@using Sandbox.UI

@namespace sGBA

@inherits PanelComponent

<root class="@(IsVisible ? "visible" : "") @(_showConfirmDialog ? "confirm-open" : "") @(_showSavingDialog ? "saving-open" : "") @(InNetworkedSession ? "networked" : "")">
	<div class="overlay">
		<div class="menu-container">
			<div class="menu-left @(_inSlotPanel ? "in-slots" : "")">
				@for (int i = 0; i < ActiveMenuItems.Length; i++)
				{
					var idx = i;
					<div class="menu-item @(idx == _selectedIndex ? "selected" : "")" onmouseenter=@(() => SelectItem(idx)) onclick=@(() => ActivateItemWithMouse(idx))>
						@ActiveMenuItems[idx]
					</div>
				}
			</div>
			<div class="menu-divider @(HasSlotPanel ? "visible" : "")"></div>
			<div class="menu-right @(HasSlotPanel ? "visible" : "")">
				@for (int i = 1; i <= GbaSerialize.SlotCount; i++)
				{
					var slot = i;
					<div class="slot @(slot == _highlightedSlot && HasSlotPanel ? "highlighted" : "")" onmouseenter=@(() => SelectSlotWithMouse(slot)) onclick=@(() => ActivateSlotWithMouse(slot))>
						<div class="slot-preview">
							@if (SlotTextures[slot - 1] != null)
							{
								<Image Texture=@SlotTextures[slot - 1] />
							}
							else
							{
								<span>#pause.slot.empty</span>
							}
						</div>
						<div class="slot-info">
							<div class="slot-label"><span>#pause.slot.label</span><span>@slot</span></div>
							@if (SlotTimestamps[slot - 1] != null)
							{
								<div class="slot-timestamp">@SlotTimestamps[slot - 1].Value.ToString("dd/MM/yyyy - HH:mm")</div>
							}
						</div>
					</div>
				}
			</div>
		</div>
	</div>

	<div class="dialog-overlay @(_showConfirmDialog ? "visible" : "")">
		<div class="confirm-box">
			<div class="dialog-message">#pause.confirm.message</div>
			<div class="confirm-buttons">
				<div class="confirm-btn @(_confirmSelection == 0 ? "selected" : "")" onmouseenter=@(() => SelectConfirmWithMouse(0)) onclick=@(() => ConfirmOverwriteWithMouse())>#pause.confirm.yes</div>
				<div class="confirm-btn @(_confirmSelection == 1 ? "selected" : "")" onmouseenter=@(() => SelectConfirmWithMouse(1)) onclick=@(() => CancelOverwriteWithMouse())>#pause.confirm.no</div>
			</div>
		</div>
	</div>

	<div class="dialog-overlay @(_showSavingDialog ? "visible" : "")">
		<div class="dialog-box">
			<div class="dialog-message">#pause.saving</div>
		</div>
	</div>
</root>

@code
{
	private const int MenuContinue = 0;
	private const int MenuLoad = 1;
	private const int MenuCreate = 2;
	private const int MenuControls = 3;
	private const int MenuReset = 4;
	private const int MenuGoToHome = 5;

	private readonly string[] MenuItems =
	[
		"#pause.continue",
		"#pause.load",
		"#pause.create",
		"#pause.controls",
		"#pause.reset",
		"#pause.home"
	];

	private static readonly string[] ClientMenuItems =
	[
		"#pause.continue",
		"#pause.controls",
		"#pause.home"
	];

	private static bool InNetworkedSession => NetworkManager.Current?.IsActive == true;
	private string[] ActiveMenuItems => InNetworkedSession ? ClientMenuItems : MenuItems;

	public bool IsVisible { get; private set; }
	private int _selectedIndex;
	private string SelectedKey => _selectedIndex >= 0 && _selectedIndex < ActiveMenuItems.Length ? ActiveMenuItems[_selectedIndex] : null;
	private bool HasSlotPanel => SelectedKey is "#pause.load" or "#pause.create";
	private bool IsLoadMode => SelectedKey == "#pause.load";

	private bool _inSlotPanel;
	private int _highlightedSlot = 1;

	private readonly Texture[] SlotTextures = new Texture[GbaSerialize.SlotCount];
	private readonly bool[] SlotOccupied = new bool[GbaSerialize.SlotCount];
	private readonly DateTime?[] SlotTimestamps = new DateTime?[GbaSerialize.SlotCount];
	private int _slotVersion;

	private bool _showConfirmDialog;
	private int _confirmSelection;
	private int _pendingOverwriteSlot;
	private bool _showSavingDialog;

