From b4bbfecd093b0032fa8795369ed914854a8b706e Mon Sep 17 00:00:00 2001
From: Kristian Sloth Lauszus <lauszus@gmail.com>
Date: Tue, 26 Jan 2021 23:41:05 +0100
Subject: [PATCH] Store the timestamp of the last Bluetooth DATA input report
 received on the interrupt channel

This can be used detect if the connection to a Bluetooth device is lost fx if the battery runs out or it gets out of range
---
 BTHID.cpp |  2 ++
 BTHID.h   | 11 +++++++++++
 2 files changed, 13 insertions(+)

diff --git a/BTHID.cpp b/BTHID.cpp
index d0d93c2e..7fb429ad 100644
--- a/BTHID.cpp
+++ b/BTHID.cpp
@@ -337,6 +337,8 @@ void BTHID::ACLData(uint8_t* l2capinbuf) {
                         }
 #endif
                         if(l2capinbuf[8] == 0xA1) { // HID BT DATA (0xA0) | Report Type (Input 0x01)
+                                lastBtDataInputIntMillis = (uint32_t)millis(); // Store the timestamp of the report
+
                                 uint16_t length = ((uint16_t)l2capinbuf[5] << 8 | l2capinbuf[4]);
                                 ParseBTHIDData((uint8_t)(length - 1), &l2capinbuf[9]); // First byte will be the report ID
 
diff --git a/BTHID.h b/BTHID.h
index f493adce..dabf70f9 100644
--- a/BTHID.h
+++ b/BTHID.h
@@ -93,6 +93,15 @@ public:
                         pBtd->pairWithHID();
         };
 
+        /**
+         * Used to get the millis() of the last Bluetooth DATA input report received on the interrupt channel.
+         * This can be used detect if the connection to a Bluetooth device is lost fx if the battery runs out or if it gets out of range.
+         * @return      Timestamp in milliseconds of the last Bluetooth DATA input report received on the interrupt channel.
+         */
+        uint32_t getLastMessageTime() {
+                return lastBtDataInputIntMillis;
+        };
+
 protected:
         /** @name BluetoothService implementation */
         /**
@@ -173,5 +182,7 @@ private:
         uint8_t interrupt_dcid[2]; // L2CAP device CID for HID_Interrupt - Always 0x0071
         uint8_t sdp_dcid[2];
         uint8_t l2cap_state;
+
+        uint32_t lastBtDataInputIntMillis; // Variable used to store the millis value of the last Bluetooth DATA input report received on the interrupt channel
 };
 #endif