//------------------------------------------------------------------------------
/*
    This file is part of clio: https://github.com/XRPLF/clio
    Copyright (c) 2025, the clio developers.

    Permission to use, copy, modify, and distribute this software for any
    purpose with or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.

    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================

#include "util/Assert.hpp"
#include "util/Channel.hpp"
#include "util/Mutex.hpp"
#include "util/OverloadSet.hpp"
#include "util/Spawn.hpp"

#include <boost/asio/io_context.hpp>
#include <boost/asio/post.hpp>
#include <boost/asio/spawn.hpp>
#include <boost/asio/steady_timer.hpp>
#include <boost/asio/thread_pool.hpp>
#include <boost/system/detail/error_code.hpp>
#include <gtest/gtest.h>

#include <algorithm>
#include <atomic>
#include <chrono>
#include <cstddef>
#include <memory>
#include <optional>
#include <semaphore>
#include <string>
#include <utility>
#include <variant>
#include <vector>

using namespace testing;

namespace {

constexpr auto kDEFAULT_THREAD_POOL_SIZE = 4;
constexpr auto kTEST_TIMEOUT = std::chrono::seconds{10};

constexpr auto kNUM_SENDERS = 3uz;
constexpr auto kNUM_RECEIVERS = 3uz;
constexpr auto kVALUES_PER_SENDER = 500uz;
constexpr auto kTOTAL_EXPECTED = kNUM_SENDERS * kVALUES_PER_SENDER;

enum class ContextType { IOContext, ThreadPool };

constexpr int
generateValue(std::size_t senderId, std::size_t i)
{
    return static_cast<int>((senderId * 100) + i);
}

std::vector<int>
generateExpectedValues()
{
    std::vector<int> expectedValues;
    expectedValues.reserve(kTOTAL_EXPECTED);
    for (auto senderId = 0uz; senderId < kNUM_SENDERS; ++senderId) {
        for (auto i = 0uz; i < kVALUES_PER_SENDER; ++i) {
            expectedValues.push_back(generateValue(senderId, i));
        }
    }
    std::ranges::sort(expectedValues);
    return expectedValues;
}

std::vector<int> const kEXPECTED_VALUES = generateExpectedValues();

std::string
contextTypeToString(ContextType type)
{
    return type == ContextType::IOContext ? "IOContext" : "ThreadPool";
}

class ContextWrapper {
public:
    using ContextVariant = std::variant<boost::asio::io_context, boost::asio::thread_pool>;

    explicit ContextWrapper(ContextType type)
        : context_([type] {
            if (type == ContextType::IOContext)
                return ContextVariant(std::in_place_type_t<boost::asio::io_context>());

            if (type == ContextType::ThreadPool)
                return ContextVariant(std::in_place_type_t<boost::asio::thread_pool>(), kDEFAULT_THREAD_POOL_SIZE);

            ASSERT(false, "Unknown new type of context");
            std::unreachable();
        }())
    {
    }

    template <typename Fn>
    void
    withExecutor(Fn&& fn)
    {
        std::visit(std::forward<Fn>(fn), context_);
    }

    void
    run()
    {
        std::visit(
            util::OverloadSet{
                [](boost::asio::io_context& context) { context.run_for(kTEST_TIMEOUT); },
                [](boost::asio::thread_pool& context) { context.join(); },
            },
            context_
        );
    }

private:
    ContextVariant context_;
};

}  // namespace

class ChannelSpawnTest : public TestWithParam<ContextType> {
protected:
    ChannelSpawnTest() : context_(GetParam())
    {
    }

    ContextWrapper context_;
};

class ChannelCallbackTest : public TestWithParam<ContextType> {
protected:
    ChannelCallbackTest() : context_(GetParam())
    {
    }

    ContextWrapper context_;
};

TEST_P(ChannelSpawnTest, MultipleSendersOneReceiver)
{
    context_.withExecutor([this](auto& executor) {
        auto [sender, receiver] = util::Channel<int>::create(executor, 10);
        util::Mutex<std::vector<int>> receivedValues;

        util::spawn(executor, [&receiver, &receivedValues](boost::asio::yield_context yield) mutable {
            while (true) {
                auto value = receiver.asyncReceive(yield);
                if (not value.has_value())
                    break;
                receivedValues.lock()->push_back(*value);
            }
        });

