add Baby kicks face (#70)

watch-faces/complication/baby_kicks_face.h

@@ -0,0 +1,132 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2025 Gábor Nyéki
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#pragma once
+
+/*
+ * Baby kicks face
+ *
+ * Count the movements of your in-utero baby.
+ *
+ * Background:
+ *
+ * This practice is recommended particularly in the third trimester
+ * (from week 28 onwards).  The exact recommendations vary as to how to
+ * count the baby's movements.  Some recommend drawing a chart with the
+ * number of "kicks" within a 12-hour period:
+ *
+ * - https://en.wikipedia.org/wiki/Kick_chart
+ *
+ * Others recommend measuring the time that it takes for the baby to
+ * "kick" 10 times:
+ *
+ * - https://my.clevelandclinic.org/health/articles/23497-kick-counts
+ * - https://healthy.kaiserpermanente.org/health-wellness/health-encyclopedia/he.pregnancy-kick-counts.aa107042
+ *
+ * (Of course, not every movement that the baby makes is a kick, and we
+ * are interested in all movements, not only kicks.)
+ *
+ * This watch face follows the latter set of recommendations.  When you
+ * start the counter, it measures the number of elapsed minutes, and it
+ * tracks the number of movements as you increment the counter.  Since
+ * some consecutive movements made by the baby are actually part of a
+ * longer maneuver, the watch face also displays the number of
+ * one-minute stretches in which the baby moved at least once.
+ *
+ * Usage:
+ *
+ * - ALARM button, short press:
+ *   * start the counter if it isn't running
+ *   * increment the count otherwise
+ * - ALARM button, long press: undo the last count
+ * - MODE button, long press: reset the count to zero
+ *
+ * The watch face displays two numbers in the "clock digits" positions:
+ *
+ * 1. Count of movements (in the "second" and "minute" positions).
+ * 2. Count of one-minute stretches in which at least one movement
+ *    occurred (in the "hour" position).
+ *
+ * The number of elapsed minutes, up to and including 29, is shown in
+ * the "day digits" position.  Due to the limitations of the classic LCD
+ * display, completed 30-minute intervals are shown in the "weekday
+ * digits" position.  The total number of elapsed minutes is the sum of
+ * these two numbers.
+ *
+ * The watch face times out after 99 minutes, since it cannot display
+ * more than 99 one-minute stretches in the "hour" position.  When this
+ * happens, the "weekday digits" position shows "TO".
+ */
+
+#include "movement.h"
+
+typedef enum {
+    BABY_KICKS_MODE_SPLASH = 0,
+    BABY_KICKS_MODE_ACTIVE,
+    BABY_KICKS_MODE_TIMED_OUT,
+    BABY_KICKS_MODE_LE_MODE,
+} baby_kicks_mode_t;
+
+/* Stop counting after 99 minutes.  The classic LCD cannot display any
+ * larger number in the "weekday digits" position. */
+#define BABY_KICKS_TIMEOUT 99
+
+/* Ring buffer to store and allow undoing up to 10 movements. */
+typedef struct {
+    /* For each movement in the undo buffer, this array stores the value
+     * of `state->stretch_count` right before the movement was
+     * recorded.  This is used for decrementing `state->stretch_count`
+     * as part of the undo operation if necessary. */
+    uint8_t stretches[10];
+
+    /* Index of the next available slot in `.stretches`. */
+    uint8_t head;
+} baby_kicks_undo_buffer_t;
+
+typedef struct {
+    bool currently_displayed;
+    baby_kicks_mode_t mode;
+    watch_date_time_t now;
+    uint32_t start;
+    uint32_t latest_stretch_start;
+    uint8_t stretch_count;   /* Between 0 and `BABY_KICKS_TIMEOUT`. */
+    uint16_t movement_count; /* Between 0 and 9999. */
+    baby_kicks_undo_buffer_t undo_buffer;
+} baby_kicks_state_t;
+
+void baby_kicks_face_setup(uint8_t watch_face_index, void **context_ptr);
+void baby_kicks_face_activate(void *context);
+bool baby_kicks_face_loop(movement_event_t event, void *context);
+void baby_kicks_face_resign(void *context);
+movement_watch_face_advisory_t baby_kicks_face_advise(void *context);
+
+#define baby_kicks_face ((const watch_face_t) { \
+    baby_kicks_face_setup, \
+    baby_kicks_face_activate, \
+    baby_kicks_face_loop, \
+    baby_kicks_face_resign, \
+    baby_kicks_face_advise, \
+})