#include <gtest/gtest.h>

#include <atomic>
#include <chrono>
#include <thread>
#include <vector>

#include "utils/spsc_queue.h"

namespace rk3588 {
namespace {

TEST(SpscQueueTest, BasicPushPop) {
    SpscQueue<int> q(4, QueueDropStrategy::DropOldest);
    EXPECT_EQ(q.Capacity(), 4u);
    EXPECT_EQ(q.Size(), 0u);

    EXPECT_TRUE(q.Push(1));
    EXPECT_TRUE(q.Push(2));
    EXPECT_TRUE(q.Push(3));
    EXPECT_EQ(q.Size(), 3u);

    int v = 0;
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 1);
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 2);
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 3);
    EXPECT_EQ(q.Size(), 0u);
}

TEST(SpscQueueTest, TryPopEmpty) {
    SpscQueue<int> q(4, QueueDropStrategy::DropOldest);
    int v = -1;
    EXPECT_FALSE(q.TryPop(v));
    EXPECT_EQ(v, -1);  // unchanged
}

TEST(SpscQueueTest, DropOldestStrategy) {
    SpscQueue<int> q(2, QueueDropStrategy::DropOldest);

    EXPECT_TRUE(q.Push(1));
    EXPECT_TRUE(q.Push(2));
    EXPECT_EQ(q.Size(), 2u);
    EXPECT_EQ(q.DroppedCount(), 0u);

    // Queue full, should drop oldest (1)
    EXPECT_TRUE(q.Push(3));
    EXPECT_EQ(q.DroppedCount(), 1u);

    int v = 0;
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 2);
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 3);
}

TEST(SpscQueueTest, DropNewestStrategy) {
    SpscQueue<int> q(2, QueueDropStrategy::DropNewest);

    EXPECT_TRUE(q.Push(1));
    EXPECT_TRUE(q.Push(2));
    EXPECT_EQ(q.DroppedCount(), 0u);

    // Queue full, should drop newest (the one being pushed)
    EXPECT_TRUE(q.Push(3));
    EXPECT_EQ(q.DroppedCount(), 1u);

    int v = 0;
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 1);
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 2);
    EXPECT_FALSE(q.TryPop(v));  // 3 was dropped
}

TEST(SpscQueueTest, BlockingStrategy) {
    SpscQueue<int> q(2, QueueDropStrategy::Block);

    EXPECT_TRUE(q.Push(1));
    EXPECT_TRUE(q.Push(2));

    // Start a thread that will pop after a delay
    std::thread popper([&q]() {
        std::this_thread::sleep_for(std::chrono::milliseconds(50));
        int v;
        q.TryPop(v);
    });

    // This should block until popper makes space
    auto start = std::chrono::steady_clock::now();
    EXPECT_TRUE(q.Push(3));
    auto elapsed = std::chrono::steady_clock::now() - start;
    EXPECT_GE(std::chrono::duration_cast<std::chrono::milliseconds>(elapsed).count(), 40);

    popper.join();

    int v;
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 2);
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 3);
}

TEST(SpscQueueTest, PopWithTimeout) {
    SpscQueue<int> q(4, QueueDropStrategy::DropOldest);

    // Pop on empty queue should timeout
    int v = -1;
    auto start = std::chrono::steady_clock::now();
    bool got = q.Pop(v, std::chrono::milliseconds(50));
    auto elapsed = std::chrono::steady_clock::now() - start;

    EXPECT_FALSE(got);
    EXPECT_GE(std::chrono::duration_cast<std::chrono::milliseconds>(elapsed).count(), 40);
}

TEST(SpscQueueTest, PopWithTimeoutSuccess) {
    SpscQueue<int> q(4, QueueDropStrategy::DropOldest);

    std::thread pusher([&q]() {
        std::this_thread::sleep_for(std::chrono::milliseconds(30));
        q.Push(42);
    });

    int v = -1;
    bool got = q.Pop(v, std::chrono::milliseconds(200));
    EXPECT_TRUE(got);
    EXPECT_EQ(v, 42);

    pusher.join();
}

TEST(SpscQueueTest, Stop) {
    SpscQueue<int> q(4, QueueDropStrategy::Block);
    q.Push(1);

    EXPECT_FALSE(q.IsStopped());
    q.Stop();
    EXPECT_TRUE(q.IsStopped());

