package net.corda.node.services.identity

import com.google.common.util.concurrent.ThreadFactoryBuilder
import net.corda.core.crypto.Crypto
import net.corda.core.crypto.toStringShort
import net.corda.core.identity.AbstractParty
import net.corda.core.identity.AnonymousParty
import net.corda.core.identity.CordaX500Name
import net.corda.core.identity.Party
import net.corda.core.identity.PartyAndCertificate
import net.corda.core.identity.x500Matches
import net.corda.core.internal.CertRole
import net.corda.core.internal.NamedCacheFactory
import net.corda.core.internal.hash
import net.corda.core.internal.toSet
import net.corda.core.node.NotaryInfo
import net.corda.core.node.services.UnknownAnonymousPartyException
import net.corda.core.serialization.SingletonSerializeAsToken
import net.corda.core.utilities.MAX_HASH_HEX_SIZE
import net.corda.core.utilities.contextLogger
import net.corda.core.utilities.debug
import net.corda.node.internal.schemas.NodeInfoSchemaV1
import net.corda.node.services.api.IdentityServiceInternal
import net.corda.node.services.keys.BasicHSMKeyManagementService
import net.corda.node.services.network.NotaryUpdateListener
import net.corda.node.services.network.PersistentNetworkMapCache
import net.corda.node.services.persistence.PublicKeyHashToExternalId
import net.corda.node.services.persistence.WritablePublicKeyToOwningIdentityCache
import net.corda.node.utilities.AppendOnlyPersistentMap
import net.corda.node.utilities.NonInvalidatingCache
import net.corda.nodeapi.internal.KeyOwningIdentity
import net.corda.nodeapi.internal.crypto.X509CertificateFactory
import net.corda.nodeapi.internal.crypto.X509Utilities
import net.corda.nodeapi.internal.crypto.x509Certificates
import net.corda.nodeapi.internal.persistence.CordaPersistence
import net.corda.nodeapi.internal.persistence.NODE_DATABASE_PREFIX
import net.corda.nodeapi.internal.persistence.currentDBSession
import org.hibernate.Session
import org.hibernate.annotations.Type
import org.hibernate.internal.util.collections.ArrayHelper.EMPTY_BYTE_ARRAY
import java.security.InvalidAlgorithmParameterException
import java.security.PublicKey
import java.security.cert.CertPathValidatorException
import java.security.cert.CertStore
import java.security.cert.CertificateExpiredException
import java.security.cert.CertificateNotYetValidException
import java.security.cert.CollectionCertStoreParameters
import java.security.cert.TrustAnchor
import java.security.cert.X509Certificate
import java.util.HashSet
import java.util.Optional
import java.util.UUID
import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors
import java.util.stream.Stream
import javax.annotation.concurrent.ThreadSafe
import javax.persistence.Column
import javax.persistence.Entity
import javax.persistence.Id

/**
 * An identity service that stores parties and their identities to a key value tables in the database. The entries are
 * cached for efficient lookup.
 */
@ThreadSafe
@Suppress("TooManyFunctions")
class PersistentIdentityService(cacheFactory: NamedCacheFactory) : SingletonSerializeAsToken(), IdentityServiceInternal, NotaryUpdateListener {

    companion object {
        private val log = contextLogger()

        private fun createKeyToPartyAndCertMap(cacheFactory: NamedCacheFactory): AppendOnlyPersistentMap<String, PartyAndCertificate,
                PersistentPublicKeyHashToCertificate, String> {
            return AppendOnlyPersistentMap(
                    cacheFactory = cacheFactory,
                    name = "PersistentIdentityService_keyToPartyAndCert",
                    toPersistentEntityKey = { it },
                    fromPersistentEntity = {
                        Pair(
                                it.publicKeyHash,
                                PartyAndCertificate(X509CertificateFactory().delegate.generateCertPath(it.identity.inputStream()))
                        )
                    },
                    toPersistentEntity = { key: String, value: PartyAndCertificate ->
                        PersistentPublicKeyHashToCertificate(key, value.certPath.encoded)
                    },
                    persistentEntityClass = PersistentPublicKeyHashToCertificate::class.java
            )
        }

