feature: add ping counting and name filtering

Related to digital-twin/twinzo/initiatives#4

Added counting of ping from unique & duplicate devices, this was we can
estimate how many of their pings are being captured per second.
Also added name filtering for our beacons, with the name "INFOTECH".

main/main.cpp

@@ -15,12 +15,15 @@
 
 #include <string>
 #include <unordered_set>
+#include <algorithm>
 
 #define LOG_LOCAL_LEVEL ESP_LOG_DEBUG
 
 static const char* TAG = "main";
 
 std::unordered_set<std::string> devices;
+uint8_t unique_pings = 0;
+uint16_t total_pings = 0;
 
 static esp_ble_scan_params_t ble_scan_params = {
   .scan_type          = BLE_SCAN_TYPE_ACTIVE,
@@ -93,6 +96,8 @@ void app_main(void) {
       ESP_LOGE(TAG, "set scan params error, error code = %x", ret);
     }
 
+    unique_pings = 0;
+    total_pings = 0;
     devices.clear();
     // Set scan duration to 30s, we can control it with the delay below
     esp_ble_gap_start_scanning(30);
@@ -100,7 +105,10 @@ void app_main(void) {
     vTaskDelay(pdMS_TO_TICKS(2000));
     ESP_ERROR_CHECK(esp_ble_gap_stop_scanning());
 
-    vTaskDelay(1);
+    ESP_LOGI(TAG, "[%s]: Unique devices captured: %u", __func__, unique_pings);
+    ESP_LOGI(TAG, "[%s]: Total pings captured: %u", __func__, total_pings);
+
+    vTaskDelay(2);
     ESP_LOGI(TAG, "[%s]: Slep", __func__);
     esp_light_sleep_start();
     ESP_LOGI(TAG, "[%s]: Wakey", __func__);
@@ -133,17 +141,26 @@ static void esp_gap_cb(
         snprintf(mac, 18, "%.2x %.2x %.2x %.2x %.2x %.2x",
           addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);
 
-        if (devices.find(mac) == devices.end()) {
-          devices.insert(mac);
-          adv_name = esp_ble_resolve_adv_data(
-            scan_result->scan_rst.ble_adv,
-            ESP_BLE_AD_TYPE_NAME_CMPL,
-            &adv_name_len
-          );
-          
-          ESP_LOGI(TAG, "%s (%ddBm, %.*s)", 
-            mac, scan_result->scan_rst.rssi, adv_name_len, adv_name);
-        } else {
+        adv_name = esp_ble_resolve_adv_data(
+          scan_result->scan_rst.ble_adv,
+          ESP_BLE_AD_TYPE_NAME_CMPL,
+          &adv_name_len
+        );
+
+        if (adv_name_len > 0 && strncmp(
+            (char*) adv_name, "INFOTECH", std::min(adv_name_len, (uint8_t) 8)
+          ) == 0
+        ) {
+          if (devices.find(mac) == devices.end()) {
+            devices.insert(mac);
+            unique_pings += 1;
+
+            ESP_LOGI(TAG, "%s (%ddBm, %.*s)", 
+              mac, scan_result->scan_rst.rssi, adv_name_len, adv_name); 
+          }
+
+          // Also count duplicates here
+          total_pings += 1;
           ESP_LOGD(TAG, "%s", mac);
         }