feat: add home screen clock counter support

Within this commit, we introduce a device twin configuration manager.
This device twin singleton instance will hold all the details about the
hardware. Furthermore, we store the latest time information on the
device twin and update the home screen view every minute to track the
time information.

Author: electricalgorithm

src/devicetwin/devicetwin.c

@@ -0,0 +1,18 @@
+#include <stdlib.h>
+#include "devicetwin/devicetwin.h"
+
+// Function to construct a single device twin instance. This is a singleton.
+static device_twin_t* s_device_twin_instance = NULL;
+
+device_twin_t* get_device_twin_instance(void) {
+    return s_device_twin_instance;
+}
+
+device_twin_t* create_device_twin_instance(utc_time_t current_time, int8_t utc_zone) {
+    device_twin_t* instance = malloc(sizeof(device_twin_t));
+    instance->current_time = current_time;
+    instance->utc_zone = utc_zone;
+    // For now, we'll assume the singleton instance is always created.
+    s_device_twin_instance = instance;
+    return instance;
+}

src/devicetwin/devicetwin.h

@@ -0,0 +1,34 @@
+#ifndef _DEVICE_TWIN_H
+#define _DEVICE_TWIN_H
+
+#include <timeutils/timeutils.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* A struct that holds the device settings.
+ * This datatype will hold the neccesarry details
+ * about the smart-watch's daily usage such as
+ * health monitoring, time, user settings, etc.
+ */
+typedef struct {
+    utc_time_t current_time;
+    int8_t utc_zone;
+} device_twin_t;
+
+/*
+ * Function to construct a new device twin instance with given parameters.
+ */
+device_twin_t* create_device_twin_instance(utc_time_t current_timei, int8_t utc_zone);
+
+/*
+ * Factory method to get the existing or newly constructed singleton device twin instance.
+ */
+device_twin_t* get_device_twin_instance(void);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif

src/display/screens/home/home.c

@@ -3,27 +3,50 @@
 
 // Holds the home screen object.
 lv_obj_t *home_screen;
-
+lv_obj_t *label_clock;
 
 void home_screen_init() {
     // Create the screen object which is the LV object with no parent.
     home_screen = lv_obj_create(NULL);
+    // Remove the ability to scroll the screen.
     lv_obj_remove_flag(home_screen, LV_OBJ_FLAG_SCROLLABLE);
 
-    lv_obj_t *ui_ClockText = lv_label_create(home_screen);
-    lv_obj_set_width( ui_ClockText, LV_SIZE_CONTENT);  /// 2
-    lv_obj_set_height( ui_ClockText, LV_SIZE_CONTENT);   /// 2
-    lv_obj_set_align( ui_ClockText, LV_ALIGN_CENTER );
-    lv_label_set_text(ui_ClockText,"21\n14");
-    lv_obj_set_style_text_letter_space(ui_ClockText, 5, LV_PART_MAIN| LV_STATE_DEFAULT);
-    lv_obj_set_style_text_line_space(ui_ClockText, 0, LV_PART_MAIN| LV_STATE_DEFAULT);
-    lv_obj_set_style_text_align(ui_ClockText, LV_TEXT_ALIGN_AUTO, LV_PART_MAIN| LV_STATE_DEFAULT);
-    lv_obj_set_style_text_decor(ui_ClockText, LV_TEXT_DECOR_NONE, LV_PART_MAIN| LV_STATE_DEFAULT);
-    lv_obj_set_style_text_font(ui_ClockText, &lv_font_montserrat_46, LV_PART_MAIN| LV_STATE_DEFAULT);
+    // Create a new label and expand its size to content size and align it to center.
+    label_clock = lv_label_create(home_screen);
+    lv_obj_set_width(label_clock, LV_SIZE_CONTENT);
+    lv_obj_set_height(label_clock, LV_SIZE_CONTENT);
+    lv_obj_set_align(label_clock, LV_ALIGN_CENTER);
+    
+    // Set the default text.
+    lv_label_set_text(label_clock, "HH\nMM");
+
+    // Format the clock text string.
+    /* 1. Set the letter spacing to 5. (Between letters)
+     * 2. Set the line spacing to 0. (Between new lines)
+     * 3. Align the text automatically.
+     * 4. Set no decoration on the text.
+     * 5. Set the font and the size to Montserrat 46.
+     */
+    lv_obj_set_style_text_letter_space(label_clock, 5, LV_PART_MAIN | LV_STATE_DEFAULT);
+    lv_obj_set_style_text_line_space(label_clock, 0, LV_PART_MAIN | LV_STATE_DEFAULT);
+    lv_obj_set_style_text_align(label_clock, LV_TEXT_ALIGN_AUTO, LV_PART_MAIN | LV_STATE_DEFAULT);
+    lv_obj_set_style_text_decor(label_clock, LV_TEXT_DECOR_NONE, LV_PART_MAIN | LV_STATE_DEFAULT);
+    lv_obj_set_style_text_font(label_clock, &lv_font_montserrat_46, LV_PART_MAIN | LV_STATE_DEFAULT);
 
