package net.corda.core.transactions

import net.corda.core.CordaInternal
import net.corda.core.KeepForDJVM
import net.corda.core.StubOutForDJVM
import net.corda.core.contracts.Attachment
import net.corda.core.contracts.Command
import net.corda.core.contracts.CommandData
import net.corda.core.contracts.CommandWithParties
import net.corda.core.contracts.ComponentGroupEnum
import net.corda.core.contracts.ContractState
import net.corda.core.contracts.PrivacySalt
import net.corda.core.contracts.StateAndRef
import net.corda.core.contracts.TimeWindow
import net.corda.core.contracts.TransactionState
import net.corda.core.contracts.TransactionVerificationException
import net.corda.core.crypto.SecureHash
import net.corda.core.flows.FlowLogic
import net.corda.core.identity.Party
import net.corda.core.internal.BasicVerifier
import net.corda.core.internal.SerializedStateAndRef
import net.corda.core.internal.Verifier
import net.corda.core.internal.castIfPossible
import net.corda.core.internal.deserialiseCommands
import net.corda.core.internal.deserialiseComponentGroup
import net.corda.core.internal.isUploaderTrusted
import net.corda.core.internal.uncheckedCast
import net.corda.core.node.NetworkParameters
import net.corda.core.serialization.internal.AttachmentsClassLoaderBuilder
import net.corda.core.utilities.contextLogger
import java.util.Collections.unmodifiableList
import java.util.function.Predicate

/**
 * A LedgerTransaction is derived from a [WireTransaction]. It is the result of doing the following operations:
 *
 * - Downloading and locally storing all the dependencies of the transaction.
 * - Resolving the input states and loading them into memory.
 * - Doing some basic key lookups on the [Command]s to see if any keys are from a recognised party, thus converting the
 *   [Command] objects into [CommandWithParties].
 * - Deserialising the output states.
 *
 * All the above refer to inputs using a (txhash, output index) pair.
 *
 * Usage notes:
 *
 * [LedgerTransaction] is an abstraction that is meant to be used during the transaction verification stage.
 * It needs full access to input states that might be in transactions that are encrypted and unavailable for code running outside the secure enclave.
 * Also, it might need to deserialize states with code that might not be available on the classpath.
 *
 * Because of this, trying to create or use a [LedgerTransaction] for any other purpose then transaction verification can result in unexpected exceptions,
 * which need de be handled.
 *
 * [LedgerTransaction]s should never be instantiated directly from client code, but rather via WireTransaction.toLedgerTransaction
 */
@Suppress("LongParameterList")
@KeepForDJVM
class LedgerTransaction
private constructor(
        // DOCSTART 1
        /** The resolved input states which will be consumed/invalidated by the execution of this transaction. */
        override val inputs: List<StateAndRef<ContractState>>,
        /** The outputs created by the transaction. */
        override val outputs: List<TransactionState<ContractState>>,
        /** Arbitrary data passed to the program of each input state. */
        val commands: List<CommandWithParties<CommandData>>,
        /** A list of [Attachment] objects identified by the transaction that are needed for this transaction to verify. */
        val attachments: List<Attachment>,
        /** The hash of the original serialised WireTransaction. */
        override val id: SecureHash,
        /** The notary that the tx uses, this must be the same as the notary of all the inputs, or null if there are no inputs. */
        override val notary: Party?,
        /** The time window within which the tx is valid, will be checked against notary pool member clocks. */
        val timeWindow: TimeWindow?,
        /** Random data used to make the transaction hash unpredictable even if the contents can be predicted; needed to avoid some obscure attacks. */
        val privacySalt: PrivacySalt,
        /**
         * Network parameters that were in force when the transaction was constructed. This is nullable only for backwards
         * compatibility for serialized transactions. In reality this field will always be set when on the normal codepaths.
         */
        override val networkParameters: NetworkParameters?,
        /** Referenced states, which are like inputs but won't be consumed. */
        override val references: List<StateAndRef<ContractState>>,
        //DOCEND 1

        private val componentGroups: List<ComponentGroup>?,
        private val serializedInputs: List<SerializedStateAndRef>?,
        private val serializedReferences: List<SerializedStateAndRef>?,
        private val isAttachmentTrusted: (Attachment) -> Boolean,
        private val verifierFactory: (LedgerTransaction, ClassLoader) -> Verifier
) : FullTransaction() {

    init {
        if (timeWindow != null) check(notary != null) { "Transactions with time-windows must be notarised" }
        checkNotaryWhitelisted()
    }

