next iteration on display, still some artifacting issues, and ux with buttons states and updating

main/api/ha_data.h

@@ -56,6 +56,27 @@ typedef struct {
     bool dimmable;
 } ha_light_cfg_t;
 
+/*
+ * Which way a reading has moved over the last hour.
+ *
+ * UNKNOWN is deliberately 0 so a freshly wiped ha_data_t renders no arrow --
+ * after boot there is no history, and "no arrow" is the honest display until
+ * at least HA_TREND_MIN_AGE_MS of samples exist.
+ */
+typedef enum {
+    HA_TREND_UNKNOWN = 0,
+    HA_TREND_FLAT,
+    HA_TREND_RISING,
+    HA_TREND_FALLING,
+} ha_trend_t;
+
+enum {
+    HA_TREND_CH_INDOOR = 0,
+    HA_TREND_CH_OUTDOOR,
+    HA_TREND_CH_PRESSURE,
+    HA_TREND_CHANNELS,
+};
+
 /* Generated from HA_LIGHT_LIST; index-aligned with ha_data_t.lights. */
 extern const ha_light_cfg_t HA_LIGHTS[HA_LIGHT_COUNT];
 
@@ -93,6 +114,16 @@ typedef struct {
 
     ha_forecast_day_t forecast[HA_FORECAST_DAYS];
     uint8_t forecast_count;   /* 0 when no forecast has been fetched yet */
+
+    /*
+     * Filled by the CALLER after parsing, from ha_trend_feed/compute --
+     * the parser wipes them to UNKNOWN. Local ring-buffer history, not an HA
+     * query: an /api/history call returns hundreds of points per entity,
+     * which is silly when the device already sees every reading each poll.
+     */
+    ha_trend_t trend_indoor;
+    ha_trend_t trend_outdoor;
+    ha_trend_t trend_pressure;
 } ha_data_t;
 
 /*
@@ -133,4 +164,19 @@ const char *ha_condition_short(const char *slug);
 /* Compass point for a bearing in degrees ("NNE"). */
 const char *ha_wind_cardinal(float degrees);
 
+/*
+ * Trend tracking. Feed one sample per poll; compute compares the newest
+ * sample against the one closest to an hour old. Timestamps come from the
+ * caller (lv_tick_get() or xTaskGetTickCount-derived ms) so this file stays
+ * free of LVGL and FreeRTOS. Wrap-safe on uint32 ms.
+ *
+ * compute returns UNKNOWN until the oldest usable sample is at least
+ * HA_TREND_MIN_AGE_MS old -- "trending" over 90 seconds is noise.
+ */
+#define HA_TREND_WINDOW_MS  (60u * 60u * 1000u)
+#define HA_TREND_MIN_AGE_MS (5u * 60u * 1000u)
+
+void ha_trend_feed(int channel, float value, uint32_t now_ms);
+ha_trend_t ha_trend_compute(int channel, float threshold_per_hour, uint32_t now_ms);
+
 #endif