feat(split): Make locality work nested behavior invocations

Co-authored-by: Tokazio <tokazio@hotmail.com>

app/src/behavior.c

@@ -17,11 +17,18 @@
 
 #endif
 
+#include <zmk/ble.h>
+#if ZMK_BLE_IS_CENTRAL
+#include <zmk/split/bluetooth/central.h>
+#endif
+
 #include <drivers/behavior.h>
 #include <zmk/behavior.h>
 #include <zmk/hid.h>
 #include <zmk/matrix.h>
 
+#include <zmk/events/position_state_changed.h>
+
 #include <zephyr/logging/log.h>
 LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
@@ -49,6 +56,66 @@ const struct device *z_impl_behavior_get_binding(const char *name) {
     return NULL;
 }
 
+static int invoke_locally(struct zmk_behavior_binding *binding,
+                          struct zmk_behavior_binding_event event, bool pressed) {
+    if (pressed) {
+        return behavior_keymap_binding_pressed(binding, event);
+    } else {
+        return behavior_keymap_binding_released(binding, event);
+    }
+}
+
+int zmk_behavior_invoke_binding(const struct zmk_behavior_binding *src_binding,
+                                struct zmk_behavior_binding_event event, bool pressed) {
+    // We want to make a copy of this, since it may be converted from
+    // relative to absolute before being invoked
+    struct zmk_behavior_binding binding = *src_binding;
+
+    const struct device *behavior = zmk_behavior_get_binding(binding.behavior_dev);
+
+    if (!behavior) {
+        LOG_WRN("No behavior assigned to %d on layer %d", event.position, event.layer);
+        return 1;
+    }
+
+    int err = behavior_keymap_binding_convert_central_state_dependent_params(&binding, event);
+    if (err) {
+        LOG_ERR("Failed to convert relative to absolute behavior binding (err %d)", err);
+        return err;
+    }
+
+    enum behavior_locality locality = BEHAVIOR_LOCALITY_CENTRAL;
+    err = behavior_get_locality(behavior, &locality);
+    if (err) {
+        LOG_ERR("Failed to get behavior locality %d", err);
+        return err;
+    }
+
+    switch (locality) {
+    case BEHAVIOR_LOCALITY_CENTRAL:
+        return invoke_locally(&binding, event, pressed);
+    case BEHAVIOR_LOCALITY_EVENT_SOURCE:
+#if ZMK_BLE_IS_CENTRAL
+        if (event.source == ZMK_POSITION_STATE_CHANGE_SOURCE_LOCAL) {
+            return invoke_locally(&binding, event, pressed);
+        } else {
+            return zmk_split_bt_invoke_behavior(event.source, &binding, event, pressed);
+        }
+#else
+        return invoke_locally(&binding, event, pressed);
+#endif
+    case BEHAVIOR_LOCALITY_GLOBAL:
+#if ZMK_BLE_IS_CENTRAL
+        for (int i = 0; i < ZMK_SPLIT_BLE_PERIPHERAL_COUNT; i++) {
+            zmk_split_bt_invoke_behavior(i, &binding, event, pressed);
+        }
+#endif
+        return invoke_locally(&binding, event, pressed);
+    }
+
+    return -ENOTSUP;
+}
+
 #if IS_ENABLED(CONFIG_ZMK_BEHAVIOR_METADATA)
 
 int zmk_behavior_get_empty_param_metadata(const struct device *dev,