/**
 * @file tests/unit/platform/linux/test_wayland.cpp
 * @brief Test Wayland output mode selection.
 */
#ifdef SUNSHINE_BUILD_WAYLAND
  // test includes
  #include "../../../tests_common.h"

  // standard includes
  #include <array>
  #include <cerrno>
  #include <chrono>
  #include <cstdint>
  #include <cstdio>
  #include <filesystem>
  #include <format>
  #include <fstream>
  #include <map>
  #include <optional>
  #include <string>
  #include <string_view>
  #include <system_error>
  #include <vector>

  // system includes
  #include <drm_fourcc.h>
  #include <fcntl.h>
  #include <unistd.h>
  #include <xf86drm.h>

  // local includes
  #include <src/platform/linux/wayland.h>
  #ifdef SUNSHINE_BUILD_CUDA
    #include <src/platform/linux/cuda.h>
  #endif

namespace {
  struct fake_gbm_bo_t {
    int plane_count {};
    int failed_plane {-1};
    std::uint64_t modifier {};
    std::array<std::uint32_t, 4> strides {};
    std::array<std::uint32_t, 4> offsets {};
    std::array<int, 4> exported_fds {-1, -1, -1, -1};
  };

  fake_gbm_bo_t &fake_bo(gbm_bo *bo) {
    return *static_cast<fake_gbm_bo_t *>(static_cast<void *>(bo));
  }

  int get_plane_count(gbm_bo *bo) {
    return fake_bo(bo).plane_count;
  }

  int get_fd_for_plane(gbm_bo *bo, int plane) {
    auto &fake = fake_bo(bo);
    if (plane == fake.failed_plane) {
      return -1;
    }

    fake.exported_fds[plane] = open("/dev/null", O_RDONLY | O_CLOEXEC);
    return fake.exported_fds[plane];
  }

  std::uint32_t get_stride_for_plane(gbm_bo *bo, int plane) {
    return fake_bo(bo).strides[plane];
  }

  std::uint32_t get_offset(gbm_bo *bo, int plane) {
    return fake_bo(bo).offsets[plane];
  }

  std::uint64_t get_modifier(gbm_bo *bo) {
    return fake_bo(bo).modifier;
  }

  const wl::gbm_bo_accessors_t fake_accessors {
    .get_plane_count = get_plane_count,
    .get_fd_for_plane = get_fd_for_plane,
    .get_stride_for_plane = get_stride_for_plane,
    .get_offset = get_offset,
    .get_modifier = get_modifier,
  };
}  // namespace

TEST(WaylandMonitorTest, IgnoresNonCurrentModesAroundCurrentMode) {
  wl::monitor_t monitor {nullptr};

  monitor.wl_mode(nullptr, WL_OUTPUT_MODE_PREFERRED, 1280, 720, 60000);
  monitor.wl_mode(nullptr, WL_OUTPUT_MODE_CURRENT, 1920, 1080, 60000);
  monitor.wl_mode(nullptr, 0, 2560, 1440, 60000);

  EXPECT_EQ(monitor.viewport.width, 1920);
  EXPECT_EQ(monitor.viewport.height, 1080);
}

TEST(WaylandMonitorTest, UpdatesCurrentMode) {
  wl::monitor_t monitor {nullptr};

  monitor.wl_mode(nullptr, WL_OUTPUT_MODE_CURRENT | WL_OUTPUT_MODE_PREFERRED, 1920, 1080, 60000);
  monitor.wl_mode(nullptr, WL_OUTPUT_MODE_CURRENT, 2560, 1440, 120000);

  EXPECT_EQ(monitor.viewport.width, 2560);
  EXPECT_EQ(monitor.viewport.height, 1440);
}

TEST(WaylandMonitorTest, RecordsRefreshOfCurrentMode) {
  wl::monitor_t monitor {nullptr};

  EXPECT_EQ(monitor.refresh_mhz, 0);

  monitor.wl_mode(nullptr, WL_OUTPUT_MODE_PREFERRED, 1920, 1080, 60000);
  EXPECT_EQ(monitor.refresh_mhz, 0);

  monitor.wl_mode(nullptr, WL_OUTPUT_MODE_CURRENT, 1920, 1080, 120000);
  monitor.wl_mode(nullptr, 0, 1920, 1080, 144000);
  EXPECT_EQ(monitor.refresh_mhz, 120000);
}

/**
 * @brief Ignored wl-output events must not overwrite xdg-output placement or the active pixel mode.
 */
TEST(WaylandMonitorTest, ListenerIgnoresPhysicalGeometryScaleAndDone) {
  wl::monitor_t monitor {nullptr};
  monitor.xdg_position(nullptr, 100, 200);
  monitor.xdg_size(nullptr, 1280, 720);
  monitor.wl_mode(nullptr, WL_OUTPUT_MODE_CURRENT, 2560, 1440, 120000);
  monitor.name = "DP-1";
  monitor.description = "Logical monitor";

  monitor.wl_listener.geometry(&monitor, nullptr, -500, -600, 600, 340, WL_OUTPUT_SUBPIXEL_UNKNOWN, "Other", "Physical monitor", WL_OUTPUT_TRANSFORM_90);
  monitor.wl_listener.scale(&monitor, nullptr, 3);
  monitor.wl_listener.done(&monitor, nullptr);

  EXPECT_EQ(monitor.viewport.offset_x, 100);
  EXPECT_EQ(monitor.viewport.offset_y, 200);
  EXPECT_EQ(monitor.viewport.logical_width, 1280);
  EXPECT_EQ(monitor.viewport.logical_height, 720);
  EXPECT_EQ(monitor.viewport.width, 2560);
  EXPECT_EQ(monitor.viewport.height, 1440);
  EXPECT_EQ(monitor.refresh_mhz, 120000);
  EXPECT_EQ(monitor.name, "DP-1");
  EXPECT_EQ(monitor.description, "Logical monitor");
}

TEST(WaylandCaptureTest, UsesDamageCaptureOnlyOnAFasterOutput) {
  // An output at twice the stream's rate, and one just at the threshold.
  EXPECT_TRUE(wl::use_damage_capture(3, 60.0, 120000));
  EXPECT_TRUE(wl::use_damage_capture(3, 60.0, 90000));