        {
            auto localSender = std::move(sender);
            for (auto senderId = 0uz; senderId < kNUM_SENDERS; ++senderId) {
                util::spawn(executor, [senderCopy = localSender, senderId](boost::asio::yield_context yield) mutable {
                    for (auto i = 0uz; i < kVALUES_PER_SENDER; ++i) {
                        if (not senderCopy.asyncSend(generateValue(senderId, i), yield))
                            break;
                    }
                });
            }
        }

        context_.run();

        EXPECT_EQ(receivedValues.lock()->size(), kTOTAL_EXPECTED);
        std::ranges::sort(receivedValues.lock().get());

        EXPECT_EQ(receivedValues.lock().get(), kEXPECTED_VALUES);
    });
}

TEST_P(ChannelSpawnTest, MultipleSendersMultipleReceivers)
{
    context_.withExecutor([this](auto& executor) {
        auto [sender, receiver] = util::Channel<int>::create(executor, 10);
        util::Mutex<std::vector<int>> receivedValues;
        std::vector<decltype(receiver)> receivers(kNUM_RECEIVERS, receiver);

        for (auto receiverId = 0uz; receiverId < kNUM_RECEIVERS; ++receiverId) {
            util::spawn(
                executor,
                [&receiverRef = receivers[receiverId], &receivedValues](boost::asio::yield_context yield) mutable {
                    while (true) {
                        auto value = receiverRef.asyncReceive(yield);
                        if (not value.has_value())
                            break;
                        receivedValues.lock()->push_back(*value);
                    }
                }
            );
        }

        {
            auto localSender = std::move(sender);
            for (auto senderId = 0uz; senderId < kNUM_SENDERS; ++senderId) {
                util::spawn(executor, [senderCopy = localSender, senderId](boost::asio::yield_context yield) mutable {
                    for (auto i = 0uz; i < kVALUES_PER_SENDER; ++i) {
                        auto const value = generateValue(senderId, i);
                        if (not senderCopy.asyncSend(value, yield))
                            break;
                    }
                });
            }
        }

        context_.run();

        EXPECT_EQ(receivedValues.lock()->size(), kTOTAL_EXPECTED);
        std::ranges::sort(receivedValues.lock().get());

        EXPECT_EQ(receivedValues.lock().get(), kEXPECTED_VALUES);
    });
}

TEST_P(ChannelSpawnTest, ChannelClosureScenarios)
{
    context_.withExecutor([this](auto& executor) {
        std::atomic_bool testCompleted{false};

        util::spawn(executor, [&executor, &testCompleted](boost::asio::yield_context yield) mutable {
            auto [sender, receiver] = util::Channel<int>::create(executor, 5);

            EXPECT_FALSE(receiver.isClosed());

            bool const success = sender.asyncSend(42, yield);
            EXPECT_TRUE(success);

            auto value = receiver.asyncReceive(yield);
            EXPECT_TRUE(value.has_value());
            EXPECT_EQ(*value, 42);

            {
                [[maybe_unused]] auto tempSender = std::move(sender);
            }

            EXPECT_TRUE(receiver.isClosed());

            auto closedValue = receiver.asyncReceive(yield);
            EXPECT_FALSE(closedValue.has_value());

            testCompleted = true;
        });

        context_.run();
        EXPECT_TRUE(testCompleted);
    });
}

TEST_P(ChannelSpawnTest, TrySendTryReceiveMethods)
{
    context_.withExecutor([this](auto& executor) {
        std::atomic_bool testCompleted{false};

        util::spawn(executor, [&executor, &testCompleted](boost::asio::yield_context) mutable {
            auto [sender, receiver] = util::Channel<int>::create(executor, 3);

            EXPECT_FALSE(receiver.tryReceive().has_value());

            EXPECT_TRUE(sender.trySend(42));
            EXPECT_TRUE(sender.trySend(43));
            EXPECT_TRUE(sender.trySend(44));
            EXPECT_FALSE(sender.trySend(45));  // channel full

            auto value1 = receiver.tryReceive();
            EXPECT_TRUE(value1.has_value());
            EXPECT_EQ(*value1, 42);

            auto value2 = receiver.tryReceive();
            EXPECT_TRUE(value2.has_value());
            EXPECT_EQ(*value2, 43);