        /**
         * [Party] with owning key replaced by its hash.
         */
        private data class PartyWithHash(val name: CordaX500Name, val owningKeyHash: String) {
            constructor(party: Party) : this(party.name, party.owningKey.toStringShort())
        }

        private fun createKeyToPartyMap(cacheFactory: NamedCacheFactory): AppendOnlyPersistentMap<String, PartyWithHash,
                PersistentPublicKeyHashToParty, String> {
            return AppendOnlyPersistentMap(
                    cacheFactory = cacheFactory,
                    name = "PersistentIdentityService_keyToParty",
                    toPersistentEntityKey = { it },
                    fromPersistentEntity = {
                        Pair(
                                it.publicKeyHash,
                                PartyWithHash(CordaX500Name.parse(it.name), it.owningKeyHash)
                        )
                    },
                    toPersistentEntity = { key: String, value: PartyWithHash ->
                        PersistentPublicKeyHashToParty(key, value.name.toString(), value.owningKeyHash)
                    },
                    persistentEntityClass = PersistentPublicKeyHashToParty::class.java)
        }

        private fun createNameToPartyMap(cacheFactory: NamedCacheFactory): NonInvalidatingCache<CordaX500Name, Optional<Party>> {
            return NonInvalidatingCache(
                    cacheFactory = cacheFactory,
                    name = "PersistentIdentityService_nameToParty",
                    loadFunction = {
                        val result = currentDBSession().find(NodeInfoSchemaV1.DBPartyAndCertificate::class.java, it.toString())
                        Optional.ofNullable(result?.toLegalIdentityAndCert()?.party)
                    }
            )
        }

        fun createHashToKeyMap(cacheFactory: NamedCacheFactory): AppendOnlyPersistentMap<String, PublicKey, PersistentHashToPublicKey,
                String> {
            return AppendOnlyPersistentMap(
                    cacheFactory = cacheFactory,
                    name = "PersistentIdentityService_hashToKey",
                    toPersistentEntityKey = { it },
                    fromPersistentEntity = {
                        Pair(
                                it.publicKeyHash,
                                Crypto.decodePublicKey(it.publicKey)
                        )
                    },
                    toPersistentEntity = { key: String, value: PublicKey ->
                        PersistentHashToPublicKey(key, Crypto.encodePublicKey(value))
                    },
                    persistentEntityClass = PersistentHashToPublicKey::class.java)
        }

        private fun mapToKey(party: PartyAndCertificate) = party.owningKey.toStringShort()
    }

    val archiveIdentityExecutor: ExecutorService = Executors.newCachedThreadPool(ThreadFactoryBuilder().setNameFormat("archive-named-identity-thread-%d").build())

    @Entity
    @javax.persistence.Table(name = "${NODE_DATABASE_PREFIX}identities")
    class PersistentPublicKeyHashToCertificate(
            @Id
            @Column(name = "pk_hash", length = MAX_HASH_HEX_SIZE, nullable = false)
            var publicKeyHash: String = "",

            @Type(type = "corda-blob")
            @Column(name = "identity_value", nullable = false)
            var identity: ByteArray = EMPTY_BYTE_ARRAY
    )

    @Entity
    @javax.persistence.Table(name = "${NODE_DATABASE_PREFIX}identities_no_cert")
    class PersistentPublicKeyHashToParty(
            @Id
            @Column(name = "pk_hash", length = MAX_HASH_HEX_SIZE, nullable = false)
            var publicKeyHash: String = "",

            @Column(name = "name", length = 128, nullable = false)
            var name: String = "",

            @Column(name = "owning_pk_hash", length = MAX_HASH_HEX_SIZE, nullable = false)
            var owningKeyHash: String = ""
    )