  // An output at the stream's own rate keeps the paced copy, as does one only slightly faster.
  EXPECT_FALSE(wl::use_damage_capture(3, 60.0, 60000));
  EXPECT_FALSE(wl::use_damage_capture(3, 60.0, 89999));
  EXPECT_FALSE(wl::use_damage_capture(3, 120.0, 120000));
}

TEST(WaylandCaptureTest, KeepsPacedCaptureWithoutProtocolOrRates) {
  // copy_with_damage arrived in version 2 of the protocol.
  EXPECT_FALSE(wl::use_damage_capture(1, 60.0, 120000));
  EXPECT_TRUE(wl::use_damage_capture(2, 60.0, 120000));

  // A compositor that never reported a mode, and a stream without a rate.
  EXPECT_FALSE(wl::use_damage_capture(3, 60.0, 0));
  EXPECT_FALSE(wl::use_damage_capture(3, 0.0, 120000));
}

TEST(WaylandCaptureTest, DamageRequestBudgetFollowsASourceAtTheStreamRate) {
  using namespace std::chrono_literals;
  constexpr std::chrono::nanoseconds delay = 16ms;
  const std::chrono::steady_clock::time_point start {1s};

  // Frames one interval apart: the next request is always allowed a quarter interval before
  // the next frame is due, however long that goes on.
  auto next_request = std::chrono::steady_clock::time_point {};
  for (int i = 0; i < 100; ++i) {
    const auto frame_time = start + i * delay;
    next_request = wl::next_damage_request(next_request, frame_time, delay);
    EXPECT_EQ(next_request, frame_time + delay - delay / 4);
  }
}

TEST(WaylandCaptureTest, DamageRequestBudgetHoldsAFasterSourceToTheStreamRate) {
  using namespace std::chrono_literals;
  constexpr std::chrono::nanoseconds delay = 16ms;
  const std::chrono::steady_clock::time_point start {1s};

  // Frames arriving twice as fast as the stream: each one still costs a whole interval.
  auto next_request = wl::next_damage_request({}, start, delay);
  const auto first = next_request;
  for (int i = 1; i <= 10; ++i) {
    next_request = wl::next_damage_request(next_request, start + i * (delay / 2), delay);
  }
  EXPECT_EQ(next_request, first + 10 * delay);
}

TEST(WaylandCaptureTest, DamageRequestBudgetResetsAfterALateFrame) {
  using namespace std::chrono_literals;
  constexpr std::chrono::nanoseconds delay = 16ms;
  const std::chrono::steady_clock::time_point start {1s};

  // A still picture, then a frame a second later: no budget is carried over from the pause.
  auto next_request = wl::next_damage_request({}, start, delay);
  const auto late = start + 1s;
  next_request = wl::next_damage_request(next_request, late, delay);
  EXPECT_EQ(next_request, late + delay - delay / 4);
}

TEST(WaylandCaptureTest, WaitsOnlyForADamageRequestWithinOneInterval) {
  using namespace std::chrono_literals;
  constexpr std::chrono::nanoseconds delay = 16ms;
  const std::chrono::steady_clock::time_point now {1s};

  EXPECT_TRUE(wl::should_wait_for_damage_request(now + 4ms, now, delay));

  // Already due.
  EXPECT_FALSE(wl::should_wait_for_damage_request(now, now, delay));
  EXPECT_FALSE(wl::should_wait_for_damage_request(now - 4ms, now, delay));
  EXPECT_FALSE(wl::should_wait_for_damage_request({}, now, delay));

  // Further off than one interval: a budget gone wrong, not something to sleep on.
  EXPECT_FALSE(wl::should_wait_for_damage_request(now + delay, now, delay));
  EXPECT_FALSE(wl::should_wait_for_damage_request(now + 1h, now, delay));
}

TEST(WaylandCaptureTest, DamageFrameTimeTrustsOnlyATimestampFromItsOwnClock) {
  using namespace std::chrono_literals;
  constexpr std::chrono::nanoseconds delay = 16ms;
  const std::chrono::steady_clock::time_point now {2h};

  // Presented a moment before it was received.
  EXPECT_EQ(wl::damage_frame_time(now - 1ms, now, delay), now - 1ms);
  EXPECT_EQ(wl::damage_frame_time(now, now, delay), now);

  // Ahead of the clock, a whole interval or more behind it, or missing.
  EXPECT_EQ(wl::damage_frame_time(now + 1ms, now, delay), now);
  EXPECT_EQ(wl::damage_frame_time(now + 1h, now, delay), now);
  EXPECT_EQ(wl::damage_frame_time(now - delay, now, delay), now);
  EXPECT_EQ(wl::damage_frame_time(now - 1h, now, delay), now);
  EXPECT_EQ(wl::damage_frame_time(std::nullopt, now, delay), now);
}

TEST(WaylandCaptureTest, DamageRequestBudgetCapsTheRateWhateverClockTheCompositorUses) {
  using namespace std::chrono_literals;
  constexpr std::chrono::nanoseconds delay = 10ms;
  constexpr std::chrono::nanoseconds source_interval = delay / 2;
  const std::chrono::steady_clock::time_point start {2h};

  // A source at twice the stream's rate, captured for one second the way the capture loop does
  // it: wait for the budget, ask, and take the source's next frame.
  for (const auto clock_offset : std::initializer_list<std::chrono::nanoseconds> {0ns, 3ms, -3ms, 1s, -1s, 1h, -1h}) {
    auto next_request = std::chrono::steady_clock::time_point {};
    auto now = start;
    int frames = 0;

    while (now < start + 1s) {
      if (wl::should_wait_for_damage_request(next_request, now, delay)) {
        now = next_request;
      }

      const auto since_start = now - start;
      const auto ticks = (since_start + source_interval - 1ns) / source_interval;
      now = start + ticks * source_interval;

      const auto frame_time = wl::damage_frame_time(now + clock_offset, now, delay);
      next_request = wl::next_damage_request(next_request, frame_time, delay);
      ++frames;