            EXPECT_TRUE(sender.trySend(46));

            auto value3 = receiver.tryReceive();
            EXPECT_TRUE(value3.has_value());
            EXPECT_EQ(*value3, 44);

            auto value4 = receiver.tryReceive();
            EXPECT_TRUE(value4.has_value());
            EXPECT_EQ(*value4, 46);

            EXPECT_FALSE(receiver.tryReceive().has_value());

            testCompleted = true;
        });

        context_.run();
        EXPECT_TRUE(testCompleted);
    });
}

TEST_P(ChannelSpawnTest, TryMethodsWithClosedChannel)
{
    context_.withExecutor([this](auto& executor) {
        std::atomic_bool testCompleted{false};

        util::spawn(executor, [&executor, &testCompleted](boost::asio::yield_context) mutable {
            auto [sender, receiver] = util::Channel<int>::create(executor, 3);

            EXPECT_TRUE(sender.trySend(42));
            EXPECT_TRUE(sender.trySend(43));

            {
                [[maybe_unused]] auto tempSender = std::move(sender);
            }

            EXPECT_TRUE(receiver.isClosed());

            auto value1 = receiver.tryReceive();
            EXPECT_TRUE(value1.has_value());
            EXPECT_EQ(*value1, 42);

            auto value2 = receiver.tryReceive();
            EXPECT_TRUE(value2.has_value());
            EXPECT_EQ(*value2, 43);

            EXPECT_FALSE(receiver.tryReceive().has_value());

            testCompleted = true;
        });

        context_.run();
        EXPECT_TRUE(testCompleted);
    });
}

INSTANTIATE_TEST_SUITE_P(
    SpawnTests,
    ChannelSpawnTest,
    Values(ContextType::IOContext, ContextType::ThreadPool),
    [](TestParamInfo<ContextType> const& info) { return contextTypeToString(info.param); }
);

TEST_P(ChannelCallbackTest, MultipleSendersOneReceiver)
{
    context_.withExecutor([this](auto& executor) {
        auto [sender, receiver] = util::Channel<int>::create(executor, 10);
        util::Mutex<std::vector<int>> receivedValues;

        auto receiveNext = [&receiver, &receivedValues](this auto&& self) -> void {
            if (receivedValues.lock()->size() >= kTOTAL_EXPECTED)
                return;

            receiver.asyncReceive([&receivedValues, self = std::forward<decltype(self)>(self)](auto value) {
                if (value.has_value()) {
                    receivedValues.lock()->push_back(*value);
                    self();
                }
            });
        };

        boost::asio::post(executor, receiveNext);

        {
            auto localSender = std::move(sender);
            for (auto senderId = 0uz; senderId < kNUM_SENDERS; ++senderId) {
                auto senderCopy = localSender;
                boost::asio::post(executor, [senderCopy = std::move(senderCopy), senderId, &executor]() mutable {
                    auto sendNext = [senderCopy = std::move(senderCopy),
                                     senderId,
                                     &executor](this auto&& self, std::size_t i) -> void {
                        if (i >= kVALUES_PER_SENDER)
                            return;

                        senderCopy.asyncSend(
                            generateValue(senderId, i),
                            [self = std::forward<decltype(self)>(self), &executor, i](bool success) mutable {
                                if (success)
                                    boost::asio::post(executor, [self = std::move(self), i]() mutable { self(i + 1); });
                            }
                        );
                    };
                    sendNext(0);
                });
            }
        }

        context_.run();

        EXPECT_EQ(receivedValues.lock()->size(), kTOTAL_EXPECTED);
        std::ranges::sort(receivedValues.lock().get());

        EXPECT_EQ(receivedValues.lock().get(), kEXPECTED_VALUES);
    });
}

TEST_P(ChannelCallbackTest, MultipleSendersMultipleReceivers)
{
    context_.withExecutor([this](auto& executor) {
        auto [sender, receiver] = util::Channel<int>::create(executor, 10);
        util::Mutex<std::vector<int>> receivedValues;
        std::vector<decltype(receiver)> receivers(kNUM_RECEIVERS, receiver);

        for (auto receiverId = 0uz; receiverId < kNUM_RECEIVERS; ++receiverId) {
            auto& receiverRef = receivers[receiverId];
            auto receiveNext = [&receiverRef, &receivedValues](this auto&& self) -> void {
                receiverRef.asyncReceive([&receivedValues, self = std::forward<decltype(self)>(self)](auto value) {
                    if (value.has_value()) {
                        receivedValues.lock()->push_back(*value);
                        self();
                    }
                });
            };
            boost::asio::post(executor, receiveNext);
        }

