// Copyright 2020 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.

#ifndef SRC_UI_TESTS_INTEGRATION_FLUTTER_TESTS_EMBEDDER_FLUTTER_EMBEDDER_TEST_IP_H_
#define SRC_UI_TESTS_INTEGRATION_FLUTTER_TESTS_EMBEDDER_FLUTTER_EMBEDDER_TEST_IP_H_

#include <fuchsia/input/injection/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 <lib/async/cpp/task.h>
#include <lib/fidl/cpp/binding_set.h>
#include <lib/sys/component/cpp/testing/realm_builder.h>
#include <lib/syslog/cpp/macros.h>
#include <lib/ui/scenic/cpp/view_token_pair.h>
#include <lib/zx/clock.h>
#include <zircon/status.h>
#include <zircon/time.h>

#include <optional>
#include <vector>

#include "embedder_view.h"
#include "src/lib/testing/loop_fixture/real_loop_fixture.h"
#include "src/ui/input/testing/fake_input_report_device/fake.h"
#include "src/ui/input/testing/fake_input_report_device/reports_reader.h"
#include "src/ui/testing/views/color.h"

namespace flutter_embedder_test_ip {

// Timeout for Scenic's |TakeScreenshot| FIDL call.
constexpr zx::duration kScreenshotTimeout = zx::sec(10);
// Timeout to fail the test if it goes beyond this duration.
constexpr zx::duration kTestTimeout = zx::min(1);

class FlutterEmbedderTestIp : public ::loop_fixture::RealLoop, public ::testing::Test {
 public:
  FlutterEmbedderTestIp() : realm_builder_(component_testing::RealmBuilder::Create()) {
    FX_VLOGS(1) << "Setting up base realm";
    SetUpRealmBase();

    // Post a "just in case" quit task, if the test hangs.
    async::PostDelayedTask(
        dispatcher(),
        [] { FX_LOGS(FATAL) << "\n\n>> Test did not complete in time, terminating.  <<\n\n"; },
        kTestTimeout);
  }

  embedder_tests::ViewContext CreatePresentationContext() {
    FX_CHECK(scenic()) << "Scenic is not connected.";

    return {
        .session_and_listener_request = scenic::CreateScenicSessionPtrAndListenerRequest(scenic()),
        .view_token = CreatePresentationViewToken(),
    };
  }

  fuchsia::ui::views::ViewToken CreatePresentationViewToken() {
    auto [view_token, view_holder_token] = scenic::ViewTokenPair::New();

    auto presenter = realm_->Connect<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);
  }

  scenic::Screenshot TakeScreenshot() {
    FX_LOGS(INFO) << "Taking screenshot... ";
    fuchsia::ui::scenic::ScreenshotData screenshot_out;
    scenic_->TakeScreenshot(
        [this, &screenshot_out](fuchsia::ui::scenic::ScreenshotData screenshot, bool status) {
          EXPECT_TRUE(status) << "Failed to take screenshot";
          screenshot_out = std::move(screenshot);
          QuitLoop();
        });
    EXPECT_FALSE(RunLoopWithTimeout(kScreenshotTimeout)) << "Timed out waiting for screenshot.";
    FX_LOGS(INFO) << "Screenshot captured.";

    return scenic::Screenshot(screenshot_out);
  }

  void BuildRealmAndLaunchApp(const std::string& component_url);

  bool TakeScreenshotUntil(scenic::Color color,
                           fit::function<void(std::map<scenic::Color, size_t>)> callback = nullptr,
                           zx::duration timeout = kTestTimeout) {
    return RunLoopWithTimeoutOrUntil(
        [this, &callback, &color] {
          auto screenshot = TakeScreenshot();
          auto histogram = screenshot.Histogram();

          bool color_found = histogram[color] > 0;
          if (color_found && callback != nullptr) {
            callback(std::move(histogram));
          }
          return color_found;
        },
        timeout);
  }

  void RegisterInjectionDevice() {
    registry_ = realm_->Connect<fuchsia::input::injection::InputDeviceRegistry>();

    // Create a FakeInputDevice
    fake_input_device_ = std::make_unique<fake_input_report_device::FakeInputDevice>(
        input_device_ptr_.NewRequest(), dispatcher());

