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

public class DialogueUI : MonoBehaviour
{
    [Header("References")]
    public CanvasGroup root;                // Whole dialogue panel
    public TMP_Text speakerNameText;
    public Image speakerPortraitImage;
    public TMP_Text bodyText;

    [Header("Choices")]
    public Transform choicesParent;
    public Button choiceButtonPrefab;

    [Header("Typing")]
    [Range(0.005f, 0.1f)] public float charDelay = 0.02f;

    string _targetFull;
    bool _completeThisFrame;

    void Reset()
    {
        root = GetComponent<CanvasGroup>();
    }

    public void Show(bool on)
    {
        if (!root) return;
        root.alpha = on ? 1f : 0f;
        root.interactable = on;
        root.blocksRaycasts = on;

        if (!on)
        {
            bodyText?.SetText(string.Empty);
            HideChoices();
        }
    }

    public void BindSpeaker(string speakerName, Sprite portrait)
    {
        if (speakerNameText) speakerNameText.text = speakerName ?? "";
        if (speakerPortraitImage)
        {
            speakerPortraitImage.sprite = portrait;
            speakerPortraitImage.enabled = portrait != null;
        }
    }

    public IEnumerator TypeText(string text)
    {
        _targetFull = text ?? string.Empty;
        bodyText.text = string.Empty;
        _completeThisFrame = false;

        foreach (char c in _targetFull)
        {
            if (_completeThisFrame) break;
            bodyText.text += c;
            yield return new WaitForSeconds(charDelay);
        }

        bodyText.text = _targetFull;
        _completeThisFrame = false;
    }

    public void CompleteTypeThisFrame()
    {
        _completeThisFrame = true;
    }

    public List<DialogueAsset.Choice> BuildVisibleChoices(
        List<DialogueAsset.Choice> all,
        HashSet<string> flags)
    {
        var list = new List<DialogueAsset.Choice>();
        if (all == null) return list;

        foreach (var c in all)
        {
            if (string.IsNullOrEmpty(c.requireFlag) || flags.Contains(c.requireFlag))
                list.Add(c);
        }
        return list;
    }

    public void ShowChoices(
        List<DialogueAsset.Choice> choices,
        Action<DialogueAsset.Choice> onPick)
    {
        HideChoices();

        foreach (var c in choices)
        {
            var btn = Instantiate(choiceButtonPrefab, choicesParent);
            var label = btn.GetComponentInChildren<TMP_Text>();
            if (label) label.text = c.text;

            btn.onClick.AddListener(() => onPick?.Invoke(c));
        }
    }

    public void HideChoices()
    {
        if (!choicesParent) return;
        for (int i = choicesParent.childCount - 1; i >= 0; i--)
            Destroy(choicesParent.GetChild(i).gameObject);
    }
}