      // The source has moved on by the time the next frame is asked for.
      now += 1ns;
    }

    // One hundred for the second, the frame that opens it, and at most one more at the start
    // from a timestamp that lags by less than an interval.
    EXPECT_GE(frames, 100) << "clock offset " << clock_offset.count() << " ns";
    EXPECT_LE(frames, 102) << "clock offset " << clock_offset.count() << " ns";
  }
}

TEST(WaylandCaptureTest, AsksForTheFirstFrameOutrightAndThenForChanges) {
  using enum wl::screencopy_request_e;

  EXPECT_EQ(wl::next_screencopy_request(false, false, true, true, false), copy);
  EXPECT_EQ(wl::next_screencopy_request(false, true, true, true, true), copy_with_damage);

  // Paced capture asks outright every time.
  EXPECT_EQ(wl::next_screencopy_request(false, true, true, false, true), copy);
}

TEST(WaylandCaptureTest, ReplacesAPendingRequestWhenTheCursorIsToggledOnAStillPicture) {
  using enum wl::screencopy_request_e;

  // A still picture: the request for the next change outlives one timeout after another.
  EXPECT_EQ(wl::next_screencopy_request(true, true, true, true, true), keep);
  EXPECT_EQ(wl::next_screencopy_request(true, true, true, true, true), keep);

  // The cursor is switched off, which damages nothing. The pending request would still answer
  // with the cursor in the picture, so it gives way to a plain copy.
  EXPECT_EQ(wl::next_screencopy_request(true, true, false, true, true), copy);

  // That copy was made with the new setting and is kept in turn, then changes are asked for again.
  EXPECT_EQ(wl::next_screencopy_request(true, false, false, true, true), keep);
  EXPECT_EQ(wl::next_screencopy_request(false, false, false, true, true), copy_with_damage);

  // And back on.
  EXPECT_EQ(wl::next_screencopy_request(true, false, true, true, true), copy);

  // Paced capture replaces a request that did not answer in time the same way.
  EXPECT_EQ(wl::next_screencopy_request(true, true, false, false, true), copy);
}

TEST(WaylandCaptureTest, AsksOutrightWhenTheCursorIsToggledBetweenRequests) {
  using enum wl::screencopy_request_e;

  // A frame with the cursor was delivered and nothing is pending. The cursor is switched off
  // before the next request is made. Nothing on the output changes, so a request for the next
  // change would wait while the stream goes on showing the cursor.
  EXPECT_EQ(wl::next_screencopy_request(false, true, false, true, true), copy);

  // That copy was made without the cursor. The picture is up to date, changes are asked for
  // again and the request is kept over timeouts.
  EXPECT_EQ(wl::next_screencopy_request(false, false, false, true, true), copy_with_damage);
  EXPECT_EQ(wl::next_screencopy_request(true, false, false, true, true), keep);

  // And back on.
  EXPECT_EQ(wl::next_screencopy_request(false, false, true, true, true), copy);
}

TEST(WaylandCaptureTest, AsksOutrightAfterARequestThatCouldNotBeWithdrawn) {
  using enum wl::screencopy_request_e;

  // The cursor is switched off while a request made with it is out. It is to be replaced, but
  // its buffer is still being set up and it can not be withdrawn. The caller keeps it and leaves
  // the setting it remembers alone, because no request was made with the new one.
  bool requested_cursor = true;
  EXPECT_EQ(wl::next_screencopy_request(true, requested_cursor, false, true, true), copy);

  // The old request is answered, with the cursor in the picture. The next request has to bring
  // the picture up to date, not wait for a change.
  EXPECT_EQ(wl::next_screencopy_request(false, requested_cursor, false, true, true), copy);

  // Only that request was made with the new setting.
  requested_cursor = false;
  EXPECT_EQ(wl::next_screencopy_request(false, requested_cursor, false, true, true), copy_with_damage);
}

TEST(WaylandCaptureTest, UsesVramForVaapi) {
  EXPECT_TRUE(wl::use_vram_capture(platf::mem_type_e::vaapi));
}

TEST(WaylandCaptureTest, UsesSystemMemoryForSoftwareEncoding) {
  EXPECT_FALSE(wl::use_vram_capture(platf::mem_type_e::system));
}

TEST(WaylandCaptureTest, UsesVramForCudaOnlyWhenCaptureNodeMatchesCudaPci) {
  #ifdef SUNSHINE_BUILD_CUDA
  const wl::render_node_pci_reader_t render_reader = [](const std::string &) {
    return std::optional<std::string> {"0000:0f:00.0"};
  };
  const wl::cuda_device_pci_reader_t matching_cuda_reader = [](int) {
    return std::optional<std::string> {"00000000:0F:00.0"};
  };
  const wl::cuda_device_pci_reader_t other_cuda_reader = [](int) {
    return std::optional<std::string> {"00000000:0E:00.0"};
  };
  EXPECT_TRUE(wl::use_vram_capture(platf::mem_type_e::cuda, render_reader, matching_cuda_reader));
  EXPECT_FALSE(wl::use_vram_capture(platf::mem_type_e::cuda, render_reader, other_cuda_reader));
  #else
  EXPECT_FALSE(wl::use_vram_capture(platf::mem_type_e::cuda));
  #endif
}

TEST(WaylandCaptureTest, ParsesCudaAndSysfsPciBusIds) {
  const auto cuda_form = wl::parse_pci_bus_id("00000000:0F:00.0");
  const auto short_cuda_form = wl::parse_pci_bus_id("0000:0F:00.0");
  const auto sysfs_form = wl::parse_pci_bus_id("0000:0f:00.0");
  ASSERT_TRUE(cuda_form.has_value());
  ASSERT_TRUE(short_cuda_form.has_value());
  ASSERT_TRUE(sysfs_form.has_value());
  EXPECT_EQ(*cuda_form, *sysfs_form);
  EXPECT_EQ(*short_cuda_form, *sysfs_form);
  EXPECT_EQ(cuda_form->domain, 0u);
  EXPECT_EQ(cuda_form->bus, 0x0fu);
  EXPECT_EQ(cuda_form->device, 0x00u);
  EXPECT_EQ(cuda_form->function, 0u);
}

