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

public class ObjectiveManager : MonoBehaviour
{
    [System.Serializable]
    public class Objective
    {
        [TextArea] public string text;
        public bool completed;
    }

    public static ObjectiveManager Instance { get; private set; }

    [Header("UI")]
    public TextMeshProUGUI objectiveText;   // Assign a TMP Text in Canvas
    [Tooltip("Prefix/suffix for visual flair")]
    public string prefix = "Objective: ";
    public string completedPrefix = "✔ ";
    public string incompletePrefix = "• ";

    [Header("Data")]
    public List<Objective> objectives = new List<Objective>();
    public int activeIndex = 0;             // Which objective is currently shown
    public bool autoAdvanceOnComplete = true;
    public List<string> _queuedNextObjectives = null;
    private int _queuedNextStartIndex = 0;
    void Awake()
    {
        if (Instance != null && Instance != this) { Destroy(gameObject); return; }
        Instance = this;
    }

    void Start() => RefreshUI();

    // ----- Public API -----
    public void SetSingle(string text)
    {
        objectives.Clear();
        objectives.Add(new Objective { text = text, completed = false });
        activeIndex = 0;
        RefreshUI();
    }

    public void SetList(IEnumerable<string> list, int startIndex = 0)
    {
        objectives.Clear();
        foreach (var s in list) objectives.Add(new Objective { text = s, completed = false });
        activeIndex = Mathf.Clamp(startIndex, 0, Mathf.Max(0, objectives.Count - 1));
        RefreshUI();
    }

    public void SetActive(int index)
    {
        activeIndex = Mathf.Clamp(index, 0, Mathf.Max(0, objectives.Count - 1));
        RefreshUI();
    }

    public void MarkComplete(int index)
    {
        if (index < 0 || index >= objectives.Count) return;
        objectives[index].completed = true;

        if (autoAdvanceOnComplete && index == activeIndex)
            Advance();
        Debug.Log("Mark Completed");
        RefreshUI();
    }
    public void QueueNextList(IEnumerable<string> list, int startIndex = 0)
    {
        _queuedNextObjectives = (list != null) ? new List<string>(list) : null;
        _queuedNextStartIndex = startIndex;
    }
    public void Advance()
    {
        // If there is a next objective in the current list, just move to it.
        if (activeIndex + 1 < objectives.Count)
        {
            activeIndex++;
            RefreshUI();
            return;
        }

        // We are at (or beyond) the last item of the current list.
        // If a next list was queued, switch to it now.
        if (_queuedNextObjectives != null && _queuedNextObjectives.Count > 0)
        {
            SetList(_queuedNextObjectives, _queuedNextStartIndex);
            _queuedNextObjectives = null;
            _queuedNextStartIndex = 0;
            RefreshUI();
            return;
        }

        // No queued list—stay on the last item.
        RefreshUI();
    }

    //public void Advance()
    //{
    //    // Jump to next incomplete objective if any
    //    for (int i = activeIndex + 1; i < objectives.Count; i++)
    //    {
    //        if (!objectives[i].completed)
    //        {
    //            activeIndex = i;
    //            RefreshUI();
    //            return;
    //        }
    //    }

    //    // --- Only when EVERYTHING is completed, switch to queued next list (if any)
    //    bool allCompleted = objectives.Count == 0 || objectives.TrueForAll(o => o.completed);
    //    if (allCompleted && _queuedNextObjectives != null && _queuedNextObjectives.Count > 0)
    //    {
    //        SetList(_queuedNextObjectives, _queuedNextStartIndex);
    //        _queuedNextObjectives = null;
    //        _queuedNextStartIndex = 0;
    //        RefreshUI();
    //        return;
    //    }

    //    // Nothing left → keep last shown as completed
    //    RefreshUI();
    //}

    //public void Advance()
    //{
    //    // Jump to next incomplete objective if any
    //    for (int i = activeIndex + 1; i < objectives.Count; i++)
    //    {
    //        if (!objectives[i].completed) { activeIndex = i; RefreshUI(); return; }
    //    }
    //    // Nothing left → keep last shown as completed
    //    RefreshUI();
    //}

    public void RefreshUI()
    {
        if (objectiveText == null) return;

        if (objectives.Count == 0)
        {
            objectiveText.text = "";
            return;
        }

        var o = objectives[Mathf.Clamp(activeIndex, 0, objectives.Count - 1)];
        var statePrefix = o.completed ? completedPrefix : incompletePrefix;
        objectiveText.text = prefix + statePrefix + o.text;
    }
}