    @Entity
    @javax.persistence.Table(name = "${NODE_DATABASE_PREFIX}hash_to_key")
    class PersistentHashToPublicKey(
            @Id
            @Column(name = "pk_hash", length = MAX_HASH_HEX_SIZE, nullable = false)
            var publicKeyHash: String = "",

            @Type(type = "corda-blob")
            @Column(name = "public_key", nullable = false)
            var publicKey: ByteArray = EMPTY_BYTE_ARRAY
    )

    private lateinit var _caCertStore: CertStore
    override val caCertStore: CertStore get() = _caCertStore

    private lateinit var _trustRoot: X509Certificate
    override val trustRoot: X509Certificate get() = _trustRoot

    private lateinit var _trustAnchor: TrustAnchor
    override val trustAnchor: TrustAnchor get() = _trustAnchor

    private lateinit var _trustAnchors: Set<TrustAnchor>
    override val trustAnchors: Set<TrustAnchor> get() = _trustAnchors

    private lateinit var ourParty: Party

    /** Stores notary identities obtained from the network parameters, for which we don't need to perform a database lookup. */
    @Volatile
    private var notaryIdentityCache = HashSet<Party>()

    // CordaPersistence is not a c'tor parameter to work around the cyclic dependency
    lateinit var database: CordaPersistence

    private lateinit var _pkToIdCache: WritablePublicKeyToOwningIdentityCache

    private val keyToPartyAndCert = createKeyToPartyAndCertMap(cacheFactory)
    private val keyToParty = createKeyToPartyMap(cacheFactory)
    private val nameToParty = createNameToPartyMap(cacheFactory)
    private val hashToKey = createHashToKeyMap(cacheFactory)

    fun start(
            trustRoots: Set<X509Certificate>,
            ourIdentity: PartyAndCertificate,
            notaryIdentities: List<Party> = emptyList(),
            pkToIdCache: WritablePublicKeyToOwningIdentityCache
    ) {
        _trustRoot = ourIdentity.certPath.certificates.last() as X509Certificate
        _trustAnchor = TrustAnchor(trustRoot, null)
        _trustAnchors = trustRoots.map { TrustAnchor(it, null) }.toSet()
        // Extract Node CA certificate from node identity certificate path
        val certificates = setOf(ourIdentity.certificate, ourIdentity.certPath.certificates[1], trustRoot)
        _caCertStore = CertStore.getInstance("Collection", CollectionCertStoreParameters(certificates))
        _pkToIdCache = pkToIdCache
        notaryIdentityCache.addAll(notaryIdentities)
        ourParty = ourIdentity.party
    }

    fun loadIdentities(identities: Collection<PartyAndCertificate>) {
        identities.forEach {
            val key = mapToKey(it)
            keyToPartyAndCert.addWithDuplicatesAllowed(key, it, false)
            keyToParty.addWithDuplicatesAllowed(it.owningKey.toStringShort(), PartyWithHash(it.party), false)
            nameToParty.asMap()[it.name] = Optional.of(it.party)
        }
        log.debug("Identities loaded")
    }

    @Throws(CertificateExpiredException::class, CertificateNotYetValidException::class, InvalidAlgorithmParameterException::class)
    override fun verifyAndRegisterIdentity(identity: PartyAndCertificate): PartyAndCertificate? {
        return verifyAndRegisterIdentity(trustAnchors, identity)
    }

    @Throws(CertificateExpiredException::class, CertificateNotYetValidException::class, InvalidAlgorithmParameterException::class)
    override fun verifyAndRegisterNewRandomIdentity(identity: PartyAndCertificate) {
        verifyAndRegisterIdentity(trustAnchors, identity, true)
    }

