//
// BLEServiceCoreTests.swift
// bitchatTests
//
// Focused BLEService tests for packet handling behavior.
//

import Testing
import Foundation
import CoreBluetooth
import BitFoundation
@testable import bitchat

struct BLEServiceCoreTests {

    @Test
    func duplicatePacket_isDeduped() async throws {
        let ble = makeService()
        let delegate = PublicCaptureDelegate()
        ble.delegate = delegate

        // Public messages must carry a valid signature from the claimed sender;
        // sign the packet and preseed the sender's signing key so the receiver
        // can verify it (production `sendMessage` signs public broadcasts too).
        let signer = NoiseEncryptionService(keychain: MockKeychain())
        let sender = PeerID(str: "1122334455667788")
        let timestamp = UInt64(Date().timeIntervalSince1970 * 1000)
        let unsigned = makePublicPacket(content: "Hello", sender: sender, timestamp: timestamp)
        let packet = try #require(signer.signPacket(unsigned), "Failed to sign public message")
        let signingKey = signer.getSigningPublicKeyData()

        ble._test_handlePacket(packet, fromPeerID: sender, signingPublicKey: signingKey)
        let receivedFirst = await TestHelpers.waitUntil(
            { delegate.publicMessagesSnapshot().count == 1 },
            timeout: TestConstants.longTimeout
        )
        #expect(receivedFirst)

        ble._test_handlePacket(packet, fromPeerID: sender, signingPublicKey: signingKey)
        let receivedDuplicate = await TestHelpers.waitUntil(
            { delegate.publicMessagesSnapshot().count > 1 },
            timeout: TestConstants.shortTimeout
        )
        #expect(!receivedDuplicate)

        let messages = delegate.publicMessagesSnapshot()
        #expect(messages.count == 1)
        #expect(messages.first?.content == "Hello")
    }

    @Test
    func staleBroadcast_isIgnored() async {
        let ble = makeService()
        let delegate = PublicCaptureDelegate()
        ble.delegate = delegate

        let sender = PeerID(str: "A1B2C3D4E5F60708")
        let oldTimestamp = UInt64(Date().addingTimeInterval(-901).timeIntervalSince1970 * 1000)
        let packet = makePublicPacket(content: "Old", sender: sender, timestamp: oldTimestamp)

        ble._test_handlePacket(packet, fromPeerID: sender)

        let didReceive = await TestHelpers.waitUntil({ !delegate.publicMessagesSnapshot().isEmpty }, timeout: 0.3)
        #expect(!didReceive)
        #expect(delegate.publicMessagesSnapshot().isEmpty)
    }

    @Test
    func announceSenderMismatch_isRejected() async throws {
        let ble = makeService()

        let signer = NoiseEncryptionService(keychain: MockKeychain())
        let announcement = AnnouncementPacket(
            nickname: "Spoof",
            noisePublicKey: signer.getStaticPublicKeyData(),
            signingPublicKey: signer.getSigningPublicKeyData(),
            directNeighbors: nil
        )
        let payload = try #require(announcement.encode(), "Failed to encode announcement")

        let derivedPeerID = PeerID(publicKey: announcement.noisePublicKey)
        let wrongFirst = derivedPeerID.bare.first == "0" ? "1" : "0"
        let wrongBare = String(wrongFirst) + String(derivedPeerID.bare.dropFirst())
        let wrongPeerID = PeerID(str: wrongBare)
        let packet = BitchatPacket(
            type: MessageType.announce.rawValue,
            senderID: Data(hexString: wrongPeerID.id) ?? Data(),
            recipientID: nil,
            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
            payload: payload,
            signature: nil,
            ttl: 7
        )
        let signed = try #require(signer.signPacket(packet), "Failed to sign announce packet")

        ble._test_handlePacket(signed, fromPeerID: wrongPeerID, preseedPeer: false)

        _ = await TestHelpers.waitUntil({ !ble.currentPeerSnapshots().isEmpty }, timeout: 0.3)
        #expect(ble.currentPeerSnapshots().isEmpty)
    }

    @Test
    func ingressAllowsRelayedSenderOnBoundLink() async throws {
        let ble = makeService()
        let boundPeer = PeerID(str: "1122334455667788")
        let relayedSender = PeerID(str: "8899aabbccddeeff")
        let packet = makePublicPacket(
            content: "Relayed",
            sender: relayedSender,
            timestamp: UInt64(Date().timeIntervalSince1970 * 1000)
        )