        {
            auto localSender = std::move(sender);
            for (auto senderId = 0uz; senderId < kNUM_SENDERS; ++senderId) {
                auto senderCopy = localSender;
                boost::asio::post(executor, [senderCopy = std::move(senderCopy), senderId, &executor]() mutable {
                    auto sendNext = [senderCopy = std::move(senderCopy),
                                     senderId,
                                     &executor](this auto&& self, std::size_t i) -> void {
                        if (i >= kVALUES_PER_SENDER)
                            return;

                        senderCopy.asyncSend(
                            generateValue(senderId, i),
                            [self = std::forward<decltype(self)>(self), &executor, i](bool success) mutable {
                                if (success)
                                    boost::asio::post(executor, [self = std::move(self), i]() mutable { self(i + 1); });
                            }
                        );
                    };
                    sendNext(0);
                });
            }
        }

        context_.run();

        EXPECT_EQ(receivedValues.lock()->size(), kTOTAL_EXPECTED);
        std::ranges::sort(receivedValues.lock().get());

        EXPECT_EQ(receivedValues.lock().get(), kEXPECTED_VALUES);
    });
}

TEST_P(ChannelCallbackTest, ChannelClosureScenarios)
{
    context_.withExecutor([this](auto& executor) {
        std::atomic_bool testCompleted{false};
        auto [sender, receiver] = util::Channel<int>::create(executor, 5);
        auto receiverPtr = std::make_shared<decltype(receiver)>(std::move(receiver));
        auto senderPtr = std::make_shared<std::optional<decltype(sender)>>(std::move(sender));

        EXPECT_FALSE(receiverPtr->isClosed());

        senderPtr->value().asyncSend(42, [&executor, receiverPtr, senderPtr, &testCompleted](bool success) {
            EXPECT_TRUE(success);

            receiverPtr->asyncReceive([&executor, receiverPtr, senderPtr, &testCompleted](auto value) {
                EXPECT_TRUE(value.has_value());
                EXPECT_EQ(*value, 42);

                boost::asio::post(executor, [&executor, receiverPtr, senderPtr, &testCompleted]() {
                    senderPtr->reset();
                    EXPECT_TRUE(receiverPtr->isClosed());

                    boost::asio::post(executor, [receiverPtr, &testCompleted]() {
                        receiverPtr->asyncReceive([&testCompleted](auto closedValue) {
                            EXPECT_FALSE(closedValue.has_value());
                            testCompleted = true;
                        });
                    });
                });
            });
        });

        context_.run();
        EXPECT_TRUE(testCompleted);
    });
}

TEST_P(ChannelCallbackTest, TrySendTryReceiveMethods)
{
    context_.withExecutor([this](auto& executor) {
        std::atomic_bool testCompleted{false};
        auto [sender, receiver] = util::Channel<int>::create(executor, 2);
        auto receiverPtr = std::make_shared<decltype(receiver)>(std::move(receiver));
        auto senderPtr = std::make_shared<decltype(sender)>(std::move(sender));

        boost::asio::post(executor, [receiverPtr, senderPtr, &testCompleted]() {
            EXPECT_FALSE(receiverPtr->tryReceive().has_value());

            EXPECT_TRUE(senderPtr->trySend(100));
            EXPECT_TRUE(senderPtr->trySend(101));
            EXPECT_FALSE(senderPtr->trySend(102));  // channel full

            auto value1 = receiverPtr->tryReceive();
            EXPECT_TRUE(value1.has_value());
            EXPECT_EQ(*value1, 100);