    @KeepForDJVM
    companion object {
        private val logger = contextLogger()

        private fun <T> protect(list: List<T>?): List<T>? {
            return list?.run {
                if (isEmpty()) {
                    emptyList()
                } else {
                    unmodifiableList(this)
                }
            }
        }

        @CordaInternal
        internal fun create(
                inputs: List<StateAndRef<ContractState>>,
                outputs: List<TransactionState<ContractState>>,
                commands: List<CommandWithParties<CommandData>>,
                attachments: List<Attachment>,
                id: SecureHash,
                notary: Party?,
                timeWindow: TimeWindow?,
                privacySalt: PrivacySalt,
                networkParameters: NetworkParameters,
                references: List<StateAndRef<ContractState>>,
                componentGroups: List<ComponentGroup>? = null,
                serializedInputs: List<SerializedStateAndRef>? = null,
                serializedReferences: List<SerializedStateAndRef>? = null,
                isAttachmentTrusted: (Attachment) -> Boolean
        ): LedgerTransaction {
            return LedgerTransaction(
                inputs = inputs,
                outputs = outputs,
                commands = commands,
                attachments = attachments,
                id = id,
                notary = notary,
                timeWindow = timeWindow,
                privacySalt = privacySalt,
                networkParameters = networkParameters,
                references = references,
                componentGroups = protect(componentGroups),
                serializedInputs = protect(serializedInputs),
                serializedReferences = protect(serializedReferences),
                isAttachmentTrusted = isAttachmentTrusted,
                verifierFactory = ::BasicVerifier
            )
        }

        /**
         * This factory function will create an instance of [LedgerTransaction]
         * that will be used inside the DJVM sandbox.
         */
        @CordaInternal
        fun createForSandbox(
                inputs: List<StateAndRef<ContractState>>,
                outputs: List<TransactionState<ContractState>>,
                commands: List<CommandWithParties<CommandData>>,
                attachments: List<Attachment>,
                id: SecureHash,
                notary: Party?,
                timeWindow: TimeWindow?,
                privacySalt: PrivacySalt,
                networkParameters: NetworkParameters,
                references: List<StateAndRef<ContractState>>): LedgerTransaction {
            return LedgerTransaction(
                inputs = inputs,
                outputs = outputs,
                commands = commands,
                attachments = attachments,
                id = id,
                notary = notary,
                timeWindow = timeWindow,
                privacySalt = privacySalt,
                networkParameters = networkParameters,
                references = references,
                componentGroups = null,
                serializedInputs = null,
                serializedReferences = null,
                isAttachmentTrusted = { true },
                verifierFactory = ::BasicVerifier
            )
        }
    }

    val inputStates: List<ContractState> get() = inputs.map { it.state.data }
    val referenceStates: List<ContractState> get() = references.map { it.state.data }

    /**
     * Returns the typed input StateAndRef at the specified index
     * @param index The index into the inputs.
     * @return The [StateAndRef]
     */
    fun <T : ContractState> inRef(index: Int): StateAndRef<T> = uncheckedCast(inputs[index])

    /**
     * Verifies this transaction and runs contract code. At this stage it is assumed that signatures have already been verified.
     *
     * The contract verification logic is run in a custom classloader created for the current transaction.
     * This classloader is only used during verification and does not leak to the client code.
     *
     * The reason for this is that classes (contract states) deserialized in this classloader would actually be a different type from what
     * the calling code would expect.
     *
     * @throws TransactionVerificationException if anything goes wrong.
     */
    @Throws(TransactionVerificationException::class)
    fun verify() {
        internalPrepareVerify(attachments).verify()
    }

