountPicoMobHigh.
        return firstly(on: DispatchQueue.global()) { () -> Promise<TSPaymentAmount> in
            let (promise, future) = Promise<TSPaymentAmount>.pending()
            if DebugFlags.paymentsNoRequestsComplete.get() {
                // Never resolve.
                return promise
            }
            client.estimateTotalFee(toSendAmount: Amount(paymentAmount.picoMob, in: .MOB),
                                    feeLevel: Self.feeLevel) { (result: Swift.Result<UInt64,
                                                                                     TransactionEstimationFetcherError>) in
                switch result {
                case .success(let feePicoMob):
                    let fee = TSPaymentAmount(currency: .mobileCoin, picoMob: feePicoMob)
                    guard fee.isValidAmount(canBeEmpty: false) else {
                        future.reject(OWSAssertionError("Invalid amount."))
                        return
                    }
                    Logger.verbose("Success paymentAmount: \(paymentAmount), fee: \(fee), ")
                    future.resolve(fee)
                case .failure(let error):
                    let error = Self.convertMCError(error: error)
                    future.reject(error)
                }
            }
            return promise
        }.recover(on: DispatchQueue.global()) { (error: Error) -> Promise<TSPaymentAmount> in
            if case PaymentsError.insufficientFunds = error {
                Logger.warn("Error: \(error)")
            } else {
                owsFailDebugUnlessMCNetworkFailure(error)
            }
            throw error
        }.timeout(seconds: Self.timeoutDuration, description: "getEstimatedFee") { () -> Error in
            PaymentsError.timeout
        }
    }

    func maxTransactionAmount() throws -> Promise<TSPaymentAmount> {
        // We don't need to support amountPicoMobHigh.

        let client = self.client

        return firstly(on: DispatchQueue.global()) { () -> Promise<TSPaymentAmount> in
            let (promise, future) = Promise<TSPaymentAmount>.pending()
            if DebugFlags.paymentsNoRequestsComplete.get() {
                // Never resolve.
                return promise
            }
            client.amountTransferable(tokenId: .MOB, feeLevel: Self.feeLevel) { (result: Swift.Result<UInt64,
                                                                                       BalanceTransferEstimationFetcherError>) in
                switch result {
                case .success(let feePicoMob):
                    let paymentAmount = TSPaymentAmount(currency: .mobileCoin, picoMob: feePicoMob)
                    guard paymentAmount.isValidAmount(canBeEmpty: true) else {
                        future.reject(OWSAssertionError("Invalid amount."))
                        return
                    }
                    Logger.verbose("Success paymentAmount: \(paymentAmount), ")
                    future.resolve(paymentAmount)
                case .failure(let error):
                    let error = Self.convertMCError(error: error)
                    future.reject(error)
                }
            }
            return promise
        }.recover(on: DispatchQueue.global()) { (error: Error) -> Promise<TSPaymentAmount> in
            if case PaymentsError.insufficientFunds = error {
                Logger.warn("Error: \(error)")
            } else {
                owsFailDebugUnlessMCNetworkFailure(error)
            }
            throw error
        }.timeout(seconds: Self.timeoutDuration, description: "maxTransactionAmount") { () -> Error in
            PaymentsError.timeout
        }
    }

    struct PreparedTransaction: PreparedPayment {
        let transaction: MobileCoin.Transaction
        let receipt: MobileCoin.Receipt
        let feeAmount: TSPaymentAmount
    }

    func prepareTransaction(paymentAmount: TSPaymentAmount,
                            recipientPublicAddress: MobileCoin.PublicAddress,
                            shouldUpdateBalance: Bool) -> Promise<PreparedTransaction> {
        Logger.verbose("")

