using Avalonia;
using Avalonia.Collections;
using Avalonia.Controls;
using Avalonia.Controls.Selection;
using Avalonia.Media;
using Mesen.Config;
using Mesen.Debugger.Labels;
using Mesen.Debugger.Utilities;
using Mesen.Debugger.Windows;
using Mesen.Interop;
using Mesen.Utilities;
using Mesen.ViewModels;
using ReactiveUI.Fody.Helpers;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;

namespace Mesen.Debugger.ViewModels
{
	public class CallStackViewModel : DisposableViewModel
	{
		public CpuType CpuType { get; }
		public DebuggerWindowViewModel Debugger { get; }

		[Reactive] public MesenList<StackInfo> CallStackContent { get; private set; } = new();
		[Reactive] public SelectionModel<StackInfo?> Selection { get; set; } = new();
		public List<int> ColumnWidths { get; } = ConfigManager.Config.Debug.Debugger.CallStackColumnWidths;

		private StackFrameInfo[] _stackFrames = Array.Empty<StackFrameInfo>();

		[Obsolete("For designer only")]
		public CallStackViewModel() : this(CpuType.Snes, new()) { }

		public CallStackViewModel(CpuType cpuType, DebuggerWindowViewModel debugger)
		{
			Debugger = debugger;
			CpuType = cpuType;
		}

		public void UpdateCallStack()
		{
			_stackFrames = DebugApi.GetCallstack(CpuType);
			RefreshCallStack();
		}

		public void RefreshCallStack()
		{
			CallStackContent.Replace(GetStackInfo());
		}

		private List<StackInfo> GetStackInfo()
		{
			StackFrameInfo[] stackFrames = _stackFrames;

			List<StackInfo> stack = new List<StackInfo>();
			for(int i = 0; i < stackFrames.Length; i++) {
				bool isMapped = DebugApi.GetRelativeAddress(stackFrames[i].AbsSource, CpuType).Address >= 0;
				stack.Insert(0, new StackInfo() {
					EntryPoint = GetEntryPoint(i == 0 ? null : stackFrames[i - 1]),
					EntryPointAddr = i == 0 ? null : stackFrames[i - 1].AbsTarget,
					RelAddress = stackFrames[i].Source,
					Address = stackFrames[i].AbsSource,
					RowBrush = isMapped ? AvaloniaProperty.UnsetValue : Brushes.Gray,
					RowStyle = isMapped ? FontStyle.Normal : FontStyle.Italic
				});
			}

			//Add current location
			stack.Insert(0, new StackInfo() {
				EntryPoint = GetEntryPoint(stackFrames.Length > 0 ? stackFrames[^1] : null),
				EntryPointAddr = stackFrames.Length > 0 ? stackFrames[^1].AbsTarget : null,
				RelAddress = DebugApi.GetProgramCounter(CpuType, true),
				Address = DebugApi.GetAbsoluteAddress(new AddressInfo() { Address = (int)DebugApi.GetProgramCounter(CpuType, true), Type = CpuType.ToMemoryType() })
			});

			return stack;
		}

		private string GetEntryPoint(StackFrameInfo? stackFrame)
		{
			if(stackFrame == null) {
				return "[bottom of stack]";
			}

			StackFrameInfo entry = stackFrame.Value;

			string format = "X" + CpuType.GetAddressSize();
			CodeLabel? label = entry.AbsTarget.Address >= 0 ? LabelManager.GetLabel(entry.AbsTarget) : null;
			if(label != null) {
				return label.Label + " ($" + entry.Target.ToString(format) + ")";
			} else if(entry.Flags == StackFrameFlags.Nmi) {
				return "[nmi] $" + entry.Target.ToString(format);
			} else if(entry.Flags == StackFrameFlags.Irq) {
				return "[irq] $" + entry.Target.ToString(format);
			}

			return "$" + entry.Target.ToString(format);
		}

		private bool IsMapped(StackInfo entry)
		{
			return DebugApi.GetRelativeAddress(entry.Address, CpuType).Address >= 0;
		}

		public void GoToLocation(StackInfo entry)
		{
			if(IsMapped(entry)) {
				Debugger.ScrollToAddress((int)entry.RelAddress);
			}
		}

		public void InitContextMenu(Control parent)
		{
			AddDisposables(DebugShortcutManager.CreateContextMenu(parent, new object[] {
				new ContextMenuAction() {
					ActionType = ActionType.EditLabel,
					Shortcut = () => ConfigManager.Config.Debug.Shortcuts.Get(DebuggerShortcut.CallStack_EditLabel),
					IsEnabled = () => Selection.SelectedItem is StackInfo entry && entry.EntryPointAddr != null,
					OnClick = () => {
						if(Selection.SelectedItem is StackInfo entry && entry.EntryPointAddr != null) {
							AddressInfo addr = entry.EntryPointAddr.Value;
							CodeLabel? label = LabelManager.GetLabel((uint)addr.Address, addr.Type);
							if(label == null) {
								label = new CodeLabel() {
									Address = (uint)entry.EntryPointAddr.Value.Address,
									MemoryType = entry.EntryPointAddr.Value.Type
								};
							}
							LabelEditWindow.EditLabel(CpuType, parent, label);
						}
					}
				},

				new ContextMenuAction() {
					ActionType = ActionType.GoToLocation,
					Shortcut = () => ConfigManager.Config.Debug.Shortcuts.Get(DebuggerShortcut.CallStack_GoToLocation),
					IsEnabled = () => Selection.SelectedItem is StackInfo entry && IsMapped(entry),
					OnClick = () => {
						if(Selection.SelectedItem is StackInfo entry) {
							GoToLocation(entry);
						}
					}
				},
			}));
		}
	}

	public class StackInfo
	{
		public string EntryPoint { get; set; } = "";

		public string PcAddress => $"${RelAddress:X4}";

		public string AbsAddress
		{
			get
			{
				if(Address.Address >= 0) {
					return $"${Address.Address:X4} [{Address.Type.GetShortName()}]";
				} else {
					return "";
				}
			}
		}

		public AddressInfo? EntryPointAddr { get; set; }

		public UInt32 RelAddress { get; set; }
		public AddressInfo Address { get; set; }

		public object RowBrush { get; set; } = AvaloniaProperty.UnsetValue;
		public FontStyle RowStyle { get; set; }
	}
}