        #expect(ble._test_acceptsIngress(packet: packet, boundPeerID: boundPeer))
    }

    @Test
    func ingressAllowsDirectAnnounceThatConflictsWithBoundLink() async throws {
        // Peer-ID rotation heal: the announce must reach signature
        // verification, which decides whether the link rebinds.
        let ble = makeService()
        let boundPeer = PeerID(str: "1122334455667788")
        let claimedPeer = PeerID(str: "8899aabbccddeeff")
        let packet = BitchatPacket(
            type: MessageType.announce.rawValue,
            senderID: Data(hexString: claimedPeer.id) ?? Data(),
            recipientID: nil,
            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
            payload: Data(),
            signature: nil,
            ttl: 7
        )

        #expect(ble._test_acceptsIngress(packet: packet, boundPeerID: boundPeer))
    }

    @Test
    func ingressRejectsRequestSyncThatConflictsWithBoundLink() async throws {
        let ble = makeService()
        let boundPeer = PeerID(str: "1122334455667788")
        let claimedPeer = PeerID(str: "8899aabbccddeeff")
        let packet = BitchatPacket(
            type: MessageType.requestSync.rawValue,
            senderID: Data(hexString: claimedPeer.id) ?? Data(),
            recipientID: nil,
            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
            payload: Data(),
            signature: nil,
            ttl: 0
        )

        #expect(!ble._test_acceptsIngress(packet: packet, boundPeerID: boundPeer))
    }

    @Test
    func verifiedDirectAnnounceRebindsRotatedLinkAndRetiresOldPeer() async throws {
        let ble = makeService()
        let oldPeerID = PeerID(str: "1122334455667788")
        let centralUUID = "central-rotation"

        // A connected peer whose link binding predates its relaunch.
        ble._test_seedConnectedPeer(oldPeerID, nickname: "alice")
        ble._test_bindCentral(centralUUID, to: oldPeerID)

        // The relaunched device re-announces its rotated identity over the
        // still-open link.
        let signer = NoiseEncryptionService(keychain: MockKeychain())
        let announcement = AnnouncementPacket(
            nickname: "alice",
            noisePublicKey: signer.getStaticPublicKeyData(),
            signingPublicKey: signer.getSigningPublicKeyData(),
            directNeighbors: nil
        )
        let payload = try #require(announcement.encode(), "Failed to encode announcement")
        let newPeerID = PeerID(publicKey: announcement.noisePublicKey)
        let unsigned = BitchatPacket(
            type: MessageType.announce.rawValue,
            senderID: Data(hexString: newPeerID.id) ?? Data(),
            recipientID: nil,
            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
            payload: payload,
            signature: nil,
            ttl: 7
        )
        let packet = try #require(signer.signPacket(unsigned), "Failed to sign announce packet")

        #expect(ble._test_recordIngressIfNew(packet: packet, linkID: centralUUID))
        ble._test_handlePacket(packet, fromPeerID: newPeerID, preseedPeer: false)

        let rebound = await TestHelpers.waitUntil(
            { ble._test_centralBinding(centralUUID) == newPeerID },
            timeout: TestConstants.longTimeout
        )
        #expect(rebound)

        let retired = await TestHelpers.waitUntil(
            {
                let peerIDs = ble.currentPeerSnapshots().map(\.peerID)
                return peerIDs.contains(newPeerID) && !peerIDs.contains(oldPeerID)
            },
            timeout: TestConstants.longTimeout
        )
        #expect(retired)
    }

    @Test
    func replayedDirectAnnounceCannotStealBoundIdentity() async throws {
        let ble = makeService()
        let attackerPeerID = PeerID(str: "1122334455667788")
        let victimLink = "central-victim"
        let attackerLink = "central-attacker"

        // The victim's identity, genuinely bound on its own link.
        let victimSigner = NoiseEncryptionService(keychain: MockKeychain())
        let announcement = AnnouncementPacket(
            nickname: "victim",
            noisePublicKey: victimSigner.getStaticPublicKeyData(),
            signingPublicKey: victimSigner.getSigningPublicKeyData(),
            directNeighbors: nil
        )
        let payload = try #require(announcement.encode(), "Failed to encode announcement")
        let victimPeerID = PeerID(publicKey: announcement.noisePublicKey)
        ble._test_seedConnectedPeer(victimPeerID, nickname: "victim")
        ble._test_bindCentral(victimLink, to: victimPeerID)
        ble._test_seedConnectedPeer(attackerPeerID, nickname: "attacker")
        ble._test_bindCentral(attackerLink, to: attackerPeerID)