    /**
     * This method has to be called in a context where it has access to the database.
     */
    @CordaInternal
    internal fun internalPrepareVerify(txAttachments: List<Attachment>): Verifier {
        // Switch thread local deserialization context to using a cached attachments classloader. This classloader enforces various rules
        // like no-overlap, package namespace ownership and (in future) deterministic Java.
        return AttachmentsClassLoaderBuilder.withAttachmentsClassloaderContext(
                txAttachments,
                getParamsWithGoo(),
                id,
                isAttachmentTrusted = isAttachmentTrusted) { transactionClassLoader ->
            // Create a copy of the outer LedgerTransaction which deserializes all fields inside the [transactionClassLoader].
            // Only the copy will be used for verification, and the outer shell will be discarded.
            // This artifice is required to preserve backwards compatibility.
            verifierFactory(createLtxForVerification(), transactionClassLoader)
        }
    }

    /**
     * Pass all of this [LedgerTransaction] object's serialized state to a [transformer] function.
     */
    @CordaInternal
    fun <T> transform(transformer: (List<ComponentGroup>, List<SerializedStateAndRef>, List<SerializedStateAndRef>) -> T): T {
        return transformer(componentGroups ?: emptyList(), serializedInputs ?: emptyList(), serializedReferences ?: emptyList())
    }

    /**
     * We need a way to customise transaction verification inside the
     * Node without changing either the wire format or any public APIs.
     */
    @CordaInternal
    fun specialise(alternateVerifier: (LedgerTransaction, ClassLoader) -> Verifier): LedgerTransaction = LedgerTransaction(
        inputs = inputs,
        outputs = outputs,
        commands = commands,
        attachments = attachments,
        id = id,
        notary = notary,
        timeWindow = timeWindow,
        privacySalt = privacySalt,
        networkParameters = networkParameters,
        references = references,
        componentGroups = componentGroups,
        serializedInputs = serializedInputs,
        serializedReferences = serializedReferences,
        isAttachmentTrusted = isAttachmentTrusted,
        verifierFactory = alternateVerifier
    )

    // Read network parameters with backwards compatibility goo.
    private fun getParamsWithGoo(): NetworkParameters {
        var params = networkParameters
        if (params == null) {
            // This path is triggered if someone used old constructors that were accidentally exposed; darn Kotlin's lack of package-private
            // visibility! We did originally try to maintain verification codepaths that supported lack of network parameters, but, it
            // got too convoluted and people kept just !! asserting the nullity away because on normal codepaths this is always set.
            logger.warn("Network parameters on the LedgerTransaction with id: $id are null. Please don't use deprecated constructors of the LedgerTransaction. " +
                    "Use WireTransaction.toLedgerTransaction instead. The result of the verify method would not be accurate.")
            // Roll the dice - we're probably in flow context if we got here at all, which means we can fish the current params out.
            try {
                params = getParamsFromFlowLogic()
            } catch (e: UnsupportedOperationException) {
                // Inside DJVM, ignore.
            }
            if (params == null)
                throw UnsupportedOperationException("Cannot verify a LedgerTransaction created using deprecated constructors outside of flow context.")
        }
        return params
    }

    @StubOutForDJVM
    private fun getParamsFromFlowLogic(): NetworkParameters? {
        return FlowLogic.currentTopLevel?.serviceHub?.networkParameters
    }

    /**
     * Create the [LedgerTransaction] instance that will be used by contract verification.
     *
     * This method needs to run in the special transaction attachments classloader context.
     */
    private fun createLtxForVerification(): LedgerTransaction {
        val serializedInputs = this.serializedInputs
        val serializedReferences = this.serializedReferences
        val componentGroups = this.componentGroups

        val transaction= if (serializedInputs != null && serializedReferences != null && componentGroups != null) {
            // Deserialize all relevant classes in the transaction classloader.
            val deserializedInputs = serializedInputs.map { it.toStateAndRef() }
            val deserializedReferences = serializedReferences.map { it.toStateAndRef() }
            val deserializedOutputs = deserialiseComponentGroup(componentGroups, TransactionState::class, ComponentGroupEnum.OUTPUTS_GROUP, forceDeserialize = true)
            val deserializedCommands = deserialiseCommands(componentGroups, forceDeserialize = true)
            val authenticatedDeserializedCommands = deserializedCommands.map { cmd ->
                @Suppress("DEPRECATION")   // Deprecated feature.
                val parties = commands.find { it.value.javaClass.name == cmd.value.javaClass.name }!!.signingParties
                CommandWithParties(cmd.signers, parties, cmd.value)
            }

