using System;
using System.Collections.Generic;
using System.Collections.Concurrent;

namespace AcDream.Core.Chat;

/// <summary>
/// Unified chat log — mirrors every chat-bearing message the server
/// sends (local HearSpeech, broadcast ChannelBroadcast, whispered
/// Tell, system TransientMessage, PopupString).
///
/// <para>
/// Sits behind the UI chat panel (Phase D.2) and the scripting
/// plugin API so plugins can react to chat (e.g. auto-reply, loot
/// logging).
/// </para>
///
/// <para>
/// Retail keeps ~200 lines of scrollback. Our ring buffer defaults to
/// 500 and is configurable.
/// </para>
/// </summary>
public sealed class ChatLog
{
    private readonly ConcurrentQueue<ChatEntry> _buffer = new();
    private readonly int _maxEntries;
    private uint _localPlayerGuid;

    // Phase J follow-up: ACE often sends the same system text via two
    // wire paths (GameMessageSystemChat 0xF7E0 + GameEventCommunication-
    // TransientString 0x02EB) for back-compat — we wired both to
    // OnSystemMessage in I.5/J, so the user saw lines like "Unknown
    // command: help" twice. Dedupe within a short window: track the
    // last system text + arrival time; if a second identical text
    // shows up within one second, skip.
    private string _lastSystemText = "";
    private DateTime _lastSystemAt = DateTime.MinValue;
    private static readonly TimeSpan SystemDedupWindow = TimeSpan.FromSeconds(1);

    public ChatLog(int maxEntries = 500)
    {
        if (maxEntries < 1) throw new ArgumentOutOfRangeException(nameof(maxEntries));
        _maxEntries = maxEntries;
    }

    /// <summary>Fires every time a new entry is appended.</summary>
    public event Action<ChatEntry>? EntryAppended;

    /// <summary>Snapshot of all current entries, oldest first.</summary>
    public ChatEntry[] Snapshot() => _buffer.ToArray();

    public int Count => _buffer.Count;

    /// <summary>
    /// Push the authoritative local-player GUID from <c>WorldSession</c>.
    /// One-way setter — only <c>GameWindow</c> should call it, exactly
    /// once per live session. Used by <see cref="OnLocalSpeech"/> to
    /// recognize ACE's HearSpeech echo of our own /say (server's
    /// HandleActionTalk broadcasts to all in range INCLUDING the
    /// sender) and re-render it as <c>"You say, ..."</c>.
    /// </summary>
    public void SetLocalPlayerGuid(uint guid) => _localPlayerGuid = guid;

    // ── Inbound adapters ─────────────────────────────────────────────────────

    /// <summary>Local or ranged HearSpeech (0x02BB / 0x02BC).</summary>
    /// <remarks>
    /// Phase I.5: an empty <paramref name="sender"/> is substituted with
    /// "You" — the server uses this convention to indicate that the
    /// player is the speaker (e.g. their own ranged shouts echo back).
    /// Port from holtburger
    /// <c>references/holtburger/.../client/messages.rs</c> lines 476-487.
    /// </remarks>
    public void OnLocalSpeech(string sender, string text, uint senderGuid, bool isRanged)
    {
        // Phase J: ACE's HandleActionTalk broadcasts a HearSpeech echo
        // back to the sender too. Detect own echo by guid match and
        // substitute "" so the formatter renders "You say, ..." (single
        // first-person echo) instead of "+Acdream says, ..."
        // (third-person duplicate of our optimistic, already dropped).
        bool isOwnEcho = _localPlayerGuid != 0 && senderGuid == _localPlayerGuid;
        string effectiveSender = (isOwnEcho || string.IsNullOrEmpty(sender)) ? "You" : sender;
        Append(new ChatEntry(
            Kind: isRanged ? ChatKind.RangedSpeech : ChatKind.LocalSpeech,
            Sender: effectiveSender,
            Text: text,
            SenderGuid: senderGuid,
            ChannelId: 0));
    }

    /// <summary>EmoteText (0x01E0) — server-driven third-person emote.</summary>
    public void OnEmote(string senderName, string text, uint senderGuid)
    {
        Append(new ChatEntry(
            Kind: ChatKind.Emote,
            Sender: senderName,
            Text: text,
            SenderGuid: senderGuid,
            ChannelId: 0));
    }

    /// <summary>SoulEmote (0x01E2) — complex emote (chat + paired animation).</summary>
    public void OnSoulEmote(string senderName, string text, uint senderGuid)
    {
        Append(new ChatEntry(
            Kind: ChatKind.SoulEmote,
            Sender: senderName,
            Text: text,
            SenderGuid: senderGuid,
            ChannelId: 0));
    }

