Strider.c

#include <pebble.h>

static Window *s_window;
static Layer *s_window_layer;
static TextLayer *s_time_layer, *s_step_layer;

static char s_current_time_buffer[8], s_current_steps_buffer[16];
static int s_step_count = 0, s_step_goal = 0, s_step_average = 0;

// Is step data available?
bool step_data_is_available() {
  return HealthServiceAccessibilityMaskAvailable &
    health_service_metric_accessible(HealthMetricStepCount,
      time_start_of_today(), time(NULL));
}

// Daily step goal
static void get_step_goal() {
  const time_t start = time_start_of_today();
  const time_t end = start + SECONDS_PER_DAY;
  s_step_goal = (int)health_service_sum_averaged(HealthMetricStepCount,
    start, end, HealthServiceTimeScopeDaily);
}

// Todays current step count
static void get_step_count() {
  s_step_count = (int)health_service_sum_today(HealthMetricStepCount);
}

// Average daily step count for this time of day
static void get_step_average() {
  const time_t start = time_start_of_today();
  const time_t end = time(NULL);
  s_step_average = (int)health_service_sum_averaged(HealthMetricStepCount,
    start, end, HealthServiceTimeScopeDaily);
}

static void display_step_count() {
  int thousands = s_step_count / 1000;
  int hundreds = s_step_count % 1000;
  static char s_emoji[5];

  if(s_step_count >= s_step_average) {
    text_layer_set_text_color(s_step_layer, GColorJaegerGreen);
    snprintf(s_emoji, sizeof(s_emoji), "\U0001F60C");
  } else {
    text_layer_set_text_color(s_step_layer, GColorPictonBlue);
    snprintf(s_emoji, sizeof(s_emoji), "\U0001F4A9");
  }

  if(thousands > 0) {
    snprintf(s_current_steps_buffer, sizeof(s_current_steps_buffer),
      "%d,%03d %s", thousands, hundreds, s_emoji);
  } else {
    snprintf(s_current_steps_buffer, sizeof(s_current_steps_buffer),
      "%d %s", hundreds, s_emoji);
  }

  text_layer_set_text(s_step_layer, s_current_steps_buffer);
}

static void health_handler(HealthEventType event, void *context) {
  if(event == HealthEventSignificantUpdate) {
    get_step_goal();
  }
  if(event != HealthEventSleepUpdate) {
    get_step_count();
    display_step_count();
  }
}

static void tick_handler(struct tm *tick_time, TimeUnits changed) {
  strftime(s_current_time_buffer, sizeof(s_current_time_buffer),
           clock_is_24h_style() ? "%H:%M" : "%l:%M", tick_time);

  text_layer_set_text(s_time_layer, s_current_time_buffer);
}

static void window_load(Window *window) {
  GRect window_bounds = layer_get_bounds(s_window_layer);

  // Create a layer to hold the current time
  s_time_layer = text_layer_create(
      GRect(0, PBL_IF_ROUND_ELSE(82, 78), window_bounds.size.w, 38));
  text_layer_set_text_color(s_time_layer, GColorWhite);
  text_layer_set_background_color(s_time_layer, GColorClear);
  text_layer_set_font(s_time_layer,
                      fonts_get_system_font(FONT_KEY_BITHAM_30_BLACK));
  text_layer_set_text_alignment(s_time_layer, GTextAlignmentCenter);
  layer_add_child(s_window_layer, text_layer_get_layer(s_time_layer));

  // Create a layer to hold the current step count
  s_step_layer = text_layer_create(
      GRect(0, PBL_IF_ROUND_ELSE(58, 54), window_bounds.size.w, 38));
  text_layer_set_background_color(s_step_layer, GColorClear);
  text_layer_set_font(s_step_layer,
                      fonts_get_system_font(FONT_KEY_GOTHIC_24_BOLD));
  text_layer_set_text_alignment(s_step_layer, GTextAlignmentCenter);
  layer_add_child(s_window_layer, text_layer_get_layer(s_step_layer));

  // Subscribe to health events if we can
  if(step_data_is_available()) {
    health_service_events_subscribe(health_handler, NULL);
  }
}

static void window_unload(Window *window) {
  layer_destroy(text_layer_get_layer(s_time_layer));
  layer_destroy(text_layer_get_layer(s_step_layer));
}

void init() {
  s_window = window_create();
  s_window_layer = window_get_root_layer(s_window);
  window_set_background_color(s_window, GColorBlack);

  window_set_window_handlers(s_window, (WindowHandlers) {
    .load = window_load,
    .unload = window_unload
  });

  window_stack_push(s_window, true);

  tick_timer_service_subscribe(MINUTE_UNIT, tick_handler);
}

void deinit() {}

int main() {
  init();
  app_event_loop();
  deinit();
}