Convert Arduino sketch to PlatformIO project

Restructure BikeAudio for PlatformIO while preserving the original
build specs from the .ino header:
  - platform espressif32 @ ~6.6.0  -> ESP32 Arduino core 2.0.17
  - board esp32dev (ESP32 DevKitC v4)
  - board_build.partitions = huge_app.csv (Huge APP, required for BT stack)
  - monitor_speed = 115200

Changes:
  - BikeAudio.ino -> src/main.cpp (+ #include <Arduino.h>, print_status()
    forward declaration; PlatformIO compiles .cpp directly and does not
    auto-generate prototypes like the Arduino IDE).
  - Add platformio.ini with pschatzmann ESP32-A2DP + arduino-audio-tools
    pinned to exact commits (ESP32-A2DP 1.8.11, audio-tools 1.2.4) for
    reproducible builds.
  - Adapt three spots to the current library API (behavior preserved):
      * RingBuffer<uint8_t>::read() -> bool read(T&)
      * connection-state callbacks: drop esp_bd_addr_t arg
        -> (esp_a2d_connection_state_t, void*)
      * BluetoothA2DPSource::start(name, bool) -> start(name)
        (auto-reconnect already configured via set_auto_reconnect(true))

Verified: pio run -e esp32dev succeeds.
RAM 14.5% (47.6 KB), Flash 42.0% (1.32 MB / 3 MB).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

platformio.ini

@@ -0,0 +1,27 @@
+; PlatformIO project configuration for BikeAudio
+; Converted from Arduino IDE sketch (BikeAudio.ino).
+;
+; Board:            ESP32 Dev Module (DevKitC v4)  -> esp32dev
+; ESP32 Arduino core: 2.0.17 (provided by platform espressif32 @ ~6.6.0)
+;                   Do NOT move to core 3.x — BT stack regression.
+; Partition scheme: Huge APP (3MB No OTA / 1MB SPIFFS) -> huge_app.csv
+; Serial monitor:   115200 baud
+
+[env:esp32dev]
+platform = espressif32 @ ~6.6.0
+board = esp32dev
+framework = arduino
+
+; Huge APP partition table — required for the Bluetooth stack size.
+board_build.partitions = huge_app.csv
+
+monitor_speed = 115200
+
+; Phil Schatzmann's libraries (referenced by git URL, as in the .ino header —
+; not published in the PlatformIO registry under these names).
+;   ESP32-A2DP depends on arduino-audio-tools. Pinned to exact commits for
+;   reproducible builds (ESP32-A2DP 1.8.11, audio-tools 1.2.4); src/main.cpp
+;   was adapted to match this API surface.
+lib_deps =
+    https://github.com/pschatzmann/ESP32-A2DP#42601717cd70d5300c9b519f3c2bf1d64d77ea2b
+    https://github.com/pschatzmann/arduino-audio-tools#64b64dcb9bde18a0a17766eeb6529c3a53d920a8

src/main.cpp

@@ -27,11 +27,18 @@
  *   - Done — play audio, both speakers output simultaneously
  */
 
+#include <Arduino.h>
+
 #include "AudioTools.h"
 #include "BluetoothA2DPSink.h"
 #include "BluetoothA2DPSource.h"
 #include "BluetoothA2DPCommon.h"
 
+// Forward declaration — defined below. Required in .cpp builds: the Arduino IDE
+// auto-generates prototypes for .ino files, but PlatformIO compiles .cpp directly
+// and print_status() is called in setup()/loop() before its definition.
+void print_status();
+
 // ─── CONFIGURATION ────────────────────────────────────────────────────────────
 
