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

namespace Learn.Component;


public partial class MainTreePanel : Tree
{
	private readonly HashSet<string> _columns = new();
	private readonly HashSet<TreeNode> _selectingNodes = new ();
	private readonly Dictionary<TreeItem, TreeNode> _mapper = new();

	public HashSet<TreeNode> SelectingNodes => _selectingNodes;
	
	public override void _Ready()
	{
		Columns = 1;
		SetColumnTitlesVisible(true);
		
		SetColumnTitle(0, "文件名");
		SetColumnCustomMinimumWidth(0, 400);
		SetColumnExpand(0, true);
		
		MultiSelected += OnMultiSelected;
	}

	public void AddColumn(string columnName)
	{
		if (string.IsNullOrEmpty(columnName)) return;
		_columns.Add(columnName);
		UpdateColumns();
	}

	public void RemoveColumn(string columnName)
	{
		if (string.IsNullOrEmpty(columnName)) return;
		_columns.Remove(columnName);
		UpdateColumns();
	}

	public void UpdateColumns()
	{
		Columns = _columns.Count + 1;
		int index = 1;
		foreach (var column in _columns)
		{
			SetColumnTitle(index, column);
			SetColumnCustomMinimumWidth(index, 200);
			SetColumnExpand(index, true);
			index += 1;
		}

		foreach (var kv in _mapper)
		{
			index = 1;
			foreach (var column in _columns)
			{
				if (kv.Value.TryGetValue(column, out var value, out _))
				{
					kv.Key.SetText(index, value);
				}
				else
				{
					kv.Key.SetText(index, "");
				}
				index += 1;
			}
		}
	}

	private void OnMultiSelected(TreeItem item, long column, bool selected)
	{
		if(selected) _selectingNodes.Add(_mapper[item]);
		else _selectingNodes.Remove(_mapper[item]);
	}


	private TreeItem CreateNode(TreeItem father, Item item)
	{
		var node = CreateItem(father);
        node.SetText(0, item.Info["Name"]);
        return node;
	}
	
	private Item InitItem(string path, bool isDir)
	{
		var name = Path.GetFileName(path);
		var item = new Item();
		item.Info["Name"] = name;
		item.Info["IsDir"] = isDir ? "True" : "False";
		item.Info["Path"] = path;
		return item;
	}
	
	public void Build(string path)
	{
		Clear();
		_mapper.Clear();
		_selectingNodes.Clear();
		
		TreeItem root = CreateItem();
		BuildTree(root, path);
	}
	
	private void BuildTree(TreeItem root, string path)
	{
		var nodes = new Stack<(TreeItem node, string path)>();
		_mapper[root] = new TreeNode(null);
		nodes.Push((root, path));
		while (nodes.Count > 0)
		{
			var node = nodes.Pop();
			var father = node.node;
			var fatherNode = _mapper[father];

			foreach (var filePath in Directory.GetFiles(node.path))
			{
				var item = InitItem(filePath, false);
				var childNode = new TreeNode(item);
				fatherNode.AddNode(childNode);
				var child = CreateNode(father, item);
				_mapper[child] = childNode;
			}
			
			foreach (var subDirPath in Directory.GetDirectories(node.path))
			{
				var item = InitItem(subDirPath, true);
				var childNode = new TreeNode(item);
				fatherNode.AddNode(childNode);
				var child = CreateNode(father, item);
				_mapper[child] = childNode;
				nodes.Push((child, subDirPath));
			}
		}
	}
}