/*
 *
 *    Copyright (c) 2025 Project CHIP Authors
 *    All rights reserved.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

#include <pw_unit_test/framework.h>

#include <controller/CHIPDeviceController.h>
#include <controller/SetUpCodePairer.h>
#include <controller/tests/SetUpCodePairerTestAccess.h>
#include <inet/IPAddress.h>
#include <inet/InetInterface.h>
#include <lib/core/CHIPError.h>
#include <lib/dnssd/Types.h>
#include <lib/support/CodeUtils.h>
#include <system/SystemClock.h>
#include <transport/raw/PeerAddress.h>

#include <memory>

using namespace chip;
using namespace chip::Controller;
using PairerAccess = chip::Testing::SetUpCodePairerTestAccess;

namespace {

constexpr uint16_t kDiscriminatorA = 0xABC;
constexpr uint16_t kDiscriminatorB = 0xDEF;

Inet::IPAddress ParseIP(const char * str)
{
    Inet::IPAddress addr;
    // The callers pass valid literals; treat a parse failure as a test bug.
    VerifyOrDie(Inet::IPAddress::FromString(str, addr));
    return addr;
}

// InterfaceId::PlatformType is an integer on the host builds these tests run on; cast explicitly so
// the suite's -Wconversion stays clean regardless of the exact underlying type.
Inet::InterfaceId MakeInterfaceId(unsigned int id)
{
    return Inet::InterfaceId(static_cast<Inet::InterfaceId::PlatformType>(id));
}

// Build a single-address commissionable-node resolution record for the given address and interface.
Dnssd::CommonResolutionData MakeResolutionData(const Inet::IPAddress & ip, Inet::InterfaceId interfaceId)
{
    Dnssd::CommonResolutionData data;
    data.interfaceId  = interfaceId;
    data.numIPs       = 1;
    data.ipAddress[0] = ip;
    data.port         = 5540;
    return data;
}

// DeviceCommissioner is too large to embed in a test fixture (it exceeds
// the pw_unit_test light backend's static memory pool).  Heap-allocate it
// along with the SetUpCodePairer and test accessor that depend on it.
class TestSetUpCodePairer : public ::testing::Test
{
public:
    static void SetUpTestSuite() { ASSERT_EQ(Platform::MemoryInit(), CHIP_NO_ERROR); }
    static void TearDownTestSuite() { Platform::MemoryShutdown(); }

    void SetUp() override
    {
        mCommissioner = std::make_unique<DeviceCommissioner>();
        mPairer       = std::make_unique<SetUpCodePairer>(mCommissioner.get());
        mAccess       = std::make_unique<PairerAccess>(mPairer.get());
    }

    void TearDown() override
    {
        mAccess.reset();
        mPairer.reset();
        mCommissioner.reset();
    }

protected:
    PairerAccess & Access() { return *mAccess; }

private:
    std::unique_ptr<DeviceCommissioner> mCommissioner;
    std::unique_ptr<SetUpCodePairer> mPairer;
    std::unique_ptr<PairerAccess> mAccess;
};

// When the discovery timeout fires while a PASE attempt is in progress,
// DNS-SD should be stopped (it runs indefinitely) but other transports
// (BLE, Wi-Fi PAF, NFC) should be left alone since they self-terminate.
TEST_F(TestSetUpCodePairer, TimeoutDuringPASE_StopsDNSSD_PreservesOtherTransports)
{
    Access().SetRemoteId(1);
    Access().SetWaitingForPASE(true);
    Access().SetWaitingForDiscovery(PairerAccess::kIPTransport, true);
    Access().SetWaitingForDiscovery(PairerAccess::kBLETransport, true);

    Access().FireTimeoutCallback();

    // DNS-SD must be stopped to prevent DiscoveryInProgress() from being stuck true.
    EXPECT_FALSE(Access().GetWaitingForDiscovery(PairerAccess::kIPTransport));
    // BLE must be preserved — it may still discover a commissionee.
    EXPECT_TRUE(Access().GetWaitingForDiscovery(PairerAccess::kBLETransport));
    // PASE state must not be disturbed.
    EXPECT_TRUE(Access().GetWaitingForPASE());
}

// When the discovery timeout fires with no PASE in progress,
// all transports should be stopped and failure reported.
TEST_F(TestSetUpCodePairer, TimeoutNoPASE_StopsAllTransports)
{
    Access().SetRemoteId(1);
    Access().SetWaitingForPASE(false);
    Access().SetWaitingForDiscovery(PairerAccess::kIPTransport, true);
    Access().SetWaitingForDiscovery(PairerAccess::kBLETransport, true);

    Access().FireTimeoutCallback();