TEST(WaylandCaptureTest, RejectsMalformedPciBusIds) {
  for (const char *bus_id : {"", "0000:0f:00", "0000:0f:00.0:1", "0000:0f:00.8", "0000:0f:00.0 ", "pci:0000:0f:00.0", "0000:0g:00.0", "0x10de"}) {
    EXPECT_FALSE(wl::parse_pci_bus_id(bus_id).has_value()) << bus_id;
  }
}

TEST(WaylandCaptureTest, FallsBackToRamBridgeWhenPciIsUnprovable) {
  const wl::render_node_pci_reader_t render_reader = [](const std::string &) {
    return std::optional<std::string> {"0000:0f:00.0"};
  };
  const wl::render_node_pci_reader_t missing_render_reader = [](const std::string &) {
    return std::optional<std::string> {};
  };
  const wl::cuda_device_pci_reader_t cuda_reader = [](int) {
    return std::optional<std::string> {"00000000:0F:00.0"};
  };
  const wl::cuda_device_pci_reader_t missing_cuda_reader = [](int) {
    return std::optional<std::string> {};
  };
  EXPECT_FALSE(wl::capture_node_is_cuda_device(missing_render_reader, cuda_reader));
  EXPECT_FALSE(wl::capture_node_is_cuda_device(render_reader, missing_cuda_reader));
  EXPECT_FALSE(wl::capture_node_is_cuda_device(missing_render_reader, missing_cuda_reader));
  #ifdef SUNSHINE_BUILD_CUDA
  EXPECT_FALSE(wl::use_vram_capture(platf::mem_type_e::cuda, missing_render_reader, cuda_reader));
  EXPECT_FALSE(wl::use_vram_capture(platf::mem_type_e::cuda, render_reader, missing_cuda_reader));
  #endif
}

TEST(WaylandCaptureTest, ResolvesRenderNodeAliasBeforePciLookup) {
  const wl::render_path_resolver_t fake_resolver = [](const std::string &) {
    return "/dev/dri/renderD128";
  };
  std::string observed_path;
  const wl::render_node_pci_reader_t recording_reader = [&observed_path](std::string_view render_path) {
    observed_path = render_path;
    return std::optional<std::string> {"0000:0f:00.0"};
  };
  const wl::cuda_device_pci_reader_t cuda_reader = [](int) {
    return std::optional<std::string> {"00000000:0F:00.0"};
  };
  EXPECT_TRUE(wl::capture_node_is_cuda_device(recording_reader, cuda_reader, fake_resolver));
  EXPECT_EQ(observed_path, "/dev/dri/renderD128");
}

TEST(WaylandLinearCopyTest, SkipsLinearAttemptUnlessAdvertised) {
  const std::vector<std::uint64_t> without_linear {0x100000000000004};
  const std::vector<std::uint64_t> with_linear {0x100000000000004, DRM_FORMAT_MOD_LINEAR};
  EXPECT_FALSE(wl::should_attempt_linear_copy(false, with_linear));
  EXPECT_FALSE(wl::should_attempt_linear_copy(true, without_linear));
  EXPECT_FALSE(wl::should_attempt_linear_copy(true, {}));
  EXPECT_TRUE(wl::should_attempt_linear_copy(true, with_linear));
}

TEST(WaylandAdvertisedModifiersTest, ReturnsNullWhenUnavailable) {
  const std::map<std::uint32_t, std::vector<std::uint64_t>> empty_map {};
  const std::map<std::uint32_t, std::vector<std::uint64_t>> map_with_empty_list {{0x34325258, {}}};
  EXPECT_EQ(wl::find_advertised_modifiers(nullptr, 0x34325258), nullptr);
  EXPECT_EQ(wl::find_advertised_modifiers(&empty_map, 0x34325258), nullptr);
  EXPECT_EQ(wl::find_advertised_modifiers(&map_with_empty_list, 0x34325258), nullptr);
  EXPECT_EQ(wl::find_advertised_modifiers(&map_with_empty_list, 0xdeadbeef), nullptr);
}

TEST(WaylandAdvertisedModifiersTest, ReturnsAdvertisedListWhenPresent) {
  const std::vector<std::uint64_t> expected {0x100000000000004, DRM_FORMAT_MOD_LINEAR};
  const std::map<std::uint32_t, std::vector<std::uint64_t>> modifiers {{0x34325258, expected}};
  const auto *actual = wl::find_advertised_modifiers(&modifiers, 0x34325258);
  ASSERT_NE(actual, nullptr);
  EXPECT_EQ(*actual, expected);
}

/**
 * @brief Test fixture for DRM render-node path resolution.
 */
class WaylandResolvePathTest: public BaseTest {
protected:
  /**
   * @brief Create an empty directory for the current test.
   */
  void SetUp() override {
    BaseTest::SetUp();
    std::filesystem::remove_all(test_dir);
    std::filesystem::create_directories(test_dir);
  }

  /**
   * @brief Remove files created by the current test.
   */
  void TearDown() override {
    std::filesystem::remove_all(test_dir);
    BaseTest::TearDown();
  }

  const std::filesystem::path test_dir {std::filesystem::path {SUNSHINE_TEST_BIN_DIR} / "wayland_resolve_path_tests"};  ///< Directory containing resolve-path test files.
};

TEST_F(WaylandResolvePathTest, FollowsSymlinkedAliasToTarget) {
  std::error_code ec;
  const auto dir = std::filesystem::weakly_canonical(test_dir, ec);
  ASSERT_FALSE(ec);
  const auto target = dir / "renderD128";
  const auto alias = dir / "by-path" / "pci-0000:00:02.0-render";
  std::filesystem::create_directories(alias.parent_path(), ec);
  ASSERT_FALSE(ec) << ec.message();
  {
    std::ofstream out {target};
    ASSERT_TRUE(out.good());
  }
  std::filesystem::remove(alias, ec);
  std::filesystem::create_symlink(target, alias, ec);
  ASSERT_FALSE(ec) << ec.message();
  EXPECT_EQ(wl::resolve_drm_node_path(alias.string()), target.string());
}

