using UnityEngine;
using TMPro;
using BaseGames.Core;
using BaseGames.Core.Events;
using BaseGames.Core.Save;

namespace BaseGames.Support.Speedrun
{
/// <summary>
/// 速通计时器（架构 16_SupportingModules §8）。
/// 使用 Time.unscaledDeltaTime 以免被 HitStop（timeScale &lt; 1）拉慢；游戏暂停时须由外部调用 PauseTimer()。
/// 实现 ISaveable，计时持久化到 <see cref="StatsSaveData.SpeedrunTime"/>。
/// </summary>
public class SpeedrunTimer : MonoBehaviour, ISaveable
{
    [Header("显示设置")]
    [SerializeField] private TMP_Text          _display;
    [SerializeField] private GlobalSettingsSO  _settings;

    [Header("事件频道")]
    [SerializeField] private VoidEventChannelSO _onTimerReset;
    [SerializeField] private BoolEventChannelSO _onTimerVisibilityChanged;

    public float ElapsedSeconds { get; private set; }
    public bool  IsRunning      { get; private set; }

    private bool _paused;
    /// <summary>上一帧已显示的整秒值，展示内容未变化时跳过字符串重建。</summary>
    private int  _lastDisplayedSecond = -1;

    private void Start()
    {
        bool show = _settings != null && _settings.ShowSpeedrunTimer;
        SetVisible(show);
        if (show) StartTimer();
    }

    private void Update()
    {
        if (!IsRunning || _paused) return;
        ElapsedSeconds += Time.unscaledDeltaTime;
        // 仅当整秒数发生变化时才重建展示字符串，避免每帧分配
        int currentSecond = (int)ElapsedSeconds;
        if (currentSecond != _lastDisplayedSecond)
        {
            _lastDisplayedSecond = currentSecond;
            UpdateDisplay();
        }
    }

    // ── 控制接口 ──────────────────────────────────────────────────────────────
    public void StartTimer()
    {
        IsRunning = true;
        _paused   = false;
    }

    public void StopTimer()  => IsRunning = false;

    public void PauseTimer() => _paused = true;

    public void ResumeTimer() => _paused = false;

    public void ResetTimer()
    {
        ElapsedSeconds = 0f;
        UpdateDisplay();
        _onTimerReset?.Raise();
    }

    public void SetVisible(bool visible)
    {
        if (_display != null) _display.gameObject.SetActive(visible);
        _onTimerVisibilityChanged?.Raise(visible);
    }

    // ── ISaveable ─────────────────────────────────────────────────────────────
    public void OnSave(SaveData saveData)
    {
        if (saveData?.Stats != null)
            saveData.Stats.SpeedrunTime = ElapsedSeconds;
    }

    public void OnLoad(SaveData saveData)
    {
        if (saveData?.Stats != null)
            ElapsedSeconds = saveData.Stats.SpeedrunTime;
        UpdateDisplay();
    }

    // ── 内部 ──────────────────────────────────────────────────────────────────
    private void UpdateDisplay()
    {
        if (_display == null) return;
        int hours   = (int)(ElapsedSeconds / 3600);
        int minutes = (int)(ElapsedSeconds % 3600 / 60);
        int seconds = (int)(ElapsedSeconds % 60);
        int ms      = (int)(ElapsedSeconds * 100 % 100);
        _display.text = hours > 0
            ? $"{hours:00}:{minutes:00}:{seconds:00}.{ms:00}"
            : $"{minutes:00}:{seconds:00}.{ms:00}";
    }
}
}