// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <iomanip>
#include <map>
#include <string>
#include <vector>

#include <fuchsia/sys/cpp/fidl.h>
#include <fuchsia/ui/app/cpp/fidl.h>
#include <fuchsia/ui/policy/cpp/fidl.h>
#include <fuchsia/ui/scenic/cpp/fidl.h>
#include <fuchsia/ui/views/cpp/fidl.h>
#include <gtest/gtest.h>
#include <lib/component/cpp/startup_context.h>
#include <lib/fdio/spawn.h>
#include <lib/fit/function.h>
#include <lib/fsl/vmo/vector.h>
#include <src/lib/fxl/logging.h>
#include <src/lib/fxl/strings/string_printf.h>
#include <lib/gtest/real_loop_fixture.h>
#include <lib/ui/scenic/cpp/view_token_pair.h>
#include <lib/zx/time.h>
#include <src/lib/files/file.h>
#include <zircon/status.h>

#include "topaz/tests/web_runner_tests/chromium_context.h"
#include "topaz/tests/web_runner_tests/test_server.h"

namespace {

// Max time to wait in failure cases before bailing.
constexpr zx::duration kTimeout = zx::sec(15);
constexpr uint32_t kBlankColor = 0x00000000;

std::map<uint32_t, size_t> Histogram(
    const fuchsia::ui::scenic::ScreenshotData& screenshot) {
  EXPECT_GT(screenshot.info.width, 0u);
  EXPECT_GT(screenshot.info.height, 0u);

  std::vector<uint8_t> data;
  EXPECT_TRUE(fsl::VectorFromVmo(screenshot.data, &data))
      << "Failed to read screenshot";

  std::map<uint32_t, size_t> histogram;
  const uint32_t* bitmap = reinterpret_cast<const uint32_t*>(data.data());
  const size_t size = screenshot.info.width * screenshot.info.height;
  EXPECT_EQ(size * sizeof(uint32_t), data.size());
  for (size_t i = 0; i < size; ++i) {
    ++histogram[bitmap[i]];
  }

  return histogram;
}

// Responds to a GET request, testing that the request looks as expected.
void MockHttpGetResponse(web_runner_tests::TestServer* server,
                         const char* resource) {
  const std::string expected_prefix =
      fxl::StringPrintf("GET /%s HTTP", resource);
  // |Read| requires preallocate (see sys/socket.h: read)
  std::string buf(expected_prefix.size(), 0);

  EXPECT_TRUE(server->Read(&buf));
  EXPECT_EQ(expected_prefix, buf);
  std::string content;
  FXL_CHECK(files::ReadFileToString(fxl::StringPrintf("/pkg/data/%s", resource),
                                    &content));
  FXL_CHECK(server->WriteContent(content));
}

// Invokes the input tool for input injection.
// See garnet/bin/ui/input/README.md or `input --help` for usage details.
// Commands used here:
//  * tap <x> <y> (scaled out of 1000)
//  * text <text>
// TODO(SCN-1262): Expose as a FIDL service.
void Input(std::vector<const char*> args) {
  // start with proc name, end with nullptr
  args.insert(args.begin(), "input");
  args.push_back(nullptr);

  zx_handle_t proc;
  zx_status_t status = fdio_spawn(ZX_HANDLE_INVALID, FDIO_SPAWN_CLONE_ALL,
                                  "/bin/input", args.data(), &proc);
  FXL_CHECK(status == ZX_OK) << "fdio_spawn: " << zx_status_get_string(status);

  status = zx_object_wait_one(proc, ZX_PROCESS_TERMINATED,
                              (zx::clock::get_monotonic() + kTimeout).get(),
                              nullptr);
  FXL_CHECK(status == ZX_OK)
      << "zx_object_wait_one: " << zx_status_get_string(status);

  zx_info_process_t info;
  status = zx_object_get_info(proc, ZX_INFO_PROCESS, &info, sizeof(info),
                              nullptr, nullptr);
  FXL_CHECK(status == ZX_OK)
      << "zx_object_get_info: " << zx_status_get_string(status);
  FXL_CHECK(info.return_code == 0) << info.return_code;
}

