namespace AcDream.Core.Chat;

/// <summary>
/// Source/transport classification for a chat channel — distinguishes
/// retail's two parallel chat channel pipelines.
/// </summary>
public enum ChatChannelSource
{
    /// <summary>Legacy <c>ChatChannel</c> bitflag id rides 0x0147 ChatChannel.</summary>
    Legacy,

    /// <summary>Turbine room id rides 0xF7DE TurbineChat.</summary>
    Turbine,
}

/// <summary>
/// Unified info about a chat channel — either a legacy ChatChannel id
/// (Fellowship, Allegiance, Vassals, Patron, Monarch, CoVassals) or a
/// Turbine room id (General, Trade, LFG, Roleplay, Society*, Olthoi).
///
/// <para>
/// Mirrors holtburger's <c>ChatChannelInfo</c>
/// (<c>references/holtburger/crates/holtburger-core/src/client/types.rs</c>
/// lines 63-102). The two retail channel pipelines run side by side —
/// legacy <c>ChatChannel</c> for the player-organisation channels and
/// <c>TurbineChat</c> for the global community rooms — and a single
/// abstraction over both keeps the chat panel and command bus from
/// having to special-case the transport at every call site.
/// </para>
///
/// <para>
/// <see cref="IsSelfEchoChannel"/> tells callers whether the server
/// echoes the client's own outgoing messages back on this channel
/// (so the client should suppress its optimistic local echo). Per
/// holtburger's predicate at <c>chat.rs::is_self_echo_channel</c>
/// (lines 492-507) this is true ONLY for the legacy fellowship/vassals/
/// patron/monarch/co-vassals channels — server resends those with
/// empty sender. Turbine and tells do not echo.
/// </para>
/// </summary>
public abstract record ChatChannelInfo(string DisplayName, ChatChannelSource Source)
{
    /// <summary>Legacy <c>ChatChannel</c> bitflag id (0x00000800 etc.).</summary>
    public sealed record Legacy(uint ChannelId, string DisplayName)
        : ChatChannelInfo(DisplayName, ChatChannelSource.Legacy)
    {
        public override bool IsSelfEchoChannel()
        {
            // Per holtburger: the legacy fellowship + allegiance-tree
            // channels are the ones the server echoes back to the sender
            // with an empty sender field. Bitflag values from
            // references/holtburger/.../messages/chat/types.rs::ChatChannel.
            return ChannelId switch
            {
                0x00000800u => true,  // Fellow
                0x00001000u => true,  // Vassals
                0x00002000u => true,  // Patron
                0x00004000u => true,  // Monarch
                0x01000000u => true,  // CoVassals
                _ => false,
            };
        }
    }

    /// <summary>
    /// TurbineChat room. <see cref="RoomId"/> is the runtime channel id
    /// the server hands out via <c>SetTurbineChatChannels</c> (0x0295).
    /// <see cref="ChatType"/> classifies the room semantically (General,
    /// Trade, etc.); <see cref="DispatchType"/> chooses the wire dispatch
    /// (SendToRoomById for outbound, SendToRoomByName for inbound events).
    /// </summary>
    public sealed record Turbine(
        uint RoomId,
        uint ChatType,
        uint DispatchType,
        string DisplayName)
        : ChatChannelInfo(DisplayName, ChatChannelSource.Turbine)
    {
        public override bool IsSelfEchoChannel()
        {
            // Turbine rooms do NOT echo the sender's own messages back.
            // The client must emit its own optimistic local echo to give
            // the player feedback that the message was sent.
            return false;
        }
    }

    /// <summary>
    /// True iff the server echoes our own outgoing messages on this
    /// channel — caller should suppress optimistic local echo to avoid
    /// double-printing.
    /// </summary>
    public abstract bool IsSelfEchoChannel();
}