From 06023f91c92e7ba01e6c0e29d26b336928ff26b0 Mon Sep 17 00:00:00 2001
From: Chengxin Wang <w@hxdl.org>
Date: Fri, 28 Jul 2023 21:14:49 +0000
Subject: [PATCH] feat(ble): handle BLE disconnection request

- added switch `CONFIG_ZMK_HANDLE_BLE_DISCONNECTION`
- fix KinesisCorporation/Adv360-Pro-ZMK#172
---
 app/Kconfig                |  4 +++
 app/src/ble.c              | 55 +++++++++++++++++++++++++++++++-------
 docs/docs/config/system.md |  1 +
 3 files changed, 51 insertions(+), 9 deletions(-)

diff --git a/app/Kconfig b/app/Kconfig
index bc134fa8379..9661a669ac9 100644
--- a/app/Kconfig
+++ b/app/Kconfig
@@ -162,6 +162,10 @@ config ZMK_BLE_PASSKEY_ENTRY
     bool "Experimental: Requiring typing passkey from host to pair BLE connection"
     default n
 
+config ZMK_HANDLE_BLE_DISCONNECTION
+    bool "Experimental: Respect user disconnection request from computer"
+    default n
+
 config BT_PERIPHERAL_PREF_MIN_INT
     default 6
 
diff --git a/app/src/ble.c b/app/src/ble.c
index ac0e40a39af..350b72552b8 100644
--- a/app/src/ble.c
+++ b/app/src/ble.c
@@ -36,6 +36,11 @@ LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 #include <zmk/event_manager.h>
 #include <zmk/events/ble_active_profile_changed.h>
 
+#if IS_ENABLED(CONFIG_ZMK_HANDLE_BLE_DISCONNECTION)
+#include <zmk/activity.h>
+#include <zmk/events/keycode_state_changed.h>
+#endif /* IS_ENABLED(CONFIG_ZMK_HANDLE_BLE_DISCONNECTION) */
+
 #if IS_ENABLED(CONFIG_ZMK_BLE_PASSKEY_ENTRY)
 #include <zmk/events/keycode_state_changed.h>
 
@@ -68,6 +73,10 @@ enum advertising_type {
 static struct zmk_ble_profile profiles[ZMK_BLE_PROFILE_COUNT];
 static uint8_t active_profile;
 
+#if IS_ENABLED(CONFIG_ZMK_HANDLE_BLE_DISCONNECTION)
+bool active_profile_seeking_connection = true;
+#endif
+
 #define DEVICE_NAME CONFIG_BT_DEVICE_NAME
 #define DEVICE_NAME_LEN (sizeof(DEVICE_NAME) - 1)
 
@@ -173,15 +182,23 @@ int update_advertising() {
 
     if (zmk_ble_active_profile_is_open()) {
         desired_adv = ZMK_ADV_CONN;
-    } else if (!zmk_ble_active_profile_is_connected()) {
-        desired_adv = ZMK_ADV_CONN;
-        // Need to fix directed advertising for privacy centrals. See
-        // https://github.com/zephyrproject-rtos/zephyr/pull/14984 char
-        // addr_str[BT_ADDR_LE_STR_LEN]; bt_addr_le_to_str(zmk_ble_active_profile_addr(), addr_str,
-        // sizeof(addr_str));
-
-        // LOG_DBG("Directed advertising to %s", addr_str);
-        // desired_adv = ZMK_ADV_DIR;
+    } else {
+#if IS_ENABLED(CONFIG_ZMK_HANDLE_BLE_DISCONNECTION)
+        if (!zmk_ble_active_profile_is_connected() && active_profile_seeking_connection) {
+            desired_adv = ZMK_ADV_CONN;
+        }
+#else
+        if (!zmk_ble_active_profile_is_connected()) {
+            desired_adv = ZMK_ADV_CONN;
+            // Need to fix directed advertising for privacy centrals. See
+            // https://github.com/zephyrproject-rtos/zephyr/pull/14984 char
+            // addr_str[BT_ADDR_LE_STR_LEN]; bt_addr_le_to_str(zmk_ble_active_profile_addr(),
+            // addr_str, sizeof(addr_str));
+
+            // LOG_DBG("Directed advertising to %s", addr_str);
+            // desired_adv = ZMK_ADV_DIR;
+        }
+#endif /* IS_ENABLED(CONFIG_ZMK_HANDLE_BLE_DISCONNECTION) */
     }
     LOG_DBG("advertising from %d to %d", advertising_status, desired_adv);
 
@@ -268,6 +285,9 @@ int zmk_ble_prof_select(uint8_t index) {
     active_profile = index;
     ble_save_profile();
 
+#if IS_ENABLED(CONFIG_ZMK_HANDLE_BLE_DISCONNECTION)
+    active_profile_seeking_connection = true;
+#endif
     update_advertising();
 
     raise_profile_changed_event();
@@ -406,6 +426,9 @@ static void connected(struct bt_conn *conn, uint8_t err) {
     update_advertising();
 
     if (is_conn_active_profile(conn)) {
+#if IS_ENABLED(CONFIG_ZMK_HANDLE_BLE_DISCONNECTION)
+        active_profile_seeking_connection = false;
+#endif
         LOG_DBG("Active profile connected");
         k_work_submit(&raise_profile_changed_event_work);
     }
@@ -694,4 +717,18 @@ ZMK_LISTENER(zmk_ble, zmk_ble_listener);
 ZMK_SUBSCRIPTION(zmk_ble, zmk_keycode_state_changed);
 #endif /* IS_ENABLED(CONFIG_ZMK_BLE_PASSKEY_ENTRY) */
 
+#if IS_ENABLED(CONFIG_ZMK_HANDLE_BLE_DISCONNECTION)
+/* Restart BLE advertsing after user key press */
+static int ble_keypress_listener(const zmk_event_t *eh) {
+    if (as_zmk_keycode_state_changed(eh) != NULL && !active_profile_seeking_connection &&
+        !zmk_ble_active_profile_is_connected()) {
+        active_profile_seeking_connection = true;
+        k_work_submit(&update_advertising_work);
+    }
+    return 0;
+}
+ZMK_LISTENER(ble_keypress, ble_keypress_listener);
+ZMK_SUBSCRIPTION(ble_keypress, zmk_keycode_state_changed);
+#endif /* IS_ENABLED(CONFIG_ZMK_HANDLE_BLE_DISCONNECTION) */
+
 SYS_INIT(zmk_ble_init, APPLICATION, CONFIG_ZMK_BLE_INIT_PRIORITY);
diff --git a/docs/docs/config/system.md b/docs/docs/config/system.md
index 5a5ae5a55a0..b4235a17eea 100644
--- a/docs/docs/config/system.md
+++ b/docs/docs/config/system.md
@@ -77,6 +77,7 @@ for more information on configuring Bluetooth.
 | `CONFIG_ZMK_BLE_THREAD_PRIORITY`            | int  | Priority of the BLE notify thread                                     | 5       |
 | `CONFIG_ZMK_BLE_THREAD_STACK_SIZE`          | int  | Stack size of the BLE notify thread                                   | 512     |
 | `CONFIG_ZMK_BLE_PASSKEY_ENTRY`              | bool | Experimental: require typing passkey from host to pair BLE connection | n       |
+| `CONFIG_ZMK_HANDLE_BLE_DISCONNECTION`       | bool | Experimental: respect user BLE disconnection request from computer    | n       |
 
 Note that `CONFIG_BT_MAX_CONN` and `CONFIG_BT_MAX_PAIRED` should be set to the same value. On a split keyboard they should only be set for the central and must be set to one greater than the desired number of bluetooth profiles.