// Copyright 2015 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 "garnet/bin/ui/root_presenter/app.h"

#include <fuchsia/ui/input/cpp/fidl.h>
#include <lib/component/cpp/connect.h>
#include <lib/fidl/cpp/clone.h>
#include <lib/ui/input/cpp/formatting.h>
#include <lib/ui/scenic/cpp/view_token_pair.h>
#include <src/lib/fxl/logging.h>
#include <trace/event.h>

#include <algorithm>
#include <cstdlib>
#include <string>

#include "src/lib/files/file.h"

namespace root_presenter {

App::App(const fxl::CommandLine& command_line)
    : startup_context_(component::StartupContext::CreateFromStartupInfo()),
      input_reader_(this) {
  FXL_DCHECK(startup_context_);

  input_reader_.Start();

  startup_context_->outgoing().AddPublicService(
      presenter_bindings_.GetHandler(this));
  startup_context_->outgoing().AddPublicService(
      input_receiver_bindings_.GetHandler(this));
}

App::~App() {}

void App::PresentView(fuchsia::ui::views::ViewHolderToken view_holder_token,
                      fidl::InterfaceRequest<fuchsia::ui::policy::Presentation>
                          presentation_request) {
  InitializeServices();

  int32_t display_startup_rotation_adjustment = 0;
  {
    std::string rotation_value;
    if (files::ReadFileToString("/config/data/display_rotation",
                                &rotation_value)) {
      display_startup_rotation_adjustment = atoi(rotation_value.c_str());
      FXL_LOG(INFO) << "Display rotation adjustment applied: "
                    << display_startup_rotation_adjustment << " degrees.";
    }
  }

  auto presentation = std::make_unique<Presentation>(
      scenic_.get(), session_.get(), compositor_->id(),
      std::move(view_holder_token), std::move(presentation_request),
      renderer_params_, display_startup_rotation_adjustment,
      [this](bool yield_to_next) {
        if (yield_to_next) {
          SwitchToNextPresentation();
        } else {
          SwitchToPreviousPresentation();
        }
      });

  AddPresentation(std::move(presentation));
}

void App::AddPresentation(std::unique_ptr<Presentation> presentation) {
  for (auto& it : devices_by_id_) {
    presentation->OnDeviceAdded(it.second.get());
  }

  presentations_.push_back(std::move(presentation));
  SwitchToPresentation(presentations_.size() - 1);
}

void App::HACK_SetRendererParams(
    bool enable_clipping,
    ::std::vector<fuchsia::ui::gfx::RendererParam> params) {
  renderer_params_.clipping_enabled = enable_clipping;
  FXL_LOG(INFO)
      << "Presenter::HACK_SetRendererParams: Setting clipping enabled to "
      << (enable_clipping ? "true" : "false");
  for (auto& param : params) {
    switch (param.Which()) {
      case ::fuchsia::ui::gfx::RendererParam::Tag::kShadowTechnique:
        renderer_params_.shadow_technique = param.shadow_technique();
        FXL_LOG(INFO)
            << "Presenter::HACK_SetRendererParams: Setting shadow technique to "
            << fidl::ToUnderlying(param.shadow_technique());
        continue;
      case fuchsia::ui::gfx::RendererParam::Tag::kRenderFrequency:
        renderer_params_.render_frequency = param.render_frequency();
        FXL_LOG(INFO)
            << "Presenter::HACK_SetRendererParams: Setting render frequency to "
            << fidl::ToUnderlying(param.render_frequency());
        continue;
      case fuchsia::ui::gfx::RendererParam::Tag::kEnableDebugging:
        renderer_params_.debug_enabled = param.enable_debugging();
        FXL_LOG(INFO)
            << "Presenter::HACK_SetRendererParams: Setting debug enabled to "
            << param.enable_debugging();
        continue;
      case fuchsia::ui::gfx::RendererParam::Tag::Invalid:
        continue;
    }
  }
  for (const auto& presentation : presentations_) {
    presentation->OverrideRendererParams(renderer_params_);
  }
}

void App::ShutdownPresentation(size_t presentation_idx) {
  if (presentation_idx == active_presentation_idx_) {
    // This works fine when idx == 0, because the previous idx
    // chosen will also be 0, and it will be an no-op within
    // SwitchToPreviousPresentation. Finally, at the end of the
    // callback, everything will be cleaned up.
    SwitchToPreviousPresentation();
  }

  presentations_.erase(presentations_.begin() + presentation_idx);
  if (presentation_idx < active_presentation_idx_) {
    // Adjust index into presentations_.
    active_presentation_idx_--;
  }

  if (presentations_.empty()) {
    layer_stack_->RemoveAllLayers();
    active_presentation_idx_ = std::numeric_limits<size_t>::max();
  }
}

void App::SwitchToPresentation(const size_t presentation_idx) {
  FXL_DCHECK(presentation_idx < presentations_.size());
  if (presentation_idx == active_presentation_idx_) {
    return;
  }
  active_presentation_idx_ = presentation_idx;
  layer_stack_->RemoveAllLayers();
  layer_stack_->AddLayer(presentations_[presentation_idx]->layer());
  session_->Present(0, [](fuchsia::images::PresentationInfo info) {});
}

void App::SwitchToNextPresentation() {
  SwitchToPresentation((active_presentation_idx_ + 1) % presentations_.size());
}

void App::SwitchToPreviousPresentation() {
  SwitchToPresentation((active_presentation_idx_ + presentations_.size() - 1) %
                       presentations_.size());
}

void App::RegisterDevice(fuchsia::ui::input::DeviceDescriptor descriptor,
                         fidl::InterfaceRequest<fuchsia::ui::input::InputDevice>
                             input_device_request) {
  uint32_t device_id = ++next_device_token_;