    @Throws(CertificateExpiredException::class, CertificateNotYetValidException::class, InvalidAlgorithmParameterException::class)
    private fun verifyAndRegisterIdentity(trustAnchors: Set<TrustAnchor>, identity: PartyAndCertificate, isNewRandomIdentity: Boolean = false):
            PartyAndCertificate? {
        // Validate the chain first, before we do anything clever with it
        val identityCertChain = identity.certPath.x509Certificates
        try {
            identity.verify(trustAnchors)
        } catch (e: CertPathValidatorException) {
            val roots = trustAnchors.map { it.trustedCert.subjectX500Principal }
            log.warn("Certificate validation failed for ${identity.name} against trusted roots $roots.")
            log.warn("Certificate path :")
            identityCertChain.reversed().forEachIndexed { index, certificate ->
                val space = (0 until index).joinToString("") { "   " }
                log.warn("$space${certificate.subjectX500Principal}")
            }
            throw e
        }
        // Ensure we record the first identity of the same name, first
        val wellKnownCert = identityCertChain.single { CertRole.extract(it)?.isWellKnown ?: false }
        if (wellKnownCert != identity.certificate && !isNewRandomIdentity) {
            val idx = identityCertChain.lastIndexOf(wellKnownCert)
            val firstPath = X509Utilities.buildCertPath(identityCertChain.slice(idx until identityCertChain.size))
            verifyAndRegisterIdentity(trustAnchors, PartyAndCertificate(firstPath))
        }
        return registerIdentity(identity, isNewRandomIdentity)
    }

    private fun registerIdentity(identity: PartyAndCertificate, isNewRandomIdentity: Boolean): PartyAndCertificate? {
        log.debug { "Registering identity $identity" }
        val identityCertChain = identity.certPath.x509Certificates
        val key = mapToKey(identity)

        return database.transaction {
            if (isNewRandomIdentity) {
                // Because this is supposed to be new and random, there's no way we have it in the database already, so skip the this check
                keyToPartyAndCert[key] = identity
                // keyToParty is already registered via KMS freshKeyInternal()
            } else {
                keyToPartyAndCert.addWithDuplicatesAllowed(key, identity, false)
                keyToParty.addWithDuplicatesAllowed(identity.owningKey.toStringShort(), PartyWithHash(identity.party), false)
            }
            val parentId = identityCertChain[1].publicKey.toStringShort()
            keyToPartyAndCert[parentId]
        }
    }

    override fun invalidateCaches(name: CordaX500Name) {
        nameToParty.invalidate(name)
    }

    override fun certificateFromKey(owningKey: PublicKey): PartyAndCertificate? = database.transaction {
        keyToPartyAndCert[owningKey.toStringShort()]
    }

    override fun partyFromKey(key: PublicKey): Party? {
        return certificateFromKey(key)?.takeIf { CertRole.extract(it.certificate)?.isWellKnown == false }?.party ?:
        database.transaction {
            keyToParty[key.toStringShort()]
        }?.let { wellKnownPartyFromX500Name(it.name) }
    }

    // We give the caller a copy of the data set to avoid any locking problems
    override fun getAllIdentities(): Iterable<PartyAndCertificate> {
        return database.transaction {
            keyToPartyAndCert.allPersisted.use { it.map { it.second }.toList() }
        }
    }

    override fun wellKnownPartyFromX500Name(name: CordaX500Name): Party? = database.transaction {
        if (nameToParty[name]?.isPresent == true) {
            nameToParty[name]?.get()
        }
        else {
            retrievePartyFromArchive(name)
        }
    }

    private fun retrievePartyFromArchive(name: CordaX500Name): Party? {
        val hashKey = database.transaction {
            val query = session.criteriaBuilder.createQuery(PersistentNetworkMapCache.PersistentPartyToPublicKeyHash::class.java)
            val queryRoot = query.from(PersistentNetworkMapCache.PersistentPartyToPublicKeyHash::class.java)
            query.where(session.criteriaBuilder.equal(queryRoot.get<String>("name"), name.toString()))
            val resultList = session.createQuery(query).resultList
            if (resultList.isNotEmpty()) {
                resultList?.first()?.publicKeyHash
            }
            else {
                retrieveHashKeyAndCacheParty(name)
            }
        }
        return hashKey?.let { keyToPartyAndCert[it]?.party }
    }

