From 180a32ec59339cf07323412457ec771fba69ea61 Mon Sep 17 00:00:00 2001
From: Drashna Jaelre <drashna@live.com>
Date: Sun, 18 Apr 2021 23:26:37 -0700
Subject: Enhancement of WPM feature (#11727)

---
 quantum/wpm.c | 36 +++++++++++++++++++++++++++++++-----
 quantum/wpm.h | 12 ++++++++++++
 2 files changed, 43 insertions(+), 5 deletions(-)

(limited to 'quantum')

diff --git a/quantum/wpm.c b/quantum/wpm.c
index da30bd252c..c44b1172b5 100644
--- a/quantum/wpm.c
+++ b/quantum/wpm.c
@@ -19,11 +19,10 @@
 
 // WPM Stuff
 static uint8_t  current_wpm = 0;
-static uint8_t  latest_wpm  = 0;
 static uint16_t wpm_timer   = 0;
 
 // This smoothing is 40 keystrokes
-static const float wpm_smoothing = 0.0487;
+static const float wpm_smoothing = WPM_SMOOTHING;
 
 void set_current_wpm(uint8_t new_wpm) { current_wpm = new_wpm; }
 
@@ -46,19 +45,46 @@ __attribute__((weak)) bool wpm_keycode_user(uint16_t keycode) {
     return false;
 }
 
+#ifdef WPM_ALLOW_COUNT_REGRESSION
+__attribute__((weak)) uint8_t wpm_regress_count(uint16_t keycode) {
+    bool weak_modded = (keycode >= QK_LCTL && keycode < QK_LSFT) || (keycode >= QK_RCTL && keycode < QK_RSFT);
+
+    if ((keycode >= QK_MOD_TAP && keycode <= QK_MOD_TAP_MAX) || (keycode >= QK_LAYER_TAP && keycode <= QK_LAYER_TAP_MAX) || (keycode >= QK_MODS && keycode <= QK_MODS_MAX)) {
+        keycode = keycode & 0xFF;
+    } else if (keycode > 0xFF) {
+        keycode = 0;
+    }
+    if (keycode == KC_DEL || keycode == KC_BSPC) {
+        if (((get_mods() | get_oneshot_mods()) & MOD_MASK_CTRL) || weak_modded) {
+            return WPM_ESTIMATED_WORD_SIZE;
+        } else {
+            return 1;
+        }
+    } else {
+        return 0;
+    }
+}
+#endif
+
 void update_wpm(uint16_t keycode) {
     if (wpm_keycode(keycode)) {
         if (wpm_timer > 0) {
-            latest_wpm  = 60000 / timer_elapsed(wpm_timer) / 5;
-            current_wpm = (latest_wpm - current_wpm) * wpm_smoothing + current_wpm;
+            current_wpm += ((60000 / timer_elapsed(wpm_timer) / WPM_ESTIMATED_WORD_SIZE) - current_wpm) * wpm_smoothing;
         }
         wpm_timer = timer_read();
     }
+#ifdef WPM_ALLOW_COUNT_REGRESSION
+    uint8_t regress = wpm_regress_count(keycode);
+    if (regress) {
+        current_wpm -= regress;
+        wpm_timer = timer_read();
+    }
+#endif
 }
 
 void decay_wpm(void) {
     if (timer_elapsed(wpm_timer) > 1000) {
-        current_wpm = (0 - current_wpm) * wpm_smoothing + current_wpm;
+        current_wpm += (-current_wpm) * wpm_smoothing;
         wpm_timer   = timer_read();
     }
 }
diff --git a/quantum/wpm.h b/quantum/wpm.h
index 15ab4ffcd1..079401eb4d 100644
--- a/quantum/wpm.h
+++ b/quantum/wpm.h
@@ -19,10 +19,22 @@
 
 #include "quantum.h"
 
+
+#ifndef WPM_ESTIMATED_WORD_SIZE
+#    define WPM_ESTIMATED_WORD_SIZE 5
+#endif
+#ifndef WPM_SMOOTHING
+#    define WPM_SMOOTHING 0.0487
+#endif
+
 bool wpm_keycode(uint16_t keycode);
 bool wpm_keycode_kb(uint16_t keycode);
 bool wpm_keycode_user(uint16_t keycode);
 
+#ifdef WPM_ALLOW_COUNT_REGRESSION
+uint8_t wpm_regress_count(uint16_t keycode);
+#endif
+
 void    set_current_wpm(uint8_t);
 uint8_t get_current_wpm(void);
 void    update_wpm(uint16_t);
-- 
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