namespace AcDream.UI.Abstractions;

/// <summary>
/// Maps a <see cref="ChatChannelKind"/> to the legacy <c>ChatChannel</c>
/// bitflag id used by the 0x0147 ChatChannel GameAction. Ported from
/// holtburger's <c>resolve_legacy_channel</c>
/// (<c>references/holtburger/crates/holtburger-core/src/client/commands.rs</c>
/// lines 50-62) cross-referenced against the <c>ChatChannel</c> enum
/// (<c>references/holtburger/crates/holtburger-protocol/src/messages/chat/types.rs</c>
/// lines 8-24) for the actual numeric ids.
///
/// <para>
/// Returns <c>null</c> for non-legacy kinds (Say, Tell, Unknown, and the
/// Turbine-routed General/Trade/etc.) — those callers handle dispatch
/// themselves. <see cref="ChatChannelKind.Say"/> rides Talk (0x0015) and
/// <see cref="ChatChannelKind.Tell"/> rides Tell (0x005D); the Turbine
/// channels need TurbineChat wiring not yet in place (Phase I.6).
/// </para>
/// </summary>
public static class ChannelResolver
{
    /// <summary>Result of a successful legacy-channel resolution.</summary>
    public readonly record struct Resolved(uint ChannelId, string DisplayName);

    /// <summary>
    /// Resolve <paramref name="kind"/> to a legacy ChatChannel id + a
    /// human-readable display name for chat-log echo. Returns <c>null</c>
    /// for non-legacy kinds; the caller routes those separately.
    /// </summary>
    public static Resolved? Resolve(ChatChannelKind kind) => kind switch
    {
        // ChatChannel values from holtburger-protocol/src/messages/chat/types.rs:
        //   Fellow              = 0x00000800
        //   Vassals             = 0x00001000
        //   Patron              = 0x00002000
        //   Monarch             = 0x00004000
        //   CoVassals           = 0x01000000
        //   AllegianceBroadcast = 0x02000000
        ChatChannelKind.Fellowship => new Resolved(0x00000800u, "Fellowship"),
        ChatChannelKind.Allegiance => new Resolved(0x02000000u, "Allegiance"),
        ChatChannelKind.Vassals    => new Resolved(0x00001000u, "Vassals"),
        ChatChannelKind.Patron     => new Resolved(0x00002000u, "Patron"),
        ChatChannelKind.Monarch    => new Resolved(0x00004000u, "Monarch"),
        ChatChannelKind.CoVassals  => new Resolved(0x01000000u, "CoVassals"),
        _ => null,
    };
}