 // Name this device shows to iPhone
@@ -104,8 +111,9 @@ void audio_received_mirror_cb(const uint8_t *data, uint32_t len) {
 
 int32_t get_audio_for_jbl(uint8_t *data, int32_t len) {
     int32_t bytes_read = 0;
-    while (bytes_read < len && !ring_buf.isEmpty()) {
-        data[bytes_read++] = ring_buf.read();
+    uint8_t b;
+    while (bytes_read < len && ring_buf.read(b)) {
+        data[bytes_read++] = b;
     }
     // Pad with silence if buffer underrun
     if (bytes_read < len) {
@@ -116,8 +124,9 @@ int32_t get_audio_for_jbl(uint8_t *data, int32_t len) {
 
 int32_t get_audio_for_cardo(uint8_t *data, int32_t len) {
     int32_t bytes_read = 0;
-    while (bytes_read < len && !ring_buf_cardo.isEmpty()) {
-        data[bytes_read++] = ring_buf_cardo.read();
+    uint8_t b;
+    while (bytes_read < len && ring_buf_cardo.read(b)) {
+        data[bytes_read++] = b;
     }
     if (bytes_read < len) {
         memset(data + bytes_read, 0, len - bytes_read);
@@ -127,7 +136,7 @@ int32_t get_audio_for_cardo(uint8_t *data, int32_t len) {
 
 // ─── CONNECTION CALLBACKS ─────────────────────────────────────────────────────
 
-void sink_connected_cb(esp_bd_addr_t addr, esp_a2d_connection_state_t state, void *obj) {
+void sink_connected_cb(esp_a2d_connection_state_t state, void *obj) {
     if (state == ESP_A2D_CONNECTION_STATE_CONNECTED) {
         Serial.println("[SINK] iPhone connected");
         iphone_connected = true;
@@ -137,7 +146,7 @@ void sink_connected_cb(esp_bd_addr_t addr, esp_a2d_connection_state_t state, voi
     }
 }
 
-void jbl_connected_cb(esp_bd_addr_t addr, esp_a2d_connection_state_t state, void *obj) {
+void jbl_connected_cb(esp_a2d_connection_state_t state, void *obj) {
     if (state == ESP_A2D_CONNECTION_STATE_CONNECTED) {
         Serial.println("[JBL] Connected");
         jbl_connected = true;
@@ -148,7 +157,7 @@ void jbl_connected_cb(esp_bd_addr_t addr, esp_a2d_connection_state_t state, void
     }
 }
 
-void cardo_connected_cb(esp_bd_addr_t addr, esp_a2d_connection_state_t state, void *obj) {
+void cardo_connected_cb(esp_a2d_connection_state_t state, void *obj) {
     if (state == ESP_A2D_CONNECTION_STATE_CONNECTED) {
         Serial.println("[CARDO] Connected");
         cardo_connected = true;
@@ -171,7 +180,7 @@ void setup() {
     src_jbl.set_data_callback(get_audio_for_jbl);
     src_jbl.set_on_connection_state_changed(jbl_connected_cb);
     src_jbl.set_auto_reconnect(true);
-    src_jbl.start(JBL_NAME, true);   // true = reconnect if known device
+    src_jbl.start(JBL_NAME);   // auto-reconnect handled by set_auto_reconnect() above
 
     // Give it time to connect before starting second source
     // (Bluedroid needs sequential connection setup)
@@ -190,7 +199,7 @@ void setup() {
     src_cardo.set_data_callback(get_audio_for_cardo);
     src_cardo.set_on_connection_state_changed(cardo_connected_cb);
     src_cardo.set_auto_reconnect(true);
-    src_cardo.start(CARDO_NAME, true);
+    src_cardo.start(CARDO_NAME);
 
     t = millis();
     while (!cardo_connected && millis() - t < 10000) {
@@ -219,14 +228,14 @@ void loop() {
     // Auto-reconnect JBL if lost
     if (!jbl_connected && millis() - last_reconnect_jbl > RECONNECT_MS) {
         Serial.println("[JBL] Retrying connection...");
-        src_jbl.start(JBL_NAME, true);
+        src_jbl.start(JBL_NAME);
         last_reconnect_jbl = millis();
     }
 
     // Auto-reconnect Cardo if lost
     if (!cardo_connected && millis() - last_reconnect_cardo > RECONNECT_MS) {
         Serial.println("[CARDO] Retrying connection...");
-        src_cardo.start(CARDO_NAME, true);
+        src_cardo.start(CARDO_NAME);
         last_reconnect_cardo = millis();
     }