From 7b83933c6f7822783b490eebeabeb6eebd691fa8 Mon Sep 17 00:00:00 2001
From: Nicole <frega.nicole@gmail.com>
Date: Thu, 22 Jan 2026 21:36:33 +0100
Subject: [PATCH] Added support for Kawai CA49 BLE Midi with added virtual midi
 compatible with any DAW

---
 etc/nixos/configuration.nix     | 14 +++++-
 etc/nixos/modules/KawaiCA49.nix | 81 +++++++++++++++++++++++++++++++++
 etc/nixos/modules/bluetooth.nix |  1 +
 etc/nixos/modules/programs.nix  |  2 +
 4 files changed, 97 insertions(+), 1 deletion(-)
 create mode 100644 etc/nixos/modules/KawaiCA49.nix

diff --git a/etc/nixos/configuration.nix b/etc/nixos/configuration.nix
index 049854c..13ad6ed 100644
--- a/etc/nixos/configuration.nix
+++ b/etc/nixos/configuration.nix
@@ -26,6 +26,7 @@ in
       ./modules/ld-fix.nix
       ./modules/programs.nix
       ./modules/bluetooth.nix
+      ./modules/KawaiCA49.nix
       ./cachix.nix
     ];
 
@@ -33,7 +34,7 @@ in
     device = "/dev/disk/by-uuid/fc0150d8-4f57-4d95-abe9-4b979336b3ce";
     fsType = "ext4";
   };
-  
+
 
 #░█▀▄░█▀█░█▀█░▀█▀░█░░░█▀█░█▀█░█▀▄░█▀▀░█▀▄
 #░█▀▄░█░█░█░█░░█░░█░░░█░█░█▀█░█░█░█▀▀░█▀▄
@@ -71,6 +72,12 @@ in
 
     loader.timeout = 0;
     loader.systemd-boot.consoleMode = "auto";
+    
+    # Add a midi bridge for BLE MIDI devices
+    kernelModules = [ "snd-virmidi" ];
+    extraModprobeConfig = ''
+      options snd-virmidi midi_devs=1
+    '';
   };
 
 
@@ -182,6 +189,11 @@ in
     jack.enable = true;
   };
 
+  hardware.kawaiCA49 = {
+    enable = true;
+    user = "nicole";
+  };
+
   # ISO mounting utils #
   programs.cdemu.enable = true;
   
diff --git a/etc/nixos/modules/KawaiCA49.nix b/etc/nixos/modules/KawaiCA49.nix
new file mode 100644
index 0000000..a635c55
--- /dev/null
+++ b/etc/nixos/modules/KawaiCA49.nix
@@ -0,0 +1,81 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.hardware.kawaiCA49;
+in
+{
+  options.hardware.kawaiCA49 = {
+    enable = mkEnableOption "Kawai CA49 Bluetooth MIDI support";
+    
+    user = mkOption {
+      type = types.str;
+      description = "User to run the MIDI connection service as";
+    };
+    
+    virtualMidiDevice = mkOption {
+      type = types.str;
+      default = "Virtual Raw MIDI";
+      description = "Virtual MIDI device name to connect to";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    # Load virtual MIDI kernel module
+    boot.kernelModules = [ "snd-virmidi" ];
+    boot.extraModprobeConfig = ''
+      options snd-virmidi midi_devs=1
+    '';
+
+    # Create a system service that runs as the user
+    systemd.services.midi-connect-ca49 = {
+      description = "Monitor and connect CA49 Piano to Virtual MIDI";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "sound.target" "bluetooth.target" ];
+      serviceConfig = {
+        Type = "simple";
+        User = cfg.user;
+        Restart = "always";
+        RestartSec = "5s";
+        ExecStart = pkgs.writeShellScript "monitor-ca49-midi" ''
+          set -euo pipefail
+          
+          connect_ca49() {
+            # Find CA49 client number (not port number)
+            CA49_CLIENT=$(${pkgs.alsa-utils}/bin/aconnect -l | grep -oP "client \K[0-9]+(?=:.*CA49)" || true)
+            
+            # Find Virtual MIDI client number
+            VIRMIDI_CLIENT=$(${pkgs.alsa-utils}/bin/aconnect -l | grep -oP "client \K[0-9]+(?=:.*${cfg.virtualMidiDevice})" || true)
+            
+            if [ -z "$CA49_CLIENT" ] || [ -z "$VIRMIDI_CLIENT" ]; then
+              return 0
+            fi
+            
+            # Check if already connected
+            if ${pkgs.alsa-utils}/bin/aconnect -l | grep -q "$CA49_CLIENT:0.*Connecting To:.*$VIRMIDI_CLIENT:0"; then
+              return 0
+            fi
+            
+            # Try to connect
+            if ${pkgs.alsa-utils}/bin/aconnect "$CA49_CLIENT:0" "$VIRMIDI_CLIENT:0" 2>/dev/null; then
+              echo "Connected CA49 (client $CA49_CLIENT) to Virtual MIDI (client $VIRMIDI_CLIENT)"
+            fi
+          }
+          
+          # Initial connection attempt
+          sleep 2
+          connect_ca49
+          
+          # Monitor for new ALSA sequencer events
+          ${pkgs.alsa-utils}/bin/aseqdump -p 0:1 | while read -r line; do
+            if echo "$line" | grep -q "Port subscribed\|Port start"; then
+              sleep 1
+              connect_ca49
+            fi
+          done
+        '';
+      };
+    };
+  };
+}
diff --git a/etc/nixos/modules/bluetooth.nix b/etc/nixos/modules/bluetooth.nix
index 6bad02b..f8e1672 100644
--- a/etc/nixos/modules/bluetooth.nix
+++ b/etc/nixos/modules/bluetooth.nix
@@ -4,6 +4,7 @@
   hardware.bluetooth = {
     enable = true;
     powerOnBoot = true;
+    package = pkgs.bluez;
     settings.General = {
       experimental = true; # show battery
       Privacy = "device";
diff --git a/etc/nixos/modules/programs.nix b/etc/nixos/modules/programs.nix
index 314590c..20dad53 100644
--- a/etc/nixos/modules/programs.nix
+++ b/etc/nixos/modules/programs.nix
@@ -104,6 +104,7 @@
     gcc
     uv
     nodejs_24
+    dbgate
 
     # GAMING #
     mangohud
@@ -153,6 +154,7 @@
     yabridgectl
     alsa-scarlett-gui
     qjackctl
+    alsa-utils
 
     # WINE #
     wineWowPackages.stable