    // Push should fail after stop
    EXPECT_FALSE(q.Push(2));

    // Pop should still work for existing items
    int v = 0;
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 1);

    // After draining, pop should fail
    EXPECT_FALSE(q.TryPop(v));
}

TEST(SpscQueueTest, StopUnblocksWaiters) {
    SpscQueue<int> q(4, QueueDropStrategy::Block);

    std::atomic<bool> popped{false};
    std::thread waiter([&q, &popped]() {
        int v;
        q.Pop(v);  // Will block
        popped = true;
    });

    std::this_thread::sleep_for(std::chrono::milliseconds(30));
    EXPECT_FALSE(popped.load());

    q.Stop();

    waiter.join();
    EXPECT_TRUE(popped.load());
}

TEST(SpscQueueTest, Stats) {
    SpscQueue<int> q(2, QueueDropStrategy::DropOldest);

    q.Push(1);
    q.Push(2);
    q.Push(3);  // drops 1

    int v;
    q.TryPop(v);

    auto stats = q.GetStats();
    EXPECT_EQ(stats.capacity, 2u);
    EXPECT_EQ(stats.size, 1u);
    EXPECT_EQ(stats.pushed, 3u);
    EXPECT_EQ(stats.popped, 1u);
    EXPECT_EQ(stats.dropped, 1u);
    EXPECT_FALSE(stats.stopped);
}

TEST(SpscQueueTest, TryPopBatch) {
    SpscQueue<int> q(10, QueueDropStrategy::DropOldest);

    for (int i = 0; i < 5; ++i) {
        q.Push(i);
    }

    std::vector<int> batch;
    bool got = q.TryPopBatch(batch, 3);
    EXPECT_TRUE(got);
    EXPECT_EQ(batch.size(), 3u);
    EXPECT_EQ(batch[0], 0);
    EXPECT_EQ(batch[1], 1);
    EXPECT_EQ(batch[2], 2);

    got = q.TryPopBatch(batch, 10);  // request more than available
    EXPECT_TRUE(got);
    EXPECT_EQ(batch.size(), 2u);
    EXPECT_EQ(batch[0], 3);
    EXPECT_EQ(batch[1], 4);

    got = q.TryPopBatch(batch, 5);  // empty queue
    EXPECT_FALSE(got);
    EXPECT_TRUE(batch.empty());
}

TEST(SpscQueueTest, OnDataAvailableCallback) {
    SpscQueue<int> q(4, QueueDropStrategy::DropOldest);

    std::atomic<int> callback_count{0};
    q.SetOnDataAvailable([&callback_count]() { callback_count.fetch_add(1); });

    q.Push(1);  // empty -> non-empty, should trigger
    EXPECT_EQ(callback_count.load(), 1);

    q.Push(2);  // not empty -> still not empty, no trigger
    EXPECT_EQ(callback_count.load(), 1);

    int v;
    q.TryPop(v);
    q.TryPop(v);  // now empty

    q.Push(3);  // empty -> non-empty, should trigger
    EXPECT_EQ(callback_count.load(), 2);
}

TEST(SpscQueueTest, ConcurrentPushPop) {
    SpscQueue<int> q(100, QueueDropStrategy::DropOldest);
    constexpr int kNumItems = 10000;

    std::atomic<int> sum{0};

    std::thread producer([&q]() {
        for (int i = 1; i <= kNumItems; ++i) {
            q.Push(i);
        }
    });

    std::thread consumer([&q, &sum]() {
        int received = 0;
        while (received < kNumItems) {
            int v;
            if (q.TryPop(v)) {
                sum.fetch_add(v);
                ++received;
            } else {
                std::this_thread::yield();
            }
        }
    });

    producer.join();
    consumer.join();

    // Sum of 1 to kNumItems
    int expected = kNumItems * (kNumItems + 1) / 2;
    EXPECT_EQ(sum.load(), expected);
}

TEST(SpscQueueTest, ZeroCapacityBecomesOne) {
    SpscQueue<int> q(0, QueueDropStrategy::DropOldest);
    EXPECT_EQ(q.Capacity(), 1u);

    EXPECT_TRUE(q.Push(42));
    int v;
    EXPECT_TRUE(q.TryPop(v));
    EXPECT_EQ(v, 42);
}

}  // namespace
}  // namespace rk3588