	private readonly FocusInput _input = new();

	protected override void OnUpdate()
	{
		if (!EmulatorComponent.Current.IsValid() || !EmulatorComponent.Current.IsReady)
			return;

		if (Input.EscapePressed)
		{
			Input.EscapePressed = false;

			if (IsVisible && !new Game.Overlay().IsOpen)
				Resume();
			else if (!IsVisible)
				Pause();

			return;
		}

		if (!IsVisible) return;
		if (new Game.Overlay().IsOpen) return;

		if (_showConfirmDialog)
		{
			HandleConfirmInput();
			return;
		}

		if (_showSavingDialog) return;

		var nav = _input.TickRepeating();

		if (nav.Up) NavigateUp();
		if (nav.Down) NavigateDown();

		if (nav.Right)
		{
			if (!_inSlotPanel && HasSlotPanel)
				EnterSlotPanel();
		}

		if (nav.Left)
		{
			if (_inSlotPanel)
				ExitSlotPanel();
		}

		if (Input.Pressed("GBA_A"))
		{
			SetGamepadMode();
			Sound.Play("ui.button.press");

			if (_inSlotPanel)
				ActivateSlot(_highlightedSlot);
			else if (HasSlotPanel)
				EnterSlotPanel();
			else
				ActivateItem(_selectedIndex);
		}

		if (Input.Pressed("GBA_B"))
		{
			SetGamepadMode();
			Sound.Play("ui.button.press");

			if (_inSlotPanel)
				ExitSlotPanel();
			else
				Resume();
		}
	}

	private void SetGamepadMode() => _input.ForceGamepadMode();

	private void NavigateUp()
	{
		SetGamepadMode();
		Sound.Play("ui.button.over");

		if (_inSlotPanel)
			_highlightedSlot = _highlightedSlot <= 1 ? GbaSerialize.SlotCount : _highlightedSlot - 1;
		else
			_selectedIndex = _selectedIndex <= 0 ? ActiveMenuItems.Length - 1 : _selectedIndex - 1;
	}

	private void NavigateDown()
	{
		SetGamepadMode();
		Sound.Play("ui.button.over");

		if (_inSlotPanel)
			_highlightedSlot = _highlightedSlot >= GbaSerialize.SlotCount ? 1 : _highlightedSlot + 1;
		else
			_selectedIndex = _selectedIndex >= ActiveMenuItems.Length - 1 ? 0 : _selectedIndex + 1;
	}

	private void EnterSlotPanel()
	{
		SetGamepadMode();
		Sound.Play("ui.button.press");
		_inSlotPanel = true;
		_highlightedSlot = 1;
	}

	private void ExitSlotPanel()
	{
		SetGamepadMode();
		Sound.Play("ui.button.press");
		_inSlotPanel = false;
		_selectedIndex = MenuContinue;
	}

	private void Pause()
	{
		IsVisible = true;
		_selectedIndex = 0;
		_inSlotPanel = false;
		_highlightedSlot = 1;
		_input.Begin(useGamepad: true);
		Sound.Play("ui.popup.message.open");
		EmulatorComponent.Current.SetPaused(true);
		RefreshSlotPreviews();
	}

	private void Resume()
	{
		IsVisible = false;
		_selectedIndex = MenuContinue;
		_inSlotPanel = false;
		_input.End();
		Mouse.Visibility = MouseVisibility.Hidden;
		Sound.Play("ui.popup.message.close");
		EmulatorComponent.Current.SetPaused(false);
	}

	private void SelectItem(int index)
	{
		_input.ForceMouseMode();
		_selectedIndex = index;
		_inSlotPanel = false;
		if (HasSlotPanel)
			_highlightedSlot = 1;
	}

	private void SelectSlotWithMouse(int slot)
	{
		_input.ForceMouseMode();
		_highlightedSlot = slot;
	}

	private void ActivateSlotWithMouse(int slot)
	{
		_input.ForceMouseMode();
		ActivateSlot(slot);
	}

	private void SelectConfirmWithMouse(int index)
	{
		_input.ForceMouseMode();
		_confirmSelection = index;
	}

	private void ConfirmOverwriteWithMouse()
	{
		_input.ForceMouseMode();
		ConfirmOverwrite();
	}

	private void CancelOverwriteWithMouse()
	{
		_input.ForceMouseMode();
		CancelOverwrite();
	}

	private void ActivateItem(int index)
	{
		if (index < 0 || index >= ActiveMenuItems.Length) return;