            EXPECT_TRUE(senderPtr->trySend(103));

            auto value2 = receiverPtr->tryReceive();
            EXPECT_TRUE(value2.has_value());
            EXPECT_EQ(*value2, 101);

            auto value3 = receiverPtr->tryReceive();
            EXPECT_TRUE(value3.has_value());
            EXPECT_EQ(*value3, 103);

            testCompleted = true;
        });

        context_.run();
        EXPECT_TRUE(testCompleted);
    });
}

TEST_P(ChannelCallbackTest, TryMethodsWithClosedChannel)
{
    context_.withExecutor([this](auto& executor) {
        std::atomic_bool testCompleted{false};
        auto [sender, receiver] = util::Channel<int>::create(executor, 3);
        auto receiverPtr = std::make_shared<decltype(receiver)>(std::move(receiver));
        auto senderPtr = std::make_shared<std::optional<decltype(sender)>>(std::move(sender));

        boost::asio::post(executor, [receiverPtr, senderPtr, &testCompleted]() {
            EXPECT_TRUE(senderPtr->value().trySend(100));
            EXPECT_TRUE(senderPtr->value().trySend(101));

            senderPtr->reset();

            EXPECT_TRUE(receiverPtr->isClosed());

            auto value1 = receiverPtr->tryReceive();
            EXPECT_TRUE(value1.has_value());
            EXPECT_EQ(*value1, 100);

            auto value2 = receiverPtr->tryReceive();
            EXPECT_TRUE(value2.has_value());
            EXPECT_EQ(*value2, 101);

            EXPECT_FALSE(receiverPtr->tryReceive().has_value());

            testCompleted = true;
        });

        context_.run();
        EXPECT_TRUE(testCompleted);
    });
}

INSTANTIATE_TEST_SUITE_P(
    CallbackTests,
    ChannelCallbackTest,
    Values(ContextType::IOContext, ContextType::ThreadPool),
    [](TestParamInfo<ContextType> const& info) { return contextTypeToString(info.param); }
);

TEST(ChannelTest, MultipleSenderCopiesErrorHandling)
{
    boost::asio::io_context executor;
    bool testCompleted = false;

    util::spawn(executor, [&executor, &testCompleted](boost::asio::yield_context yield) mutable {
        auto [sender, receiver] = util::Channel<int>::create(executor, 5);

        bool const success = sender.asyncSend(42, yield);
        EXPECT_TRUE(success);

        auto value = receiver.asyncReceive(yield);
        EXPECT_TRUE(value.has_value());
        EXPECT_EQ(*value, 42);

        auto senderCopy = sender;
        {
            [[maybe_unused]] auto tempSender = std::move(sender);
            // tempSender destroyed here, but senderCopy still exists
        }

        EXPECT_FALSE(receiver.isClosed());

        {
            [[maybe_unused]] auto tempSender = std::move(senderCopy);
            // now all senders are destroyed, channel should close
        }

        EXPECT_TRUE(receiver.isClosed());

        auto closedValue = receiver.asyncReceive(yield);
        EXPECT_FALSE(closedValue.has_value());

        testCompleted = true;
    });

    executor.run_for(kTEST_TIMEOUT);
    EXPECT_TRUE(testCompleted);
}

TEST(ChannelTest, ChannelClosesWhenAllSendersDestroyed)
{
    boost::asio::io_context executor;
    auto [sender, receiver] = util::Channel<int>::create(executor, 5);

    EXPECT_FALSE(receiver.isClosed());

    auto senderCopy = sender;
    {
        [[maybe_unused]] auto temp = std::move(sender);
    }
    EXPECT_FALSE(receiver.isClosed());  // one sender still exists

    {
        [[maybe_unused]] auto temp = std::move(senderCopy);
    }
    EXPECT_TRUE(receiver.isClosed());  // all senders destroyed
}

TEST(ChannelTest, ChannelClosesWhenAllReceiversDestroyed)
{
    boost::asio::io_context executor;
    auto [sender, receiver] = util::Channel<int>::create(executor, 5);

    EXPECT_TRUE(sender.trySend(42));

    auto receiverCopy = receiver;
    {
        [[maybe_unused]] auto temp = std::move(receiver);
    }
    EXPECT_TRUE(sender.trySend(43));  // one receiver still exists, can send

    {
        [[maybe_unused]] auto temp = std::move(receiverCopy);
    }
    EXPECT_FALSE(sender.trySend(44));  // all receivers destroyed, channel closed
}

