using Dalamud.Bindings.ImGui;
using Dalamud.Interface.Colors;
using LightlessSync.LightlessConfiguration;
using LightlessSync.LightlessConfiguration.Models;
using LightlessSync.PlayerData.Handlers;
using LightlessSync.Services;
using LightlessSync.Services.Mediator;
using LightlessSync.Services.PairProcessing;
using LightlessSync.WebAPI.Files;
using LightlessSync.WebAPI.Files.Models;
using Microsoft.Extensions.Logging;
using System.Collections.Concurrent;
using System.Numerics;

namespace LightlessSync.UI;

public class DownloadUi : WindowMediatorSubscriberBase
{
    private readonly LightlessConfigService _configService;
    private readonly ConcurrentDictionary<GameObjectHandler, Dictionary<string, FileDownloadStatus>> _currentDownloads = new();
    private readonly DalamudUtilService _dalamudUtilService;
    private readonly FileUploadManager _fileTransferManager;
    private readonly UiSharedService _uiShared;
    private readonly PairProcessingLimiter _pairProcessingLimiter;
    private readonly ConcurrentDictionary<GameObjectHandler, bool> _uploadingPlayers = new();
    private readonly Dictionary<GameObjectHandler, Vector2> _smoothed = [];
    private readonly Dictionary<GameObjectHandler, DownloadSpeedTracker> _downloadSpeeds = new();

    private sealed class DownloadSpeedTracker
    {
        public long LastBytes;
        public double LastTime;
        public double SpeedBytesPerSecond;
    }

    private bool _notificationDismissed = true;
    private int _lastDownloadStateHash = 0;

    public DownloadUi(ILogger<DownloadUi> logger, DalamudUtilService dalamudUtilService, LightlessConfigService configService,
        PairProcessingLimiter pairProcessingLimiter, FileUploadManager fileTransferManager, LightlessMediator mediator, UiSharedService uiShared, 
        PerformanceCollectorService performanceCollectorService)
        : base(logger, mediator, "Lightless Sync Downloads", performanceCollectorService)
    {
        _dalamudUtilService = dalamudUtilService;
        _configService = configService;
        _pairProcessingLimiter = pairProcessingLimiter;
        _fileTransferManager = fileTransferManager;
        _uiShared = uiShared;

        SizeConstraints = new WindowSizeConstraints()
        {
            MaximumSize = new Vector2(500, 90),
            MinimumSize = new Vector2(500, 90),
        };

        Flags |= ImGuiWindowFlags.NoMove;
        Flags |= ImGuiWindowFlags.NoBackground;
        Flags |= ImGuiWindowFlags.NoInputs;
        Flags |= ImGuiWindowFlags.NoNavFocus;
        Flags |= ImGuiWindowFlags.NoResize;
        Flags |= ImGuiWindowFlags.NoScrollbar;
        Flags |= ImGuiWindowFlags.NoTitleBar;
        Flags |= ImGuiWindowFlags.NoDecoration;
        Flags |= ImGuiWindowFlags.NoFocusOnAppearing;

        DisableWindowSounds = true;

        ForceMainWindow = true;

        IsOpen = true;

        Mediator.Subscribe<DownloadStartedMessage>(this, (msg) => 
        {
            _currentDownloads[msg.DownloadId] = msg.DownloadStatus;
            _notificationDismissed = false;
        });
        Mediator.Subscribe<DownloadFinishedMessage>(this, (msg) => 
        {
            _currentDownloads.TryRemove(msg.DownloadId, out _);
            
            // Dismiss notification if all downloads are complete
            if (!_currentDownloads.Any() && !_notificationDismissed)
            {
                Mediator.Publish(new LightlessNotificationDismissMessage("pair_download_progress"));
                _notificationDismissed = true;
                _lastDownloadStateHash = 0;
            }
        });
        Mediator.Subscribe<GposeStartMessage>(this, (_) => IsOpen = false);
        Mediator.Subscribe<GposeEndMessage>(this, (_) => IsOpen = true);
        Mediator.Subscribe<PlayerUploadingMessage>(this, (msg) =>
        {
            if (msg.IsUploading)
            {
                _uploadingPlayers[msg.Handler] = true;
            }
            else
            {
                _uploadingPlayers.TryRemove(msg.Handler, out _);
            }
        });
    }

    protected override void DrawInternal()
    {
        if (_configService.Current.ShowTransferWindow)
        {
            var limiterSnapshot = _pairProcessingLimiter.GetSnapshot();

