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;

    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;

    // ── 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)
    {
        string effectiveSender = 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>GameEvent ChannelBroadcast (0x0147).</summary>
    public void OnChannelBroadcast(uint channelId, string sender, string text)
    {
        Append(new ChatEntry(
            Kind: ChatKind.Channel,
            Sender: sender,
            Text: text,
            SenderGuid: 0,
            ChannelId: channelId));
    }

    /// <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>GameEvent CommunicationTransientString (0x02EB) — e.g. "Your spell fizzled!"</summary>
    public void OnSystemMessage(string text, uint chatType)
    {
        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>
    public void OnSelfSent(ChatKind kind, string text, string targetOrChannel = "")
    {
        Append(new ChatEntry(
            Kind: kind,
            Sender: targetOrChannel,    // used as "to whom" for Tell / channel name for Channel
            Text: text,
            SenderGuid: 0,
            ChannelId: 0));
    }

    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; }
}