using System;
using System.Collections.Generic;
using System.Linq;
using Godot;
using Learn.Models;

namespace Learn.Component;

public partial class NodeInfoEditPanel : Tree
{
	public event Action OnNodeInfoEdited;
	
	private IEnumerable<TreeNode> _nodes;
	private ItemGroup _itemGroup;

	private readonly Dictionary<TreeItem, string> _nodeKeys = new ();
	private readonly HashSet<TreeItem> _selectingNodes = new ();
	
	#region Columns Definitions
	private const int KeyColumn = 0;
	private const int ValueColumn = 1;
	#endregion
	
	public override void _Ready()
	{
		Columns = 2;
		SetColumnTitlesVisible(true);
		
		SetColumnTitle(KeyColumn, "键");
		SetColumnCustomMinimumWidth(KeyColumn, 100);
		SetColumnExpand(KeyColumn, false);
		
		SetColumnTitle(ValueColumn, "值");
		SetColumnExpand(ValueColumn, true);

		ItemEdited += OnItemEdited;
		MultiSelected += OnMultiSelected;
	}
	
	private void OnMultiSelected(TreeItem item, long column, bool selected)
	{
		for (int i = 0; i < Columns; i++)
		{
			if (i == column ? selected : item.IsSelected(i))
			{
				_selectingNodes.Add(item);
				return;
			}
		}
		_selectingNodes.Remove(item);
	}
	
	private void OnItemEdited()
	{
		var node = GetEdited();
		var prevKey = _nodeKeys[node];
		var currentKey = node.GetText(KeyColumn);
		var value = node.GetText(ValueColumn);
		if (prevKey != currentKey)
		{
			_itemGroup.Remove(prevKey);
		}
		_itemGroup.SetValue(currentKey, value);
		OnNodeInfoEdited?.Invoke();
	}

	public void SetNodes(IEnumerable<TreeNode> nodes)
	{
		if (nodes == null)
		{
			_nodes = null;
			_itemGroup = null;
		}
		else
		{
			_nodes = nodes;
			_itemGroup = new ItemGroup(_nodes.Select(node => node.Info).ToList());
		}
		OnNodesChanged();
	}
	
	public void OnNodesChanged()
	{
		Clear();
		_nodeKeys.Clear();
		_selectingNodes.Clear();
		if (_itemGroup == null) return;
		var root = CreateItem();
		foreach (var key in _itemGroup.GetKeys())
		{
			if(!_itemGroup.TryGetValue(key, out var value, out var isSame)) continue;
			var node = CreateItem(root);
			
			node.SetText(KeyColumn, key);
			node.SetText(ValueColumn, isSame ? value : "-");
			node.SetEditable(KeyColumn, true);
			node.SetEditable(ValueColumn, true);
			_nodeKeys.Add(node, key);
		}
		OnNodeInfoEdited?.Invoke();
	}

	public void AddKeyValue()
	{
		if(_itemGroup == null) return;
		var newFieldName = "newField";
		int index = 0;
		while (!_itemGroup.TryAdd(newFieldName + (index == 0 ? "" : index.ToString()), ""))
		{
			index += 1;
		}
		OnNodesChanged();
	}

	public void RemoveKeyValue()
	{
		if(_itemGroup == null) return;
		
		var root = GetRoot();
		foreach (var node in _selectingNodes)
		{
			_itemGroup.Remove(_nodeKeys[node]);
			root.RemoveChild(node);
		}
		_selectingNodes.Clear();
		OnNodeInfoEdited?.Invoke();
	}
}