            // Check if download notifications are enabled (not set to TextOverlay)
            var useNotifications = _configService.Current.UseLightlessNotifications
                ? _configService.Current.LightlessDownloadNotification != NotificationLocation.TextOverlay
                : _configService.Current.UseNotificationsForDownloads;

            if (useNotifications)
            {
                if (!_currentDownloads.IsEmpty)
                {
                    UpdateDownloadNotificationIfChanged(limiterSnapshot);
                    _notificationDismissed = false;
                }
                else if (!_notificationDismissed)
                {
                    Mediator.Publish(new LightlessNotificationDismissMessage("pair_download_progress"));
                    _notificationDismissed = true;
                    _lastDownloadStateHash = 0;
                }
            }
            
            DrawDownloadSummaryBox();

            if (_configService.Current.ShowUploading)
            {
                const int transparency = 100;
                foreach (var player in _uploadingPlayers.Select(p => p.Key).ToList())
                {
                    var screenPos = _dalamudUtilService.WorldToScreen(player.GetGameObject());
                    if (screenPos == Vector2.Zero) continue;

                    try
                    {
                        using var _ = _uiShared.UidFont.Push();
                        var uploadText = "Uploading";
                        var textSize = ImGui.CalcTextSize(uploadText);

                        var drawList = ImGui.GetBackgroundDrawList();
                        UiSharedService.DrawOutlinedFont(drawList, uploadText, screenPos with { X = screenPos.X - textSize.X / 2f - 1, Y = screenPos.Y - textSize.Y / 2f - 1 },
                            UiSharedService.Color(255, 255, 0, transparency),
                            UiSharedService.Color(0, 0, 0, transparency),
                            2
                        );
                    }
                    catch
                    {
                        _logger.LogDebug("Error drawing upload progress");
                    }
                }
            }
        }

        if (_configService.Current.ShowTransferBars)
        {
            const int transparency = 100;
            const int dlBarBorder = 3;
            const float rounding = 6f;
            var shadowOffset = new Vector2(2, 2);   

            foreach (var transfer in _currentDownloads.ToList())
            {
                var transferKey = transfer.Key;
                var rawPos = _dalamudUtilService.WorldToScreen(transferKey.GetGameObject());

                //If RawPos is zero, remove it from smoothed dictionary
                if (rawPos == Vector2.Zero)
                {
                    _smoothed.Remove(transferKey);
                    continue;
                }

                //Smoothing out the movement and fix jitter around the position.
                Vector2 screenPos = _smoothed.TryGetValue(transferKey, out var lastPos)
                    ? (rawPos - lastPos).Length() < 4f ? lastPos : rawPos
                    : rawPos;
                _smoothed[transferKey] = screenPos;

                var totalBytes = transfer.Value.Sum(c => c.Value.TotalBytes);
                var transferredBytes = transfer.Value.Sum(c => c.Value.TransferredBytes);

                var maxDlText = $"{UiSharedService.ByteToString(totalBytes, addSuffix: false)}/{UiSharedService.ByteToString(totalBytes)}";
                var textSize = _configService.Current.TransferBarsShowText
                    ? ImGui.CalcTextSize(maxDlText)
                    : new Vector2(10, 10);

                int dlBarHeight = _configService.Current.TransferBarsHeight > ((int)textSize.Y + 5)
                    ? _configService.Current.TransferBarsHeight
                    : (int)textSize.Y + 5;
                int dlBarWidth = _configService.Current.TransferBarsWidth > ((int)textSize.X + 10)
                    ? _configService.Current.TransferBarsWidth
                    : (int)textSize.X + 10;

                var dlBarStart = new Vector2(screenPos.X - dlBarWidth / 2f, screenPos.Y - dlBarHeight / 2f);
                var dlBarEnd = new Vector2(screenPos.X + dlBarWidth / 2f, screenPos.Y + dlBarHeight / 2f);

                // Precompute rects
                var outerStart = new Vector2(dlBarStart.X - dlBarBorder - 1, dlBarStart.Y - dlBarBorder - 1);
                var outerEnd = new Vector2(dlBarEnd.X + dlBarBorder + 1, dlBarEnd.Y + dlBarBorder + 1);
                var borderStart = new Vector2(dlBarStart.X - dlBarBorder, dlBarStart.Y - dlBarBorder);
                var borderEnd = new Vector2(dlBarEnd.X + dlBarBorder, dlBarEnd.Y + dlBarBorder);

                var drawList = ImGui.GetBackgroundDrawList();