        // The victim's fresh signed announce replayed on the attacker's bound
        // link with its direct TTL restored (TTL is excluded from signing, so
        // the signature still verifies).
        let unsigned = BitchatPacket(
            type: MessageType.announce.rawValue,
            senderID: Data(hexString: victimPeerID.id) ?? Data(),
            recipientID: nil,
            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
            payload: payload,
            signature: nil,
            ttl: 7
        )
        let packet = try #require(victimSigner.signPacket(unsigned), "Failed to sign announce packet")

        #expect(ble._test_recordIngressIfNew(packet: packet, linkID: attackerLink))
        ble._test_handlePacket(packet, fromPeerID: victimPeerID, preseedPeer: false)

        // The rebind must be refused: the identity already owns a live link.
        let stolen = await TestHelpers.waitUntil(
            { ble._test_centralBinding(attackerLink) == victimPeerID },
            timeout: 0.3
        )
        #expect(!stolen)
        #expect(ble._test_centralBinding(attackerLink) == attackerPeerID)
        #expect(ble._test_centralBinding(victimLink) == victimPeerID)
        // And the replay must not retire the link's real bound peer.
        #expect(ble.currentPeerSnapshots().map(\.peerID).contains(attackerPeerID))
    }

    @Test
    func ingressRejectsSelfLoopbackBeforeSpoofChecks() async throws {
        let ble = makeService()
        let packet = makePublicPacket(
            content: "Loopback",
            sender: ble.myPeerID,
            timestamp: UInt64(Date().timeIntervalSince1970 * 1000)
        )

        #expect(!ble._test_acceptsIngress(packet: packet, boundPeerID: PeerID(str: "1122334455667788")))
    }

    @Test
    func ingressAllowsSelfAuthoredRSRWithTTLZeroFromBoundPeer() async throws {
        let ble = makeService()
        var packet = makePublicPacket(
            content: "Recovered by sync",
            sender: ble.myPeerID,
            timestamp: UInt64(Date().timeIntervalSince1970 * 1000)
        )
        packet.isRSR = true
        packet.ttl = 0

        #expect(ble._test_acceptsIngress(packet: packet, boundPeerID: PeerID(str: "1122334455667788")))
    }

    @Test
    func ingressRecordSuppressesSecondLinkDuplicate() async throws {
        let ble = makeService()
        let packet = makePublicPacket(
            content: "Duplicate link copy",
            sender: PeerID(str: "1122334455667788"),
            timestamp: UInt64(Date().timeIntervalSince1970 * 1000)
        )

        #expect(ble._test_recordIngressIfNew(packet: packet, linkID: "central-a"))
        #expect(!ble._test_recordIngressIfNew(packet: packet, linkID: "central-b"))
    }

    @Test
    func panicReset_rotatesPeerIDDerivedFromNewNoiseFingerprint() async throws {
        let ble = makeService()
        let originalPeerID = ble.myPeerID
        let originalFingerprint = ble.noiseIdentityFingerprint()
        #expect(originalPeerID == PeerID(str: originalFingerprint.prefix(16)))

        ble.resetIdentityForPanic(currentNickname: "anon")

        // The Noise identity is regenerated and the peer ID swaps with it
        // (atomically, behind a messageQueue barrier).
        let newFingerprint = ble.noiseIdentityFingerprint()
        #expect(newFingerprint != originalFingerprint)
        #expect(ble.myPeerID != originalPeerID)
        #expect(ble.myPeerID == PeerID(str: newFingerprint.prefix(16)))
    }

    @Test
    func modifiedServices_rediscoverWhenBitChatServiceIsInvalidated() async throws {
        let otherService = CBUUID(string: "0000180F-0000-1000-8000-00805F9B34FB")

        #expect(BLEService._test_shouldRediscoverBitChatService(
            invalidatedServiceUUIDs: [BLEService.serviceUUID],
            cachedServiceUUIDs: [otherService]
        ))
    }

    @Test
    func modifiedServices_rediscoverWhenCachedServicesNoLongerIncludeBitChat() async throws {
        let otherService = CBUUID(string: "0000180F-0000-1000-8000-00805F9B34FB")

        #expect(BLEService._test_shouldRediscoverBitChatService(
            invalidatedServiceUUIDs: [otherService],
            cachedServiceUUIDs: [otherService]
        ))
    }

    @Test
    func modifiedServices_ignoreUnrelatedInvalidationWhenBitChatIsStillCached() async throws {
        let otherService = CBUUID(string: "0000180F-0000-1000-8000-00805F9B34FB")