            LedgerTransaction(
                    inputs = deserializedInputs,
                    outputs = deserializedOutputs,
                    commands = authenticatedDeserializedCommands,
                    attachments = this.attachments,
                    id = this.id,
                    notary = this.notary,
                    timeWindow = this.timeWindow,
                    privacySalt = this.privacySalt,
                    networkParameters = this.networkParameters,
                    references = deserializedReferences,
                    componentGroups = componentGroups,
                    serializedInputs = serializedInputs,
                    serializedReferences = serializedReferences,
                    isAttachmentTrusted = isAttachmentTrusted,
                    verifierFactory = verifierFactory
            )
        } else {
            // This branch is only present for backwards compatibility.
            logger.warn("The LedgerTransaction should not be instantiated directly from client code. Please use WireTransaction.toLedgerTransaction." +
                    "The result of the verify method might not be accurate.")
            this
        }

        // This check accesses input states and must be run in this context.
        // It must run on the instance that is verified, not on the outer LedgerTransaction shell.
        transaction.checkBaseInvariants()

        return transaction
    }

    /**
     * Given a type and a function that returns a grouping key, associates inputs and outputs together so that they
     * can be processed as one. The grouping key is any arbitrary object that can act as a map key (so must implement
     * equals and hashCode).
     *
     * The purpose of this function is to simplify the writing of verification logic for transactions that may contain
     * similar but unrelated state evolutions which need to be checked independently. Consider a transaction that
     * simultaneously moves both dollars and euros (e.g. is an atomic FX trade). There may be multiple dollar inputs and
     * multiple dollar outputs, depending on things like how fragmented the owner's vault is and whether various privacy
     * techniques are in use. The quantity of dollars on the output side must sum to the same as on the input side, to
     * ensure no money is being lost track of. This summation and checking must be repeated independently for each
     * currency. To solve this, you would use groupStates with a type of Cash.State and a selector that returns the
     * currency field: the resulting list can then be iterated over to perform the per-currency calculation.
     */
    // DOCSTART 2
    fun <T : ContractState, K : Any> groupStates(ofType: Class<T>, selector: (T) -> K): List<InOutGroup<T, K>> {
        val inputs = inputsOfType(ofType)
        val outputs = outputsOfType(ofType)

        val inGroups: Map<K, List<T>> = inputs.groupBy(selector)
        val outGroups: Map<K, List<T>> = outputs.groupBy(selector)

        val result = ArrayList<InOutGroup<T, K>>()

        for ((k, v) in inGroups.entries)
            result.add(InOutGroup(v, outGroups[k] ?: emptyList(), k))
        for ((k, v) in outGroups.entries) {
            if (inGroups[k] == null)
                result.add(InOutGroup(emptyList(), v, k))
        }

        return result
    }
    // DOCEND 2

    /** See the documentation for the reflection-based version of [groupStates] */
    inline fun <reified T : ContractState, K : Any> groupStates(noinline selector: (T) -> K): List<InOutGroup<T, K>> {
        return groupStates(T::class.java, selector)
    }

    /** Utilities for contract writers to incorporate into their logic. */

    /**
     * A set of related inputs and outputs that are connected by some common attributes. An InOutGroup is calculated
     * using [groupStates] and is useful for handling cases where a transaction may contain similar but unrelated
     * state evolutions, for example, a transaction that moves cash in two different currencies. The numbers must add
     * up on both sides of the transaction, but the values must be summed independently per currency. Grouping can
     * be used to simplify this logic.
     */
    // DOCSTART 3
    @KeepForDJVM
    data class InOutGroup<out T : ContractState, out K : Any>(val inputs: List<T>, val outputs: List<T>, val groupingKey: K)
    // DOCEND 3

    /**
     * Helper to simplify getting an indexed input [ContractState].
     * @param index the position of the item in the inputs.
     * @return The [StateAndRef] at the requested index
     */
    fun getInput(index: Int): ContractState = inputs[index].state.data