                //Shadow, background, border, bar background
                drawList.AddRectFilled(outerStart + shadowOffset, outerEnd + shadowOffset, UiSharedService.Color(0, 0, 0, transparency / 2), rounding + 2);
                drawList.AddRectFilled(outerStart, outerEnd, UiSharedService.Color(0, 0, 0, transparency), rounding + 2);
                drawList.AddRectFilled(borderStart, borderEnd, UiSharedService.Color(ImGuiColors.DalamudGrey), rounding);
                drawList.AddRectFilled(dlBarStart, dlBarEnd, UiSharedService.Color(0, 0, 0, transparency), rounding);

                var dlProgressPercent = transferredBytes / (double)totalBytes;
                var progressEndX = dlBarStart.X + (float)(dlProgressPercent * dlBarWidth);
                var progressEnd = new Vector2(progressEndX, dlBarEnd.Y);

                drawList.AddRectFilled(dlBarStart, progressEnd, UiSharedService.Color(UIColors.Get("LightlessPurple")), rounding);

                if (_configService.Current.TransferBarsShowText)
                {
                    var downloadText = $"{UiSharedService.ByteToString(transferredBytes, addSuffix: false)}/{UiSharedService.ByteToString(totalBytes)}";
                    UiSharedService.DrawOutlinedFont(drawList, downloadText, screenPos with { X = screenPos.X - textSize.X / 2f - 1, Y = screenPos.Y - textSize.Y / 2f - 1 },
                        UiSharedService.Color(ImGuiColors.DalamudGrey),
                        UiSharedService.Color(0, 0, 0, transparency),
                        1
                    );
                }
            }

            if (_configService.Current.ShowUploading)
            {
                foreach (var player in _uploadingPlayers.Select(p => p.Key).ToList())
                {
                    var screenPos = _dalamudUtilService.WorldToScreen(player.GetGameObject());
                    if (screenPos == Vector2.Zero) continue;

                    try
                    {
                        using var _ = _uiShared.UidFont.Push();
                        var uploadText = "Uploading";

                        var textSize = ImGui.CalcTextSize(uploadText);

                        var drawList = ImGui.GetBackgroundDrawList();
                        UiSharedService.DrawOutlinedFont(drawList, uploadText, screenPos with { X = screenPos.X - textSize.X / 2f - 1, Y = screenPos.Y - textSize.Y / 2f - 1 },
                            UiSharedService.Color(ImGuiColors.DalamudYellow),
                            UiSharedService.Color(0, 0, 0, transparency),
                            2
                        );
                    }
                    catch
                    {
                        _logger.LogDebug("Error drawing upload progress");
                    }
                }
            }
        }
    }

    private void DrawDownloadSummaryBox()
    {
        if (!_currentDownloads.Any())
            return;

        const int transparency = 150;
        const float padding = 6f;
        const float spacingY = 2f;
        const float minBoxWidth = 320f;

        var now = ImGui.GetTime();

        int totalFiles = 0;
        int transferredFiles = 0;
        long totalBytes = 0;
        long transferredBytes = 0;

        var perPlayer = new List<(string Name, int TransferredFiles, int TotalFiles, long TransferredBytes, long TotalBytes, double SpeedBytesPerSecond)>();

        foreach (var transfer in _currentDownloads.ToList())
        {
            var handler = transfer.Key;
            var statuses = transfer.Value.Values;

            var playerTotalFiles = statuses.Sum(s => s.TotalFiles);
            var playerTransferredFiles = statuses.Sum(s => s.TransferredFiles);
            var playerTotalBytes = statuses.Sum(s => s.TotalBytes);
            var playerTransferredBytes = statuses.Sum(s => s.TransferredBytes);

            totalFiles += playerTotalFiles;
            transferredFiles += playerTransferredFiles;
            totalBytes += playerTotalBytes;
            transferredBytes += playerTransferredBytes;

            double speed = 0;
            if (playerTotalBytes > 0)
            {
                if (!_downloadSpeeds.TryGetValue(handler, out var tracker))
                {
                    tracker = new DownloadSpeedTracker
                    {
                        LastBytes = playerTransferredBytes,
                        LastTime = now,
                        SpeedBytesPerSecond = 0
                    };
                    _downloadSpeeds[handler] = tracker;
                }

                var dt = now - tracker.LastTime;
                var dBytes = playerTransferredBytes - tracker.LastBytes;

                if (dt > 0.1 && dBytes >= 0)
                {
                    var instant = dBytes / dt;
                    tracker.SpeedBytesPerSecond = tracker.SpeedBytesPerSecond <= 0
                        ? instant
                        : tracker.SpeedBytesPerSecond * 0.8 + instant * 0.2;
                }