    // Set descriptor
    auto device_descriptor = std::make_unique<fuchsia::input::report::DeviceDescriptor>();
    auto touch = device_descriptor->mutable_touch()->mutable_input();
    touch->set_touch_type(fuchsia::input::report::TouchType::TOUCHSCREEN);
    touch->set_max_contacts(10);

    fuchsia::input::report::Axis axis;
    axis.unit.type = fuchsia::input::report::UnitType::NONE;
    axis.unit.exponent = 0;
    axis.range.min = -1000;
    axis.range.max = 1000;

    fuchsia::input::report::ContactInputDescriptor contact;
    contact.set_position_x(axis);
    contact.set_position_y(axis);
    contact.set_pressure(axis);

    touch->mutable_contacts()->push_back(std::move(contact));

    fake_input_device_->SetDescriptor(std::move(device_descriptor));

    // Register the FakeInputDevice
    registry_->Register(std::move(input_device_ptr_));
  }

  // Inject directly into Input Pipeline, using fuchsia.input.injection FIDLs.
  void InjectInput() {
    FX_LOGS(INFO) << "Injecting input... ";

    // Set InputReports to inject. One contact at the center of the display, followed
    // by no contacts.
    fuchsia::input::report::ContactInputReport contact_input_report;
    contact_input_report.set_contact_id(1);
    contact_input_report.set_position_x(0);
    contact_input_report.set_position_y(0);

    fuchsia::input::report::TouchInputReport touch_input_report;
    auto contacts = touch_input_report.mutable_contacts();
    contacts->push_back(std::move(contact_input_report));

    fuchsia::input::report::InputReport input_report;
    input_report.set_touch(std::move(touch_input_report));

    std::vector<fuchsia::input::report::InputReport> input_reports;
    input_reports.push_back(std::move(input_report));

    fuchsia::input::report::TouchInputReport remove_touch_input_report;
    fuchsia::input::report::InputReport remove_input_report;
    remove_input_report.set_touch(std::move(remove_touch_input_report));
    input_reports.push_back(std::move(remove_input_report));
    fake_input_device_->SetReports(std::move(input_reports));

    FX_LOGS(INFO) << "Input dispatched.";
  }

  // Injects an input event, and posts a task to retry after `kTapRetryInterval`.
  //
  // We post the retry task because the first input event we send to Flutter may be lost.
  // The reason the first event may be lost is that there is a race condition as the scene
  // owner starts up.
  //
  // More specifically: in order for our app
  // to receive the injected input, two things must be true before we inject touch input:
  // * The Scenic root view must have been installed, and
  // * The Input Pipeline must have received a viewport to inject touch into.
  //
  // The problem we have is that the `is_rendering` signal that we monitor only guarantees us
  // the view is ready. If the viewport is not ready in Input Pipeline at that time, it will
  // drop the touch event.
  //
  // TODO(fxbug.dev/96986): Improve synchronization and remove retry logic.
  void TryInject() {
    InjectInput();
    async::PostDelayedTask(
        dispatcher(), [this] { TryInject(); }, kTapRetryInterval);
  }

 private:
  fuchsia::ui::scenic::Scenic* scenic() { return scenic_.get(); }

  void SetUpRealmBase();

  fuchsia::ui::scenic::ScenicPtr scenic_;

  // Wrapped in optional since the view is not created until the middle of SetUp
  std::optional<embedder_tests::EmbedderView> embedder_view_;
  component_testing::RealmBuilder realm_builder_;
  std::unique_ptr<component_testing::RealmRoot> realm_;
  fuchsia::input::injection::InputDeviceRegistryPtr registry_;
  std::unique_ptr<fake_input_report_device::FakeInputDevice> fake_input_device_;
  fuchsia::input::report::InputDevicePtr input_device_ptr_;

  // The typical latency on devices we've tested is ~60 msec. The retry interval is chosen to be
  // a) Long enough that it's unlikely that we send a new tap while a previous tap is still being
  //    processed. That is, it should be far more likely that a new tap is sent because the first
  //    tap was lost, than because the system is just running slowly.
  // b) Short enough that we don't slow down tryjobs.
  //
  // The first property is important to avoid skewing the latency metrics that we collect.
  // For an explanation of why a tap might be lost, see the documentation for TryInject().
  static constexpr auto kTapRetryInterval = zx::sec(1);
};

}  // namespace flutter_embedder_test_ip

#endif  // SRC_UI_TESTS_INTEGRATION_FLUTTER_TESTS_EMBEDDER_FLUTTER_EMBEDDER_TEST_IP_H_