Refactored nodemcu/statusclient

- Fix init_wifi: removed `ESP8266WiFiMulti`; replaced with simple
  wifi ap connection
- Fix send_status: refactored return type into `bool`
- Fix send_status: optimized if-branch for calculation of `status` into
  array access
- Fix send_status: removed `client.connected()` => `client.connect(...)`
  is enough
- Fix: renamed `reed` into `read`
- Cleanup: changed int variables into uint8_t
- Cleanup: moved static data (`ca_certs`, `client_cert/key` into global
  data
- Style: changed typedef enum into scoped enum (enum class decl)
- Style: changed int const definitions into anonymous enum constants
- Style: reorderd headers alphabetically

source/client/nodemcu/statusclient/statusclient.ino

@@ -1,31 +1,46 @@
 /*
  * file: statusclient.ino
  * desc: This file is part of the Krautspace Doorstatus project. It's the
- * main file for a client, who deals with the input from a reed sensor and
+ * main file for a client, who deals with the input from a read sensor and
  * push these values to a server. The code is make to run on a NodeMCU with
  * ESP8266 chip. 
  */
 
-#include <ESP8266WiFiMulti.h>
-#include <WiFiClientSecure.h>
 #include <time.h>
+#include <ESP8266WiFi.h>
+#include <WiFiClientSecure.h>
 
-#include "config.h"
 #include "certs.h"
+#include "config.h"
 #include "credentials.h"
 
-const int LED_PIN = 16; // D0
+// cpp23 utility
-const int REED_PIN = 5; // D1
+namespace cpp23 {
+    template <typename Enum>
+    constexpr std::underlying_type_t<Enum> to_underlying(Enum e) noexcept { return static_cast<std::underlying_type_t<Enum>>(e);}
+}
 
-typedef enum {
+// defining some constants
-    DOOR_CLOSED = 0,
+enum : int {
-    DOOR_OPEN = 1
+    LED_PIN = 16, // D0
-}   door_state;
+    READ_PIN = 5 // D1
-door_state current_door_state = DOOR_CLOSED;
+};
 
-BearSSL::WiFiClientSecure client;
+enum class door_state {
+    closed = 0,
+    open = 1
+};
 
-void blink_led(int blink_count, int delay_time) {
+// defining some globals
+static inline door_state current_door_state = door_state::closed;
+constexpr static inline std::array<char const[2], 2> state_str {{"0", "1"}};
+
+// initializing 
+static inline BearSSL::X509List const ca_certs { CA_CERTS };
+static inline BearSSL::X509List const client_cert { CLIENT_CERT };
+static inline BearSSL::PrivateKey const client_key { CLIENT_KEY };
+
+void blink_led(uint8_t blink_count, uint8_t delay_time) {
     /*
      * zur ausgabe von meldungen blinkt die interne led.
      * erfolgreichesmeldungen werden durch kurze blinkzeichen angezeigt,
@@ -39,7 +54,7 @@ void blink_led(int blink_count, int delay_time) {
      * param 1: integer
      * param 2: integer
      */
-    for(int i=0; i!= blink_count; ++i) {
+    for (; blink_count; --blink_count) {
         digitalWrite(LED_PIN, LOW);
         delay(delay_time);
         digitalWrite(LED_PIN, HIGH);
@@ -53,58 +68,45 @@ void init_serial() {
      */
     Serial.begin(BAUD_RATE);
     Serial.setDebugOutput(DEBUG);
-    Serial.println();
+    Serial.println("\n[Srl] Serial interface initialized");
-    Serial.println("[Srl] Serial interface initialized");
 }
 
 void init_pins() {
     /*
-     *   set gpio for reed sensor and led
+     * set gpio for read sensor and led
      */
-    pinMode(REED_PIN, INPUT_PULLUP);
+    pinMode(READ_PIN, INPUT_PULLUP);
     pinMode(LED_PIN, OUTPUT);
     digitalWrite(LED_PIN, HIGH);
-    Serial.println("[Pin] LED and REED initialized");
+    Serial.println("[Pin] LED and READ initialized");
 }
 