    EXPECT_FALSE(Access().GetWaitingForDiscovery(PairerAccess::kIPTransport));
    EXPECT_FALSE(Access().GetWaitingForDiscovery(PairerAccess::kBLETransport));
    // StopPairingIfTransportsExhausted should have reported failure and cleared mRemoteId.
    EXPECT_EQ(Access().GetRemoteId(), kUndefinedNodeId);
}

// When a PASE attempt fails (OnPairingComplete with error) and DNS-SD
// is still running, DNS-SD should NOT be stopped.  Keeping DNS-SD alive
// keeps DiscoveryInProgress() true, which suppresses premature failure
// through OnStatusUpdate, TryNextRendezvousParameters, and
// StopPairingIfTransportsExhausted.
TEST_F(TestSetUpCodePairer, PASEFailure_DNSSDStaysAlive)
{
    Access().SetRemoteId(1);
    Access().SetWaitingForDiscovery(PairerAccess::kIPTransport, true);
    Access().SetWaitingForDiscovery(PairerAccess::kBLETransport, true);

    // Simulate a UDP PASE attempt: set mCurrentPASEParameters and enter
    // the PASE-waiting state (as ConnectToDiscoveredDevice would).
    SetUpCodePairerParameters udpParams;
    udpParams.SetPeerAddress(Transport::PeerAddress::UDP(Inet::IPAddress::Any, 5540));
    Access().SetCurrentPASEParameters(udpParams);
    Access().ExpectPASEEstablishment();

    // PASE fails.
    Access().CallOnPairingComplete(CHIP_ERROR_TIMEOUT);

    // DNS-SD must still be running — the 30s timeout is its natural upper bound.
    EXPECT_TRUE(Access().GetWaitingForDiscovery(PairerAccess::kIPTransport));
    // BLE must still be running.
    EXPECT_TRUE(Access().GetWaitingForDiscovery(PairerAccess::kBLETransport));
    // The pairer should still be active (not yet reported failure).
    EXPECT_NE(Access().GetRemoteId(), kUndefinedNodeId);
    // The error should be saved for later.
    EXPECT_EQ(Access().GetLastPASEError(), CHIP_ERROR_TIMEOUT);
    // mCurrentPASEParameters should have been cleared.
    EXPECT_FALSE(Access().HasCurrentPASEParameters());
}

// When a PASE attempt fails synchronously in ConnectToDiscoveredDevice,
// mCurrentPASEParameters must be cleared so a later non-UDP PASE
// completion cannot incorrectly use stale parameters for ReconfirmRecord.
TEST_F(TestSetUpCodePairer, SyncPASEFailure_ClearsCurrentPASEParameters)
{
    Access().SetRemoteId(1);
    Access().SetWaitingForDiscovery(PairerAccess::kIPTransport, true);

    // Set up stale UDP parameters (as if ConnectToDiscoveredDevice had set
    // them before calling PairDevice, which then failed synchronously).
    SetUpCodePairerParameters udpParams;
    udpParams.SetPeerAddress(Transport::PeerAddress::UDP(Inet::IPAddress::Any, 5540));
    Access().SetCurrentPASEParameters(udpParams);

    // Now simulate a subsequent non-UDP PASE completion (e.g., BLE PASE
    // succeeds or fails).  ExpectPASEEstablishment + OnPairingComplete
    // with success exercises ResetDiscoveryState which clears everything.
    // Instead, verify directly that after a PASE failure the stale
    // parameters don't persist: simulate a PASE completion with error.
    Access().ExpectPASEEstablishment();
    Access().CallOnPairingComplete(CHIP_ERROR_CONNECTION_ABORTED);

    // mCurrentPASEParameters must be cleared — stale UDP params must not
    // survive to confuse a later ReconfirmRecord check.
    EXPECT_FALSE(Access().HasCurrentPASEParameters());
}

// A non-link-local address advertised on two different interfaces resolves to the same
// interface-less PeerAddress (we rely on the routing table, not the discovery interface), so the
// two candidates must be treated as coalescible.
TEST_F(TestSetUpCodePairer, CanCoalesce_NonLinkLocalSameAddressDifferentInterfaces)
{
    const Inet::IPAddress global = ParseIP("2001:db8::1");
    SetUpCodePairerParameters a(MakeResolutionData(global, MakeInterfaceId(1)), kDiscriminatorA, 0);
    SetUpCodePairerParameters b(MakeResolutionData(global, MakeInterfaceId(2)), kDiscriminatorA, 0);
    EXPECT_TRUE(a.CanCoalesceWith(b));
}