        Logger.verbose("paymentAmount: \(paymentAmount.picoMob)")

        let client = self.client

        return firstly(on: DispatchQueue.global()) { () throws -> Promise<Void> in
            guard shouldUpdateBalance else {
                return Promise.value(())
            }
            return firstly(on: DispatchQueue.global()) { () throws -> Promise<TSPaymentAmount> in
                // prepareTransaction() will fail if local balance is not yet known.
                self.getLocalBalance()
            }.done(on: DispatchQueue.global()) { (balance: TSPaymentAmount) in
                Logger.verbose("balance: \(balance.picoMob)")
            }
        }.then(on: DispatchQueue.global()) { () -> Promise<TSPaymentAmount> in
            try self.getEstimatedFee(forPaymentAmount: paymentAmount)
        }.then(on: DispatchQueue.global()) { (estimatedFeeAmount: TSPaymentAmount) -> Promise<PreparedTransaction> in
            Logger.verbose("estimatedFeeAmount: \(estimatedFeeAmount.picoMob)")
            guard paymentAmount.isValidAmount(canBeEmpty: false) else {
                throw OWSAssertionError("Invalid amount.")
            }
            guard estimatedFeeAmount.isValidAmount(canBeEmpty: false) else {
                throw OWSAssertionError("Invalid fee.")
            }

            let (promise, future) = Promise<PreparedTransaction>.pending()
            if DebugFlags.paymentsNoRequestsComplete.get() {
                // Never resolve.
                return promise
            }
            // We don't need to support amountPicoMobHigh.
            client.prepareTransaction(to: recipientPublicAddress,
                                      amount: Amount(paymentAmount.picoMob, in: .MOB),
                                      fee: estimatedFeeAmount.picoMob) { (result: Swift.Result<PendingSinglePayloadTransaction,
                                                                                                TransactionPreparationError>) in
                switch result {
                case .success(let payload):
                    let transaction = payload.transaction
                    let receipt = payload.receipt
                    let finalFeeAmount = TSPaymentAmount(currency: .mobileCoin,
                                                         picoMob: transaction.fee)
                    owsAssertDebug(estimatedFeeAmount == finalFeeAmount)
                    let preparedTransaction = PreparedTransaction(transaction: transaction,
                                                                  receipt: receipt,
                                                                  feeAmount: finalFeeAmount)
                    future.resolve(preparedTransaction)
                case .failure(let error):
                    let error = Self.convertMCError(error: error)
                    future.reject(error)
                }
            }
            return promise
        }.recover(on: DispatchQueue.global()) { (error: Error) -> Promise<PreparedTransaction> in
            owsFailDebugUnlessMCNetworkFailure(error)
            throw error
        }.timeout(seconds: Self.timeoutDuration, description: "prepareTransaction") { () -> Error in
            PaymentsError.timeout
        }
    }

    // TODO: Are we always going to use _minimum_ fee?
    private static let feeLevel: MobileCoin.FeeLevel = .minimum

    func requiresDefragmentation(forPaymentAmount paymentAmount: TSPaymentAmount) -> Promise<Bool> {
        Logger.verbose("")

        let client = self.client

        return firstly(on: DispatchQueue.global()) { () -> Promise<Bool> in
            let (promise, future) = Promise<Bool>.pending()
            if DebugFlags.paymentsNoRequestsComplete.get() {
                // Never resolve.
                return promise
            }
            client.requiresDefragmentation(toSendAmount: Amount(paymentAmount.picoMob, in: .MOB),
                                           feeLevel: Self.feeLevel) { (result: Swift.Result<Bool,
                                                                                            TransactionEstimationFetcherError>) in
                switch result {
                case .success(let shouldDefragment):
                    future.resolve(shouldDefragment)
                case .failure(let error):
                    let error = Self.convertMCError(error: error)
                    future.reject(error)
                }
            }
            return promise
        }.recover(on: DispatchQueue.global()) { (error: Error) -> Promise<Bool> in
            owsFailDebugUnlessMCNetworkFailure(error)
            throw error
        }.timeout(seconds: Self.timeoutDuration, description: "requiresDefragmentation") { () -> Error in
            PaymentsError.timeout
        }
    }

