zcash-android-wallet-sdk/sdk-lib/src/main/java/cash/z/ecc/android/sdk/exception/Exceptions.kt

package cash.z.ecc.android.sdk.exception

import cash.z.ecc.android.sdk.internal.SaplingParameters
import cash.z.ecc.android.sdk.internal.model.Checkpoint
import cash.z.ecc.android.sdk.model.BlockHeight
import cash.z.ecc.android.sdk.model.ZcashNetwork
import cash.z.wallet.sdk.rpc.Service
import io.grpc.Status
import io.grpc.Status.Code.UNAVAILABLE

/**
 * Marker for all custom exceptions from the SDK. Making it an interface would result in more typing
 * so it's a supertype, instead.
 */
open class SdkException(message: String, cause: Throwable?) : RuntimeException(message, cause)

/**
 * Exceptions thrown in the Rust layer of the SDK. We may not always be able to surface details about this
 * exception so it's important for the SDK to provide helpful messages whenever these errors are encountered.
 */
sealed class RustLayerException(message: String, cause: Throwable? = null) : SdkException(message, cause) {
    class BalanceException(cause: Throwable) : RustLayerException(
        "Error while requesting the current balance over " +
            "JNI. This might mean that the database has been corrupted and needs to be rebuilt. Verify that " +
            "blocks are not missing or have not been scanned out of order.",
        cause
    )
}

/**
 * User-facing exceptions thrown by the transaction repository.
 */
sealed class RepositoryException(message: String, cause: Throwable? = null) : SdkException(message, cause) {
    object FalseStart : RepositoryException(
        "The channel is closed. Note that once a repository has stopped it " +
            "cannot be restarted. Verify that the repository is not being restarted."
    )
    object Unprepared : RepositoryException(
        "Unprepared repository: Data cannot be accessed before the repository is prepared." +
            " Ensure that things have been properly initialized. If you see this error it most" +
            " likely means that you are accessing transactions or other data before starting the" +
            " Synchronizer. Previously, this was a silent bug that would cause problems later." +
            " Mostly, during database migrations. Now, we catch this early and explicitly prevent" +
            " it from happening."
    )
}

/**
 * High-level exceptions thrown by the synchronizer, which do not fall within the umbrella of a
 * child component.
 */
sealed class SynchronizerException(message: String, cause: Throwable? = null) : SdkException(message, cause) {
    object FalseStart : SynchronizerException(
        "This synchronizer was already started. Multiple calls to start are not" +
            "allowed and once a synchronizer has stopped it cannot be restarted."
    )
    object NotYetStarted : SynchronizerException(
        "The synchronizer has not yet started. Verify that" +
            " start has been called prior to this operation and that the coroutineScope is not" +
            " being accessed before it is initialized."
    )
}

/**
 * Potentially user-facing exceptions that occur while processing compact blocks.
 */
sealed class CompactBlockProcessorException(message: String, cause: Throwable? = null) : SdkException(message, cause) {
    class DataDbMissing(path: String) : CompactBlockProcessorException(
        "No data db file found at path $path. Verify " +
            "that the data DB has been initialized via `rustBackend.initDataDb(path)`"
    )
    open class ConfigurationException(
        message: String,
        cause: Throwable?
    ) : CompactBlockProcessorException(message, cause)
    class FileInsteadOfPath(fileName: String) : ConfigurationException(
        "Invalid Path: the given path appears to be a" +
            " file name instead of a path: $fileName. The RustBackend expects the absolutePath to the database rather" +
            " than just the database filename because Rust does not access the app Context." +
            " So pass in context.getDatabasePath(dbFileName).absolutePath instead of just dbFileName alone.",
        null
    )
    class FailedReorgRepair(message: String) : CompactBlockProcessorException(message)
    class FailedDownload(cause: Throwable? = null) : CompactBlockProcessorException(
        "Error while downloading blocks. This most " +
            "likely means the server is down or slow to respond. See logs for details.",
        cause
    )
    class FailedScan(cause: Throwable? = null) : CompactBlockProcessorException(
        "Error while scanning blocks. This most " +
            "likely means a block was missed or a reorg was mishandled. See logs for details.",
        cause
    )
    class Disconnected(cause: Throwable? = null) :
        CompactBlockProcessorException("Disconnected Error. Unable to download blocks due to ${cause?.message}", cause)
    object Uninitialized : CompactBlockProcessorException(
        "Cannot process blocks because the wallet has not been" +
            " initialized. Verify that the seed phrase was properly created or imported. If so, then this problem" +
            " can be fixed by re-importing the wallet."
    )
    object NoAccount : CompactBlockProcessorException(
        "Attempting to scan without an account. This is probably a setup error or a race condition."
    )

