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

namespace GameFramework
{
    /// <summary>
    /// 单条玩家得分记录。
    /// </summary>
    [Serializable]
    public class PlayerScore
    {
        public int score;
        public string playerName;

        public PlayerScore(int score, string playerName)
        {
            this.score = score;
            this.playerName = playerName;
        }
    }

    /// <summary>
    /// 可序列化的玩家得分列表（用于 JSON 存档）。
    /// </summary>
    [Serializable]
    public class PlayerScoreData
    {
        public List<PlayerScore> list = new List<PlayerScore>();
    }

    /// <summary>
    /// 得分管理器（持久单例）。
    /// 维护当前局得分，通过事件通知 UI，并管理 Top-10 排行榜存档。
    /// </summary>
    public class ScoreManager : PersistentSingleton<ScoreManager>
    {
        const int LEADERBOARD_SIZE = 10;
        const string SAVE_FILE = "leaderboard.json";

        // 当前局得分
        int currentScore = 0;

        // 当得分变化时触发，参数为最新得分（动画过程中的中间值也会触发）
        public static event Action<int> onScoreChanged;
        // 当得分完成最终增加时触发，参数为最终得分
        public static event Action<int> onScoreSettled;

        /// <summary>当前得分（只读）。</summary>
        public int CurrentScore => currentScore;

        /// <summary>默认玩家名，可在 Inspector 设置。</summary>
        [SerializeField] string defaultPlayerName = "Player";

        protected override void Awake()
        {
            base.Awake();
            if (Instance != this) return;
            currentScore = 0;
        }

        /// <summary>
        /// 增加得分（带数字滚动动画）。
        /// </summary>
        public void AddScore(int amount)
        {
            if (amount <= 0) return;
            StartCoroutine(ScoreCountUpCoroutine(currentScore, currentScore + amount));
        }

        /// <summary>
        /// 直接设置得分（无动画）。
        /// </summary>
        public void SetScore(int value)
        {
            currentScore = Mathf.Max(0, value);
            onScoreChanged?.Invoke(currentScore);
            onScoreSettled?.Invoke(currentScore);
        }

        /// <summary>
        /// 重置当前局得分。
        /// </summary>
        public void ResetScore()
        {
            currentScore = 0;
            onScoreChanged?.Invoke(0);
            onScoreSettled?.Invoke(0);
        }

        IEnumerator ScoreCountUpCoroutine(int from, int to)
        {
            currentScore = to;
            float duration = 0.5f;
            float elapsed = 0f;

            while (elapsed < duration)
            {
                elapsed += Time.unscaledDeltaTime;
                float t = Mathf.Clamp01(elapsed / duration);
                int display = Mathf.RoundToInt(Mathf.Lerp(from, to, t));
                onScoreChanged?.Invoke(display);
                yield return null;
            }

            onScoreChanged?.Invoke(to);
            onScoreSettled?.Invoke(to);
        }

        #region 排行榜
        /// <summary>
        /// 当前得分是否能进入排行榜 Top-10。
        /// </summary>
        public bool HasNewHighScore
        {
            get
            {
                var data = LoadPlayerScoreData();
                if (data.list.Count < LEADERBOARD_SIZE)
                    return true;
                return currentScore > data.list[LEADERBOARD_SIZE - 1].score;
            }
        }

        /// <summary>
        /// 将当前得分以指定名字保存到排行榜。
        /// 排行榜按分数降序排列，只保留 Top-10。
        /// </summary>
        public void SavePlayerScore(string playerName)
        {
            if (string.IsNullOrEmpty(playerName))
                playerName = defaultPlayerName;

            var data = LoadPlayerScoreData();
            data.list.Add(new PlayerScore(currentScore, playerName));
            data.list.Sort((a, b) => b.score.CompareTo(a.score));
            if (data.list.Count > LEADERBOARD_SIZE)
                data.list.RemoveRange(LEADERBOARD_SIZE, data.list.Count - LEADERBOARD_SIZE);
            SaveSystem.Save(SAVE_FILE, data);
        }

        /// <summary>
        /// 读取排行榜数据。
        /// </summary>
        public PlayerScoreData LoadPlayerScoreData()
        {
            if (SaveSystem.SaveFileExists(SAVE_FILE))
                return SaveSystem.Load<PlayerScoreData>(SAVE_FILE);
            return new PlayerScoreData();
        }

        /// <summary>
        /// 清空排行榜存档。
        /// </summary>
        public void ClearLeaderboard()
        {
            SaveSystem.DeleteSaveFile(SAVE_FILE);
        }
        #endregion
    }
}