// A link-local address keeps its interface in the PeerAddress, so the same address on two
// interfaces is two genuinely distinct destinations and must not coalesce.
TEST_F(TestSetUpCodePairer, CannotCoalesce_LinkLocalSameAddressDifferentInterfaces)
{
    const Inet::IPAddress lla = ParseIP("fe80::1");
    SetUpCodePairerParameters a(MakeResolutionData(lla, MakeInterfaceId(1)), kDiscriminatorA, 0);
    SetUpCodePairerParameters b(MakeResolutionData(lla, MakeInterfaceId(2)), kDiscriminatorA, 0);
    EXPECT_FALSE(a.CanCoalesceWith(b));
}

// The long discriminator selects which setup payload's passcode we use, so candidates that share a
// PeerAddress but carry different discriminators must not coalesce.
TEST_F(TestSetUpCodePairer, CannotCoalesce_DifferentLongDiscriminator)
{
    const Inet::IPAddress global = ParseIP("2001:db8::1");
    SetUpCodePairerParameters a(MakeResolutionData(global, Inet::InterfaceId::Null()), kDiscriminatorA, 0);
    SetUpCodePairerParameters b(MakeResolutionData(global, Inet::InterfaceId::Null()), kDiscriminatorB, 0);
    EXPECT_FALSE(a.CanCoalesceWith(b));
}

// MRP configuration is a PASE connection input; candidates that differ only in their MRP intervals
// must not coalesce.
TEST_F(TestSetUpCodePairer, CannotCoalesce_DifferentMRPConfig)
{
    const Inet::IPAddress global = ParseIP("2001:db8::1");
    auto dataA                   = MakeResolutionData(global, Inet::InterfaceId::Null());
    dataA.mrpRetryIntervalIdle   = System::Clock::Milliseconds32(1000);
    auto dataB                   = MakeResolutionData(global, Inet::InterfaceId::Null());
    dataB.mrpRetryIntervalIdle   = System::Clock::Milliseconds32(2000);
    SetUpCodePairerParameters a(dataA, kDiscriminatorA, 0);
    SetUpCodePairerParameters b(dataB, kDiscriminatorA, 0);
    EXPECT_FALSE(a.CanCoalesceWith(b));
}

// Different IP addresses are different destinations and must not coalesce.
TEST_F(TestSetUpCodePairer, CannotCoalesce_DifferentAddress)
{
    SetUpCodePairerParameters a(MakeResolutionData(ParseIP("2001:db8::1"), Inet::InterfaceId::Null()), kDiscriminatorA, 0);
    SetUpCodePairerParameters b(MakeResolutionData(ParseIP("2001:db8::2"), Inet::InterfaceId::Null()), kDiscriminatorA, 0);
    EXPECT_FALSE(a.CanCoalesceWith(b));
}

// NotifyCommissionableDeviceDiscovered must drop a duplicate address within a single advertisement
// (the same non-link-local IP listed twice) instead of queuing a redundant PASE attempt.  Waiting
// for PASE is asserted so ConnectToDiscoveredDevice does not drain the queue before we inspect it.
TEST_F(TestSetUpCodePairer, NotifyDiscovered_DropsDuplicateAddressesInOneRecord)
{
    Access().SetRemoteId(1);
    Access().SetWaitingForPASE(true);

    const Inet::IPAddress global = ParseIP("2001:db8::1");
    auto data                    = MakeResolutionData(global, Inet::InterfaceId::Null());
    data.numIPs                  = 2;
    data.ipAddress[0]            = global;
    data.ipAddress[1]            = global; // same address advertised twice

    Access().NotifyCommissionableDeviceDiscovered(data, kDiscriminatorA);
    EXPECT_EQ(Access().GetDiscoveredParametersCount(), 1u);
}

// The same non-link-local device rediscovered on a second interface must not add a second identical
// queue entry, but a genuinely different address must.
TEST_F(TestSetUpCodePairer, NotifyDiscovered_CoalescesAcrossCallbacks)
{
    Access().SetRemoteId(1);
    Access().SetWaitingForPASE(true);

    const Inet::IPAddress global = ParseIP("2001:db8::1");
    Access().NotifyCommissionableDeviceDiscovered(MakeResolutionData(global, MakeInterfaceId(1)), kDiscriminatorA);
    EXPECT_EQ(Access().GetDiscoveredParametersCount(), 1u);

    // Same non-link-local address, different interface -> coalesces.
    Access().NotifyCommissionableDeviceDiscovered(MakeResolutionData(global, MakeInterfaceId(2)), kDiscriminatorA);
    EXPECT_EQ(Access().GetDiscoveredParametersCount(), 1u);

    // Different address -> new entry.
    Access().NotifyCommissionableDeviceDiscovered(MakeResolutionData(ParseIP("2001:db8::2"), MakeInterfaceId(1)), kDiscriminatorA);
    EXPECT_EQ(Access().GetDiscoveredParametersCount(), 2u);
}

} // namespace