using System.Runtime.InteropServices;

// Raw P/Invoke surface over core/include/voicecat.h, via LibraryImport (source-generated —
// no runtime reflection marshaling stub; see docs/tech-stack.md §2). One entry per voicecat.h
// function. `vc_client*` is represented as a raw `nint` here — VoiceCatClientHandle (a
// SafeHandle) owns the create/destroy lifetime one level up; these declarations never see a
// SafeHandle directly, per .NET's own SafeHandle convention.
//
// "voicecat" resolves to voicecat.dll via the OS's standard DLL search order (same directory
// as the .exe first) — see clients/windows/README.md for how it gets there at build time.
namespace VoiceCat.Interop;

internal static partial class NativeMethods
{
    private const string LibName = "voicecat";

    // ── Lifecycle ────────────────────────────────────────────────────────────────────────
    // NOTE: these two return `const char*` pointing at STATIC string literals the core never
    // expects the caller to free. Declaring them as `string` with StringMarshalling.Utf8
    // would be wrong: the built-in Utf8StringMarshaller's return-value convention assumes the
    // native callee allocated the string FOR this call and that the marshaller should free it
    // afterward — calling that on a static literal corrupts the heap (confirmed: it crashes
    // with STATUS_HEAP_CORRUPTION / 0xC0000374). Return the raw pointer instead and convert
    // with Marshal.PtrToStringUTF8 ourselves, without ever freeing it — see VoiceCatClient.cs.
    [LibraryImport(LibName)]
    internal static partial nint vc_version_string();

    [LibraryImport(LibName)]
    internal static partial nint vc_result_string(VcResult code);

    [LibraryImport(LibName)]
    internal static partial nint vc_client_create(in VcConfigNative cfg, VcCallbacksNative cb);

    [LibraryImport(LibName)]
    internal static partial void vc_client_destroy(nint c);

    // ── Connection & auth (async; results via on_event) ────────────────────────────────────
    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_connect(nint c, string host, ushort port);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_disconnect(nint c);

    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_authenticate_guest(nint c, string nickname);

    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_authenticate_user(nint c, string username, string password);

    // ── Channels ─────────────────────────────────────────────────────────────────────────
    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_join_channel(nint c, uint channelId, string? password);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_leave_channel(nint c);

    // ── Local media streams ─────────────────────────────────────────────────────────────────
    [LibraryImport(LibName)]
    internal static partial VcResult vc_stream_start(nint c, in VcStreamDescNative desc,
        out uint outStreamId);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_stream_stop(nint c, uint streamId);

    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_set_input_device(nint c, uint streamId, string? deviceId);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_capture_channels(nint c, uint streamId, uint channels);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_audio_restart(nint c);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_input_mode(nint c, VcInputMode mode);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_vad_threshold(nint c, float threshold);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_push_to_talk(nint c, int active);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_self_mute(nint c, int micMuted, int deafened);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_output_volume(nint c, float gain);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_input_gain(nint c, float gain);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_input_noise_reduction(nint c, int enable);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_remote_stream(nint c, uint userId, uint streamId,
        float gain, int muted, int noiseReduction);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_get_remote_stream(nint c, uint userId, uint streamId,
        out VcRemoteStreamStateNative outState);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_get_stream_audio_config(nint c, uint userId,
        uint streamId, out VcAudioConfigNative outCfg);

    // TEST-ONLY in the core (see voicecat.h) — declared for ABI parity; the real app never
    // calls this (no microphone-bypass path in production UI).
    [LibraryImport(LibName)]
    internal static unsafe partial VcResult vc_test_inject_capture(nint c, uint streamId,
        short* pcm, nuint samples);

    // ── External PCM feed / tap ──────────────────────────────────────────────────────────

    [LibraryImport(LibName)]
    internal static unsafe partial VcResult vc_stream_feed_pcm(nint c, uint streamId,
        short* pcm, nuint samplesPerChannel, uint channels);

    // Delegate type for the PCM sink callback — callers convert to a native function
    // pointer via Marshal.GetFunctionPointerForDelegate (for instance members) or by casting
    // a static lambda to delegate* unmanaged<> (for [UnmanagedCallersOnly] statics).
    // Keep the delegate alive for the lifetime of the sink registration.
    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate void VcPcmSinkCallback(IntPtr user, uint userId, uint streamId,
        IntPtr pcm, nuint samplesPerChannel, uint channels, uint sampleRate);

    // cb is a raw function pointer (IntPtr.Zero = disable). Use
    // Marshal.GetFunctionPointerForDelegate(sinkDelegate) to convert from VcPcmSinkCallback.
    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_pcm_sink(nint c, nint cb, IntPtr user);

    // ── Text ─────────────────────────────────────────────────────────────────────────────
    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_send_text(nint c, VcTextScope scope, uint targetId,
        string utf8);

    // ── Device enumeration ───────────────────────────────────────────────────────────────
    [LibraryImport(LibName)]
    internal static partial VcResult vc_list_devices(nint c, VcDeviceKind kind,
        out VcDeviceListNative outList);

    [LibraryImport(LibName)]
    internal static partial void vc_free_device_list(ref VcDeviceListNative list);

    // ── M4: channel / user / stream snapshot getters ────────────────────────────────────────
    [LibraryImport(LibName)]
    internal static partial VcResult vc_list_channels(nint c, out VcChannelListNative outList);

    [LibraryImport(LibName)]
    internal static partial void vc_free_channel_list(ref VcChannelListNative list);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_list_users(nint c, out VcUserListNative outList);

    [LibraryImport(LibName)]
    internal static partial void vc_free_user_list(ref VcUserListNative list);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_list_user_streams(nint c, uint userId,
        out VcStreamSummaryListNative outList);

    [LibraryImport(LibName)]
    internal static partial void vc_free_stream_summary_list(ref VcStreamSummaryListNative list);

    // ── M4: TOFU server-identity gate ───────────────────────────────────────────────────────
    [LibraryImport(LibName)]
    internal static partial VcResult vc_confirm_server_identity(nint c, int accept);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_get_server_identity_display(nint c, nint outBuf,
        nuint bufCap, out nuint outLen);

    // ── M5: Moderation & admin ─────────────────────────────────────────────────────────────
    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_kick_user(nint c, uint userId, string? reason);

    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_ban_user(nint c, uint userId, string? reason,
        ulong expiresUnixMs);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_permission(nint c, uint userId,
        in VcPermissionsNative perms);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_set_server_mute(nint c, uint userId, int muted,
        int deafened);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_move_user(nint c, uint userId, uint channelId);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_create_channel(nint c, in VcChannelInfoNative info);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_edit_channel(nint c, in VcChannelInfoNative info);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_delete_channel(nint c, uint channelId);

    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_create_account(nint c, string username, string password);

    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_reset_password(nint c, string username,
        string newPassword);

    [LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
    internal static partial VcResult vc_delete_account(nint c, string username);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_list_accounts(nint c);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_get_account_list(nint c, out VcAccountListNative outList);

    [LibraryImport(LibName)]
    internal static partial void vc_free_account_list(ref VcAccountListNative list);

    [LibraryImport(LibName)]
    internal static partial VcResult vc_get_permissions(nint c, out VcPermissionsNative outPerms);
}