    func prepareDefragmentationStepTransactions(forPaymentAmount paymentAmount: TSPaymentAmount) -> Promise<[MobileCoin.Transaction]> {
        Logger.verbose("")

        let client = self.client

        return firstly(on: DispatchQueue.global()) { () throws -> Promise<[MobileCoin.Transaction]> in
            let (promise, future) = Promise<[MobileCoin.Transaction]>.pending()
            if DebugFlags.paymentsNoRequestsComplete.get() {
                // Never resolve.
                return promise
            }
            client.prepareDefragmentationStepTransactions(toSendAmount: Amount(paymentAmount.picoMob, in: .MOB),
                                                          feeLevel: Self.feeLevel) { (result: Swift.Result<[MobileCoin.Transaction],
                                                                                                           MobileCoin.DefragTransactionPreparationError>) in
                switch result {
                case .success(let transactions):
                    future.resolve(transactions)
                case .failure(let error):
                    let error = Self.convertMCError(error: error)
                    future.reject(error)
                }
            }
            return promise
        }.timeout(seconds: Self.timeoutDuration, description: "prepareDefragmentationStepTransactions") { () -> Error in
            PaymentsError.timeout
        }
    }

    func submitTransaction(transaction: MobileCoin.Transaction) -> Promise<Void> {
        Logger.verbose("")

        guard !DebugFlags.paymentsFailOutgoingSubmission.get() else {
            return Promise(error: OWSGenericError("Failed."))
        }

        return firstly(on: DispatchQueue.global()) { () throws -> Promise<Void> in
            let (promise, future) = Promise<Void>.pending()
            if DebugFlags.paymentsNoRequestsComplete.get() {
                // Never resolve.
                return promise
            }
            let client = self.client
            client.submitTransaction(transaction: transaction) { (result: Result<UInt64, SubmitTransactionError>) in
                switch result {
                case .success:
                    future.resolve()
                case .failure(let error):
                    future.reject(Self.convertMCError(error: error.submissionError))
                }
            }
            return promise
        }.map(on: DispatchQueue.global()) { () -> Void in
            Logger.verbose("Success.")
        }.recover(on: DispatchQueue.global()) { (error: Error) -> Promise<Void> in
            owsFailDebugUnlessMCNetworkFailure(error)
            throw error
        }.timeout(seconds: Self.timeoutDuration, description: "submitTransaction") { () -> Error in
            PaymentsError.timeout
        }
    }

    func getOutgoingTransactionStatus(transaction: MobileCoin.Transaction) -> Promise<MCOutgoingTransactionStatus> {
        Logger.verbose("")

        guard !DebugFlags.paymentsFailOutgoingVerification.get() else {
            return Promise(error: OWSGenericError("Failed."))
        }

        let client = self.client
        return firstly(on: DispatchQueue.global()) { () -> Promise<MCOutgoingTransactionStatus> in
            let (promise, future) = Promise<MCOutgoingTransactionStatus>.pending()
            if DebugFlags.paymentsNoRequestsComplete.get() {
                // Never resolve.
                return promise
            }
            client.txOutStatus(
                of: transaction
            ) { (result: Swift.Result<MobileCoin.TransactionStatus, ConnectionError>) in
                switch result {
                case .success(let transactionStatus):
                    future.resolve(MCOutgoingTransactionStatus(transactionStatus: transactionStatus))
                    Self.paymentsSwift.clearCurrentPaymentBalance()
                case .failure(let error):
                    let error = Self.convertMCError(error: error)
                    future.reject(error)
                }
            }
            return promise
        }.map(on: DispatchQueue.global()) { (value: MCOutgoingTransactionStatus) -> MCOutgoingTransactionStatus in
            Logger.verbose("Success: \(value)")
            return value
        }.recover(on: DispatchQueue.global()) { (error: Error) -> Promise<MCOutgoingTransactionStatus> in
            owsFailDebugUnlessMCNetworkFailure(error)
            throw error
        }.timeout(seconds: Self.timeoutDuration, description: "getOutgoingTransactionStatus") { () -> Error in
            PaymentsError.timeout
        }
    }

