using System.Windows;
using System.Windows.Input;
using System.Windows.Media;

namespace AxCopilot.Views;

public partial class ChatWindow
{
    // 메시지 개수와 대화 ID가 바뀔 때만 재계산한다.
    private int _cachedMessageTokens;
    private int _cachedMessageCountForTokens = -1;
    private string? _cachedConvIdForTokens;

    private void RefreshContextUsageVisual()
    {
        if (TokenUsageCard == null || TokenUsageArc == null || TokenUsagePercentText == null
            || TokenUsageSummaryText == null || TokenUsageHintText == null
            || CompactNowLabel == null)
            return;

        var showContextUsage = _activeTab is "Cowork" or "Code";
        TokenUsageCard.Visibility = showContextUsage ? Visibility.Visible : Visibility.Collapsed;
        if (!showContextUsage)
        {
            if (TokenUsagePopup != null)
                TokenUsagePopup.IsOpen = false;
            return;
        }

        var llm = _settings.Settings.Llm;
        var expressionLevel = GetAgentUiExpressionLevel();
        var maxContextTokens = Math.Clamp(llm.MaxContextTokens, 1024, 1_000_000);
        var triggerPercent = Math.Clamp(llm.ContextCompactTriggerPercent, 10, 95);
        var triggerRatio = triggerPercent / 100.0;

        int messageTokens;
        lock (_convLock)
        {
            var convId = _currentConversation?.Id;
            var msgCount = _currentConversation?.Messages?.Count ?? 0;
            if (convId != _cachedConvIdForTokens || msgCount != _cachedMessageCountForTokens || _isStreaming)
            {
                _cachedMessageTokens = msgCount > 0
                    ? Services.TokenEstimator.EstimateMessages(_currentConversation!.Messages)
                    : 0;
                _cachedConvIdForTokens = convId;
                _cachedMessageCountForTokens = msgCount;
            }

            messageTokens = _cachedMessageTokens;
        }

        var draftText = InputBox?.Text ?? "";
        var draftTokens = string.IsNullOrWhiteSpace(draftText) ? 0 : Services.TokenEstimator.Estimate(draftText) + 4;

        var hasAnyMessages = messageTokens > 0 || _isStreaming;
        var baseOverhead = 0;
        if (hasAnyMessages)
        {
            var sysPromptLen = _llm?.SystemPrompt?.Length ?? 0;
            var toolCount = _toolRegistry?.GetActiveToolsForTab(_activeTab ?? "Chat")?.Count ?? 0;
            baseOverhead = Services.TokenEstimator.EstimateBaseOverhead(sysPromptLen, toolCount);
        }

        var currentTokens = Math.Max(0, messageTokens + draftTokens + baseOverhead);
        var usageRatio = Services.TokenEstimator.GetContextUsage(currentTokens, maxContextTokens);

        var accentBrush = TryFindResource("AccentColor") as Brush ?? Brushes.DodgerBlue;
        Brush progressBrush = accentBrush;
        string summary;
        string compactLabel;

        if (usageRatio >= 1.0)
        {
            progressBrush = Brushes.IndianRed;
            summary = "컨텍스트 한도 초과";
            compactLabel = "지금 압축";
        }
        else if (usageRatio >= triggerRatio)
        {
            progressBrush = Brushes.DarkOrange;
            summary = llm.EnableProactiveContextCompact ? "곧 자동 압축" : "압축 임계 도달";
            compactLabel = "압축 권장";
        }
        else if (usageRatio >= triggerRatio * 0.7)
        {
            progressBrush = Brushes.Goldenrod;
            summary = "컨텍스트 사용 증가";
            compactLabel = "미리 압축";
        }
        else
        {
            summary = "컨텍스트 여유";
            compactLabel = "압축";
        }

        string detailText;
        if (_lastCompactionAt.HasValue && _lastCompactionBeforeTokens.HasValue && _lastCompactionAfterTokens.HasValue)
        {
            var compactType = _lastCompactionWasAutomatic ? "자동" : "수동";
            detailText = $"{compactType} 압축 {Services.TokenEstimator.Format(_lastCompactionBeforeTokens.Value)} -> {Services.TokenEstimator.Format(_lastCompactionAfterTokens.Value)}";
        }
        else
        {
            detailText = $"자동 압축 시작 {triggerPercent}%";
        }

