using System.Collections.Concurrent;
using System.Diagnostics;
using System.Text;
using Dalamud.Game.Chat;
using Dalamud.Game.Text;
using Dalamud.Game.Text.SeStringHandling;
using Dalamud.Hooking;
using Dalamud.Interface.ImGuiNotification;
using Dalamud.Plugin.Services;
using FFXIVClientStructs.FFXIV.Client.UI;
using FFXIVClientStructs.FFXIV.Client.UI.Misc;
using HellionChat._Helpers;
using HellionChat.Code;
using HellionChat.Resources;
using HellionChat.Util;
using Lumina.Text.Expressions;
using Lumina.Text.Payloads;
using Lumina.Text.ReadOnly;
using Microsoft.Extensions.Logging;

namespace HellionChat;

internal class MessageManager : IAsyncDisposable
{
    internal const int MessageDisplayLimit = 10_000;

    private Plugin Plugin { get; }
    private readonly ILogger<MessageManager> _logger;
    internal MessageStore Store { get; }

    private Dictionary<ChatType, NameFormatting> Formats { get; } = [];
    private ulong LastContentId { get; set; }

    // PendingSync (main thread) → PendingAsync (worker thread); LinkedList for O(1) Last access
    private LinkedList<PendingMessage> PendingSync { get; } = [];
    private ConcurrentQueue<PendingMessage> PendingAsync { get; } = [];
    private readonly Thread PendingMessageThread;
    private readonly CancellationTokenSource PendingThreadCancellationToken = new();

    private Hook<RaptureLogModule.Delegates.AddMsgSourceEntry>? ContentIdResolverHook { get; init; }

    internal ulong CurrentContentId
    {
        get
        {
            var contentId = Plugin.PlayerState.ContentId;
            return contentId == 0 ? LastContentId : contentId;
        }
    }

    // Auto-Tell-Tabs hook: fires after a message is processed and stored, allowing
    // AutoTellTabsService to spawn or refresh temp tabs without coupling.
    public event Action<Message>? MessageProcessed;

    internal unsafe MessageManager(
        Plugin plugin,
        ILogger<MessageManager> logger,
        ILoggerFactory loggerFactory
    )
    {
        Plugin = plugin;
        _logger = logger;

        Store = new MessageStore(
            DatabasePath(),
            Plugin.PlatformUtil,
            loggerFactory.CreateLogger<MessageStore>(),
            loggerFactory
        );

        PendingMessageThread = new Thread(() =>
            ProcessPendingMessages(PendingThreadCancellationToken.Token)
        )
        {
            IsBackground = true,
        };
        PendingMessageThread.Start();

        ContentIdResolverHook =
            Plugin.GameInteropProvider.HookFromAddress<RaptureLogModule.Delegates.AddMsgSourceEntry>(
                RaptureLogModule.MemberFunctionPointers.AddMsgSourceEntry,
                ContentIdResolver
            );
        ContentIdResolverHook.Enable();

        Plugin.ChatGui.ChatMessageUnhandled += ChatMessage;
        Plugin.Framework.Update += OnFrameworkUpdate;
        Plugin.ClientState.Logout += Logout;
    }

    public async ValueTask DisposeAsync()
    {
        ContentIdResolverHook?.Dispose();
        Plugin.ClientState.Logout -= Logout;
        Plugin.Framework.Update -= OnFrameworkUpdate;
        Plugin.ChatGui.ChatMessageUnhandled -= ChatMessage;

        await PendingThreadCancellationToken.CancelAsync();

        // 10s cooperative window; Thread.Abort is gone since .NET 5, so a
        // stuck worker has to ride out the next AppDomain unload.
        var deadline = TimeSpan.FromSeconds(10);
        var stopwatch = Stopwatch.StartNew();
        while (stopwatch.Elapsed < deadline && PendingMessageThread.IsAlive)
            await Task.Delay(100);

        if (PendingMessageThread.IsAlive)
            _logger.LogWarning(
                "PendingMessageThread did not observe cancellation within 10s. "
                    + "Worker remains on background thread; next plugin reload releases it."
            );

        PendingThreadCancellationToken.Dispose();

        Store.Dispose();
    }

    internal static string DatabasePath()
    {
        return Path.Join(Plugin.Interface.ConfigDirectory.FullName, "chat-sqlite.db");
    }

    private void Logout(int _, int __)
    {
        LastContentId = 0;
    }

    private void OnFrameworkUpdate(IFramework framework)
    {
        var contentId = Plugin.PlayerState.ContentId;
        if (contentId != 0)
            LastContentId = contentId;

