Load credentials and settings from config file

src/config.cpp

@@ -0,0 +1,29 @@
+#include "config.h"
+#include <ArduinoJson.h>
+
+bool load_config_file(const char *file_path, struct Config &config) {
+  if (!LittleFS.begin())
+    return false;
+  File config_file = LittleFS.open(file_path, "r");
+  if (!config_file)
+    return false;
+  StaticJsonDocument<512> json;
+  DeserializationError err = deserializeJson(json, config_file);
+  if (err)
+    return false;
+  config = {
+      .ssid = json["ssid"],
+      .psk = json["psk"],
+      .mqtt_host = json["mqtt_host"],
+      .mqtt_user = json["mqtt_user"],
+      .mqtt_password = json["mqtt_password"],
+      .mqtt_port = json["mqtt_port"],
+      .topic = json["mqtt_topic"],
+      .device_id = json["device_id"],
+      .sleep_time = minutes_to_microseconds(json["sleep_time"]),
+      .connection_attempts = json["connection_attempts"],
+  };
+  return true;
+}
+
+long minutes_to_microseconds(int minutes) { return (minutes * 6e7); }