    /// <summary>PlayerKilled (0x019E) — death announcement.</summary>
    /// <remarks>
    /// Death messages are routed as <see cref="ChatKind.System"/> so they
    /// share styling with other server announcements. The
    /// <c>SenderGuid</c> field carries the victim guid; the
    /// <c>ChannelId</c> field carries the killer guid (a small misuse
    /// of the field but avoids a schema change).
    /// </remarks>
    public void OnPlayerKilled(string deathMessage, uint victimGuid, uint killerGuid)
    {
        Append(new ChatEntry(
            Kind: ChatKind.System,
            Sender: "",
            Text: deathMessage,
            SenderGuid: victimGuid,
            ChannelId: killerGuid));
    }

    /// <summary>WeenieError (0x028A) / WeenieErrorWithString (0x028B).</summary>
    /// <remarks>
    /// Phase I.5: previously-orphaned parser. The server fires this when a
    /// game-logic action fails (e.g. "you don't have enough mana", "you
    /// can't pick that up"). Routed as <see cref="ChatKind.System"/>; the
    /// <c>ChannelId</c> field carries the WeenieError code so plugins can
    /// filter or react. <paramref name="param"/> is the interpolated
    /// substring (null for plain WeenieError, set for WeenieErrorWithString).
    /// </remarks>
    public void OnWeenieError(uint errorId, string? param)
    {
        // Phase I (post-launch fix): translate the wire code into the
        // retail-faithful template via WeenieErrorMessages. Many codes
        // are *informational* (e.g. 0x051B "You have entered the X
        // channel.", 0x051D "Turbine Chat is enabled.") not errors;
        // the old "WeenieError 0xNNNN" framing was misleading. Unknown
        // codes still fall back to the raw "WeenieError 0xNNNN[: param]"
        // form so nothing is silently lost. See
        // WeenieErrorMessages.Format for the templates + lookup table.
        string text = WeenieErrorMessages.Format(errorId, param);
        Append(new ChatEntry(
            Kind: ChatKind.System,
            Sender: "",
            Text: text,
            SenderGuid: 0,
            ChannelId: errorId));
    }

    /// <summary>
    /// Channel broadcast — legacy <c>ChatChannel (0x0147)</c> or the
    /// TurbineChat (<c>0xF7DE</c>) global community channels (General,
    /// Trade, LFG, Roleplay, Society, Olthoi). Pass
    /// <paramref name="channelName"/> when the caller knows the
    /// friendly room name (TurbineChat dispatch always does); the
    /// <c>ChatVM</c> formatter renders entries as
    /// <c>"[ChannelName] Sender says, \"text\""</c> when set.
    /// </summary>
    public void OnChannelBroadcast(uint channelId, string sender, string text, string channelName = "")
    {
        Append(new ChatEntry(
            Kind: ChatKind.Channel,
            Sender: sender,
            Text: text,
            SenderGuid: 0,
            ChannelId: channelId)
        {
            ChannelName = channelName,
        });
    }

    /// <summary>GameEvent Tell (0x02BD) — whisper received.</summary>
    public void OnTellReceived(string sender, string text, uint senderGuid)
    {
        Append(new ChatEntry(
            Kind: ChatKind.Tell,
            Sender: sender,
            Text: text,
            SenderGuid: senderGuid,
            ChannelId: 0));
    }

    /// <summary>
    /// System chat — covers GameMessageSystemChat (0xF7E0
    /// ServerMessage) and GameEventCommunicationTransientString
    /// (0x02EB). Phase J follow-up: dedupe identical text arriving
    /// within <see cref="SystemDedupWindow"/> so flows that fire on
    /// both opcodes (e.g. "Unknown command: help" via help-command
    /// failure path) only show once.
    /// </summary>
    public void OnSystemMessage(string text, uint chatType)
    {
        var now = DateTime.UtcNow;
        if (text == _lastSystemText && (now - _lastSystemAt) < SystemDedupWindow)
        {
            // Suppress the dup — the wire-level duplicate isn't a
            // user-meaningful signal. Reset the timer so a long burst
            // of the same text still skips.
            _lastSystemAt = now;
            return;
        }
        _lastSystemText = text;
        _lastSystemAt = now;

        Append(new ChatEntry(
            Kind: ChatKind.System,
            Sender: "",
            Text: text,
            SenderGuid: 0,
            ChannelId: chatType));
    }

    /// <summary>GameEvent PopupString (0x0004) — modal dialog text.</summary>
    public void OnPopup(string text)
    {
        Append(new ChatEntry(
            Kind: ChatKind.Popup,
            Sender: "",
            Text: text,
            SenderGuid: 0,
            ChannelId: 0));
    }