+    // Add an event handler for all possible events.
     lv_obj_add_event_cb(home_screen, home_screen_event, LV_EVENT_ALL, NULL);
 }
 
 void home_screen_event(lv_event_t * e) {
     // lv_event_code_t event_code = lv_event_get_code(e);lv_obj_t * target = lv_event_get_target(e);
 }
+
+uint8_t home_screen_set_clock(uint8_t hour, uint8_t minute) {
+    // Check if the label_clock is NULL.
+    if (label_clock == NULL) return 1;
+    // Set the text of the label_clock to the current time in 24-hour format.
+    lv_label_set_text_fmt(label_clock, "%02d:%02d", hour, minute);
+    // Update the display.
+    lv_disp_flush_ready(lv_disp_get_default());
+    return 0;
+}

src/display/screens/home/home.h

@@ -14,6 +14,9 @@ extern lv_obj_t *home_screen;
 void home_screen_init();
 void home_screen_event(lv_event_t * e);
 
+// Set the time on the clock. Returns 0 if successful, 1 otherwise.
+uint8_t home_screen_set_clock(uint8_t hour, uint8_t minute);
+
 
 #ifdef __cplusplus
 } // extern "C"

src/main.c

@@ -20,13 +20,16 @@
 #include <zephyr/drivers/pwm.h>
 
 #include "display/display.h"
+#include "display/screens/home/home.h"
 #include "timeutils/timeutils.h"
+#include "devicetwin/devicetwin.h"
 
 // Define the logger.
 LOG_MODULE_REGISTER(ZephyrWatch, LOG_LEVEL_DBG);
 
 // Global value to hold time value in UNIX time.
 uint32_t unix_time = 1748554674;
+int8_t utc_zone = +1;
 
 // Define timers to track real time.
 void update_unix_time_callback(struct k_timer *timer);
@@ -43,6 +46,13 @@ const char* weekdays[] = {
 int main(void) {
 	int ret;
 
+    // Create the device twin.
+    device_twin_t* device_twin = create_device_twin_instance(unix_to_localtime(unix_time, utc_zone), utc_zone);
+    if (!device_twin) {
+        LOG_ERR("Cannot create device twin instance.");
+        return 0;
+    }
+
 	// Start the timer to track the real time.
 	k_timer_start(&unix_time_timer, K_MSEC(0), K_MSEC(1000));
 	k_timer_start(&clock_view_timer, K_SECONDS(60), K_SECONDS(60));
@@ -98,8 +108,28 @@ void update_unix_time_callback(struct k_timer *timer) {
  * the clock view in the LVGL UI by using the unix_time variable.
  */
 void update_clock_view_callback(struct k_timer *timer) {
-    utc_time_t local = unix_to_localtime(unix_time, +1); // UTC+1
-	LOG_INF("Local : %04u-%02u-%02u %02u:%02u:%02u (%s) [UTC+1]",
-           local.year, local.month, local.day, local.hour, local.minute, local.second,
-           weekdays[local.weekday]);
+    // Get the device twin to find UTC zone.
+    device_twin_t* device_twin = get_device_twin_instance();
+
+    // Construct the local time from UNIX time and save it.
+    utc_time_t local_time = unix_to_localtime(unix_time, device_twin->utc_zone);
+    device_twin->current_time = local_time;
+
+    // Log the current time.
+    LOG_INF("Setting new time. %04u-%02u-%02u %02u:%02u:%02u (%s) [UTC %d]",
+        device_twin->current_time.year,
+        device_twin->current_time.month,
+        device_twin->current_time.day,
+        device_twin->current_time.hour,
+        device_twin->current_time.minute,
+        device_twin->current_time.second,
+        weekdays[device_twin->current_time.weekday],
+        device_twin->utc_zone
+    );
+
+    // Update the clock view.
+    uint8_t ret = home_screen_set_clock(device_twin->current_time.hour, device_twin->current_time.minute);
+    if (ret != 0) {
+        LOG_ERR("Failed to update the clock view.");
+    }
 }