using VideoDownloader.Browser.Tabs;

namespace VideoDownloader.App.Browser.Features;

/// <summary>
/// 탭 절전(T2-2, Edge Sleeping Tabs 패턴): 유휴 비활성 탭을 TrySuspendAsync 로
/// 서스펜드해 메모리를 회수한다. 실제 서스펜드 수행은 주입(suspendAction) —
/// WebView2 TrySuspendAsync 는 뷰가 숨겨진(비활성) 탭에서만 동작.
/// </summary>
public sealed class TabSuspendService
{
    private readonly TimeSpan _idleTimeout;
    private readonly Func<TabItem, bool> _suspendAction;
    private readonly Func<TabItem, bool> _canSuspend;

    public TabSuspendService(TimeSpan idleTimeout, Func<TabItem, bool> suspendAction, Func<TabItem, bool> canSuspend)
    {
        _idleTimeout = idleTimeout;
        _suspendAction = suspendAction;
        _canSuspend = canSuspend;
    }

    /// <summary>유휴 비활성 탭 서스펜드. 반환: 서스펜드된 탭 수.</summary>
    public int SuspendIdleTabs(IEnumerable<TabItem> tabs, TabItem active, DateTime now)
    {
        var count = 0;
        foreach (var tab in tabs)
        {
            if (ReferenceEquals(tab, active)) continue;
            if (tab.IsSuspended) continue;
            if (!_canSuspend(tab)) continue;
            if (now - tab.LastActivated < _idleTimeout) continue;
            try
            {
                if (_suspendAction(tab)) { tab.IsSuspended = true; count++; }
            }
            catch { /* 서스펜드 실패는 건너뜀 */ }
        }
        return count;
    }
}