TEST_F(WaylandResolvePathTest, FallsBackToVerbatimPath) {
  std::error_code ec;
  const auto dir = std::filesystem::weakly_canonical(test_dir, ec);
  ASSERT_FALSE(ec);
  const auto missing = dir / "renderD999";
  EXPECT_EQ(wl::resolve_drm_node_path(missing.string()), missing.string());

  const auto dangling_target = dir / "no-such-target";
  const auto dangling_link = dir / "by-path" / "pci-0000:00:02.0-render";
  std::filesystem::create_directories(dangling_link.parent_path(), ec);
  ASSERT_FALSE(ec) << ec.message();
  std::filesystem::remove(dangling_link, ec);
  std::filesystem::create_symlink(dangling_target, dangling_link, ec);
  ASSERT_FALSE(ec) << ec.message();
  EXPECT_EQ(wl::resolve_drm_node_path(dangling_link.string()), dangling_link.string());
}

TEST_F(WaylandResolvePathTest, FallsBackToVerbatimPathOnSymlinkLoop) {
  std::error_code ec;
  const auto dir = std::filesystem::weakly_canonical(test_dir, ec);
  ASSERT_FALSE(ec);
  // A symlink pointing at itself cannot be canonicalized (ELOOP), forcing the error_code path.
  const auto loop = dir / "self-loop";
  std::filesystem::remove(loop, ec);
  std::filesystem::create_symlink(loop, loop, ec);
  ASSERT_FALSE(ec) << ec.message();
  EXPECT_EQ(wl::resolve_drm_node_path(loop.string()), loop.string());
}

TEST_F(WaylandResolvePathTest, ReturnsNoPciIdentityWhenRenderNodeCannotOpen) {
  EXPECT_FALSE(wl::render_node_pci_bus_id((test_dir / "missing-render-node").string()).has_value());
}

TEST_F(WaylandResolvePathTest, ReturnsNoPciIdentityWhenDrmQueryFails) {
  const auto regular_file = test_dir / "regular-file";
  {
    std::ofstream output {regular_file};
    ASSERT_TRUE(output.good());
  }
  EXPECT_FALSE(wl::render_node_pci_bus_id(regular_file.string()).has_value());
}

TEST(WaylandInterfaceTest, RecordsOnlyExplicitDmabufModifiers) {
  constexpr std::uint32_t format = DRM_FORMAT_XRGB8888;
  constexpr std::uint64_t explicit_modifier = 0x100000000000004;
  wl::interface_t interface;

  interface.dmabuf_modifier(nullptr, format, DRM_FORMAT_MOD_INVALID >> 32, DRM_FORMAT_MOD_INVALID & 0xffffffff);
  interface.dmabuf_modifier(nullptr, format, explicit_modifier >> 32, explicit_modifier & 0xffffffff);

  const auto modifiers = interface.supported_modifiers.find(format);
  ASSERT_NE(modifiers, interface.supported_modifiers.end());
  ASSERT_EQ(modifiers->second.size(), 1);
  EXPECT_EQ(modifiers->second.front(), explicit_modifier);
}

TEST(WaylandCaptureTest, ExportsEveryGbmBufferPlane) {
  fake_gbm_bo_t bo {
    .plane_count = 2,
    .modifier = 0x100000000000004,
    .strides = {10240, 256},
    .offsets = {0, 0x800000},
  };
  wl::frame_t frame;

  const auto plane_count = wl::export_gbm_bo_planes(static_cast<gbm_bo *>(static_cast<void *>(&bo)), frame, fake_accessors);

  ASSERT_EQ(plane_count, 2);
  EXPECT_EQ(frame.sd.modifier, bo.modifier);
  for (std::size_t plane = 0; plane < *plane_count; ++plane) {
    EXPECT_EQ(frame.sd.fds[plane], bo.exported_fds[plane]);
    EXPECT_EQ(frame.sd.pitches[plane], bo.strides[plane]);
    EXPECT_EQ(frame.sd.offsets[plane], bo.offsets[plane]);
  }
  EXPECT_EQ(frame.sd.fds[2], -1);
  EXPECT_EQ(frame.sd.fds[3], -1);

  frame.destroy();
}

TEST(WaylandCaptureTest, RejectsUnsupportedGbmPlaneCounts) {
  wl::frame_t frame;
  fake_gbm_bo_t empty_bo {};
  fake_gbm_bo_t oversized_bo {
    .plane_count = 5,
  };

  EXPECT_FALSE(wl::export_gbm_bo_planes(static_cast<gbm_bo *>(static_cast<void *>(&empty_bo)), frame, fake_accessors));
  EXPECT_FALSE(wl::export_gbm_bo_planes(static_cast<gbm_bo *>(static_cast<void *>(&oversized_bo)), frame, fake_accessors));
}

TEST(WaylandCaptureTest, ClosesExportedPlanesAfterLaterPlaneFails) {
  fake_gbm_bo_t bo {
    .plane_count = 2,
    .failed_plane = 1,
  };
  wl::frame_t frame;

  EXPECT_FALSE(wl::export_gbm_bo_planes(static_cast<gbm_bo *>(static_cast<void *>(&bo)), frame, fake_accessors));
  ASSERT_GE(bo.exported_fds[0], 0);
  const auto fd_status = fcntl(bo.exported_fds[0], F_GETFD);
  const auto fd_error = errno;
  EXPECT_EQ(fd_status, -1);
  EXPECT_EQ(fd_error, EBADF);
  EXPECT_EQ(frame.sd.fds[0], -1);
}

namespace {
  /**
   * @brief Count of fake GBM devices destroyed by the accessors below (function-local state, reset per test).
   */
  int &fake_destroyed_devices() {
    static int count = 0;
    return count;
  }

  /**
   * @brief Descriptor most recently returned by open_fake_render_node() (reset per test).
   */
  int &last_fake_render_node() {
    static int fd = -1;
    return fd;
  }

