// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/screen_details/screen_change_monitor.h"

#include "ui/display/screen.h"

namespace content {

ScreenChangeMonitor::ScreenChangeMonitor(
    base::RepeatingCallback<void(bool)> callback)
    : callback_(callback) {
  if (display::Screen* screen = display::Screen::Get()) {
    cached_displays_ = screen->GetAllDisplays();
  }
}

ScreenChangeMonitor::~ScreenChangeMonitor() = default;

void ScreenChangeMonitor::OnScreensChange() {
  if (display::Screen* screen = display::Screen::Get()) {
    const auto& displays = screen->GetAllDisplays();
    if (cached_displays_ == displays)
      return;

    const bool is_multi_screen_changed =
        (cached_displays_.size() > 1) != (displays.size() > 1);
    cached_displays_ = displays;
    callback_.Run(is_multi_screen_changed);
  }
}

void ScreenChangeMonitor::OnDisplayAdded(const display::Display& new_display) {
  OnScreensChange();
}

void ScreenChangeMonitor::OnDisplaysRemoved(
    const display::Displays& /*removed_displays*/) {
  OnScreensChange();
}

void ScreenChangeMonitor::OnDisplayMetricsChanged(
    const display::Display& display,
    uint32_t changed_metrics) {
  // TODO(msw): Use the |changed_metrics| parameter to disregard some changes.
  OnScreensChange();
}

}  // namespace content