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

public class MathQuizManager : MonoBehaviour
{
    [Header("UI")]
    [SerializeField] private TextMeshProUGUI questionText;
    [SerializeField] private TextMeshProUGUI coinText;
    [SerializeField] private GameObject answerPrefab;

    [Header("参数")]
    [SerializeField] private float wrongPenalty = 0.1f;
    [SerializeField] private int correctReward = 10;
    [SerializeField] private float answerLife = 15f;
    [SerializeField] private float floatSpeed = 0.3f;
    [SerializeField] private float correctBoost = 0.2f;
    [SerializeField] private float boostTime = 5f;
    [SerializeField] private float spawnRadius = 3f;
    [SerializeField] private float minSpawnDist = 1.5f;
    [SerializeField] private int maxAnswers = 6;
    [SerializeField] private float correctChance = 0.3f;

    private int currentAnswer;
    private int coins;
    private List<Warrior> penalized = new();
    private List<AnswerOption> answers = new();
    private Vector3 lastEnemyPos;
    private int deathCount = 0;

    void Start() { NewProblem(); UpdateCoin(); }

    void NewProblem()
    {
        int a = Random.Range(1, 11), b = Random.Range(1, 11);
        if (Random.value < 0.5f) // 加法
        {
            currentAnswer = a + b;
            questionText.text = $"{a} + {b} = ?";
        }
        else // 减法
        {
            if (b > a) (a, b) = (b, a);
            currentAnswer = a - b;
            questionText.text = $"{a} - {b} = ?";
        }
    }

    public bool CheckAnswer(AnswerOption opt)
    {
        bool correct = opt.GetAnswerValue() == currentAnswer;
        if (correct) OnCorrect();
        else OnWrong(opt);
        return correct;
    }

    void OnCorrect()
    {
        coins += correctReward;
        UpdateCoin();
        ResetPenalties();
        ClearAnswers();
        NewProblem();
    }

    void OnWrong(AnswerOption opt)
    {
        ApplyPenalty();
        RemoveAnswer(opt);
        Destroy(opt.gameObject);
    }

    void ClearAnswers()
    {
        foreach (var a in answers) if (a) Destroy(a.gameObject);
        answers.Clear();
    }

    public void RemoveAnswer(AnswerOption a) => answers.Remove(a);

    void UpdateCoin() => coinText.text = coins.ToString();

    void ApplyPenalty()
    {
        foreach (var w in FindObjectsOfType<Warrior>())
            if (!w.IsEnemy && !penalized.Contains(w))
            {
                w.ApplyDamagePenalty(wrongPenalty);
                penalized.Add(w);
            }
    }

    void ResetPenalties()
    {
        foreach (var w in penalized) if (w) w.ResetDamagePenalty();
        penalized.Clear();
    }

    public void OnEnemyDeath(Vector3 pos, int _)
    {
        lastEnemyPos = pos;
        if (++deathCount >= 2)
        {
            SpawnAnswer();
            deathCount = 0;
        }
    }

    void SpawnAnswer()
    {
        if (answers.Count >= maxAnswers) RemoveOldest();
        int val = Random.value < correctChance ? currentAnswer : Mathf.Clamp(currentAnswer + Random.Range(-3, 4), 1, 20);
        Vector3 p = lastEnemyPos + Quaternion.Euler(0, Random.Range(0, 360f), 0) * (Vector3.forward * Random.Range(minSpawnDist, spawnRadius));
        var obj = Instantiate(answerPrefab, p, Quaternion.identity);
        var opt = obj.GetComponent<AnswerOption>();
        if (opt)
        {
            opt.Initialize(this, val, val == currentAnswer);
            answers.Add(opt);
        }
        else
        {
            Destroy(obj);
        }
        // 新手引导
        if (!PlayerPrefs.HasKey("FirstQuizTutorial"))
        {
            PlayerPrefs.SetInt("FirstQuizTutorial", 1);
            var tut = FindObjectOfType<Tutorial>();
            if (tut) tut.ShowQuizTutorial(answerPrefab.transform);
        }
    }

    void RemoveOldest()
    {
        if (answers.Count > 0)
        {
            var oldest = answers[0];
            answers.RemoveAt(0);
            if (oldest) Destroy(oldest.gameObject);
        }
    }
}