        // Drain the PendingSync queue into the PendingAsync queue.
        while (PendingSync.First is { } first)
        {
            PendingSync.RemoveFirst();
            PendingAsync.Enqueue(first.Value);
        }
    }

    private void ProcessPendingMessages(CancellationToken token)
    {
        while (!token.IsCancellationRequested)
        {
            if (PendingAsync.TryDequeue(out var pendingMessage))
            {
                try
                {
                    ProcessMessage(pendingMessage);
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "Error processing pending message");
                }
            }
            else
            {
                Thread.Sleep(1);
            }
        }
    }

    internal void ClearAllTabs()
    {
        // B3: snapshot the tab LIST under the shared lock so the worker-thread
        // add/remove can't tear the enumeration; tab.Clear() then runs lock-free
        // (each tab's Messages has its own SemaphoreSlim — lock order: list outer).
        List<Tab> tabsSnapshot;
        lock (Plugin.TabsListLock)
            tabsSnapshot = Plugin.Config.Tabs.ToList();

        // TempTabs are session-only (not persisted); exclude them to preserve Tell history
        foreach (var tab in tabsSnapshot.Where(t => !t.IsTempTab))
            tab.Clear();
    }

    internal void FilterAllTabs()
    {
        DateTimeOffset? since = null;
        if (!Plugin.Config.FilterIncludePreviousSessions)
            since = Plugin.GameStarted;

        using var messages = Store.GetMostRecentMessages(CurrentContentId, since);

        // TempTabs excluded (live state from AutoTellTabsService). Bucket via the
        // pure MapMessagesToTabs so the assignment stays testable outside Dalamud (B3-1).
        // B3: snapshot under the shared lock (list copy only — short critical
        // section). The Store query above and the AddSortPrune writes below stay
        // OUTSIDE the lock (lock order: list outer, MessageList inner).
        List<Tab> nonTempTabs;
        lock (Plugin.TabsListLock)
            nonTempTabs = Plugin.Config.Tabs.Where(t => !t.IsTempTab).ToList();
        var buckets = MapMessagesToTabs(nonTempTabs, messages);

        // Apply messages to chat log all at once.
        foreach (var tab in nonTempTabs)
            tab.Messages.AddSortPrune(buckets[tab], MessageDisplayLimit);

        if (!messages.DidError)
            return;

        WrapperUtil.AddNotification(Language.LoadMessages_Error, NotificationType.Error);

        // Mark failed messages as deleted to prevent retry attempts
        var failedIds = messages.FailedMessageIds();
        _logger.LogInformation(
            $"Marking {failedIds.Count} messages as deleted due to parse failures"
        );
        foreach (var msgId in messages.FailedMessageIds())
        {
            _logger.LogDebug($"Marking message '{msgId}' as deleted due to parse failure");
            Store.DeleteMessage(msgId);
        }
    }

    // Pure message->tab bucketing for the refilter. Dalamud-free + static so the
    // assignment can be unit-pinned in the build suite; the live caller owns the
    // Store query, the snapshot and the SemaphoreSlim writes.
    internal static Dictionary<Tab, List<Message>> MapMessagesToTabs(
        IReadOnlyList<Tab> tabs,
        IEnumerable<Message> messages
    )
    {
        var buckets = new Dictionary<Tab, List<Message>>(tabs.Count);
        foreach (var tab in tabs)
            buckets[tab] = new List<Message>();

        foreach (var message in messages)
        foreach (var tab in tabs)
            if (tab.Matches(message))
                buckets[tab].Add(message);

        return buckets;
    }

    internal void FilterAllTabsAsync()
    {
        Task.Run(() =>
        {
            var stopwatch = Stopwatch.StartNew();
            try
            {
                FilterAllTabs();
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error in FilterAllTabs");
            }

            // v1.4.9 R3 profiling: Information so the xllog tail surfaces this
            // without a Debug filter. Belt-and-suspenders for future plugin-load
            // regressions; remains in place after Sub-Task 3.4 Befund.
            _logger.LogInformation($"FilterAllTabs took {stopwatch.ElapsedMilliseconds}ms");
        });
    }

    public (SeString? Sender, SeString? Message) LastMessage = (null, null);

    private void ChatMessage(IChatMessage message)
    {
        LastMessage = (message.Sender, message.Message);

        var pendingMessage = new PendingMessage
        {
            ContentId = 0,
            AccountId = 0,
            LogKind = message.LogKind,
            SourceKind = message.SourceKind,
            TargetKind = message.TargetKind,
            Sender = message.Sender,
            Content = message.Message,
        };

        // Update colour codes.
        GlobalParametersCache.Refresh();

