using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class TalentTreeUI : MonoBehaviour
{
    public TalentManager manager;
    public PlayerStats playerStats;

    [Header("Tree")]
    public GameObject panelRoot;
    public RectTransform lineRoot;
    public RectTransform nodesRoot;
    public TalentNodeUI nodePrefab;
    public TalentTooltipUI tooltip;

    [Header("Panels")]
    public Text titleText;
    public Text pointsText;
    public Text controlsText;
    public StatsPanelUI statsPanel;

    [Header("Buttons")]
    public Button saveButton;
    public Button loadButton;
    public Button resetButton;

    public bool openOnStart;

    private readonly List<TalentNodeUI> nodes = new List<TalentNodeUI>();
    private readonly List<LineConnectorUI> lines = new List<LineConnectorUI>();
    private bool isOpen;

    private void Awake()
    {
        if (manager == null)
        {
            manager = FindObjectOfType<TalentManager>();
        }

        if (playerStats == null)
        {
            playerStats = FindObjectOfType<PlayerStats>();
        }
    }

    private void OnEnable()
    {
        if (manager != null)
        {
            manager.OnTalentStateChanged += Refresh;
        }
    }

    private void OnDisable()
    {
        if (manager != null)
        {
            manager.OnTalentStateChanged -= Refresh;
        }
    }

    private void Start()
    {
        BindButtons();
        BuildTree();
        Refresh();
        SetOpen(openOnStart);
    }

    private void Update()
    {
        if (Input.GetKeyDown(KeyCode.K))
        {
            Toggle();
        }
    }

    public void Toggle()
    {
        SetOpen(!isOpen);
    }

    public void SetOpen(bool open)
    {
        isOpen = open;
        if (panelRoot != null)
        {
            panelRoot.SetActive(open);
        }

        if (open)
        {
            Refresh();
            UpdateLines();
        }
    }

    public void BuildTree()
    {
        ClearChildren(nodesRoot);
        ClearChildren(lineRoot);
        nodes.Clear();
        lines.Clear();

        if (manager == null || nodePrefab == null || nodesRoot == null)
        {
            return;
        }

        Dictionary<TalentData, TalentNodeUI> nodeByTalent = new Dictionary<TalentData, TalentNodeUI>();
        for (int i = 0; i < manager.allTalents.Count; i++)
        {
            TalentData talent = manager.allTalents[i];
            if (talent == null)
            {
                continue;
            }

            TalentNodeUI node = Instantiate(nodePrefab, nodesRoot);
            node.gameObject.SetActive(true);
            node.tooltip = tooltip;
            node.Setup(talent, manager);

            RectTransform rectTransform = node.transform as RectTransform;
            if (rectTransform != null)
            {
                rectTransform.anchoredPosition = talent.treePosition;
            }

            nodes.Add(node);
            nodeByTalent[talent] = node;
        }

        if (lineRoot == null)
        {
            return;
        }

        for (int i = 0; i < manager.allTalents.Count; i++)
        {
            TalentData talent = manager.allTalents[i];
            if (talent == null || talent.prerequisites == null)
            {
                continue;
            }

            for (int prerequisiteIndex = 0; prerequisiteIndex < talent.prerequisites.Length; prerequisiteIndex++)
            {
                TalentData prerequisite = talent.prerequisites[prerequisiteIndex];
                if (prerequisite == null || !nodeByTalent.ContainsKey(prerequisite) || !nodeByTalent.ContainsKey(talent))
                {
                    continue;
                }

                LineConnectorUI line = CreateLine(lineRoot, prerequisite, nodeByTalent[prerequisite], nodeByTalent[talent]);
                lines.Add(line);
            }
        }

        UpdateLines();
    }

    public void Refresh()
    {
        if (titleText != null)
        {
            titleText.text = "Дерево талантов";
        }

        if (pointsText != null)
        {
            int points = manager != null ? manager.GetAvailableTalentPoints() : 0;
            pointsText.text = $"Очки талантов: {points}";
        }

        if (controlsText != null)
        {
            controlsText.text = "K - дерево   X - +50 XP   T - +1 очко   E - кристалл   F5 - сохранить   F9 - загрузить   Backspace - сброс";
        }

        for (int i = 0; i < nodes.Count; i++)
        {
            if (nodes[i] != null)
            {
                nodes[i].Refresh();
            }
        }

        if (statsPanel != null)
        {
            statsPanel.Refresh();
        }

        UpdateLines();
    }

    private void BindButtons()
    {
        if (saveButton != null)
        {
            saveButton.onClick.RemoveAllListeners();
            saveButton.onClick.AddListener(() =>
            {
                if (manager != null)
                {
                    manager.SaveProgress();
                }
            });
        }

        if (loadButton != null)
        {
            loadButton.onClick.RemoveAllListeners();
            loadButton.onClick.AddListener(() =>
            {
                if (manager != null)
                {
                    manager.LoadProgress();
                }
            });
        }

        if (resetButton != null)
        {
            resetButton.onClick.RemoveAllListeners();
            resetButton.onClick.AddListener(() =>
            {
                if (manager != null)
                {
                    manager.ResetProgress();
                }
            });
        }
    }

    private LineConnectorUI CreateLine(RectTransform parent, TalentData childTalent, TalentNodeUI startNode, TalentNodeUI endNode)
    {
        GameObject lineObject = new GameObject($"Line_{startNode.talent.talentId}_to_{childTalent.talentId}", typeof(RectTransform), typeof(Image), typeof(LineConnectorUI));
        lineObject.transform.SetParent(parent, false);

        Image image = lineObject.GetComponent<Image>();
        Color color = childTalent.branchColor;
        image.color = new Color(color.r, color.g, color.b, 0.72f);
        image.raycastTarget = false;

        LineConnectorUI connector = lineObject.GetComponent<LineConnectorUI>();
        connector.lineImage = image;
        connector.thickness = 5f;
        connector.dynamicUpdate = true;
        connector.SetEndpoints(startNode.transform as RectTransform, endNode.transform as RectTransform);
        return connector;
    }

    private void UpdateLines()
    {
        Canvas.ForceUpdateCanvases();
        for (int i = 0; i < lines.Count; i++)
        {
            if (lines[i] != null)
            {
                lines[i].UpdateLine();
            }
        }
    }

    private void ClearChildren(RectTransform root)
    {
        if (root == null)
        {
            return;
        }

        for (int i = root.childCount - 1; i >= 0; i--)
        {
            Destroy(root.GetChild(i).gameObject);
        }
    }
}