    open class EnhanceTransactionError(
        message: String,
        val height: BlockHeight?,
        cause: Throwable
    ) : CompactBlockProcessorException(message, cause) {
        class EnhanceTxDownloadError(
            height: BlockHeight?,
            cause: Throwable
        ) : EnhanceTransactionError(
            "Error while attempting to download a transaction to enhance",
            height,
            cause
        )
        class EnhanceTxDecryptError(
            height: BlockHeight?,
            cause: Throwable
        ) : EnhanceTransactionError(
            "Error while attempting to decrypt and store a transaction to enhance",
            height,
            cause
        )
    }

    class MismatchedNetwork(clientNetwork: String?, serverNetwork: String?) : CompactBlockProcessorException(
        "Incompatible server: this client expects a server using $clientNetwork but it was $serverNetwork! Try " +
            "updating the client or switching servers."
    )

    class MismatchedBranch(
        clientBranch: String?,
        serverBranch: String?,
        networkName: String?
    ) : CompactBlockProcessorException(
        "Incompatible server: this client expects a server following consensus branch $clientBranch on $networkName " +
            "but it was $serverBranch! Try updating the client or switching servers."
    )
}

/**
 * Exceptions related to the wallet's birthday.
 */
sealed class BirthdayException(message: String, cause: Throwable? = null) : SdkException(message, cause) {
    object UninitializedBirthdayException : BirthdayException(
        "Error the birthday cannot be" +
            " accessed before it is initialized. Verify that the new, import or open functions" +
            " have been called on the initializer."
    )
    class MissingBirthdayFilesException(directory: String) : BirthdayException(
        "Cannot initialize wallet because no birthday files were found in the $directory directory."
    )
    class ExactBirthdayNotFoundException internal constructor(
        birthday: BlockHeight,
        nearestMatch: Checkpoint? = null
    ) : BirthdayException(
        "Unable to find birthday that exactly matches $birthday.${
            if (nearestMatch != null) {
                " An exact match was request but the nearest match found was ${nearestMatch.height}."
            } else {
                ""
            }
        }"
    )
    class BirthdayFileNotFoundException(directory: String, height: BlockHeight?) : BirthdayException(
        "Unable to find birthday file for $height verify that $directory/$height.json exists."
    )
    class MalformattedBirthdayFilesException(directory: String, file: String, cause: Throwable?) : BirthdayException(
        "Failed to parse file $directory/$file verify that it is formatted as #####.json, " +
            "where the first portion is an Int representing the height of the tree contained in the file",
        cause
    )
}

/**
 * Exceptions thrown by the initializer.
 */
sealed class InitializeException(message: String, cause: Throwable? = null) : SdkException(message, cause) {
    object SeedRequired : InitializeException(
        "A pending database migration requires the wallet's seed. Call this initialization " +
            "method again with the seed."
    )
    class FalseStart(cause: Throwable?) : InitializeException("Failed to initialize accounts due to: $cause", cause)
    class AlreadyInitializedException(cause: Throwable, dbPath: String) : InitializeException(
        "Failed to initialize the blocks table" +
            " because it already exists in $dbPath",
        cause
    )
    object MissingBirthdayException : InitializeException(
        "Expected a birthday for this wallet but failed to find one. This usually means that " +
            "wallet setup did not happen correctly. A workaround might be to interpret the " +
            "birthday,  based on the contents of the wallet data but it is probably better " +
            "not to mask this error because the root issue should be addressed."
    )
    object MissingViewingKeyException : InitializeException(
        "Expected a unified viewingKey for this wallet but failed to find one. This usually means" +
            " that wallet setup happened incorrectly. A workaround might be to derive the" +
            " unified viewingKey from the seed or seedPhrase, if they exist, but it is probably" +
            " better not to mask this error because the root issue should be addressed."
    )
    class MissingAddressException(description: String, cause: Throwable? = null) : InitializeException(
        "Expected a $description address for this wallet but failed to find one. This usually" +
            " means that wallet setup happened incorrectly. If this problem persists, a" +
            " workaround might be to go to settings and WIPE the wallet and rescan. Doing so" +
            " will restore any missing address information. Meanwhile, please report that" +
            " this happened so that the root issue can be uncovered and corrected." +
            if (cause != null) "\nCaused by: $cause" else ""
    )
    object DatabasePathException :
        InitializeException(
            "Critical failure to locate path for storing databases. Perhaps this device prevents" +
                " apps from storing data? We cannot initialize the wallet unless we can store" +
                " data."
        )