    func paymentAmount(forReceipt receipt: MobileCoin.Receipt) throws -> TSPaymentAmount {
        try Self.paymentAmount(forReceipt: receipt, localAccount: localAccount)
    }

    static func paymentAmount(forReceipt receipt: MobileCoin.Receipt,
                              localAccount: MobileCoinAccount) throws -> TSPaymentAmount {
        guard let picoMob = receipt.validateAndUnmaskValue(accountKey: localAccount.accountKey) else {
            // This can happen if the receipt was address to a different account.
            owsFailDebug("Receipt missing amount.")
            throw PaymentsError.invalidAmount
        }
        guard picoMob > 0 else {
            owsFailDebug("Receipt has invalid amount.")
            throw PaymentsError.invalidAmount
        }
        return TSPaymentAmount(currency: .mobileCoin, picoMob: picoMob)
    }

    func getIncomingReceiptStatus(receipt: MobileCoin.Receipt) -> Promise<MCIncomingReceiptStatus> {
        Logger.verbose("")

        guard !DebugFlags.paymentsFailIncomingVerification.get() else {
            return Promise(error: OWSGenericError("Failed."))
        }

        let client = self.client
        let localAccount = self.localAccount

        return firstly(on: DispatchQueue.global()) { () throws -> Promise<TSPaymentAmount> in
            // .status(of: receipt) requires an updated balance.
            //
            // TODO: We could improve perf when verifying multiple receipts by getting balance just once.
            self.getLocalBalance()
        }.map(on: DispatchQueue.global()) { (_: TSPaymentAmount) -> MCIncomingReceiptStatus in
            let paymentAmount: TSPaymentAmount
            do {
                paymentAmount = try Self.paymentAmount(forReceipt: receipt,
                                                       localAccount: localAccount)
            } catch {
                owsFailDebug("Error: \(error)")
                return MCIncomingReceiptStatus(receiptStatus: .failed,
                                               paymentAmount: .zeroMob,
                                               txOutPublicKey: Data())
            }
            let txOutPublicKey: Data = receipt.txOutPublicKey

            let result = client.status(of: receipt)
            switch result {
            case .success(let receiptStatus):
                return MCIncomingReceiptStatus(receiptStatus: receiptStatus,
                                               paymentAmount: paymentAmount,
                                               txOutPublicKey: txOutPublicKey)
            case .failure(let error):
                let error = Self.convertMCError(error: error)
                throw error
            }
        }.map(on: DispatchQueue.global()) { (value: MCIncomingReceiptStatus) -> MCIncomingReceiptStatus in
            Logger.verbose("Success: \(value)")
            return value
        }.recover(on: DispatchQueue.global()) { (error: Error) -> Promise<MCIncomingReceiptStatus> in
            owsFailDebugUnlessMCNetworkFailure(error)
            throw error
        }.timeout(seconds: Self.timeoutDuration, description: "getIncomingReceiptStatus") { () -> Error in
            PaymentsError.timeout
        }
    }

    func getAccountActivity() -> Promise<MobileCoin.AccountActivity> {
        Logger.verbose("")