                tracker.LastTime = now;
                tracker.LastBytes = playerTransferredBytes;
                speed = tracker.SpeedBytesPerSecond;
            }

            perPlayer.Add((
                handler.Name,
                playerTransferredFiles,
                playerTotalFiles,
                playerTransferredBytes,
                playerTotalBytes,
                speed
            ));
        }

        foreach (var handler in _downloadSpeeds.Keys.ToList())
        {
            if (!_currentDownloads.ContainsKey(handler))
                _downloadSpeeds.Remove(handler);
        }

        if (totalFiles == 0 || totalBytes == 0)
            return;

        var drawList = ImGui.GetBackgroundDrawList();
        var windowPos = ImGui.GetWindowPos();

        var headerText = $"Downloading {transferredFiles}/{totalFiles} files";
        var bytesText = $"{UiSharedService.ByteToString(transferredBytes, addSuffix: false)}/{UiSharedService.ByteToString(totalBytes)}";

        var totalSpeed = perPlayer.Sum(p => p.SpeedBytesPerSecond);
        var speedText = totalSpeed > 0
            ? $"{UiSharedService.ByteToString((long)totalSpeed)}/s"
            : "Calculating lightspeed...";

        var headerSize = ImGui.CalcTextSize(headerText);
        var bytesSize = ImGui.CalcTextSize(bytesText);
        var speedSize = ImGui.CalcTextSize(speedText);

        float contentWidth = headerSize.X;
        if (bytesSize.X > contentWidth) contentWidth = bytesSize.X;
        if (speedSize.X > contentWidth) contentWidth = speedSize.X;

        foreach (var p in perPlayer)
        {
            var playerSpeedText = p.SpeedBytesPerSecond > 0
                ? $"{UiSharedService.ByteToString((long)p.SpeedBytesPerSecond)}/s"
                : "-";

            var line = $"{p.Name}: {p.TransferredFiles}/{p.TotalFiles} " +
                       $"({UiSharedService.ByteToString(p.TransferredBytes, addSuffix: false)}/{UiSharedService.ByteToString(p.TotalBytes)}) " +
                       $"@ {playerSpeedText}";

            var lineSize = ImGui.CalcTextSize(line);
            if (lineSize.X > contentWidth)
                contentWidth = lineSize.X;
        }

        var boxWidth = contentWidth + padding * 2;
        if (boxWidth < minBoxWidth)
            boxWidth = minBoxWidth;

        var lineHeight = ImGui.GetTextLineHeight();
        var numTextLines = 3 + perPlayer.Count;
        var barHeight = lineHeight * 0.8f;
        var boxHeight = padding * 3 + barHeight + numTextLines * (lineHeight + spacingY);

        var origin = windowPos;

        var boxMin = origin;
        var boxMax = origin + new Vector2(boxWidth, boxHeight);

        drawList.AddRectFilled(boxMin, boxMax, UiSharedService.Color(0, 0, 0, transparency), 5f);
        drawList.AddRect(boxMin, boxMax, UiSharedService.Color(ImGuiColors.DalamudGrey), 5f);

        // Progress bar
        var cursor = boxMin + new Vector2(padding, padding);
        var barMin = cursor;
        var barMax = new Vector2(boxMin.X + boxWidth - padding, cursor.Y + barHeight);

        var progress = (float)transferredBytes / totalBytes;
        drawList.AddRectFilled(barMin, barMax, UiSharedService.Color(40, 40, 40, transparency), 3f);
        drawList.AddRectFilled(barMin, new Vector2(barMin.X + (barMax.X - barMin.X) * progress, barMax.Y), UiSharedService.Color(UIColors.Get("LightlessPurple")), 3f);

        cursor.Y = barMax.Y + padding;

        // Header
        UiSharedService.DrawOutlinedFont(drawList, headerText, cursor, UiSharedService.Color(ImGuiColors.DalamudWhite), UiSharedService.Color(0, 0, 0, transparency), 1);
        cursor.Y += lineHeight + spacingY;

        // Bytes
        UiSharedService.DrawOutlinedFont(drawList, bytesText, cursor, UiSharedService.Color(ImGuiColors.DalamudWhite), UiSharedService.Color(0, 0, 0, transparency), 1);
        cursor.Y += lineHeight + spacingY;

        // Total speed WIP
        UiSharedService.DrawOutlinedFont(drawList, speedText, cursor, UiSharedService.Color(UIColors.Get("LightlessPurple")), UiSharedService.Color(0, 0, 0, transparency), 1);
        cursor.Y += lineHeight * 1.4f;