    class InvalidBirthdayHeightException(birthday: BlockHeight?, network: ZcashNetwork) : InitializeException(
        "Invalid birthday height of ${birthday?.value}. The birthday height must be at least the height of" +
            " Sapling activation on ${network.networkName} (${network.saplingActivationHeight})."
    )

    object MissingDefaultBirthdayException : InitializeException(
        "The birthday height is missing and it is unclear which value to use as a default."
    )
}

/**
 * Exceptions thrown while interacting with lightwalletd.
 */
sealed class LightWalletException(message: String, cause: Throwable? = null) : SdkException(message, cause) {
    object InsecureConnection : LightWalletException(
        "Error: attempted to connect to lightwalletd" +
            " with an insecure connection! Plaintext connections are only allowed when the" +
            " resource value for 'R.bool.lightwalletd_allow_very_insecure_connections' is true" +
            " because this choice should be explicit."
    )
    class ConsensusBranchException(sdkBranch: String, lwdBranch: String) :
        LightWalletException(
            "Error: the lightwalletd server is using a consensus branch" +
                " (branch: $lwdBranch) that does not match the transactions being created" +
                " (branch: $sdkBranch). This probably means the SDK and Server are on two" +
                " different chains, most likely because of a recent network upgrade (NU). Either" +
                " update the SDK to match lightwalletd or use a lightwalletd that matches the SDK."
        )

    open class ChangeServerException(message: String, cause: Throwable? = null) : SdkException(message, cause) {
        class ChainInfoNotMatching(
            val propertyNames: String,
            val expectedInfo: Service.LightdInfo,
            val actualInfo: Service.LightdInfo
        ) : ChangeServerException(
            "Server change error: the $propertyNames values did not match."
        )
        class StatusException(val status: Status, cause: Throwable? = null) : SdkException(status.toMessage(), cause) {
            companion object {
                private fun Status.toMessage(): String {
                    return when (this.code) {
                        UNAVAILABLE -> {
                            "Error: the new server is unavailable. Verify that the host and port are correct. Failed " +
                                "with $this"
                        }
                        else -> "Changing servers failed with status $this"
                    }
                }
            }
        }
    }
}

/**
 * Potentially user-facing exceptions thrown while encoding transactions.
 */
sealed class TransactionEncoderException(
    message: String,
    cause: Throwable? = null
) : SdkException(message, cause) {
    class FetchParamsException internal constructor(
        internal val parameters: SaplingParameters,
        message: String
    ) : TransactionEncoderException("Failed to fetch params: $parameters, due to: $message")
    class ValidateParamsException internal constructor(
        internal val parameters: SaplingParameters,
        message: String
    ) : TransactionEncoderException("Failed to validate fetched params: $parameters, due to:$message")
    object MissingParamsException : TransactionEncoderException(
        "Cannot send funds due to missing spend or output params and attempting to download them failed."
    )
    class TransactionNotFoundException(transactionId: Long) : TransactionEncoderException(
        "Unable to find transactionId $transactionId in the repository. This means the wallet created a transaction " +
            "and then returned a row ID that does not actually exist. This is a scenario where the wallet should " +
            "have thrown an exception but failed to do so."
    )
    class TransactionNotEncodedException(transactionId: Long) : TransactionEncoderException(
        "The transaction returned by the wallet," +
            " with id $transactionId, does not have any raw data. This is a scenario where the wallet should have " +
            "thrown an exception but failed to do so."
    )
    class IncompleteScanException(lastScannedHeight: BlockHeight) : TransactionEncoderException(
        "Cannot" +
            " create spending transaction because scanning is incomplete. We must scan up to the" +
            " latest height to know which consensus rules to apply. However, the last scanned" +
            " height was $lastScannedHeight."
    )
}