		switch (ActiveMenuItems[index])
		{
			case "#pause.continue":
				Resume();
				break;
			case "#pause.load":
			case "#pause.create":
				SelectItem(index);
				_inSlotPanel = true;
				break;
			case "#pause.controls":
				Game.Overlay.ShowBinds();
				break;
			case "#pause.reset":
				EmulatorComponent.Current.ResetEmulator();
				Resume();
				break;
			case "#pause.home":
				IsVisible = false;
				_selectedIndex = MenuContinue;
				_inSlotPanel = false;
				Mouse.Visibility = MouseVisibility.Hidden;
				Sound.Play("ui.popup.message.close");
				NetworkManager.Current?.Leave();
				HomeScreen.Current?.Show();
				break;
		}
	}

	private void ActivateItemWithMouse(int index)
	{
		_input.ForceMouseMode();
		ActivateItem(index);
	}

	private void ActivateSlot(int slot)
	{
		if (IsLoadMode)
		{
			if (!SlotOccupied[slot - 1])
				return;

			EmulatorComponent.Current.LoadSuspendPoint(slot);
			Resume();
		}
		else
		{
			if (SlotOccupied[slot - 1])
			{
				_pendingOverwriteSlot = slot;
				_confirmSelection = 0;
				_showConfirmDialog = true;
				Sound.Play("ui.popup.message.open");
				return;
			}

			DoSave(slot);
		}
	}

	private void HandleConfirmInput()
	{
		var nav = _input.TickRepeating();
		if (nav.Up || nav.Down)
		{
			SetGamepadMode();
			Sound.Play("ui.button.over");
			_confirmSelection = _confirmSelection == 0 ? 1 : 0;
		}

		if (Input.Pressed("GBA_A"))
		{
			SetGamepadMode();
			Sound.Play("ui.button.press");

			if (_confirmSelection == 0)
				ConfirmOverwrite();
			else
				CancelOverwrite();
		}

		if (Input.Pressed("GBA_B"))
		{
			SetGamepadMode();
			Sound.Play("ui.button.press");
			CancelOverwrite();
		}
	}

	private void ConfirmOverwrite()
	{
		_showConfirmDialog = false;
		DoSave(_pendingOverwriteSlot);
	}

	private void CancelOverwrite()
	{
		_showConfirmDialog = false;
		Sound.Play("ui.popup.message.close");
	}

	private async void DoSave(int slot)
	{
		_showSavingDialog = true;
		await Task.Delay(100);
		EmulatorComponent.Current.CreateSuspendPoint(slot);
		RefreshSlotPreviews();
		await Task.Delay(500);
		_showSavingDialog = false;
	}

	private void RefreshSlotPreviews()
	{
		var emu = EmulatorComponent.Current;
		if (!emu.IsValid()) return;

		for (int i = 0; i < GbaSerialize.SlotCount; i++)
		{
			var path = emu.GetStatePath(i + 1);

			if (!FileSystem.Data.FileExists(path))
			{
				ClearSlot(i);
				continue;
			}

			var data = FileSystem.Data.ReadAllBytes(path).ToArray();
			SlotOccupied[i] = true;
			SlotTimestamps[i] = GbaSerialize.ReadTimestamp(data);

			var screenshot = GbaSerialize.ReadScreenshot(data);
			if (screenshot == null) continue;

			if (SlotTextures[i] == null)
			{
				SlotTextures[i] = Texture.Create(GbaConstants.ScreenWidth, GbaConstants.ScreenHeight, ImageFormat.RGBA8888)
					.WithDynamicUsage()
					.WithName($"suspend-preview-{i}")
					.Finish();
			}

			SlotTextures[i].Update(screenshot, 0, 0, GbaConstants.ScreenWidth, GbaConstants.ScreenHeight);
		}

		_slotVersion++;
	}

	private void ClearSlot(int index)
	{
		SlotOccupied[index] = false;
		SlotTimestamps[index] = null;
		SlotTextures[index]?.Dispose();
		SlotTextures[index] = null;
	}

	protected override int BuildHash()
	{
		return HashCode.Combine(
			IsVisible, _selectedIndex, _inSlotPanel, _highlightedSlot,
			_input.UseGamepad, _slotVersion, _showConfirmDialog,
			HashCode.Combine(_confirmSelection, _showSavingDialog, InNetworkedSession)
		);
	}

	protected override void OnDestroy()
	{
		for (int i = 0; i < SlotTextures.Length; i++)
		{
			SlotTextures[i]?.Dispose();
			SlotTextures[i] = null;
		}
	}
}