// Base fixture for pixel tests, containing Scenic and presentation setup, and
// screenshot utilities.
class PixelTest : public gtest::RealLoopFixture {
 protected:
  PixelTest() : context_(component::StartupContext::CreateFromStartupInfo()) {
    scenic_ =
        context_->ConnectToEnvironmentService<fuchsia::ui::scenic::Scenic>();
    scenic_.set_error_handler([](zx_status_t status) {
      FAIL() << "Lost connection to Scenic: " << zx_status_get_string(status);
    });

    // FLK-49
    //
    // These tests can flake when a screenshot captures a frame from the
    // previous test, which can advance the test logic early. This is a
    // temporary solution that waits for a blank on setup. Better solutions
    // include hermetic Scenic (complicated by CF-605) or refactoring to use
    // view state events (probably the best solution; greatly improves
    // determinism at the expense of added harness complexity).
    FXL_CHECK(WaitForBlank());
  }

  component::StartupContext* context() { return context_.get(); }

  // Gets a view token for presentation by |RootPresenter|. See also
  // garnet/examples/ui/hello_base_view
  fuchsia::ui::views::ViewToken CreatePresentationViewToken() {
    auto [view_token, view_holder_token] = scenic::NewViewTokenPair();

    auto presenter =
        context_->ConnectToEnvironmentService<fuchsia::ui::policy::Presenter>();
    presenter.set_error_handler([](zx_status_t status) {
      FAIL() << "presenter: " << zx_status_get_string(status);
    });
    presenter->PresentView(std::move(view_holder_token), nullptr);

    return std::move(view_token);
  }

  bool ScreenshotUntil(
      fit::function<bool(fuchsia::ui::scenic::ScreenshotData, bool)> condition,
      zx::duration timeout = kTimeout) {
    zx::time start = zx::clock::get_monotonic();
    while (zx::clock::get_monotonic() - start <= timeout) {
      fuchsia::ui::scenic::ScreenshotData screenshot;
      bool ok;
      scenic_->TakeScreenshot(
          [this, &screenshot, &ok](
              fuchsia::ui::scenic::ScreenshotData screenshot_in, bool status) {
            ok = status;
            screenshot = std::move(screenshot_in);
            QuitLoop();
          });

      if (!RunLoopWithTimeout(timeout) &&
          condition(std::move(screenshot), ok)) {
        return true;
      }
    }

    return false;
  }

  // Blank can manifest as invalid screenshots or blackness.
  bool WaitForBlank() {
    return ScreenshotUntil(
        [](fuchsia::ui::scenic::ScreenshotData screenshot, bool status) {
          return !status || Histogram(screenshot)[kBlankColor] > 0u;
        });
  }

  void ExpectSolidColor(uint32_t argb) {
    std::map<uint32_t, size_t> histogram;

    FXL_LOG(INFO) << "Looking for color " << std::hex << argb;
    EXPECT_TRUE(ScreenshotUntil(
        [argb, &histogram](fuchsia::ui::scenic::ScreenshotData screenshot,
                           bool status) {
          if (!status)
            return false;

          histogram = Histogram(screenshot);
          FXL_LOG(INFO) << histogram[argb] << " px";
          return histogram[argb] > 0u;
        }));

    histogram.erase(argb);
    EXPECT_EQ((std::map<uint32_t, size_t>){}, histogram) << "Unexpected colors";
  }

  void ExpectPrimaryColor(uint32_t color) {
    std::multimap<size_t, uint32_t> inverse_histogram;

