using UnityEngine;
using UnityEngine.UI;
using Cysharp.Threading.Tasks;
using System;
using System.Threading;

/// <summary>
/// 战斗加载界面，显示战斗资源加载进度。
/// 在战斗资源异步加载期间展示，加载完成后自动关闭。
/// </summary>
public class BattleLoadingWin : UIBase
{
    [SerializeField] private Slider m_ProgressSlider;
    [SerializeField] private Text m_ProgressText;
    [SerializeField] private Text m_TipText;

    private float _currentProgress;
    private float _targetProgress;
    private bool _isComplete;

    /// <summary>
    /// 创建 IProgress&lt;float&gt; 适配器，用于集成异步加载的进度回报。
    /// </summary>
    public IProgress<float> CreateProgressReporter()
    {
        return new BattleLoadingProgress(this);
    }

    protected override void InitComponent()
    {
        base.InitComponent();
        _currentProgress = 0f;
        _targetProgress = 0f;
        _isComplete = false;
    }

    protected override void OnPreOpen()
    {
        base.OnPreOpen();
        _currentProgress = 0f;
        _targetProgress = 0f;
        _isComplete = false;
        UpdateUI();
        RefreshTip();
    }

    /// <summary>
    /// 设置加载进度 (0.0 ~ 1.0)。
    /// </summary>
    public void SetProgress(float progress)
    {
        _targetProgress = Mathf.Clamp01(progress);
        if (_targetProgress >= 1f)
        {
            _isComplete = true;
        }
    }

    /// <summary>
    /// 直接设置进度并刷新 UI（无平滑过渡）。
    /// </summary>
    public void SetProgressDirectly(float progress)
    {
        _targetProgress = Mathf.Clamp01(progress);
        _currentProgress = _targetProgress;
        UpdateUI();

        if (_targetProgress >= 1f)
        {
            _isComplete = true;
        }
    }

    private void LateUpdate()
    {
        if (Mathf.Abs(_currentProgress - _targetProgress) > 0.001f)
        {
            _currentProgress = Mathf.Lerp(_currentProgress, _targetProgress, Time.deltaTime * 5f);

            // 接近目标时直接对齐，避免无限趋近
            if (Mathf.Abs(_currentProgress - _targetProgress) < 0.005f)
            {
                _currentProgress = _targetProgress;
            }

            UpdateUI();
        }

        if (_isComplete && _currentProgress >= 0.99f)
        {
            _currentProgress = 1f;
            UpdateUI();
            OnLoadComplete();
        }
    }

    private void UpdateUI()
    {
        if (m_ProgressSlider != null)
        {
            m_ProgressSlider.value = _currentProgress;
        }

        if (m_ProgressText != null)
        {
            m_ProgressText.text = $"{(int)(_currentProgress * 100)}%";
        }
    }

    private void RefreshTip()
    {
        if (m_TipText != null && GeneralDefine.loadingTips != null && GeneralDefine.loadingTips.Length > 0)
        {
            var randomIndex = UnityEngine.Random.Range(0, GeneralDefine.loadingTips.Length);
            m_TipText.text = Language.Get(GeneralDefine.loadingTips[randomIndex]);
        }
    }

    private void OnLoadComplete()
    {
        // 延迟关闭，让玩家看到 100% 状态
        CompleteAndCloseAsync().Forget();
    }

    private async UniTask CompleteAndCloseAsync()
    {
        await UniTask.Delay(300, cancellationToken: this.GetCancellationTokenOnDestroy());

        if (this != null)
        {
            UIManager.Instance.CloseWindow(this);
        }
    }

    /// <summary>
    /// 显示战斗加载界面并返回进度回报器。
    /// 用法: var progress = await BattleLoadingWin.ShowAsync();
    /// </summary>
    public static async UniTask<BattleLoadingWin> ShowAsync()
    {
        var win = await UIManager.Instance.OpenWindowAsync("BattleLoadingWin") as BattleLoadingWin;
        return win;
    }

    /// <summary>
    /// IProgress 适配器实现。
    /// </summary>
    private class BattleLoadingProgress : IProgress<float>
    {
        private readonly BattleLoadingWin _win;

        public BattleLoadingProgress(BattleLoadingWin win)
        {
            _win = win;
        }

        public void Report(float value)
        {
            if (_win != null)
            {
                _win.SetProgress(value);
            }
        }
    }
}