    /**
     * Helper to simplify getting an indexed reference input [ContractState].
     * @param index the position of the item in the references.
     * @return The [StateAndRef] at the requested index.
     */
    fun getReferenceInput(index: Int): ContractState = references[index].state.data

    /**
     * Helper to simplify getting all inputs states of a particular class, interface, or base class.
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [ContractState].
     * @return the possibly empty list of inputs matching the clazz restriction.
     */
    fun <T : ContractState> inputsOfType(clazz: Class<T>): List<T> = inputs.mapNotNull { clazz.castIfPossible(it.state.data) }

    inline fun <reified T : ContractState> inputsOfType(): List<T> = inputsOfType(T::class.java)

    /**
     * Helper to simplify getting all reference input states of a particular class, interface, or base class.
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [ContractState].
     * @return the possibly empty list of inputs matching the clazz restriction.
     */
    fun <T : ContractState> referenceInputsOfType(clazz: Class<T>): List<T> = references.mapNotNull { clazz.castIfPossible(it.state.data) }

    inline fun <reified T : ContractState> referenceInputsOfType(): List<T> = referenceInputsOfType(T::class.java)

    /**
     * Helper to simplify getting all inputs states of a particular class, interface, or base class.
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [ContractState].
     * @return the possibly empty list of inputs [StateAndRef] matching the clazz restriction.
     */
    fun <T : ContractState> inRefsOfType(clazz: Class<T>): List<StateAndRef<T>> {
        return inputs.mapNotNull { if (clazz.isInstance(it.state.data)) uncheckedCast<StateAndRef<ContractState>, StateAndRef<T>>(it) else null }
    }

    inline fun <reified T : ContractState> inRefsOfType(): List<StateAndRef<T>> = inRefsOfType(T::class.java)

    /**
     * Helper to simplify getting all reference input states of a particular class, interface, or base class.
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [ContractState].
     * @return the possibly empty list of reference inputs [StateAndRef] matching the clazz restriction.
     */
    fun <T : ContractState> referenceInputRefsOfType(clazz: Class<T>): List<StateAndRef<T>> {
        return references.mapNotNull { if (clazz.isInstance(it.state.data)) uncheckedCast<StateAndRef<ContractState>, StateAndRef<T>>(it) else null }
    }

    inline fun <reified T : ContractState> referenceInputRefsOfType(): List<StateAndRef<T>> = referenceInputRefsOfType(T::class.java)

    /**
     * Helper to simplify filtering inputs according to a [Predicate].
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [ContractState].
     * @param predicate A filtering function taking a state of type T and returning true if it should be included in the list.
     * The class filtering is applied before the predicate.
     * @return the possibly empty list of input states matching the predicate and clazz restrictions.
     */
    fun <T : ContractState> filterInputs(clazz: Class<T>, predicate: Predicate<T>): List<T> {
        return inputsOfType(clazz).filter { predicate.test(it) }
    }

    inline fun <reified T : ContractState> filterInputs(crossinline predicate: (T) -> Boolean): List<T> {
        return filterInputs(T::class.java, Predicate { predicate(it) })
    }

    /**
     * Helper to simplify filtering reference inputs according to a [Predicate].
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [ContractState].
     * @param predicate A filtering function taking a state of type T and returning true if it should be included in the list.
     * The class filtering is applied before the predicate.
     * @return the possibly empty list of reference states matching the predicate and clazz restrictions.
     */
    fun <T : ContractState> filterReferenceInputs(clazz: Class<T>, predicate: Predicate<T>): List<T> {
        return referenceInputsOfType(clazz).filter { predicate.test(it) }
    }

    inline fun <reified T : ContractState> filterReferenceInputs(crossinline predicate: (T) -> Boolean): List<T> {
        return filterReferenceInputs(T::class.java, Predicate { predicate(it) })
    }

