feat: add data manager system for background weather/calendar fetching

src/data/data_manager.cpp

@@ -0,0 +1,93 @@
+#include "data_manager.h"
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+
+namespace {
+
+constexpr unsigned long REFRESH_INTERVAL_MS = 10UL * 60UL * 1000UL;
+constexpr uint32_t TASK_STACK_WORDS = 16384; // 64 KB — JSON parsing needs headroom
+
+// --- Shared state between background task and main loop ---
+// The task is the only writer of s_weather/s_calendar; the main loop is the
+// only reader. Access to the data structs is serialized via s_mux (a
+// portMUX_TYPE critical section which, on ESP32, suspends task switches on
+// the current core). Simple flag/counter reads (bool/uint32_t) are atomic
+// on 32-bit Xtensa and only need `volatile`.
+static WeatherData s_weather;
+static CalendarData s_calendar;
+static volatile bool s_weatherOk = false;
+static volatile bool s_calendarOk = false;
+static volatile bool s_loading = false;
+static volatile uint32_t s_dataVersion = 0;
+static volatile unsigned long s_lastFetchMs = 0;
+static volatile bool s_refreshRequested = false;
+static portMUX_TYPE s_mux = portMUX_INITIALIZER_UNLOCKED;
+
+static void dataFetchTask(void *param) {
+    (void)param;
+    while (true) {
+        bool needRefresh = s_refreshRequested ||
+                           s_lastFetchMs == 0 ||
+                           (millis() - s_lastFetchMs) >= REFRESH_INTERVAL_MS;
+
+        if (needRefresh) {
+            s_refreshRequested = false;
+            s_loading = true;
+
+            WeatherData w = fetchWeather();
+            CalendarData c = fetchCalendar();
+
+            portENTER_CRITICAL(&s_mux);
+            if (w.valid) {
+                s_weather = std::move(w);
+                s_weatherOk = true;
+            } else {
+                s_weatherOk = false;
+            }
+            if (c.valid) {
+                s_calendar = std::move(c);
+                s_calendarOk = true;
+            } else {
+                s_calendarOk = false;
+            }
+            s_dataVersion++;
+            s_lastFetchMs = millis();
+            s_loading = false;
+            portEXIT_CRITICAL(&s_mux);
+        }
+
+        vTaskDelay(pdMS_TO_TICKS(1000));
+    }
+}
+
+} // namespace
+
+void dataManager_begin() {
+    s_lastFetchMs = 0; // ensure first iteration fetches immediately
+    xTaskCreatePinnedToCore(dataFetchTask, "dataFetch", TASK_STACK_WORDS,
+                            nullptr, 1, nullptr, 1);
+}
+
+void dataManager_tick() {}
+
+void dataManager_triggerRefresh() {
+    s_refreshRequested = true;
+}
+
+void dataManager_getWeather(WeatherData &out) {
+    portENTER_CRITICAL(&s_mux);
+    out = s_weather;
+    portEXIT_CRITICAL(&s_mux);
+}
+
+void dataManager_getCalendar(CalendarData &out) {
+    portENTER_CRITICAL(&s_mux);
+    out = s_calendar;
+    portEXIT_CRITICAL(&s_mux);
+}
+
+bool dataManager_isWeatherOk()    { return s_weatherOk; }
+bool dataManager_isCalendarOk()   { return s_calendarOk; }
+bool dataManager_isLoading()      { return s_loading; }
+uint32_t dataManager_dataVersion() { return s_dataVersion; }
+unsigned long dataManager_lastFetchMs() { return s_lastFetchMs; }

src/data/data_manager.h

@@ -0,0 +1,35 @@
+#pragma once
+#include <Arduino.h>
+#include "api/weather_api.h"
+#include "api/calendar_api.h"
+
+// Centralized async data manager for weather + calendar.
+//
+// A background FreeRTOS task fetches weather and calendar data every 10
+// minutes (or on manual trigger). Results are cached in memory and exposed
+// to the UI screens via thread-safe getters.
+//
+// Screens poll dataManager_dataVersion() in their tick_fn to detect changes
+// and re-render from cache. Navigation between screens never blocks on a
+// fetch — views always render instantly from whatever is cached.
+
+// Create the background task and trigger the initial fetch. Call once in setup().
+void dataManager_begin();
+
+// No-op for now (background task runs independently). Reserved for future use.
+void dataManager_tick();
+
+// Request a manual refresh (non-blocking). The background task picks this up
+// within ~1 second.
+void dataManager_triggerRefresh();
+
+// Thread-safe copy of the cached weather/calendar data into `out`.
+void dataManager_getWeather(WeatherData &out);
+void dataManager_getCalendar(CalendarData &out);
+
+// Status flags (safe to read from the main loop without a mutex).
+bool dataManager_isWeatherOk();
+bool dataManager_isCalendarOk();
+bool dataManager_isLoading();
+uint32_t dataManager_dataVersion();
+unsigned long dataManager_lastFetchMs();