    FXL_LOG(INFO) << "Looking for color " << std::hex << color;
    EXPECT_TRUE(ScreenshotUntil(
        [color, &inverse_histogram](
            fuchsia::ui::scenic::ScreenshotData screenshot, bool status) {
          if (!status)
            return false;

          std::map<uint32_t, size_t> histogram = Histogram(screenshot);
          FXL_LOG(INFO) << histogram[color] << " px";

          inverse_histogram.clear();
          for (const auto entry : histogram) {
            inverse_histogram.emplace(entry.second, entry.first);
          }

          return (--inverse_histogram.end())->second == color;
        }))
        << "Primary color: " << std::hex << (--inverse_histogram.end())->second;
  }

 private:
  std::unique_ptr<component::StartupContext> context_;
  fuchsia::sys::ComponentControllerPtr runner_ctrl_;
  fuchsia::ui::scenic::ScenicPtr scenic_;
};

using WebRunnerPixelTest = PixelTest;

// Loads a static page with a solid color via the component framework and
// verifies that the color is the only color onscreen.
TEST_F(WebRunnerPixelTest, Static) {
  static constexpr uint32_t kTargetColor = 0xffff00ff;

  web_runner_tests::TestServer server;
  FXL_CHECK(server.FindAndBindPort());

  // Chromium and the Fuchsia network package loader both send us requests. This
  // may go away after MI4-1807; although the race seems to be in Modular, the
  // fix may remove the unnecessary net request in component framework.
  auto serve = server.ServeAsync([&server] {
    while (server.Accept()) {
      MockHttpGetResponse(&server, "static.html");
    }
  });

  component::Services services;
  fuchsia::sys::ComponentControllerPtr controller;

  context()->launcher()->CreateComponent(
      {.url =
           fxl::StringPrintf("http://localhost:%d/static.html", server.port()),
       .directory_request = services.NewRequest()},
      controller.NewRequest());

  // Present the view.
  services.ConnectToService<fuchsia::ui::app::ViewProvider>()->CreateView(
      CreatePresentationViewToken().value, nullptr, nullptr);

  ExpectSolidColor(kTargetColor);
}

// This fixture uses chromium.web FIDL services to interact with Chromium.
class ChromiumPixelTest : public PixelTest {
 protected:
  ChromiumPixelTest() : chromium_(context()) {
    // And create a view for the frame.
    chromium_.frame()->CreateView2(CreatePresentationViewToken().value, nullptr,
                                   nullptr);
  }

  ChromiumContext* chromium() { return &chromium_; }

 private:
  ChromiumContext chromium_;
};

// Loads a static page with a solid color via chromium.web interfaces and
// verifies that the color is the only color onscreen.
TEST_F(ChromiumPixelTest, Static) {
  static constexpr uint32_t kTargetColor = 0xffff00ff;

  web_runner_tests::TestServer server;
  FXL_CHECK(server.FindAndBindPort());

  auto serve = server.ServeAsync([&server] {
    FXL_LOG(INFO) << "Waiting for HTTP request from Chromium";
    ASSERT_TRUE(server.Accept())
        << "Did not receive HTTP request from Chromium";
    MockHttpGetResponse(&server, "static.html");
  });

  chromium()->Navigate(
      fxl::StringPrintf("http://localhost:%d/static.html", server.port()));
  ExpectSolidColor(kTargetColor);
}

// Loads a dynamic page that starts with a Fuchsia background and has a large
// text box, with Javascript to change the background to the color typed in the
// text box. This test verifies the initial color, taps on the text box (top
// quarter of the screen), types a new color, and verifies the changed color.
TEST_F(ChromiumPixelTest, Dynamic) {
  static constexpr char kInput[] = "#40e0d0";
  static constexpr uint32_t kBeforeColor = 0xffff00ff;
  static constexpr uint32_t kAfterColor = 0xff40e0d0;

  web_runner_tests::TestServer server;
  FXL_CHECK(server.FindAndBindPort());

  auto serve = server.ServeAsync([&server] {
    ASSERT_TRUE(server.Accept());
    MockHttpGetResponse(&server, "dynamic.html");
  });

  chromium()->Navigate(
      fxl::StringPrintf("http://localhost:%d/dynamic.html", server.port()));

  ExpectPrimaryColor(kBeforeColor);
  Input({"tap", "500", "125"});  // centered in top quarter of screen
  Input({"text", kInput});
  ExpectPrimaryColor(kAfterColor);
}

}  // namespace