From 10d03ca46c84a2530701ef82e28ec018d34df905 Mon Sep 17 00:00:00 2001
From: Timoyoungster <timo.proemer04@gmail.com>
Date: Fri, 14 Jun 2024 02:28:49 +0200
Subject: [PATCH] fix: adding option to separate implicit mod release from key
 release

This adds a new config value `ZMK_HID_SEPARATE_MOD_RELEASE_REPORT`
where, if enabled, the report for a key release is sent separately to
the accompanying modifier release signals, which are then sent in a
second report.

This fixes an issue where certain applications are unable to work with
implicitly modified keys (e.g. colon) due to them registering the
modifier release prior to the actual key release.

Have tested this on my personal keyboard and `wev` now shows the signals
in the correct order.

=> **Previously:** ```LSHIFT (pressed) -> colon (pressed) -> LSHIFT
(released) -> **semi**colon (released)```

=> **Now:** ```LSHIFT (pressed) -> colon (pressed) -> colon (released)
-> LSHIFT (released)```

(This time without accidental files)
---
 app/Kconfig                |  6 ++++++
 app/src/hid_listener.c     | 13 ++++++++++++-
 docs/docs/config/system.md |  9 +++++----
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/app/Kconfig b/app/Kconfig
index 8f690175..a45f2dc2 100644
--- a/app/Kconfig
+++ b/app/Kconfig
@@ -113,6 +113,12 @@ config ZMK_HID_INDICATORS
       Enable HID indicators, used for detecting state of Caps/Scroll/Num Lock,
       Kata, and Compose.
 
+config ZMK_HID_SEPARATE_MOD_RELEASE_REPORT
+    bool "Release Modifiers Separately"
+    help
+      Send a separate release event for the modifiers, to make sure the release
+      of the modifier doesn't get recognized before the actual key's release event.
+
 menu "Output Types"
 
 config ZMK_USB
diff --git a/app/src/hid_listener.c b/app/src/hid_listener.c
index 2b847082..2d17a395 100644
--- a/app/src/hid_listener.c
+++ b/app/src/hid_listener.c
@@ -66,6 +66,17 @@ static int hid_listener_keycode_released(const struct zmk_keycode_state_changed
         return err;
     }
 
+#if IS_ENABLED(CONFIG_ZMK_HID_SEPARATE_MOD_RELEASE_REPORT)
+
+    // send report of normal key release early to fix the issue
+    // of some programs recognizing the implicit_mod release before the actual key release
+    err = zmk_endpoints_send_report(ev->usage_page);
+    if (err < 0) {
+        LOG_ERR("Failed to send key report for the released keycode (%d)", err);
+    }
+
+#endif // IS_ENABLED(CONFIG_ZMK_HID_SEPARATE_MOD_RELEASE_REPORT)
+
     explicit_mods_changed = zmk_hid_unregister_mods(ev->explicit_modifiers);
     // There is a minor issue with this code.
     // If LC(A) is pressed, then LS(B), then LC(A) is released, the shift for B will be released
@@ -73,7 +84,7 @@ static int hid_listener_keycode_released(const struct zmk_keycode_state_changed
     // Solving this would require keeping track of which key's implicit modifiers are currently
     // active and only releasing modifiers at that time.
     implicit_mods_changed = zmk_hid_implicit_modifiers_release();
-    ;
+
     if (ev->usage_page != HID_USAGE_KEY &&
         (explicit_mods_changed > 0 || implicit_mods_changed > 0)) {
         err = zmk_endpoints_send_report(HID_USAGE_KEY);
diff --git a/docs/docs/config/system.md b/docs/docs/config/system.md
index 27923453..cc342195 100644
--- a/docs/docs/config/system.md
+++ b/docs/docs/config/system.md
@@ -29,10 +29,11 @@ Making changes to any of the settings in this section modifies the HID report de
 
 :::
 
-| Config                                | Type | Description                                                    | Default |
-| ------------------------------------- | ---- | -------------------------------------------------------------- | ------- |
-| `CONFIG_ZMK_HID_INDICATORS`           | bool | Enable receipt of HID/LED indicator state from connected hosts | n       |
-| `CONFIG_ZMK_HID_CONSUMER_REPORT_SIZE` | int  | Number of consumer keys simultaneously reportable              | 6       |
+| Config                                       | Type | Description                                                    | Default |
+| -------------------------------------------- | ---- | -------------------------------------------------------------- | ------- |
+| `CONFIG_ZMK_HID_INDICATORS`                  | bool | Enable receipt of HID/LED indicator state from connected hosts | n       |
+| `CONFIG_ZMK_HID_CONSUMER_REPORT_SIZE`        | int  | Number of consumer keys simultaneously reportable              | 6       |
+| `CONFIG_ZMK_HID_SEPARATE_MOD_RELEASE_REPORT` | bool | Release the Modifiers separate from and after the modified key | n       |
 
 Exactly zero or one of the following options may be set to `y`. The first is used if none are set.