        // Per-player lines
        foreach (var p in perPlayer.OrderByDescending(p => p.TotalBytes))
        {
            var playerSpeedText = p.SpeedBytesPerSecond > 0
                ? $"{UiSharedService.ByteToString((long)p.SpeedBytesPerSecond)}/s"
                : "-";

            var line = $"{p.Name}: {p.TransferredFiles}/{p.TotalFiles} " +
                       $"({UiSharedService.ByteToString(p.TransferredBytes, addSuffix: false)}/{UiSharedService.ByteToString(p.TotalBytes)}) " +
                       $"@ {playerSpeedText}";

            UiSharedService.DrawOutlinedFont(drawList, line, cursor, UiSharedService.Color(ImGuiColors.DalamudWhite), UiSharedService.Color(0, 0, 0, transparency), 1);

            cursor.Y += lineHeight + spacingY;
        }
    }

    public override bool DrawConditions()
    {
        if (_uiShared.EditTrackerPosition) return true;
        if (!_configService.Current.ShowTransferWindow && !_configService.Current.ShowTransferBars) return false;
        if (_currentDownloads.IsEmpty && !_fileTransferManager.IsUploading && _uploadingPlayers.IsEmpty) return false;
        if (!IsOpen) return false;
        return true;
    }

    public override void PreDraw()
    {
        base.PreDraw();

        if (_uiShared.EditTrackerPosition)
        {
            Flags &= ~ImGuiWindowFlags.NoMove;
            Flags &= ~ImGuiWindowFlags.NoBackground;
            Flags &= ~ImGuiWindowFlags.NoInputs;
            Flags &= ~ImGuiWindowFlags.NoResize;
        }
        else
        {
            Flags |= ImGuiWindowFlags.NoMove;
            Flags |= ImGuiWindowFlags.NoBackground;
            Flags |= ImGuiWindowFlags.NoInputs;
            Flags |= ImGuiWindowFlags.NoResize;
        }

        var maxHeight = ImGui.GetTextLineHeight() * (_configService.Current.ParallelDownloads + 3);
        SizeConstraints = new()
        {
            MinimumSize = new Vector2(300, maxHeight),
            MaximumSize = new Vector2(300, maxHeight),
        };
    }

    private void UpdateDownloadNotificationIfChanged(PairProcessingLimiterSnapshot limiterSnapshot)
    {
        var downloadStatus = new List<(string playerName, float progress, string status)>(_currentDownloads.Count);
        var hashCode = new HashCode();

        foreach (var item in _currentDownloads)
        {
            var dlSlot = 0;
            var dlQueue = 0;
            var dlProg = 0;
            var dlDecomp = 0;
            long totalBytes = 0;
            long transferredBytes = 0;

            // Single pass through the dictionary to count everything - avoid multiple LINQ iterations
            foreach (var entry in item.Value)
            {
                var fileStatus = entry.Value;
                switch (fileStatus.DownloadStatus)
                {
                    case DownloadStatus.WaitingForSlot: dlSlot++; break;
                    case DownloadStatus.WaitingForQueue: dlQueue++; break;
                    case DownloadStatus.Downloading: dlProg++; break;
                    case DownloadStatus.Decompressing: dlDecomp++; break;
                }
                totalBytes += fileStatus.TotalBytes;
                transferredBytes += fileStatus.TransferredBytes;
            }

            var progress = totalBytes > 0 ? (float)transferredBytes / totalBytes : 0f;
            
            string status;
            if (dlDecomp > 0) status = "decompressing";
            else if (dlProg > 0) status = "downloading";
            else if (dlQueue > 0) status = "queued";
            else if (dlSlot > 0) status = "waiting";
            else status = "completed";

            downloadStatus.Add((item.Key.Name, progress, status));
            
            // Build hash from meaningful state
            hashCode.Add(item.Key.Name);
            hashCode.Add(transferredBytes);
            hashCode.Add(totalBytes);
            hashCode.Add(status);
        }

        var queueWaiting = limiterSnapshot.IsEnabled ? limiterSnapshot.Waiting : 0;
        hashCode.Add(queueWaiting);
        
        var currentHash = hashCode.ToHashCode();
        
        // Only update notification if state has actually changed
        if (currentHash != _lastDownloadStateHash)
        {
            _lastDownloadStateHash = currentHash;
            if (downloadStatus.Count > 0 || queueWaiting > 0)
            {
                Mediator.Publish(new PairDownloadStatusMessage(downloadStatus, queueWaiting));
            }
        }
    }
}