        // Delay to next tick to get content ID from ContentIdResolver hook
        PendingSync.AddLast(pendingMessage);
    }

    private unsafe void ContentIdResolver(
        RaptureLogModule* agent,
        ulong contentId,
        ulong accountId,
        int messageIndex,
        ushort worldId,
        ushort chatType
    )
    {
        try
        {
            ContentIdResolverHook?.Original(
                agent,
                contentId,
                accountId,
                messageIndex,
                worldId,
                chatType
            );
            if (PendingSync.Last is not { } last)
                return;

            last.Value.ContentId = contentId;
            last.Value.AccountId = accountId;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error in ContentIdResolver");
        }
    }

    private void ProcessMessage(PendingMessage pendingMessage)
    {
        var chatCode = new ChatCode(
            pendingMessage.LogKind,
            pendingMessage.SourceKind,
            pendingMessage.TargetKind
        );

        NameFormatting? formatting = null;
        if (pendingMessage.Sender.Payloads.Count > 0)
            formatting = FormatFor(chatCode.Type);

        var senderChunks = new List<Chunk>();
        if (formatting is { IsPresent: true })
        {
            senderChunks.Add(
                new TextChunk(ChunkSource.None, null, formatting.Before)
                {
                    FallbackColour = chatCode.Type,
                }
            );
            senderChunks.AddRange(
                ChunkUtil.ToChunks(pendingMessage.Sender, ChunkSource.Sender, chatCode.Type)
            );
            senderChunks.Add(
                new TextChunk(ChunkSource.None, null, formatting.After)
                {
                    FallbackColour = chatCode.Type,
                }
            );
        }

        var contentChunks = ChunkUtil
            .ToChunks(pendingMessage.Content, ChunkSource.Content, chatCode.Type)
            .ToList();
        var message = new Message(
            CurrentContentId,
            pendingMessage.ContentId,
            pendingMessage.AccountId,
            chatCode,
            senderChunks,
            contentChunks,
            pendingMessage.Sender,
            pendingMessage.Content
        );

        if (Plugin.Config.DatabaseBattleMessages || !message.Code.IsBattle())
            Store.UpsertMessage(message);

        // Snapshot the list, not just the active tab. This loop runs on the worker
        // thread while SaveConfig's strip and the auto-tell spawn mutate Config.Tabs
        // under TabsListLock — enumerating it live throws "collection was modified",
        // and the catch in ProcessPendingMessages swallows that, silently dropping
        // the whole message: no tab entry, no sound, no MessageProcessed.
        List<Tab> tabsSnapshot;
        lock (Plugin.TabsListLock)
            tabsSnapshot = Plugin.Config.Tabs.ToList();

        // Snapshot the active tab and whether it shows this message ONCE, so the
        // whole loop sees a consistent value (the getter is a cross-thread read of
        // MainWindow.ActiveTab).
        var currentTab = Plugin.CurrentTab;
        var currentTabMatches = currentTab.Matches(message);
        foreach (var tab in tabsSnapshot)
        {
            if (tab.Matches(message))
                tab.AddMessage(message, ShouldCountUnread(tab, currentTab, currentTabMatches));
        }

        // Deliberate O(2n): the sound pick re-walks the tab list so the selection
        // stays pure and SelfTest-able; AddMessage above and playback below keep
        // the side effects.
        var notificationSound = SelectNotificationSound(
            tabsSnapshot,
            currentTab,
            message,
            Plugin.Config.PlaySounds,
            out var soundSource
        );

        // The snapshot can outlive a tab (eviction, logout). Playing its sound would
        // be an audible artefact for a tab that is already gone, so re-check first.
        if (notificationSound is not null && soundSource is not null)
        {
            bool sourceStillPresent;
            lock (Plugin.TabsListLock)
                sourceStillPresent = Plugin.Config.Tabs.Contains(soundSource);
            if (!sourceStillPresent)
                notificationSound = null;
        }

        if (notificationSound is { } soundId)
        {
            if (soundId is >= 1 and <= 16)
            {
                // ProcessMessage runs on the PendingMessageThread worker; the native
                // UIGlobals.PlaySoundEffect must be marshalled onto the framework
                // thread (reference_dalamud_framework_thread).
                Plugin.Framework.RunOnFrameworkThread(() =>
                {
                    unsafe
                    {
                        UIGlobals.PlaySoundEffect(soundId);
                    }
                });
            }
            else if (soundId >= 17)
            {
                // Custom bundled sounds (ids 17-19) go through NAudio WaveOutEvent.
                // NAudio manages its own playback thread, so no framework marshalling needed.
                Plugin.CustomAudioPlayer.Play((int)soundId - 16, Plugin.Config.CustomSoundVolume);
            }
            // soundId == 0 (hand-edited config) falls through: plays nothing.
        }