    /**
     * Helper to simplify filtering inputs according to a [Predicate].
     * @param predicate A filtering function taking a state of type T and returning true if it should be included in the list.
     * The class filtering is applied before the predicate.
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [ContractState].
     * @return the possibly empty list of inputs [StateAndRef] matching the predicate and clazz restrictions.
     */
    fun <T : ContractState> filterInRefs(clazz: Class<T>, predicate: Predicate<T>): List<StateAndRef<T>> {
        return inRefsOfType(clazz).filter { predicate.test(it.state.data) }
    }

    inline fun <reified T : ContractState> filterInRefs(crossinline predicate: (T) -> Boolean): List<StateAndRef<T>> {
        return filterInRefs(T::class.java, Predicate { predicate(it) })
    }

    /**
     * Helper to simplify filtering reference inputs according to a [Predicate].
     * @param predicate A filtering function taking a state of type T and returning true if it should be included in the list.
     * The class filtering is applied before the predicate.
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [ContractState].
     * @return the possibly empty list of references [StateAndRef] matching the predicate and clazz restrictions.
     */
    fun <T : ContractState> filterReferenceInputRefs(clazz: Class<T>, predicate: Predicate<T>): List<StateAndRef<T>> {
        return referenceInputRefsOfType(clazz).filter { predicate.test(it.state.data) }
    }

    inline fun <reified T : ContractState> filterReferenceInputRefs(crossinline predicate: (T) -> Boolean): List<StateAndRef<T>> {
        return filterReferenceInputRefs(T::class.java, Predicate { predicate(it) })
    }

    /**
     * Helper to simplify finding a single input [ContractState] matching a [Predicate].
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of ContractState.
     * @param predicate A filtering function taking a state of type T and returning true if this is the desired item.
     * The class filtering is applied before the predicate.
     * @return the single item matching the predicate.
     * @throws IllegalArgumentException if no item, or multiple items are found matching the requirements.
     */
    fun <T : ContractState> findInput(clazz: Class<T>, predicate: Predicate<T>): T {
        return inputsOfType(clazz).single { predicate.test(it) }
    }

    inline fun <reified T : ContractState> findInput(crossinline predicate: (T) -> Boolean): T {
        return findInput(T::class.java, Predicate { predicate(it) })
    }

    /**
     * Helper to simplify finding a single reference inputs [ContractState] matching a [Predicate].
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of ContractState.
     * @param predicate A filtering function taking a state of type T and returning true if this is the desired item.
     * The class filtering is applied before the predicate.
     * @return the single item matching the predicate.
     * @throws IllegalArgumentException if no item, or multiple items are found matching the requirements.
     */
    fun <T : ContractState> findReference(clazz: Class<T>, predicate: Predicate<T>): T {
        return referenceInputsOfType(clazz).single { predicate.test(it) }
    }

    inline fun <reified T : ContractState> findReference(crossinline predicate: (T) -> Boolean): T {
        return findReference(T::class.java, Predicate { predicate(it) })
    }

    /**
     * Helper to simplify finding a single input matching a [Predicate].
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of ContractState.
     * @param predicate A filtering function taking a state of type T and returning true if this is the desired item.
     * The class filtering is applied before the predicate.
     * @return the single item matching the predicate.
     * @throws IllegalArgumentException if no item, or multiple items are found matching the requirements.
     */
    fun <T : ContractState> findInRef(clazz: Class<T>, predicate: Predicate<T>): StateAndRef<T> {
        return inRefsOfType(clazz).single { predicate.test(it.state.data) }
    }

    inline fun <reified T : ContractState> findInRef(crossinline predicate: (T) -> Boolean): StateAndRef<T> {
        return findInRef(T::class.java, Predicate { predicate(it) })
    }

    /**
     * Helper to simplify finding a single reference input matching a [Predicate].
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of ContractState.
     * @param predicate A filtering function taking a state of type T and returning true if this is the desired item.
     * The class filtering is applied before the predicate.
     * @return the single item matching the predicate.
     * @throws IllegalArgumentException if no item, or multiple items are found matching the requirements.
     */
    fun <T : ContractState> findReferenceInputRef(clazz: Class<T>, predicate: Predicate<T>): StateAndRef<T> {
        return referenceInputRefsOfType(clazz).single { predicate.test(it.state.data) }
    }

    inline fun <reified T : ContractState> findReferenceInputRef(crossinline predicate: (T) -> Boolean): StateAndRef<T> {
        return findReferenceInputRef(T::class.java, Predicate { predicate(it) })
    }