  /**
   * @brief Count of create_device calls made through the accessors below (reset per test).
   */
  int &fake_create_device_calls() {
    static int count = 0;
    return count;
  }

  int open_fake_render_node(const char *) {
    last_fake_render_node() = open("/dev/null", O_RDWR | O_CLOEXEC);
    return last_fake_render_node();
  }

  int fail_to_open_render_node(const char *) {
    return -1;
  }

  gbm_device *create_fake_device(int fd) {
    ++fake_create_device_calls();
    // The address of this object stands in for an opaque GBM device.
    static int storage = 0;
    return fd >= 0 ? static_cast<gbm_device *>(static_cast<void *>(&storage)) : nullptr;
  }

  gbm_device *fail_to_create_device(int) {
    ++fake_create_device_calls();
    return nullptr;
  }

  void destroy_fake_device(gbm_device *) {
    ++fake_destroyed_devices();
  }

  bool descriptor_is_open(int fd) {
    return fcntl(fd, F_GETFD) != -1;
  }
}  // namespace

TEST(WaylandGbmDeviceTest, ClosesRenderNodeDescriptorOnReset) {
  const wl::gbm_device_accessors_t accessors {
    .open_render_node = open_fake_render_node,
    .create_device = create_fake_device,
    .destroy_device = destroy_fake_device,
  };
  fake_destroyed_devices() = 0;

  wl::gbm_device_t device;
  ASSERT_TRUE(device.init("/dev/dri/renderD128", accessors));
  ASSERT_TRUE(device);
  const int fd = device.fd();
  ASSERT_GE(fd, 0);
  EXPECT_TRUE(descriptor_is_open(fd));

  device.reset();
  EXPECT_FALSE(device);
  EXPECT_EQ(device.fd(), -1);
  EXPECT_EQ(fake_destroyed_devices(), 1);
  EXPECT_FALSE(descriptor_is_open(fd));
}

TEST(WaylandGbmDeviceTest, ClosesRenderNodeDescriptorWhenDeviceCreationFails) {
  const wl::gbm_device_accessors_t accessors {
    .open_render_node = open_fake_render_node,
    .create_device = fail_to_create_device,
    .destroy_device = destroy_fake_device,
  };
  fake_destroyed_devices() = 0;
  fake_create_device_calls() = 0;
  last_fake_render_node() = -1;

  wl::gbm_device_t device;
  EXPECT_FALSE(device.init("/dev/dri/renderD128", accessors));
  EXPECT_FALSE(device);
  EXPECT_EQ(device.fd(), -1);
  EXPECT_EQ(fake_create_device_calls(), 1);
  EXPECT_EQ(fake_destroyed_devices(), 0);

  // Check the descriptor the fake accessor actually opened.
  const int fd = last_fake_render_node();
  ASSERT_GE(fd, 0);
  EXPECT_FALSE(descriptor_is_open(fd));
}

TEST(WaylandGbmDeviceTest, DoesNotCreateDeviceWhenRenderNodeFailsToOpen) {
  const wl::gbm_device_accessors_t accessors {
    .open_render_node = fail_to_open_render_node,
    .create_device = create_fake_device,
    .destroy_device = destroy_fake_device,
  };
  fake_destroyed_devices() = 0;
  fake_create_device_calls() = 0;

  wl::gbm_device_t device;
  EXPECT_FALSE(device.init("/dev/dri/renderD128", accessors));
  EXPECT_FALSE(device);
  EXPECT_EQ(device.get(), nullptr);
  EXPECT_EQ(device.fd(), -1);
  EXPECT_EQ(fake_create_device_calls(), 0);
  EXPECT_EQ(fake_destroyed_devices(), 0);
}

TEST(WaylandGbmDeviceTest, DestructorClosesRenderNodeDescriptor) {
  const wl::gbm_device_accessors_t accessors {
    .open_render_node = open_fake_render_node,
    .create_device = create_fake_device,
    .destroy_device = destroy_fake_device,
  };
  fake_destroyed_devices() = 0;
  int fd = -1;

  {
    wl::gbm_device_t device;
    ASSERT_TRUE(device.init("/dev/dri/renderD128", accessors));
    fd = device.fd();
    ASSERT_TRUE(descriptor_is_open(fd));
  }

  EXPECT_EQ(fake_destroyed_devices(), 1);
  EXPECT_FALSE(descriptor_is_open(fd));
}

namespace {
  /**
   * @brief Scripted answer for query_fake_drm_device().
   */
  struct fake_drm_query_t {
    int result = 0;
    drmDevice *device = nullptr;
  };

  /**
   * @brief Scripted answer returned by query_fake_drm_device() (reset per test).
   */
  fake_drm_query_t &fake_drm_query() {
    static fake_drm_query_t query;
    return query;
  }

  /**
   * @brief Count of query_fake_drm_device() calls (reset per test).
   */
  int &drm_get_device_calls() {
    static int count = 0;
    return count;
  }

  /**
   * @brief Count of free_fake_drm_device() calls (reset per test).
   */
  int &drm_free_device_calls() {
    static int count = 0;
    return count;
  }

  /**
   * @brief Fake PCI bus info backing query_fake_drm_device() (reset per test).
   */
  drmPciBusInfo &fake_pci_bus_info() {
    static drmPciBusInfo bus_info {};
    return bus_info;
  }

  /**
   * @brief Fake DRM device backing query_fake_drm_device() (reset per test).
   */
  drmDevice &fake_drm_device() {
    static drmDevice device {};
    return device;
  }

  int query_fake_drm_device(int, std::uint32_t, _drmDevice **device) {
    ++drm_get_device_calls();
    *device = fake_drm_query().device;
    return fake_drm_query().result;
  }

  void free_fake_drm_device(_drmDevice **device) {
    ++drm_free_device_calls();
    if (device) {
      *device = nullptr;
    }
  }

  /**
   * @brief Reset the fake DRM query state before a PCI reader test.
   */
  void reset_drm_pci_fakes() {
    drm_get_device_calls() = 0;
    drm_free_device_calls() = 0;
    last_fake_render_node() = -1;
    fake_pci_bus_info() = drmPciBusInfo {};
    fake_drm_device() = drmDevice {};
    fake_drm_query() = fake_drm_query_t {};
  }
}  // namespace