TEST(ChannelTest, ChannelPreservesOrderFIFO)
{
    boost::asio::io_context executor;
    bool testCompleted = false;
    std::vector<int> const valuesToSend = {42, 7, 99, 13, 5, 88, 21, 3, 67, 54};

    util::spawn(executor, [&executor, &testCompleted, &valuesToSend](boost::asio::yield_context yield) mutable {
        auto [sender, receiver] = util::Channel<int>::create(executor, 5);
        std::vector<int> receivedValues;

        // Spawn a receiver coroutine that collects all values
        util::spawn(executor, [&receiver, &receivedValues](boost::asio::yield_context yield) mutable {
            auto value = receiver.asyncReceive(yield);
            while (value.has_value()) {
                receivedValues.push_back(*value);
                value = receiver.asyncReceive(yield);
            }
        });

        // Send all values
        for (int const value : valuesToSend) {
            EXPECT_TRUE(sender.asyncSend(value, yield));
        }

        // Close sender to signal end of data
        {
            [[maybe_unused]] auto temp = std::move(sender);
        }

        // Give receiver time to process all values
        boost::asio::steady_timer timer(executor, std::chrono::milliseconds{50});
        timer.async_wait(yield);

        // Verify received values match sent values in the same order
        EXPECT_EQ(receivedValues, valuesToSend);

        testCompleted = true;
    });

    executor.run_for(kTEST_TIMEOUT);
    EXPECT_TRUE(testCompleted);
}

TEST(ChannelTest, AsyncReceiveWakesUpWhenSenderDestroyed)
{
    boost::asio::io_context executor;
    bool testCompleted = false;
    auto [sender, receiver] = util::Channel<int>::create(executor, 5);
    auto senderPtr = std::make_shared<decltype(sender)>(std::move(sender));

    util::spawn(
        executor,
        [&receiver, senderPtr = std::move(senderPtr), &testCompleted, &executor](boost::asio::yield_context) mutable {
            // Start receiving - this will block because no data is sent
            auto receiveTask = [&receiver, &testCompleted](boost::asio::yield_context yield) {
                auto const value = receiver.asyncReceive(yield);
                EXPECT_FALSE(value.has_value());  // Should receive nullopt when sender is destroyed
                testCompleted = true;
            };

            util::spawn(executor, receiveTask);

            senderPtr.reset();
        }
    );

    executor.run_for(kTEST_TIMEOUT);
    EXPECT_TRUE(testCompleted);
}

// This test verifies the workaround for a bug in boost::asio::experimental::concurrent_channel where close() does not
// cancel pending async operations. Our Channel wrapper calls cancel() after close() to ensure pending operations are
// unblocked.
// See: https://github.com/chriskohlhoff/asio/issues/1575
TEST(ChannelTest, PendingAsyncSendsAreCancelledOnClose)
{
    boost::asio::thread_pool pool{4};
    static constexpr auto kPENDING_NUM_SENDERS = 10uz;

    // Channel with capacity 0 - all sends will block waiting for a receiver
    auto [sender, receiver] = util::Channel<int>::create(pool, 0);

    std::atomic<std::size_t> completedSends{0};
    std::counting_semaphore<kPENDING_NUM_SENDERS> semaphore{kPENDING_NUM_SENDERS};

    // Spawn multiple senders that will all block (no receiver is consuming)
    for (auto i = 0uz; i < kPENDING_NUM_SENDERS; ++i) {
        util::spawn(
            pool, [senderCopy = sender, i, &completedSends, &semaphore](boost::asio::yield_context yield) mutable {
                semaphore.release(1);
                EXPECT_FALSE(senderCopy.asyncSend(static_cast<int>(i), yield));
                ++completedSends;
            }
        );
    }

    semaphore.acquire();

    // Close the channel by destroying the only receiver we have.
    // Our workaround calls cancel() after close() to unblock pending operations
    {
        [[maybe_unused]] auto r = std::move(receiver);
    }

    // All senders should complete (unblocked by our cancel() workaround)
    pool.join();

    // All sends should have completed (returned false due to closed channel)
    EXPECT_EQ(completedSends, kPENDING_NUM_SENDERS);
}

INSTANTIATE_CHANNEL_FOR_CLANG(int);