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;

    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();

        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;
    }
}