TEST(WaylandPciReaderTest, ReturnsFormattedPciIdentityOnSuccess) {
  reset_drm_pci_fakes();
  fake_pci_bus_info() = drmPciBusInfo {.domain = 0x00a5, .bus = 0x0f, .dev = 0xa0, .func = 0x1};
  fake_drm_device().bustype = DRM_BUS_PCI;
  fake_drm_device().businfo.pci = &fake_pci_bus_info();
  fake_drm_query() = {.result = 0, .device = &fake_drm_device()};
  const wl::drm_device_accessors_t accessors {
    .open_render_node = open_fake_render_node,
    .get_device = query_fake_drm_device,
    .free_device = free_fake_drm_device,
  };

  const auto bus_id = wl::render_node_pci_bus_id("/dev/dri/renderD128", accessors);

  ASSERT_TRUE(bus_id.has_value());
  EXPECT_EQ(*bus_id, "00a5:0f:a0.1");
  EXPECT_EQ(drm_get_device_calls(), 1);
  EXPECT_EQ(drm_free_device_calls(), 1);
  const int fd = last_fake_render_node();
  ASSERT_GE(fd, 0);
  EXPECT_FALSE(descriptor_is_open(fd));
}

TEST(WaylandPciReaderTest, ReturnsNoPciIdentityWhenRenderNodeCannotOpen) {
  reset_drm_pci_fakes();
  const wl::drm_device_accessors_t accessors {
    .open_render_node = fail_to_open_render_node,
    .get_device = query_fake_drm_device,
    .free_device = free_fake_drm_device,
  };

  EXPECT_FALSE(wl::render_node_pci_bus_id("/dev/dri/renderD128", accessors).has_value());
  EXPECT_EQ(drm_get_device_calls(), 0);
  EXPECT_EQ(drm_free_device_calls(), 0);
}

TEST(WaylandPciReaderTest, ReturnsNoPciIdentityWhenDrmQueryFails) {
  reset_drm_pci_fakes();
  fake_drm_query() = {.result = -1, .device = nullptr};
  const wl::drm_device_accessors_t accessors {
    .open_render_node = open_fake_render_node,
    .get_device = query_fake_drm_device,
    .free_device = free_fake_drm_device,
  };

  EXPECT_FALSE(wl::render_node_pci_bus_id("/dev/dri/renderD128", accessors).has_value());
  EXPECT_EQ(drm_get_device_calls(), 1);
  EXPECT_EQ(drm_free_device_calls(), 0);
  const int fd = last_fake_render_node();
  ASSERT_GE(fd, 0);
  EXPECT_FALSE(descriptor_is_open(fd));
}

TEST(WaylandPciReaderTest, ReturnsNoPciIdentityWhenDeviceIsMissing) {
  reset_drm_pci_fakes();
  fake_drm_query() = {.result = 0, .device = nullptr};
  const wl::drm_device_accessors_t accessors {
    .open_render_node = open_fake_render_node,
    .get_device = query_fake_drm_device,
    .free_device = free_fake_drm_device,
  };

  EXPECT_FALSE(wl::render_node_pci_bus_id("/dev/dri/renderD128", accessors).has_value());
  EXPECT_EQ(drm_free_device_calls(), 0);
  const int fd = last_fake_render_node();
  ASSERT_GE(fd, 0);
  EXPECT_FALSE(descriptor_is_open(fd));
}

TEST(WaylandPciReaderTest, ReturnsNoPciIdentityForNonPciDevice) {
  reset_drm_pci_fakes();
  fake_drm_device().bustype = DRM_BUS_PLATFORM;
  fake_drm_query() = {.result = 0, .device = &fake_drm_device()};
  const wl::drm_device_accessors_t accessors {
    .open_render_node = open_fake_render_node,
    .get_device = query_fake_drm_device,
    .free_device = free_fake_drm_device,
  };

  EXPECT_FALSE(wl::render_node_pci_bus_id("/dev/dri/renderD128", accessors).has_value());
  EXPECT_EQ(drm_free_device_calls(), 1);
  const int fd = last_fake_render_node();
  ASSERT_GE(fd, 0);
  EXPECT_FALSE(descriptor_is_open(fd));
}

TEST(WaylandPciReaderTest, ReturnsNoPciIdentityWhenPciBusInfoMissing) {
  reset_drm_pci_fakes();
  fake_drm_device().bustype = DRM_BUS_PCI;
  fake_drm_device().businfo.pci = nullptr;
  fake_drm_query() = {.result = 0, .device = &fake_drm_device()};
  const wl::drm_device_accessors_t accessors {
    .open_render_node = open_fake_render_node,
    .get_device = query_fake_drm_device,
    .free_device = free_fake_drm_device,
  };

  EXPECT_FALSE(wl::render_node_pci_bus_id("/dev/dri/renderD128", accessors).has_value());
  EXPECT_EQ(drm_free_device_calls(), 1);
  const int fd = last_fake_render_node();
  ASSERT_GE(fd, 0);
  EXPECT_FALSE(descriptor_is_open(fd));
}

  #ifdef SUNSHINE_BUILD_CUDA
namespace {
  /**
   * @brief Whether the fake CUDA function table counts as loaded (reset per test).
   */
  bool &fake_cuda_initialized() {
    static bool initialized = true;
    return initialized;
  }

  /**
   * @brief Count of fake_cuda_initialize() calls (reset per test).
   */
  int &cuda_initialize_calls() {
    static int count = 0;
    return count;
  }

  /**
   * @brief Result returned by fake_cuda_initialize() (reset per test).
   */
  int &cuda_initialize_result() {
    static int result = 0;
    return result;
  }

  /**
   * @brief Count of fake_cuda_get_device() calls (reset per test).
   */
  int &cuda_get_device_calls() {
    static int count = 0;
    return count;
  }