        let client = self.client

        return firstly(on: DispatchQueue.global()) { () throws -> Promise<MobileCoin.AccountActivity> in
            let (promise, future) = Promise<MobileCoin.AccountActivity>.pending()
            if DebugFlags.paymentsNoRequestsComplete.get() {
                // Never resolve.
                return promise
            }
            client.updateBalances { (result: Swift.Result<Balances, BalanceUpdateError>) in
                switch result {
                case .success:
                    future.resolve(client.accountActivity(for: .MOB))
                case .failure(let error):
                    let error = Self.convertMCError(error: error)
                    future.reject(error)
                }
            }
            return promise
        }.map(on: DispatchQueue.global()) { (accountActivity: MobileCoin.AccountActivity) -> MobileCoin.AccountActivity in
            Logger.verbose("Success: \(accountActivity.blockCount)")
            return accountActivity
        }.recover(on: DispatchQueue.global()) { (error: Error) -> Promise<MobileCoin.AccountActivity> in
            owsFailDebugUnlessMCNetworkFailure(error)
            throw error
        }.timeout(seconds: Self.timeoutDuration, description: "getAccountActivity") { () -> Error in
            PaymentsError.timeout
        }
    }
}

// MARK: -

extension MobileCoin.PublicAddress {
    var asPaymentAddress: TSPaymentAddress {
        return TSPaymentAddress(currency: .mobileCoin,
                                mobileCoinPublicAddressData: serializedData)
    }
}

// MARK: -

extension TSPaymentAddress {
    func asPublicAddress() throws -> MobileCoin.PublicAddress {
        guard currency == .mobileCoin else {
            throw PaymentsError.invalidCurrency
        }
        guard let address = MobileCoin.PublicAddress(serializedData: mobileCoinPublicAddressData) else {
            throw OWSAssertionError("Invalid mobileCoinPublicAddressData.")
        }
        return address
    }
}

// MARK: -

struct MCIncomingReceiptStatus {
    let receiptStatus: MobileCoin.ReceiptStatus
    let paymentAmount: TSPaymentAmount
    let txOutPublicKey: Data
}

// MARK: -

struct MCOutgoingTransactionStatus {
    let transactionStatus: MobileCoin.TransactionStatus
}

// MARK: - Error Handling

extension MobileCoinAPI {
    public static func convertMCError(error: Error) -> PaymentsError {
        func switchOnConnectionError(_ error: MobileCoin.ConnectionError) -> PaymentsError {
            switch error {
            case .connectionFailure(let reason):
                Logger.warn("Error: \(error), reason: \(reason)")
                return PaymentsError.connectionFailure
            case .authorizationFailure(let reason):
                owsFailDebug("Error: \(error), reason: \(reason)")

                // Immediately discard the SDK client instance; the auth token may be stale.
                SSKEnvironment.shared.payments.didReceiveMCAuthError()

                return PaymentsError.authorizationFailure
            case .invalidServerResponse(let reason):
                // TODO: It would be preferable to owsFailDebug()
                //       here. Ledger errors can now occur during
                //       fee transitions, but should be very rare.
                Logger.warn("Error: \(error), reason: \(reason)")
                return PaymentsError.invalidServerResponse
            case .attestationVerificationFailed(let reason):
                owsFailDebug("Error: \(error), reason: \(reason)")
                return PaymentsError.attestationVerificationFailed
            case .outdatedClient(let reason):
                owsFailDebug("Error: \(error), reason: \(reason)")
                return PaymentsError.outdatedClient
            case .serverRateLimited(let reason):
                owsFailDebug("Error: \(error), reason: \(reason)")
                return PaymentsError.serverRateLimited
            }
        }