    private fun retrieveHashKeyAndCacheParty(name: CordaX500Name): String? {
        return database.transaction {
            val cb = session.criteriaBuilder
            val query = cb.createQuery(PersistentPublicKeyHashToParty::class.java)
            val root = query.from(PersistentPublicKeyHashToParty::class.java)
            val isNotConfidentialIdentity = cb.equal(root.get<String>("publicKeyHash"), root.get<String>("owningKeyHash"))
            val matchName = cb.equal(root.get<String>("name"), name.toString())
            query.select(root).where(cb.and(matchName, isNotConfidentialIdentity))
            val resultList = session.createQuery(query).resultList
            var hashKey: String? = if (resultList.isNotEmpty()) {
                if (resultList.size == 1) {
                    resultList?.single()?.owningKeyHash
                }
                else {
                    selectIdentityHash(session, resultList.mapNotNull { it.publicKeyHash }, name)
                }
            } else {
                null
            }
            archiveNamedIdentity(name.toString(), hashKey)
            hashKey
        }
    }

    private fun selectIdentityHash(session: Session, hashList: List<String>, name: CordaX500Name): String? {
        val cb = session.criteriaBuilder
        val query = cb.createQuery(PersistentPublicKeyHashToCertificate::class.java)
        val root = query.from(PersistentPublicKeyHashToCertificate::class.java)
        query.select(root).where(root.get<String>("publicKeyHash").`in`(hashList))
        val resultList = session.createQuery(query).resultList
        resultList.sortWith(compareBy { PartyAndCertificate(X509CertificateFactory().delegate.generateCertPath(it.identity.inputStream())).certificate.notBefore })
        log.warn("Retrieving identity hash for removed identity '${name}', more that one hash found, returning last one according to notBefore validity of certificate." +
                 " Hash returned is ${resultList.last().publicKeyHash}")
        return resultList.last().publicKeyHash
    }

    override fun archiveNamedIdentity(name:String, publicKeyHash: String?) {
        archiveIdentityExecutor.submit {
            database.transaction {
                val deleteQuery = session.criteriaBuilder.createCriteriaDelete(PersistentNetworkMapCache.PersistentPartyToPublicKeyHash::class.java)
                val queryRoot = deleteQuery.from(PersistentNetworkMapCache.PersistentPartyToPublicKeyHash::class.java)
                deleteQuery.where(session.criteriaBuilder.equal(queryRoot.get<String>("name"), name))
                session.createQuery(deleteQuery).executeUpdate()
                session.save(PersistentNetworkMapCache.PersistentPartyToPublicKeyHash(name, publicKeyHash))
            }
        }.get()
    }

    override fun wellKnownPartyFromAnonymous(party: AbstractParty): Party? {
        return database.transaction {
            log.debug("Attempting to find wellKnownParty for: ${party.owningKey.toStringShort()}")
            if (party is Party) {
                val candidate = wellKnownPartyFromX500Name(party.name)
                if (candidate != null && candidate != party) {
                    // Party doesn't match existing well-known party: check that the key is registered, otherwise return null.
                    require(party.name == candidate.name) { "Candidate party $candidate does not match expected $party" }
                    keyToParty[party.owningKey.toStringShort()]?.let { candidate }
                } else {
                    // Party is a well-known party or well-known party doesn't exist: skip checks.
                    // If the notary is not in the network map cache, try getting it from the network parameters
                    // to prevent database conversion issues with vault updates (CORDA-2745).
                    candidate ?: party.takeIf { it in notaryIdentityCache }
                }
            } else {
                keyToParty[party.owningKey.toStringShort()]?.let {
                    // Resolved party can be stale due to key rotation: always convert it to the actual well-known party.
                    wellKnownPartyFromX500Name(it.name)
                }
            }
        }
    }

    private fun getAllCertificates(session: Session): Stream<NodeInfoSchemaV1.DBPartyAndCertificate> {
        val criteria = session.criteriaBuilder.createQuery(NodeInfoSchemaV1.DBPartyAndCertificate::class.java)
        criteria.select(criteria.from(NodeInfoSchemaV1.DBPartyAndCertificate::class.java))
        return session.createQuery(criteria).stream()
    }

    override fun partiesFromName(query: String, exactMatch: Boolean): Set<Party> {
        return database.transaction {
            getAllCertificates(session).use { stream ->
                stream.map { it.toLegalIdentityAndCert() }
                        .filter { x500Matches(query, exactMatch, it.name) }
                        .map { it.party }.toSet()
            }
        }
    }