        TokenUsageArc.Stroke = progressBrush;
        var percentText = $"{System.Math.Round(usageRatio * 100):0}%";
        TokenUsagePercentText.Text = percentText;
        TokenUsageSummaryText.Text = $"컨텍스트 {percentText}";
        TokenUsageHintText.Text = $"{Services.TokenEstimator.Format(currentTokens)} / {Services.TokenEstimator.Format(maxContextTokens)}";
        CompactNowLabel.Text = compactLabel;

        ViewModel.ContextTokens = currentTokens;
        ViewModel.MaxContextTokens = maxContextTokens;

        if (TokenUsagePopupTitle != null)
            TokenUsagePopupTitle.Text = $"컨텍스트 창 {percentText}";
        if (TokenUsagePopupUsage != null)
            TokenUsagePopupUsage.Text = $"{Services.TokenEstimator.Format(currentTokens)}/{Services.TokenEstimator.Format(maxContextTokens)}";
        if (TokenUsagePopupDetail != null)
            TokenUsagePopupDetail.Text = expressionLevel == "simple"
                ? detailText
                : $"{detailText} · 임계 {triggerPercent}%";
        if (TokenUsagePopupCompact != null)
        {
            TokenUsagePopupCompact.Text = _sessionCompactionCount > 0
                ? expressionLevel switch
                {
                    "simple" => $"압축 {_sessionCompactionCount}회 · {FormatTokenCount(_sessionCompactionSavedTokens)} 절감",
                    _ => $"누적 압축 {_sessionCompactionCount}회 · 절감 {FormatTokenCount(_sessionCompactionSavedTokens)}"
                }
                : expressionLevel == "rich"
                    ? "AX Agent가 컨텍스트를 자동 관리합니다"
                    : "컨텍스트 자동 관리";
        }

        TokenUsageCard.ToolTip = null;

        UpdateCircularUsageArc(TokenUsageArc, usageRatio, 15, 15, 11);
    }

    private void TokenUsageCard_MouseEnter(object sender, MouseEventArgs e)
    {
        _tokenUsagePopupCloseTimer.Stop();
        if (TokenUsagePopup != null && TokenUsageCard?.Visibility == Visibility.Visible)
            TokenUsagePopup.IsOpen = true;
    }

    private void TokenUsageCard_MouseLeave(object sender, MouseEventArgs e)
    {
        _tokenUsagePopupCloseTimer.Stop();
        _tokenUsagePopupCloseTimer.Start();
    }

    private void TokenUsagePopup_MouseEnter(object sender, MouseEventArgs e)
    {
        _tokenUsagePopupCloseTimer.Stop();
    }

    private void TokenUsagePopup_MouseLeave(object sender, MouseEventArgs e)
    {
        _tokenUsagePopupCloseTimer.Stop();
        _tokenUsagePopupCloseTimer.Start();
    }

    private void CloseTokenUsagePopupIfIdle()
    {
        if (TokenUsagePopup == null)
            return;

        var cardHovered = IsMouseInsideElement(TokenUsageCard);
        var popupHovered = TokenUsagePopup.Child is FrameworkElement popupChild && IsMouseInsideElement(popupChild);
        if (!cardHovered && !popupHovered)
            TokenUsagePopup.IsOpen = false;
    }

    private static bool IsMouseInsideElement(FrameworkElement? element)
    {
        if (element == null || !element.IsVisible || element.ActualWidth <= 0 || element.ActualHeight <= 0)
            return false;

        try
        {
            var mouse = System.Windows.Forms.Control.MousePosition;
            var point = element.PointFromScreen(new Point(mouse.X, mouse.Y));
            return point.X >= 0 && point.Y >= 0 && point.X <= element.ActualWidth && point.Y <= element.ActualHeight;
        }
        catch
        {
            return element.IsMouseOver;
        }
    }
}