QuestManager

using UnityEngine;
using System.Collections.Generic;

public class QuestManager : MonoBehaviour
{
    public static QuestManager Instance;
    public List<Quest> allQuests = new List<Quest>(); // All available quests in the game
    public List<Quest> activeQuests = new List<Quest>();
    public List<Quest> completedQuests = new List<Quest>();

    private void Awake()
    {
        if (Instance == null)
        {
            Instance = this;
            DontDestroyOnLoad(gameObject);
        }
        else
        {
            Destroy(gameObject);
        }
    }

    public void AddActiveQuest(Quest quest)
    {
        activeQuests.Add(quest);
    }

    public void MarkQuestCompleted(Quest quest)
    {
        activeQuests.Remove(quest);
        completedQuests.Add(quest);
    }

    public QuestSaveData GetSaveData()
    {
        QuestSaveData data = new QuestSaveData();
        data.activeQuestIds = activeQuests.ConvertAll(q => q.questId);
        data.completedQuestIds = completedQuests.ConvertAll(q => q.questId);
        return data;
    }

    public void LoadSaveData(QuestSaveData data)
    {
        activeQuests.Clear();
        completedQuests.Clear();

        foreach (string questId in data.activeQuestIds)
        {
            Quest quest = allQuests.Find(q => q.questId == questId);
            if (quest != null)
            {
                activeQuests.Add(quest);
            }
        }

        foreach (string questId in data.completedQuestIds)
        {
            Quest quest = allQuests.Find(q => q.questId == questId);
            if (quest != null)
            {
                completedQuests.Add(quest);
            }
        }
    }
}

[System.Serializable]
public class QuestSaveData
{
    public List<string> activeQuestIds;
    public List<string> completedQuestIds;
}