        MessageProcessed?.Invoke(message);
    }

    // Pure: picks the sound id for the first inactive tab that wants one, or null.
    // No AddMessage, no store write — those stay in the ProcessMessage loop so this
    // is exercisable from the SelfTest without polluting tab state. The "first
    // match wins" semantics live here via the running 'picked is null' guard,
    // keeping a message matching several background tabs from stacking sounds.
    // TEST-MIRROR: ../_Helpers/TabSoundDecision.cs
    // Unseen ("count only what you haven't seen") suppresses unread on an inactive
    // tab when the active tab ALSO shows this message — you already saw it in the
    // tab you're looking at (1.5.6 / upstream ChatTwo behavior). Pre-F2 the "active
    // tab" was wrongly pinned to Tabs[0], so this fired against the wrong tab; F2
    // recoupled CurrentTab to the REAL active tab, so currentTabMatches is now
    // measured against the tab you actually see. All -> always counts; None ->
    // counts here and is gated out at the display layer. Pure + SelfTest-able.
    internal static bool ShouldCountUnread(Tab tab, Tab currentTab, bool currentTabMatches) =>
        !(
            tab.UnreadMode == UnreadMode.Unseen
            && !ReferenceEquals(currentTab, tab)
            && currentTabMatches
        );

    // Reports the tab the sound came from, so the caller can drop it if that tab
    // disappeared between snapshot and playback.
    internal static uint? SelectNotificationSound(
        IEnumerable<Tab> tabs,
        Tab currentTab,
        Message probe,
        bool playSounds,
        out Tab? source
    )
    {
        uint? picked = null;
        source = null;
        foreach (var tab in tabs)
        {
            if (!tab.Matches(probe))
                continue;
            if (
                picked is null
                && TabSoundDecision.ShouldPlay(
                    currentTab == tab,
                    tab.EnableNotificationSound,
                    playSounds
                )
            )
            {
                picked = tab.NotificationSoundId;
                source = tab;
            }
        }
        return picked;
    }

    // SelfTest hook — same name discipline as InputBar.TestBuildOutgoingForSelfTest.
    internal static uint? TestSelectNotificationSoundForSelfTest(
        IEnumerable<Tab> tabs,
        Tab currentTab,
        Message probe,
        bool playSounds
    ) => SelectNotificationSound(tabs, currentTab, probe, playSounds, out _);

    internal class NameFormatting
    {
        internal string Before { get; private set; } = string.Empty;
        internal string After { get; private set; } = string.Empty;
        internal bool IsPresent { get; private set; } = true;

        internal static NameFormatting Empty()
        {
            return new NameFormatting { IsPresent = false };
        }

        internal static NameFormatting Of(string before, string after)
        {
            return new NameFormatting { Before = before, After = after };
        }
    }

    private NameFormatting FormatFor(ChatType type)
    {
        if (Formats.TryGetValue(type, out var cached))
            return cached;

        var formats = Sheets.LogKindSheet.GetRow((uint)type).Format.ToList();
        static bool IsStringParam(ReadOnlySePayload payload, byte num)
        {
            if (payload.MacroCode != MacroCode.String)
                return false;

            return payload.TryGetExpression(out var expr1)
                && expr1.TryGetParameterExpression(out var expressionType, out var operand)
                && expressionType == (byte)ExpressionType.LocalString
                && operand.TryGetInt(out var lstrIndex)
                && lstrIndex == num;
        }

        var firstStringParam = formats.FindIndex(payload => IsStringParam(payload, 1));
        var secondStringParam = formats.FindIndex(payload => IsStringParam(payload, 2));

        if (firstStringParam == -1 || secondStringParam == -1)
            return NameFormatting.Empty();

        var before = formats
            .GetRange(0, firstStringParam)
            .Where(payload => payload.Type == ReadOnlySePayloadType.Text)
            .Select(text => Encoding.UTF8.GetString(text.Body.Span));
        var after = formats
            .GetRange(firstStringParam + 1, secondStringParam - firstStringParam)
            .Where(payload => payload.Type == ReadOnlySePayloadType.Text)
            .Select(text => Encoding.UTF8.GetString(text.Body.Span));

        var nameFormatting = NameFormatting.Of(string.Join("", before), string.Join("", after));
        Formats[type] = nameFormatting;

        return nameFormatting;
    }

    private class PendingMessage
    {
        public ulong ContentId; // 0 if unknown
        public ulong AccountId; // 0 if unknown
        public XivChatType LogKind;
        public XivChatRelationKind SourceKind;
        public XivChatRelationKind TargetKind;
        public required SeString Sender;
        public required SeString Content;
    }
}