    @Throws(UnknownAnonymousPartyException::class)
    override fun assertOwnership(party: Party, anonymousParty: AnonymousParty) = database.transaction { super.assertOwnership(party,
            anonymousParty) }

    override fun registerKey(publicKey: PublicKey, party: Party, externalId: UUID?) {
        return database.transaction {
            val publicKeyHash = publicKey.toStringShort()
            // EVERY key should be mapped to a Party in the "keyToName" table. Therefore if there is already a record in that table for the
            // specified key then it's either our key which has been stored prior or another node's key which we have previously mapped.
            val existingEntryForKey = keyToParty[publicKeyHash]
            if (existingEntryForKey == null) {
                // Update the three tables as necessary. We definitely store the public key and map it to a party and we optionally update
                // the public key to external ID mapping table. This block will only ever be reached when registering keys generated on
                // other because when a node generates its own keys "registerKeyToParty" is automatically called by
                // KeyManagementService.freshKey.
                registerKeyToParty(publicKey, party)
                hashToKey[publicKeyHash] = publicKey
                if (externalId != null) {
                    registerKeyToExternalId(publicKey, externalId)
                }
            } else {
                log.info("An existing entry for $publicKeyHash already exists.")
                if (party.name != existingEntryForKey.name) {
                    throw IllegalStateException("The public publicKey $publicKeyHash is already assigned to a different party than the " +
                            "supplied party.")
                }
            }
        }
    }

    // Internal function used by the KMS to register a public key to a Corda Party.
    fun registerKeyToParty(publicKey: PublicKey, party: Party = ourParty) {
        return database.transaction {
            log.info("Linking: ${publicKey.hash} to ${party.name}")
            keyToParty[publicKey.toStringShort()] = PartyWithHash(party)
            if (party == ourParty) {
                _pkToIdCache[publicKey] = KeyOwningIdentity.UnmappedIdentity
            }
        }
    }

    // Internal function used by the KMS to register a public key to an external ID.
    fun registerKeyToExternalId(publicKey: PublicKey, externalId: UUID) {
        _pkToIdCache[publicKey] = KeyOwningIdentity.fromUUID(externalId)
    }

    override fun externalIdForPublicKey(publicKey: PublicKey): UUID? {
        return _pkToIdCache[publicKey].uuid
    }

    private fun publicKeysForExternalId(externalId: UUID, table: Class<*>): List<PublicKey> {
        return database.transaction {
            val query = session.createQuery(
                    """
                        select a.publicKey
                        from ${table.name} a, ${PublicKeyHashToExternalId::class.java.name} b
                        where b.externalId = :uuid
                        and b.publicKeyHash = a.publicKeyHash
                    """,
                    ByteArray::class.java
            )
            query.setParameter("uuid", externalId)
            query.resultList.map { Crypto.decodePublicKey(it) }
        }
    }

    override fun publicKeysForExternalId(externalId: UUID): Iterable<PublicKey> {
        // If the externalId was created by this node then we'll find the keys in the KMS, otherwise they'll be in the IdentityService.
        val keys = publicKeysForExternalId(externalId, BasicHSMKeyManagementService.PersistentKey::class.java)
        return if (keys.isEmpty()) {
            publicKeysForExternalId(externalId, PersistentHashToPublicKey::class.java)
        } else {
            keys
        }
    }

    override fun onNewNotaryList(notaries: List<NotaryInfo>) {
        notaryIdentityCache = HashSet(notaries.map { it.identity })
    }
}
