using UnityEngine;
using UnityEngine.UI;

public class DialogueUI : MonoBehaviour
{
    private const string PanelKey = "DialogueUI";

    public static DialogueUI Instance { get; private set; }

    [SerializeField] private GameObject dialoguePanel;
    [SerializeField] private Text npcNameText;
    [SerializeField] private Text dialogueText;
    [SerializeField] private Transform optionsRoot;
    [SerializeField] private Button optionButtonTemplate;
    [SerializeField] private Button closeButton;

    private NPC currentNpc;

    public bool IsOpen => dialoguePanel != null && dialoguePanel.activeSelf;

    public void Configure(
        GameObject panel,
        Text nameLabel,
        Text messageLabel,
        Transform responseRoot,
        Button responseTemplate,
        Button closePanelButton)
    {
        dialoguePanel = panel;
        npcNameText = nameLabel;
        dialogueText = messageLabel;
        optionsRoot = responseRoot;
        optionButtonTemplate = responseTemplate;
        closeButton = closePanelButton;

        if (dialoguePanel != null)
        {
            dialoguePanel.SetActive(false);
        }

        if (optionButtonTemplate != null)
        {
            optionButtonTemplate.gameObject.SetActive(false);
        }
    }

    private void Awake()
    {
        if (Instance != null && Instance != this)
        {
            Destroy(gameObject);
            return;
        }

        Instance = this;

        if (closeButton != null)
        {
            closeButton.onClick.RemoveListener(CloseDialogue);
            closeButton.onClick.AddListener(CloseDialogue);
        }
    }

    public void ShowDialogue(NPC npc)
    {
        if (npc == null || dialoguePanel == null)
        {
            return;
        }

        if (Inventory.Instance != null && Inventory.Instance.IsOpen)
        {
            Inventory.Instance.CloseInventory();
        }

        if (NoteUI.Instance != null && NoteUI.Instance.IsOpen)
        {
            NoteUI.Instance.CloseNote();
        }

        currentNpc = npc;
        npcNameText.text = npc.NPCName;
        dialogueText.text = npc.OpeningLine;
        dialoguePanel.SetActive(true);
        RebuildOptions();
        GameUIState.SetPanelOpen(PanelKey, true);
    }

    public void ShowFollowUp(string speakerName, string message)
    {
        if (dialoguePanel == null)
        {
            return;
        }

        npcNameText.text = speakerName;
        dialogueText.text = message;
        ClearOptionButtons();
        dialoguePanel.SetActive(true);
        GameUIState.SetPanelOpen(PanelKey, true);
    }

    public void CloseDialogue()
    {
        ClearOptionButtons();

        if (dialoguePanel != null)
        {
            dialoguePanel.SetActive(false);
        }

        currentNpc = null;
        GameUIState.SetPanelOpen(PanelKey, false);
    }

    private void RebuildOptions()
    {
        ClearOptionButtons();

        if (currentNpc == null || optionsRoot == null || optionButtonTemplate == null)
        {
            return;
        }

        foreach (var option in currentNpc.DialogueOptions)
        {
            var capturedOption = option;
            var optionButton = Instantiate(optionButtonTemplate, optionsRoot);
            optionButton.gameObject.SetActive(true);
            optionButton.onClick.RemoveAllListeners();
            optionButton.onClick.AddListener(() => currentNpc.SelectOption(capturedOption));
            optionButton.interactable = currentNpc.IsOptionAvailable(capturedOption);

            var label = optionButton.GetComponentInChildren<Text>();

            if (label != null)
            {
                label.text = currentNpc.GetOptionLabel(capturedOption);
                label.color = optionButton.interactable ? Color.white : new Color(0.82f, 0.82f, 0.82f, 1f);
            }
        }
    }

    private void ClearOptionButtons()
    {
        if (optionsRoot == null || optionButtonTemplate == null)
        {
            return;
        }

        for (var i = optionsRoot.childCount - 1; i >= 0; i--)
        {
            var child = optionsRoot.GetChild(i);

            if (child == optionButtonTemplate.transform)
            {
                continue;
            }

            Destroy(child.gameObject);
        }
    }
}