    /**
     * Helper to simplify getting an indexed command.
     * @param index the position of the item in the commands.
     * @return The Command at the requested index
     */
    fun <T : CommandData> getCommand(index: Int): Command<T> = Command(uncheckedCast(commands[index].value), commands[index].signers)

    /**
     * Helper to simplify getting all [Command] items with a [CommandData] of a particular class, interface, or base class.
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [CommandData].
     * @return the possibly empty list of commands with [CommandData] values matching the clazz restriction.
     */
    fun <T : CommandData> commandsOfType(clazz: Class<T>): List<Command<T>> {
        return commands.mapNotNull { (signers, _, value) -> clazz.castIfPossible(value)?.let { Command(it, signers) } }
    }

    inline fun <reified T : CommandData> commandsOfType(): List<Command<T>> = commandsOfType(T::class.java)

    /**
     * Helper to simplify filtering [Command] items according to a [Predicate].
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [CommandData].
     * @param predicate A filtering function taking a [CommandData] item of type T and returning true if it should be included in the list.
     * The class filtering is applied before the predicate.
     * @return the possibly empty list of [Command] items with [CommandData] values matching the predicate and clazz restrictions.
     */
    fun <T : CommandData> filterCommands(clazz: Class<T>, predicate: Predicate<T>): List<Command<T>> {
        return commandsOfType(clazz).filter { predicate.test(it.value) }
    }

    inline fun <reified T : CommandData> filterCommands(crossinline predicate: (T) -> Boolean): List<Command<T>> {
        return filterCommands(T::class.java, Predicate { predicate(it) })
    }

    /**
     * Helper to simplify finding a single [Command] items according to a [Predicate].
     * @param clazz The class type used for filtering via an [Class.isInstance] check.
     * [clazz] must be an extension of [CommandData].
     * @param predicate A filtering function taking a [CommandData] item of type T and returning true if it should be included in the list.
     * The class filtering is applied before the predicate.
     * @return the [Command] item with [CommandData] values matching the predicate and clazz restrictions.
     * @throws IllegalArgumentException if no items, or multiple items matched the requirements.
     */
    fun <T : CommandData> findCommand(clazz: Class<T>, predicate: Predicate<T>): Command<T> {
        return commandsOfType(clazz).single { predicate.test(it.value) }
    }

    inline fun <reified T : CommandData> findCommand(crossinline predicate: (T) -> Boolean): Command<T> {
        return findCommand(T::class.java, Predicate { predicate(it) })
    }

    /**
     * Helper to simplify getting an indexed attachment.
     * @param index the position of the item in the attachments.
     * @return The Attachment at the requested index.
     */
    fun getAttachment(index: Int): Attachment = attachments[index]

    /**
     * Helper to simplify getting an indexed attachment.
     * @param id the SecureHash of the desired attachment.
     * @return The Attachment with the matching id.
     * @throws IllegalArgumentException if no item matches the id.
     */
    fun getAttachment(id: SecureHash): Attachment = attachments.first { it.id == id }

    operator fun component1(): List<StateAndRef<ContractState>> = inputs
    operator fun component2(): List<TransactionState<ContractState>> = outputs
    operator fun component3(): List<CommandWithParties<CommandData>> = commands
    operator fun component4(): List<Attachment> = attachments
    operator fun component5(): SecureHash = id
    operator fun component6(): Party? = notary
    operator fun component7(): TimeWindow? = timeWindow
    operator fun component8(): PrivacySalt = privacySalt
    operator fun component9(): NetworkParameters? = networkParameters
    operator fun component10(): List<StateAndRef<ContractState>> = references

    override fun equals(other: Any?): Boolean = this === other || other is LedgerTransaction && this.id == other.id

    override fun hashCode(): Int = id.hashCode()

    override fun toString(): String {
        return """LedgerTransaction(
            |    id=$id
            |    inputs=$inputs
            |    outputs=$outputs
            |    commands=$commands
            |    attachments=$attachments
            |    notary=$notary
            |    timeWindow=$timeWindow
            |    references=$references
            |    networkParameters=$networkParameters
            |    privacySalt=$privacySalt
            |)""".trimMargin()
    }