    /// <summary>
    /// Phase I.7: combat-translator emits a pre-formatted line. The
    /// translator (<see cref="CombatChatTranslator"/>) subscribes to
    /// <see cref="Combat.CombatState"/> events and renders the retail
    /// template (e.g. "You hit Mosswart for 12 slashing damage (54.0%)
    /// Critical hit.") and decorates the entry with a
    /// <see cref="Combat.CombatLineKind"/> so the panel can color the
    /// line. Maps to holtburger's <c>info().combat()</c> /
    /// <c>warning().combat()</c> / <c>error().combat()</c> tag flow at
    /// <c>chat.rs:221-308</c>.
    /// </summary>
    public void OnCombatLine(string text, Combat.CombatLineKind kind = Combat.CombatLineKind.Info)
    {
        Append(new ChatEntry(
            Kind: ChatKind.Combat,
            Sender: "",
            Text: text,
            SenderGuid: 0,
            ChannelId: 0)
        {
            CombatKind = kind,
        });
    }

    /// <summary>
    /// Echo the player's own outbound message after local send.
    /// </summary>
    /// <remarks>
    /// <list type="bullet">
    ///   <item><b>Say</b>: pass <paramref name="targetOrChannel"/> as
    ///   empty; the formatter renders <c>"You say, \"text\""</c>.</item>
    ///   <item><b>Tell</b>: pass the target name; the formatter
    ///   renders <c>"You tell {target}, \"text\""</c>.</item>
    ///   <item><b>Channel</b>: <i>do not call</i> for global community
    ///   channels — the server (ACE TurbineChatHandler) echoes the
    ///   broadcast back to the sender already, so optimistic-echoing
    ///   would double-print. For legacy channels (Fellowship,
    ///   Allegiance) where the server may not echo, pass the
    ///   channel name as <paramref name="targetOrChannel"/>; it
    ///   becomes the entry's <c>ChannelName</c>.</item>
    /// </list>
    /// <c>SenderGuid == 0</c> on the resulting entry is the
    /// discriminator the formatter uses to render outgoing-vs-incoming
    /// (a real incoming Tell carries the sender's player guid).
    /// </remarks>
    public void OnSelfSent(ChatKind kind, string text, string targetOrChannel = "")
    {
        Append(new ChatEntry(
            Kind: kind,
            // For Tell, Sender carries the target name (so the formatter
            // can render "You tell {Sender}..."). For LocalSpeech, we
            // leave Sender empty and let the formatter substitute "You".
            // For Channel callers, Sender stays empty too — ChannelName
            // (below) carries the friendly name.
            Sender: kind == ChatKind.Tell ? targetOrChannel : "",
            Text: text,
            SenderGuid: 0,
            ChannelId: 0)
        {
            ChannelName = kind == ChatKind.Channel ? targetOrChannel : "",
        });
    }

    private void Append(ChatEntry entry)
    {
        _buffer.Enqueue(entry);
        while (_buffer.Count > _maxEntries)
            _buffer.TryDequeue(out _);
        EntryAppended?.Invoke(entry);
    }

    public void Clear()
    {
        while (_buffer.TryDequeue(out _)) { /* drain */ }
    }
}

public enum ChatKind
{
    LocalSpeech,
    RangedSpeech,
    Channel,
    Tell,
    System,
    Popup,
    Emote,
    SoulEmote,
    /// <summary>
    /// Phase I.7: a combat feedback line emitted by
    /// <see cref="CombatChatTranslator"/> from <see cref="Combat.CombatState"/>
    /// events. The accompanying <see cref="ChatEntry.CombatKind"/> field
    /// drives panel coloring (info / warning / error per holtburger
    /// <c>chat.rs:221-308</c>).
    /// </summary>
    Combat,
}

public readonly record struct ChatEntry(
    ChatKind Kind,
    string Sender,
    string Text,
    uint SenderGuid,
    uint ChannelId)
{
    public DateTime Received { get; init; } = DateTime.UtcNow;

    /// <summary>
    /// Phase I.7: severity bucket for <see cref="ChatKind.Combat"/>
    /// entries. Null for every other kind. Drives the
    /// <see cref="ChatPanel"/>'s <c>TextColored</c> color choice.
    /// </summary>
    public Combat.CombatLineKind? CombatKind { get; init; }

    /// <summary>
    /// Friendly name of the channel for <see cref="ChatKind.Channel"/>
    /// entries (e.g. "General", "Trade", "LFG", "Fellowship"). Empty
    /// for non-Channel kinds. Used by <c>ChatVM.FormatEntry</c> to
    /// render lines as <c>"[ChannelName] Sender says, \"text\""</c>.
    /// Falls back to <c>"ch {ChannelId}"</c> if not populated.
    /// </summary>
    public string ChannelName { get; init; } = "";
}