        #expect(!BLEService._test_shouldRediscoverBitChatService(
            invalidatedServiceUUIDs: [otherService],
            cachedServiceUUIDs: [BLEService.serviceUUID, otherService]
        ))
    }

    /// Pings are unsigned, so their claimed sender is attacker-controlled.
    /// The pong budget must be keyed on the ingress link (the directly
    /// connected peer that delivered the packet): rotating forged sender IDs
    /// over one link exhausts one budget instead of resetting it, so a single
    /// malicious link cannot turn /ping into an amplification primitive.
    @Test
    func meshPingResponseBudget_isPerIngressLinkNotClaimedSender() async throws {
        let ble = makeService()
        let outbound = OutboundPacketTap()
        ble._test_onOutboundPacket = outbound.record

        let link = PeerID(str: "1122334455667788")
        let budget = TransportConfig.meshPingInboundMaxPerLink
        let myRecipientData = try #require(Data(hexString: ble.myPeerID.id))

        for i in 0..<(budget * 2) {
            // A fresh forged sender for every ping, all arriving on one link.
            let forgedSender = PeerID(str: String(format: "%016x", 0xA0_0000 + i))
            var nonce = Data(repeating: 0, count: MeshPingPayload.nonceLength)
            nonce[0] = UInt8(i)
            let payload = try #require(MeshPingPayload(nonce: nonce, originTTL: 7))
            let packet = BitchatPacket(
                type: MessageType.ping.rawValue,
                senderID: Data(hexString: forgedSender.id) ?? Data(),
                recipientID: myRecipientData,
                timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
                payload: payload.encode(),
                signature: nil,
                ttl: 7
            )
            ble._test_handlePacket(packet, fromPeerID: link, preseedPeer: false)
        }

        let reachedBudget = await TestHelpers.waitUntil(
            { outbound.count(ofType: .pong) >= budget },
            timeout: TestConstants.longTimeout
        )
        #expect(reachedBudget)
        // Give any over-budget pong a chance to surface, then confirm the
        // rotated sender IDs never bought a sixth response.
        let exceededBudget = await TestHelpers.waitUntil(
            { outbound.count(ofType: .pong) > budget },
            timeout: TestConstants.shortTimeout
        )
        #expect(!exceededBudget)
        #expect(outbound.count(ofType: .pong) == budget)
    }
}

/// Thread-safe capture of packets leaving the service under test.
private final class OutboundPacketTap {
    private let lock = NSLock()
    private var packets: [BitchatPacket] = []

    func record(_ packet: BitchatPacket) {
        lock.lock(); packets.append(packet); lock.unlock()
    }

    func count(ofType type: MessageType) -> Int {
        lock.lock(); defer { lock.unlock() }
        return packets.filter { $0.type == type.rawValue }.count
    }
}

private func makeService() -> BLEService {
    let keychain = MockKeychain()
    let identityManager = MockIdentityManager(keychain)
    let idBridge = NostrIdentityBridge(keychain: MockKeychainHelper())
    return BLEService(
        keychain: keychain,
        idBridge: idBridge,
        identityManager: identityManager,
        initializeBluetoothManagers: false
    )
}

private func makePublicPacket(content: String, sender: PeerID, timestamp: UInt64) -> BitchatPacket {
    BitchatPacket(
        type: MessageType.message.rawValue,
        senderID: Data(hexString: sender.id) ?? Data(),
        recipientID: nil,
        timestamp: timestamp,
        payload: Data(content.utf8),
        signature: nil,
        ttl: 3
    )
}

private final class PublicCaptureDelegate: BitchatDelegate {
    private let lock = NSLock()
    private(set) var publicMessages: [BitchatMessage] = []

    func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date, messageID: String?) {
        let message = BitchatMessage(
            id: messageID,
            sender: nickname,
            content: content,
            timestamp: timestamp,
            isRelay: false,
            originalSender: nil,
            isPrivate: false,
            recipientNickname: nil,
            senderPeerID: peerID,
            mentions: nil
        )
        lock.lock()
        publicMessages.append(message)
        lock.unlock()
    }

    func didReceiveMessage(_ message: BitchatMessage) {}
    func didConnectToPeer(_ peerID: PeerID) {}
    func didDisconnectFromPeer(_ peerID: PeerID) {}
    func didUpdatePeerList(_ peers: [PeerID]) {}
    func didUpdateBluetoothState(_ state: CBManagerState) {}

    func publicMessagesSnapshot() -> [BitchatMessage] {
        lock.lock()
        defer { lock.unlock() }
        return publicMessages
    }
}