        switch error {
        case let error as MobileCoin.SecurityError:
            // Wraps errors from Apple Security framework used in SecSSLCertificate init.
            owsFailDebug("Error: \(error)")
            return PaymentsError.invalidInput
        case let error as MobileCoin.InvalidInputError:
            owsFailDebug("Error: \(error)")
            return PaymentsError.invalidInput
        case let error as MobileCoin.BalanceUpdateError:
            switch error {
            case .connectionError(let error):
                return switchOnConnectionError(error)
            case .fogSyncError(let error):
                Logger.warn("Error: \(error)")
                return PaymentsError.fogOutOfSync
            }
        case let error as MobileCoin.ConnectionError:
            return switchOnConnectionError(error)
        case let error as MobileCoin.TransactionPreparationError:
            switch error {
            case .invalidInput(let reason):
                owsFailDebug("Error: \(error), reason: \(reason)")
                return PaymentsError.invalidInput
            case .insufficientBalance:
                Logger.warn("Error: \(error)")
                return PaymentsError.insufficientFunds
            case .defragmentationRequired:
                Logger.warn("Error: \(error)")
                return PaymentsError.defragmentationRequired
            case .connectionError(let connectionError):
                // Recurse.
                return convertMCError(error: connectionError)
            }
        case let error as MobileCoin.TransactionSubmissionError:
            switch error {
            case .connectionError(let connectionError):
                // Recurse.
                return convertMCError(error: connectionError)
            case .invalidTransaction:
                Logger.warn("Error: \(error)")
                return PaymentsError.invalidTransaction
            case .feeError:
                Logger.warn("Error: \(error)")
                return PaymentsError.invalidFee
            case .tombstoneBlockTooFar:
                Logger.warn("Error: \(error)")
                // Map to .invalidTransaction
                return PaymentsError.invalidTransaction
            case .inputsAlreadySpent:
                Logger.warn("Error: \(error)")
                return PaymentsError.inputsAlreadySpent
            case .missingMemo:
                Logger.warn("Error: \(error)")
                return PaymentsError.missingMemo
            case .outputAlreadyExists:
                // Transaction with same public key already exists (idempotence)
                Logger.warn("Error: \(error)")
                return PaymentsError.invalidTransaction
            }
        case let error as MobileCoin.DefragTransactionPreparationError:
            switch error {
            case .invalidInput(let reason):
                owsFailDebug("Error: \(error), reason: \(reason)")
                return PaymentsError.invalidInput
            case .insufficientBalance:
                Logger.warn("Error: \(error)")
                return PaymentsError.insufficientFunds
            case .connectionError(let connectionError):
                // Recurse.
                return convertMCError(error: connectionError)
            }
        case let error as MobileCoin.BalanceTransferEstimationFetcherError:
            switch error {
            case .feeExceedsBalance:
                // TODO: Review this mapping.
                Logger.warn("Error: \(error)")
                return PaymentsError.insufficientFunds
            case .balanceOverflow:
                // TODO: Review this mapping.
                Logger.warn("Error: \(error)")
                return PaymentsError.insufficientFunds
            case .connectionError(let connectionError):
                // Recurse.
                return convertMCError(error: connectionError)
            }
        case let error as MobileCoin.TransactionEstimationFetcherError:
            switch error {
            case .invalidInput(let reason):
                owsFailDebug("Error: \(error), reason: \(reason)")
                return PaymentsError.invalidInput
            case .insufficientBalance:
                Logger.warn("Error: \(error)")
                return PaymentsError.insufficientFunds
            case .connectionError(let connectionError):
                // Recurse.
                return convertMCError(error: connectionError)
            }
        default:
            owsFailDebug("Unexpected error: \(error)")
            return PaymentsError.unknownSDKError
        }
    }
}

// MARK: -

public extension PaymentsError {
    var isPaymentsNetworkFailure: Bool {
        switch self {
        case .notEnabled,
             .userNotRegisteredOrAppNotReady,
             .userHasNoPublicAddress,
             .invalidCurrency,
             .invalidWalletKey,
             .invalidAmount,
             .invalidFee,
             .insufficientFunds,
             .invalidModel,
             .tooOldToSubmit,
             .indeterminateState,
             .unknownSDKError,
             .invalidInput,
             .authorizationFailure,
             .invalidServerResponse,
             .attestationVerificationFailed,
             .outdatedClient,
             .serverRateLimited,
             .serializationError,
             .verificationStatusUnknown,
             .ledgerBlockTimestampUnknown,
             .missingModel,
             .defragmentationRequired,
             .invalidTransaction,
             .inputsAlreadySpent,
             .defragmentationFailed,
             .invalidPassphrase,
             .invalidEntropy,
             .missingMemo,
             .killSwitch:
            return false
        case .connectionFailure,
             .fogOutOfSync,
             .timeout,
             .outgoingVerificationTakingTooLong:
            return true
        }
    }