    // Stuff that we can't remove and so is deprecated instead
    //
    @Deprecated("LedgerTransaction should not be created directly, use WireTransaction.toLedgerTransaction instead.")
    constructor(
            inputs: List<StateAndRef<ContractState>>,
            outputs: List<TransactionState<ContractState>>,
            commands: List<CommandWithParties<CommandData>>,
            attachments: List<Attachment>,
            id: SecureHash,
            notary: Party?,
            timeWindow: TimeWindow?,
            privacySalt: PrivacySalt
    ) : this(
            inputs = inputs,
            outputs = outputs,
            commands = commands,
            attachments = attachments,
            id = id,
            notary = notary,
            timeWindow = timeWindow,
            privacySalt = privacySalt,
            networkParameters = null,
            references = emptyList(),
            componentGroups = null,
            serializedInputs = null,
            serializedReferences = null,
            isAttachmentTrusted = { it.isUploaderTrusted() },
            verifierFactory = ::BasicVerifier
    )

    @Deprecated("LedgerTransaction should not be created directly, use WireTransaction.toLedgerTransaction instead.")
    constructor(
            inputs: List<StateAndRef<ContractState>>,
            outputs: List<TransactionState<ContractState>>,
            commands: List<CommandWithParties<CommandData>>,
            attachments: List<Attachment>,
            id: SecureHash,
            notary: Party?,
            timeWindow: TimeWindow?,
            privacySalt: PrivacySalt,
            networkParameters: NetworkParameters
    ) : this(
            inputs = inputs,
            outputs = outputs,
            commands = commands,
            attachments = attachments,
            id = id,
            notary = notary,
            timeWindow = timeWindow,
            privacySalt = privacySalt,
            networkParameters = networkParameters,
            references = emptyList(),
            componentGroups = null,
            serializedInputs = null,
            serializedReferences = null,
            isAttachmentTrusted = { it.isUploaderTrusted() },
            verifierFactory = ::BasicVerifier
    )

    @Deprecated("LedgerTransactions should not be created directly, use WireTransaction.toLedgerTransaction instead.")
    fun copy(inputs: List<StateAndRef<ContractState>>,
             outputs: List<TransactionState<ContractState>>,
             commands: List<CommandWithParties<CommandData>>,
             attachments: List<Attachment>,
             id: SecureHash,
             notary: Party?,
             timeWindow: TimeWindow?,
             privacySalt: PrivacySalt
    ): LedgerTransaction {
        return LedgerTransaction(
                inputs = inputs,
                outputs = outputs,
                commands = commands,
                attachments = attachments,
                id = id,
                notary = notary,
                timeWindow = timeWindow,
                privacySalt = privacySalt,
                networkParameters = networkParameters,
                references = references,
                componentGroups = componentGroups,
                serializedInputs = serializedInputs,
                serializedReferences = serializedReferences,
                isAttachmentTrusted = isAttachmentTrusted,
                verifierFactory = verifierFactory
        )
    }

    @Deprecated("LedgerTransactions should not be created directly, use WireTransaction.toLedgerTransaction instead.")
    fun copy(inputs: List<StateAndRef<ContractState>> = this.inputs,
             outputs: List<TransactionState<ContractState>> = this.outputs,
             commands: List<CommandWithParties<CommandData>> = this.commands,
             attachments: List<Attachment> = this.attachments,
             id: SecureHash = this.id,
             notary: Party? = this.notary,
             timeWindow: TimeWindow? = this.timeWindow,
             privacySalt: PrivacySalt = this.privacySalt,
             networkParameters: NetworkParameters? = this.networkParameters
    ): LedgerTransaction {
        return LedgerTransaction(
                inputs = inputs,
                outputs = outputs,
                commands = commands,
                attachments = attachments,
                id = id,
                notary = notary,
                timeWindow = timeWindow,
                privacySalt = privacySalt,
                networkParameters = networkParameters,
                references = references,
                componentGroups = componentGroups,
                serializedInputs = serializedInputs,
                serializedReferences = serializedReferences,
                isAttachmentTrusted = isAttachmentTrusted,
                verifierFactory = verifierFactory
        )
    }
}
