From ae3abc3aa3f60d16519e3af66193dbcc72424f28 Mon Sep 17 00:00:00 2001
From: Torrie Fischer <tdfischer@hackerbots.net>
Date: Sun, 19 Feb 2023 18:39:26 +0100
Subject: [PATCH] inputs: bpm: add support for configuring startup/idle BPM

---
 src/inputs/BPM.h | 43 +++++++++++++++++++++++++++++++++----------
 1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/src/inputs/BPM.h b/src/inputs/BPM.h
index a7ba0fc..df23c4c 100644
--- a/src/inputs/BPM.h
+++ b/src/inputs/BPM.h
@@ -1,26 +1,42 @@
 #pragma once
 #include <Figments.h>
+#include <ArduinoJson.h>
 
-class BPM : public InputSource {
+class BPM : public InputSource, ConfigTaskMixin {
 public:
   BPM() : InputSource("BPM") {}
   void handleEvent(const InputEvent& evt) override {
       if (evt.intent == InputEvent::BeatDetect) {
         m_nextBpm = millis();
         m_timings.insert(millis());
-        Log.notice("%d timings", m_timings.size());
+        Log.trace("bpm: %d timings", m_timings.size());
         if (m_timings.size() >= 5) {
           updateBPM();
         }
       }
+      ConfigTaskMixin::handleEvent(evt);
+  }
+
+  void loop() {
+      InputSource::loop();
+      ConfigTaskMixin::loop();
+  }
+
+  void handleConfigChange(const InputEvent& evt) override {
+    const JsonObject& cfg = *evt.as<JsonObject>();
+    if (cfg.containsKey("bpm.idle")) {
+        double requestedBPM = cfg["bpm.idle"];
+        m_msPerBeat = 60000.0 / (double)requestedBPM;
+        Log.notice("bpm: idle BPM set to %u (requested %lf)", msToBPM(m_msPerBeat), requestedBPM);
+    }
   }
 
   InputEvent read() override {
-    if (m_bpm > 0) {
+    if (m_msPerBeat > 0) {
       uint16_t now = millis();
       if (now >= m_nextBpm) {
-        m_nextBpm += m_bpm;
-        return InputEvent{InputEvent::Beat, m_bpm};
+        m_nextBpm += m_msPerBeat;
+        return InputEvent{InputEvent::Beat, msToBPM(m_msPerBeat)};
       }
       if (now >= m_nextLearn && m_nextLearn != 0) {
         m_timings.clear();
@@ -31,21 +47,28 @@ public:
   }
 
 private:
-  uint16_t m_bpm = 0;
+  uint16_t m_msPerBeat = 60000;
   uint16_t m_nextBpm = 0;
   uint16_t m_nextLearn = 0;
   Ringbuf<uint16_t, 7> m_timings;
 
+  constexpr uint16_t msToBPM(float msPerBeat) const {
+      if (msPerBeat == 0) {
+          return 0;
+      }
+      return 60000.0 / msPerBeat;
+  }
+
   void updateBPM() {
     uint16_t avgDelta = 0;
     for(uint8_t i = 0; i < m_timings.size() - 1; i++) {
       uint16_t delta = m_timings.peek(i+1) - m_timings.peek(i);
-      Log.notice("Timing %d Delta %d", m_timings.peek(i), delta);
+      Log.trace("bpm: Timing %d Delta %d", m_timings.peek(i), delta);
       avgDelta += delta;
     }
-    m_bpm = avgDelta / 4;
-    m_nextLearn = m_bpm * 5 + millis();
-    Log.notice("BPM is now %d", m_bpm);
+    m_msPerBeat = avgDelta / 4;
+    m_nextLearn = m_msPerBeat * 5 + millis();
+    Log.notice("bpm: BPM is now %d", msToBPM(m_msPerBeat));
     uint16_t trash;
     m_timings.take(trash);
   }