From 538cf3cd0b4d97afb5f8a97bd1b26c37f2dcdfe6 Mon Sep 17 00:00:00 2001
From: jmding8 <44815547+jmding8@users.noreply.github.com>
Date: Sat, 12 Jun 2021 08:49:51 -0700
Subject: [PATCH] :Add required keys for tap-hold behaviors

---
 app/dts/behaviors/mod_tap.dtsi                |  1 +
 .../behaviors/zmk,behavior-hold-tap.yaml      |  4 ++
 app/src/behaviors/behavior_hold_tap.c         | 53 +++++++++++++++++--
 3 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/app/dts/behaviors/mod_tap.dtsi b/app/dts/behaviors/mod_tap.dtsi
index 7a98713c3b2c..4293e61edf21 100644
--- a/app/dts/behaviors/mod_tap.dtsi
+++ b/app/dts/behaviors/mod_tap.dtsi
@@ -13,6 +13,7 @@
 			flavor = "hold-preferred";
 			tapping-term-ms = <200>;
 			bindings = <&kp>, <&kp>;
+			hold-enabler-keys = <0>;
 		};
 	};
 };
diff --git a/app/dts/bindings/behaviors/zmk,behavior-hold-tap.yaml b/app/dts/bindings/behaviors/zmk,behavior-hold-tap.yaml
index f46b36a47fc9..bf0c0175fad5 100644
--- a/app/dts/bindings/behaviors/zmk,behavior-hold-tap.yaml
+++ b/app/dts/bindings/behaviors/zmk,behavior-hold-tap.yaml
@@ -30,3 +30,7 @@ properties:
       - "tap-preferred"
   retro-tap:
     type: boolean
+  hold-enabler-keys:
+    type: array
+    required: false
+    default: []
diff --git a/app/src/behaviors/behavior_hold_tap.c b/app/src/behaviors/behavior_hold_tap.c
index c83305de0ef8..df9ea735e79f 100644
--- a/app/src/behaviors/behavior_hold_tap.c
+++ b/app/src/behaviors/behavior_hold_tap.c
@@ -58,6 +58,8 @@ struct behavior_hold_tap_config {
     int quick_tap_ms;
     enum flavor flavor;
     bool retro_tap;
+    int32_t hold_enabler_keys[ZMK_KEYMAP_LEN];
+    int32_t hold_enabler_keys_len;
 };
 
 // this data is specific for each hold-tap
@@ -90,6 +92,8 @@ struct last_tapped {
 
 struct last_tapped last_tapped;
 
+bool is_key_position_pressed[ZMK_KEYMAP_LEN] = {0};
+
 static void store_last_tapped(struct active_hold_tap *hold_tap) {
     last_tapped.position = hold_tap->position;
     last_tapped.tap_deadline = hold_tap->timestamp + hold_tap->config->quick_tap_ms;
@@ -217,16 +221,38 @@ static void clear_hold_tap(struct active_hold_tap *hold_tap) {
     hold_tap->work_is_cancelled = false;
 }
 
+static bool
+are_any_hold_enabler_keys_pressed(const struct behavior_hold_tap_config *hold_tap_config) {
+    struct behavior_hold_tap_config config = *hold_tap_config;
+    if (hold_tap_config->hold_enabler_keys_len == 0) {
+        return true;
+    }
+    for (int i = 0; i < hold_tap_config->hold_enabler_keys_len; i++) {
+        if (is_key_position_pressed[config.hold_enabler_keys[i]]) {
+            return true;
+        }
+    }
+    return false;
+}
+
 static void decide_balanced(struct active_hold_tap *hold_tap, enum decision_moment event) {
     switch (event) {
     case HT_KEY_UP:
         hold_tap->status = STATUS_TAP;
         return;
     case HT_OTHER_KEY_UP:
-        hold_tap->status = STATUS_HOLD_INTERRUPT;
+        if (are_any_hold_enabler_keys_pressed(hold_tap->config)) {
+            hold_tap->status = STATUS_HOLD_INTERRUPT;
+        } else {
+            hold_tap->status = STATUS_TAP;
+        }
         return;
     case HT_TIMER_EVENT:
-        hold_tap->status = STATUS_HOLD_TIMER;
+        if (are_any_hold_enabler_keys_pressed(hold_tap->config)) {
+            hold_tap->status = STATUS_HOLD_TIMER;
+        } else {
+            hold_tap->status = STATUS_TAP;
+        }
         return;
     case HT_QUICK_TAP:
         hold_tap->status = STATUS_TAP;
@@ -242,7 +268,11 @@ static void decide_tap_preferred(struct active_hold_tap *hold_tap, enum decision
         hold_tap->status = STATUS_TAP;
         return;
     case HT_TIMER_EVENT:
-        hold_tap->status = STATUS_HOLD_TIMER;
+        if (are_any_hold_enabler_keys_pressed(hold_tap->config)) {
+            hold_tap->status = STATUS_HOLD_TIMER;
+        } else {
+            hold_tap->status = STATUS_TAP;
+        }
         return;
     case HT_QUICK_TAP:
         hold_tap->status = STATUS_TAP;
@@ -258,10 +288,18 @@ static void decide_hold_preferred(struct active_hold_tap *hold_tap, enum decisio
         hold_tap->status = STATUS_TAP;
         return;
     case HT_OTHER_KEY_DOWN:
-        hold_tap->status = STATUS_HOLD_INTERRUPT;
+        if (are_any_hold_enabler_keys_pressed(hold_tap->config)) {
+            hold_tap->status = STATUS_HOLD_INTERRUPT;
+        } else {
+            hold_tap->status = STATUS_TAP;
+        }
         return;
     case HT_TIMER_EVENT:
-        hold_tap->status = STATUS_HOLD_TIMER;
+        if (are_any_hold_enabler_keys_pressed(hold_tap->config)) {
+            hold_tap->status = STATUS_HOLD_TIMER;
+        } else {
+            hold_tap->status = STATUS_TAP;
+        }
         return;
     case HT_QUICK_TAP:
         hold_tap->status = STATUS_TAP;
@@ -498,6 +536,9 @@ static const struct behavior_driver_api behavior_hold_tap_driver_api = {
 static int position_state_changed_listener(const zmk_event_t *eh) {
     struct zmk_position_state_changed *ev = as_zmk_position_state_changed(eh);
 
+    // Update key position state.
+    is_key_position_pressed[ev->position] = ev->state;
+
     update_hold_status_for_retro_tap(ev->position);
 
     if (undecided_hold_tap == NULL) {
@@ -608,6 +649,8 @@ static struct behavior_hold_tap_data behavior_hold_tap_data;
         .quick_tap_ms = DT_INST_PROP(n, quick_tap_ms),                                             \
         .flavor = DT_ENUM_IDX(DT_DRV_INST(n), flavor),                                             \
         .retro_tap = DT_INST_PROP(n, retro_tap),                                                   \
+        .hold_enabler_keys = DT_INST_PROP(n, hold_enabler_keys),                                   \
+        .hold_enabler_keys_len = DT_INST_PROP_LEN(n, hold_enabler_keys),                           \
     };                                                                                             \
     DEVICE_AND_API_INIT(behavior_hold_tap_##n, DT_INST_LABEL(n), behavior_hold_tap_init,           \
                         &behavior_hold_tap_data, &behavior_hold_tap_config_##n, APPLICATION,       \