 void init_wifi() {
-    /*
+    WiFi.begin(SSID, PSK);
-     * Creates the ssl context. Turns wifi off and than into
+    Serial.println("[WiFi] Wifi initialized");
-     * access point mode.
+    
-     * TODO: is 'turn of' needed!
+    while (WiFi.status() != WL_CONNECTED) {
-     */
+        Serial.println("[WiFi] Error: Failed to connect");
-    ESP8266WiFiMulti wifi;
-    WiFi.mode(WIFI_OFF);
-    WiFi.mode(WIFI_STA);
-    wifi.addAP(SSID_1, PSK_1);
-    wifi.addAP(SSID_2, NULL);
-    Serial.println("[Wifi] Wifi initialized");
-    wifi.run();
-    if (WiFi.status() == WL_CONNECTED) {
-        Serial.print("[Wif] Connected to ");
-        Serial.println(WiFi.SSID());
-        Serial.print("[Wifi] IP: ");
-        Serial.println(WiFi.localIP());
-        set_clock();
-  } else {
-        Serial.println("[Wifi] Error: Failed to connect");
         blink_led(3, 500);
     }
+    
+    Serial.printf("[WiFi] Connected to %s\n", WiFi.SSID());
+    Serial.print("[WiFi] IP: ");
+    Serial.println(WiFi.localIP());
+    
+    set_clock();
 }
 
 door_state read_door_state() {
     /* 
-     *  die initialisierung des reed-pin mit pullup bewirkt, daß am pin
+     *  die initialisierung des read-pin mit pullup bewirkt, daß am pin
      *  3,3 volt anliegen. die verbindung des pins mit GND sorgt dafür,
      *  daß die spannung "abfließen" kann. dadurch hat der pin dann den
      *  status 'low'.
-     *  geschlossene tür -> reed geschlossen -> low
+     *  geschlossene tür -> read geschlossen -> low
-     *  geöffnete tür -> reed offen -> high
+     *  geöffnete tür -> read offen -> high
      */
-    if (digitalRead(REED_PIN) == HIGH) {
+    return (digitalRead(READ_PIN) == HIGH) ? door_state::open : door_state::closed;
-     return DOOR_OPEN;
-    }
-    return DOOR_CLOSED;
 }
 
 void set_clock() {
@@ -115,58 +117,45 @@ void set_clock() {
 
     Serial.print("[Clock] Waiting for NTP time sync");
     time_t now = time(nullptr);
-    while (now < 8 * 3600 * 2) {
+    for (; now < 16 * 3600; now = time(nullptr)) { // 16 hours
         delay(500);
         Serial.print(".");
-        now = time(nullptr);
     }
     Serial.println("");
     struct tm timeinfo;
     gmtime_r(&now, &timeinfo);
-    Serial.print("[Clock] Current time: ");
+    Serial.printf("[Clock] Current time: %s\n", asctime(&timeinfo));
-    Serial.println(asctime(&timeinfo));
 }
 
-int send_status(door_state state) {
+bool send_status(door_state state) {
-
     /*
      * Inits wifi (if needed) and send the status
      */
-    char status[2] = "";
+    char const* const status = state_str[cpp23::to_underlying(state)];
 
-    if (state == DOOR_CLOSED) {
+    BearSSL::WiFiClientSecure client;
-        strncpy(status, "0", 1);
+    client.setTrustAnchors(&ca_certs);
-    } else if (state == DOOR_OPEN) {
-        strncpy(status, "1", 1);
-    } else {
-        return 1;
-    }
-
-    BearSSL::X509List server_cert(SERVER_CERT);
-    BearSSL::X509List client_cert(CLIENT_CERT);
-    BearSSL::PrivateKey client_key(CLIENT_KEY);
-    client.setTrustAnchors(&server_cert);
     client.setClientRSACert(&client_cert, &client_key);
+
     Serial.println("[Ctx] SSL Context initialized");
     Serial.printf("[Send] Connect to %s:%i\n", SERVER_URL, SERVER_PORT); 
-    client.connect(SERVER_URL, SERVER_PORT);
+    
-    if (!client.connected()) {
+    if (!client.connect(SERVER_URL, SERVER_PORT)) {
         Serial.println("[Send] Can't connect to server");
-        Serial.print("[Send] SSL Error: ");
+        Serial.printf("[Send] SSL Error: %d\n", client.getLastSSLError());
-        Serial.println(client.getLastSSLError());
         client.stop();
-        return 1;
+        return false;
-    } else {
+    }
-        ESP.resetFreeContStack();
+
-        uint32_t freeStackStart = ESP.getFreeContStack();
+    // ESP.resetFreeContStack();
+    // uint32_t freeStackStart = ESP.getFreeContStack();
     Serial.println("[Send] Connection successful established");
     Serial.printf("[Send] Send status: %s\n", status);
     client.write(status);
     client.stop();
-    }
-    return 0;
-}
 
+    return true;
+}
 
 void setup() {
 
@@ -187,12 +176,13 @@ void loop() {
     if (new_door_state != current_door_state) {
         Serial.printf("[Loop] Status has changed to %i\n", new_door_state);
         blink_led(2, 100);
-        if (send_status(new_door_state) == 0) {
+        if (send_status(new_door_state)) {
             current_door_state = new_door_state;
             blink_led(5, 100);
         } else {
             blink_led(5, 500);
         }
     }
+
     delay(FREQUENCY);
 }