  FXL_VLOG(1) << "RegisterDevice " << device_id << " " << descriptor;
  std::unique_ptr<ui_input::InputDeviceImpl> input_device =
      std::make_unique<ui_input::InputDeviceImpl>(
          device_id, std::move(descriptor), std::move(input_device_request),
          this);

  for (auto& presentation : presentations_) {
    presentation->OnDeviceAdded(input_device.get());
  }

  devices_by_id_.emplace(device_id, std::move(input_device));
}

void App::OnDeviceDisconnected(ui_input::InputDeviceImpl* input_device) {
  if (devices_by_id_.count(input_device->id()) == 0)
    return;

  FXL_VLOG(1) << "UnregisterDevice " << input_device->id();

  for (auto& presentation : presentations_) {
    presentation->OnDeviceRemoved(input_device->id());
  }
  devices_by_id_.erase(input_device->id());
}

void App::OnReport(ui_input::InputDeviceImpl* input_device,
                   fuchsia::ui::input::InputReport report) {
  TRACE_DURATION("input", "root_presenter_on_report", "id", report.trace_id);
  TRACE_FLOW_END("input", "report_to_presenter", report.trace_id);

  FXL_VLOG(3) << "OnReport from " << input_device->id() << " " << report;
  if (devices_by_id_.count(input_device->id()) == 0 ||
      presentations_.size() == 0)
    return;

  FXL_DCHECK(active_presentation_idx_ < presentations_.size());
  FXL_VLOG(3) << "OnReport to " << active_presentation_idx_;

  // Input events are only reported to the active presentation.
  TRACE_FLOW_BEGIN("input", "report_to_presentation", report.trace_id);
  presentations_[active_presentation_idx_]->OnReport(input_device->id(),
                                                     std::move(report));
}

void App::InitializeServices() {
  if (!scenic_) {
    startup_context_->ConnectToEnvironmentService(scenic_.NewRequest());
    scenic_.set_error_handler([this](zx_status_t error) {
      FXL_LOG(ERROR) << "Scenic died, destroying all presentations.";
      Reset();
    });

    session_ = std::make_unique<scenic::Session>(scenic_.get());
    session_->set_error_handler([this](zx_status_t error) {
      FXL_LOG(ERROR) << "Session died, destroying all presentations.";
      Reset();
    });
    session_->set_event_handler(
        [this](std::vector<fuchsia::ui::scenic::Event> events) {
          for (auto& event : events) {
            HandleScenicEvent(event);
          }
        });
    // Globally disable parallel dispatch of input events.
    // TODO(SCN-1047): Enable parallel dispatch.
    {
      fuchsia::ui::input::SetParallelDispatchCmd cmd;
      cmd.parallel_dispatch = false;
      fuchsia::ui::input::Command input_cmd;
      input_cmd.set_set_parallel_dispatch(std::move(cmd));
      session_->Enqueue(std::move(input_cmd));
    }

    compositor_ = std::make_unique<scenic::DisplayCompositor>(session_.get());
    layer_stack_ = std::make_unique<scenic::LayerStack>(session_.get());
    compositor_->SetLayerStack(*layer_stack_.get());
    session_->Present(0, [](fuchsia::images::PresentationInfo info) {});

    scenic_->GetDisplayOwnershipEvent([this](zx::event event) {
      input_reader_.SetOwnershipEvent(std::move(event));
    });
  }
}

void App::Reset() {
  presentations_.clear();  // must be first, holds pointers to services
  active_presentation_idx_ = std::numeric_limits<size_t>::max();
  layer_stack_ = nullptr;
  compositor_ = nullptr;
  session_ = nullptr;
  scenic_.Unbind();
}

void App::HandleScenicEvent(const fuchsia::ui::scenic::Event& event) {
  switch (event.Which()) {
    case fuchsia::ui::scenic::Event::Tag::kGfx:
      switch (event.gfx().Which()) {
        case fuchsia::ui::gfx::Event::Tag::kViewDisconnected: {
          auto& evt = event.gfx().view_disconnected();

          size_t idx = 0;
          for (idx = 0; idx < presentations_.size(); ++idx) {
            if (evt.view_holder_id == presentations_[idx]->view_holder().id()) {
              break;
            }
          }
          FXL_DCHECK(idx != presentations_.size());

          FXL_LOG(ERROR)
              << "Root presenter: Content view terminated unexpectedly.";
          ShutdownPresentation(idx);
          break;
        }
        default: {
          break;
        }
      }
    default: {
      break;
    }
  }
}

}  // namespace root_presenter