    var isExpectedFromSDK: Bool {
        switch self {
        case .notEnabled,
             .userNotRegisteredOrAppNotReady,
             .userHasNoPublicAddress,
             .invalidCurrency,
             .invalidWalletKey,
             .invalidAmount,
             .invalidFee,
             .invalidModel,
             .indeterminateState,
             .unknownSDKError,
             .invalidInput,
             .authorizationFailure,
             .invalidServerResponse,
             .attestationVerificationFailed,
             .outdatedClient,
             .serverRateLimited,
             .serializationError,
             .verificationStatusUnknown,
             .ledgerBlockTimestampUnknown,
             .missingModel,
             .defragmentationRequired,
             .invalidTransaction,
             .inputsAlreadySpent,
             .defragmentationFailed,
             .invalidPassphrase,
             .invalidEntropy,
             .killSwitch,
             .connectionFailure,
             .timeout,
             .outgoingVerificationTakingTooLong,
             .fogOutOfSync,
             .missingMemo:
            return false
        case .tooOldToSubmit,
             .insufficientFunds:
            return true
        }
    }
}

// MARK: -

// A variant of owsFailDebugUnlessNetworkFailure() that can handle
// network failures from the MobileCoin SDK.
@inlinable
public func owsFailDebugUnlessMCNetworkFailure(_ error: Error,
                                               file: String = #file,
                                               function: String = #function,
                                               line: Int = #line) {
    if let paymentsError = error as? PaymentsError {
        if paymentsError.isPaymentsNetworkFailure {
            // Log but otherwise ignore network failures.
            Logger.warn("Error: \(error)", file: file, function: function, line: line)
        } else if paymentsError.isExpectedFromSDK {
            Logger.warn("Error: \(error)", file: file, function: function, line: line)
        } else {
            owsFailDebug("Error: \(error)", file: file, function: function, line: line)
        }
    } else if nil != error as? OWSAssertionError {
        owsFailDebug("Unexpected error: \(error)")
    } else {
        owsFailDebugUnlessNetworkFailure(error)
    }
}

// MARK: - URLs

extension MobileCoinAPI {
    static func formatAsBase58(publicAddress: MobileCoin.PublicAddress) -> String {
        return Base58Coder.encode(publicAddress)
    }

    static func formatAsUrl(publicAddress: MobileCoin.PublicAddress) -> String {
        MobUri.encode(publicAddress)
    }

    static func parseAsPublicAddress(url: URL) -> MobileCoin.PublicAddress? {
        let result = MobUri.decode(uri: url.absoluteString)
        switch result {
        case .success(let payload):
            switch payload {
            case .publicAddress(let publicAddress):
                return publicAddress
            case .paymentRequest(let paymentRequest):
                // TODO: We could honor the amount and memo.
                return paymentRequest.publicAddress
            case .transferPayload:
                // TODO: We could handle transferPayload.
                owsFailDebug("Unexpected payload.")
                return nil
            }
        case .failure(let error):
            let error = Self.convertMCError(error: error)
            owsFailDebugUnlessMCNetworkFailure(error)
            return nil
        }
    }

    static func parse(publicAddressBase58 base58: String) -> MobileCoin.PublicAddress? {
        guard let result = Base58Coder.decode(base58) else {
            Logger.verbose("Invalid base58: \(base58)")
            Logger.warn("Invalid base58.")
            return nil
        }
        switch result {
        case .publicAddress(let publicAddress):
            return publicAddress
        default:
            Logger.verbose("Invalid base58: \(base58)")
            Logger.warn("Invalid base58.")
            return nil
        }
    }
}