  /**
   * @brief Result returned by fake_cuda_get_device() (reset per test).
   */
  CUresult &cuda_get_device_result() {
    static CUresult result = CUDA_SUCCESS;
    return result;
  }

  /**
   * @brief Count of fake_cuda_get_pci_bus_id() calls (reset per test).
   */
  int &cuda_get_pci_bus_id_calls() {
    static int count = 0;
    return count;
  }

  /**
   * @brief Result returned by fake_cuda_get_pci_bus_id() (reset per test).
   */
  CUresult &cuda_get_pci_bus_id_result() {
    static CUresult result = CUDA_SUCCESS;
    return result;
  }

  /**
   * @brief Bus id text written by fake_cuda_get_pci_bus_id() (reset per test).
   */
  std::string &cuda_fake_bus_id() {
    static std::string bus_id;
    return bus_id;
  }

  /**
   * @brief Device handle observed by fake_cuda_get_pci_bus_id() (reset per test).
   */
  CUdevice &cuda_seen_device() {
    static CUdevice device = 0;
    return device;
  }

  bool fake_cuda_is_initialized() {
    return fake_cuda_initialized();
  }

  int fake_cuda_initialize() {
    ++cuda_initialize_calls();
    return cuda_initialize_result();
  }

  CUresult fake_cuda_get_device(CUdevice *device, int) {
    ++cuda_get_device_calls();
    if (device) {
      *device = 7;
    }
    return cuda_get_device_result();
  }

  CUresult fake_cuda_get_pci_bus_id(char *pci_bus_id, int len, CUdevice device) {
    ++cuda_get_pci_bus_id_calls();
    cuda_seen_device() = device;
    if (cuda_get_pci_bus_id_result() == CUDA_SUCCESS && pci_bus_id != nullptr && len > 0) {
      const auto end = std::format_to_n(pci_bus_id, len - 1, "{}", cuda_fake_bus_id()).out;
      *end = '\0';
    }
    return cuda_get_pci_bus_id_result();
  }

  const cuda::cuda_pci_accessors_t fake_cuda_pci_accessors {
    .is_initialized = fake_cuda_is_initialized,
    .initialize = fake_cuda_initialize,
    .get_device = fake_cuda_get_device,
    .get_pci_bus_id = fake_cuda_get_pci_bus_id,
  };

  /**
   * @brief Reset the fake CUDA query state before a PCI reader test.
   */
  void reset_cuda_pci_fakes() {
    fake_cuda_initialized() = true;
    cuda_initialize_calls() = 0;
    cuda_initialize_result() = 0;
    cuda_get_device_calls() = 0;
    cuda_get_device_result() = CUDA_SUCCESS;
    cuda_get_pci_bus_id_calls() = 0;
    cuda_get_pci_bus_id_result() = CUDA_SUCCESS;
    cuda_fake_bus_id().clear();
    cuda_seen_device() = 0;
  }
}  // namespace

TEST(CudaPciReaderTest, ReturnsLowercaseBusIdWithoutReinitializing) {
  reset_cuda_pci_fakes();
  cuda_fake_bus_id() = "00000000:0F:00.0";

  const auto bus_id = cuda::device_pci_bus_id(0, fake_cuda_pci_accessors);

  ASSERT_TRUE(bus_id.has_value());
  EXPECT_EQ(*bus_id, "00000000:0f:00.0");
  EXPECT_EQ(cuda_initialize_calls(), 0);
  EXPECT_EQ(cuda_get_device_calls(), 1);
  EXPECT_EQ(cuda_get_pci_bus_id_calls(), 1);
  EXPECT_EQ(cuda_seen_device(), 7);
}

TEST(CudaPciReaderTest, ReturnsShortBusIdLowercased) {
  reset_cuda_pci_fakes();
  cuda_fake_bus_id() = "0000:0F:00.0";

  const auto bus_id = cuda::device_pci_bus_id(0, fake_cuda_pci_accessors);

  ASSERT_TRUE(bus_id.has_value());
  EXPECT_EQ(*bus_id, "0000:0f:00.0");
}

TEST(CudaPciReaderTest, InitializesUninitializedFunctionTable) {
  reset_cuda_pci_fakes();
  fake_cuda_initialized() = false;
  cuda_fake_bus_id() = "0000:0F:00.0";

  const auto bus_id = cuda::device_pci_bus_id(0, fake_cuda_pci_accessors);

  ASSERT_TRUE(bus_id.has_value());
  EXPECT_EQ(*bus_id, "0000:0f:00.0");
  EXPECT_EQ(cuda_initialize_calls(), 1);
  EXPECT_EQ(cuda_get_device_calls(), 1);
}

TEST(CudaPciReaderTest, ReturnsNoBusIdWhenInitFails) {
  reset_cuda_pci_fakes();
  fake_cuda_initialized() = false;
  cuda_initialize_result() = -1;

  EXPECT_FALSE(cuda::device_pci_bus_id(0, fake_cuda_pci_accessors).has_value());
  EXPECT_EQ(cuda_initialize_calls(), 1);
  EXPECT_EQ(cuda_get_device_calls(), 0);
  EXPECT_EQ(cuda_get_pci_bus_id_calls(), 0);
}

TEST(CudaPciReaderTest, ReturnsNoBusIdWhenDeviceQueryFails) {
  reset_cuda_pci_fakes();
  cuda_get_device_result() = CUDA_ERROR_UNKNOWN;

  EXPECT_FALSE(cuda::device_pci_bus_id(0, fake_cuda_pci_accessors).has_value());
  EXPECT_EQ(cuda_get_device_calls(), 1);
  EXPECT_EQ(cuda_get_pci_bus_id_calls(), 0);
}

TEST(CudaPciReaderTest, ReturnsNoBusIdWhenBusIdQueryFails) {
  reset_cuda_pci_fakes();
  cuda_get_pci_bus_id_result() = CUDA_ERROR_UNKNOWN;

  EXPECT_FALSE(cuda::device_pci_bus_id(0, fake_cuda_pci_accessors).has_value());
  EXPECT_EQ(cuda_get_pci_bus_id_calls(), 1);
}
  #endif

#endif