Add BLE MIDI transport (feature_bluetooth)

include/app_task.h

@@ -2,6 +2,7 @@
 
 #include <cstdint>
 #include "midi_transport.h"
+#include "ble_midi_transport.h"
 #include "led_stub.h"
 #include "switch_stub.h"
 
@@ -14,7 +15,7 @@ struct PadMapping {
 
 class AppTask {
 public:
-    AppTask(LedStub* led, SwitchStub* sw, UsbMidiTransport* midi);
+    AppTask(LedStub* led, SwitchStub* sw, UsbMidiTransport* usb_midi, BleMidiTransport* ble_midi = nullptr);
     
     void begin();
     void update();
@@ -23,7 +24,8 @@ public:
 private:
     LedStub* led_driver;
     SwitchStub* switch_driver;
-    UsbMidiTransport* midi_transport;
+    UsbMidiTransport* usb_midi;
+    BleMidiTransport* ble_midi;
     
     static const uint8_t NUM_PADS = 10;
     PadMapping pad_mapping[NUM_PADS];

include/ble_midi_transport.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <cstdint>
+#include <functional>
+#include "midi_transport.h"
+
+class BleMidiTransport {
+public:
+    BleMidiTransport();
+    ~BleMidiTransport();
+
+    bool begin();
+    void update();
+
+    void on_midi_receive(std::function<void(const MidiEvent&)> callback);
+
+    void send_note_on(uint8_t channel, uint8_t note, uint8_t velocity);
+    void send_note_off(uint8_t channel, uint8_t note, uint8_t velocity);
+    void send_cc(uint8_t channel, uint8_t cc, uint8_t value);
+
+    bool is_connected();
+
+private:
+    std::function<void(const MidiEvent&)> receive_callback;
+    bool initialized;
+    bool client_connected;
+
+    void send_midi_packet(const uint8_t* data, uint8_t len);
+    void on_receive(const uint8_t* data, size_t len);
+    size_t parse_ble_midi(uint8_t status, const uint8_t* data, size_t len, size_t offset, MidiEvent& event);
+};