Building StressCheck: An AI-Powered Stress Level Analyzer with ESP32 & Hugging Face

				
					// wifi_config.cpp

/**
 * @file wifi_config.cpp
 * @brief Implementation of the WiFiConfig class for managing Wi-Fi connection and configuration.
 */
#include "wifi_config.h"

/// @cond Doxygen_Skipped
// Internal Definitions
#define CONFIG_FILE "/config.json"
#define AP_SSID "StressCheck"
#define AP_PASS "11111111"
#define AP_IP IPAddress(192,168,4,1)
#define AP_NETMASK IPAddress(255,255,255,0)
#define LED_PIN 2
/// @endcond

/**
 * @brief Constructor for the WiFiConfig class.
 * Initializes member variables and loads HTML templates.
 * @param resetPin The GPIO pin used to force the configuration portal when held low at boot.
 */
WiFiConfig::WiFiConfig(uint8_t resetPin)
: server(80), resetButtonPin(resetPin),
  restartRequested(false), restartAt(0),
  ledMode(0),
  ledTaskHandle(NULL), restartTaskHandle(NULL)
{
    memset(&cfg, 0, sizeof(cfg));

/** @brief HTML content for the Wi-Fi configuration portal index page (SSID and password input). */
htmlIndex = R"rawliteral(
<title>Wi-Fi Settings</title>
body{font-family:Tahoma,Arial;margin:20px;padding:20px;max-width:420px;margin-left:auto;margin-right:auto;background:#f8f9fa;}
.container{padding:12px;background:white;border-radius:6px;box-shadow:0 1px 3px rgba(0,0,0,0.06);}
input{width:100%;padding:8px;margin-top:6px;box-sizing:border-box;border:1px solid #ddd;border-radius:4px;}
label{display:block;margin-top:10px;font-size:14px;color:#333;}
.row{display:flex;gap:8px;margin-top:8px;}
.row &gt; div{flex:1;}
button{width:100%;margin-top:14px;padding:10px;background:#1e88e5;color:#fff;border:0;border-radius:4px;cursor:pointer;}
h2{text-align:center;margin:0 0 8px 0;}
.note{font-size:13px;color:#555;margin-top:12px;}
<div class="container">
  <h2>Wi-Fi Settings</h2>
    <label>SSID</label>
    <label>Password</label>
    <div class="row">
      <div>
        <label>IP Address</label>
      </div>
      <div>
        <label>Gateway</label>
      </div>
    </div>
    <button type="submit">Save Settings</button>
  <p class="note">After saving, please restart the device to connect to the new network.</p>
</div>
)rawliteral";

/** @brief HTML content for the success page after configuration is saved. */
htmlSuccess = R"rawliteral(
<title>Saved</title>
body{font-family:Tahoma,Arial;margin:20px;padding:20px;max-width:420px;margin-left:auto;margin-right:auto;background:#f8f9fa;}
.container{padding:12px;background:white;border-radius:6px;box-shadow:0 1px 3px rgba(0,0,0,0.06);text-align:center;}
h2{margin:0 0 8px 0;color:#2e7d32;}
p{color:#333;margin-top:8px;}
a.button-link{display:inline-block;padding:10px 18px;margin-top:14px;background:#1e88e5;color:#fff;text-decoration:none;border-radius:4px;}
<div class="container">
  <h2>Settings Saved</h2>
  <p>The microcontroller is restarting and connecting to the configured network.</p>
  <a class="button-link" href="http://%%IP_ADDRESS%%/">Access Device (New IP)</a>
</div>)rawliteral";

/** @brief HTML content for the error page in the configuration portal. */
htmlError = R"rawliteral(<title>Error</title>
body{font-family:Tahoma,Arial;margin:20px;padding:20px;max-width:420px;margin-left:auto;margin-right:auto;background:#f8f9fa;}
.container{padding:12px;background:white;border-radius:6px;box-shadow:0 1px 3px rgba(0,0,0,0.06);text-align:center;}
h2{margin:0 0 8px 0;color:#c62828;}
.error-message{margin-top:15px;padding:10px;border:1px solid #D32F2F;background:#FFEBEE;text-align:right;border-radius:4px;}
a.retry{display:inline-block;padding:10px 18px;margin-top:14px;background:#757575;color:#fff;text-decoration:none;border-radius:4px;}
<div class="container">
  <h2>Error Saving Settings</h2>
  <div class="error-message">
    <p>%%ERROR_MESSAGE%%</p>
  </div>
  <a class="retry" href="/">Try Again</a>
</div>
)rawliteral";
}

/**
 * @brief FreeRTOS task to control the LED mode.
 * Blinks the LED based on the current `ledMode` state.
 * @param param Pointer to the WiFiConfig class instance.
 */
void WiFiConfig::ledTask(void* param){
    WiFiConfig* self = (WiFiConfig*)param;
    const TickType_t fast = pdMS_TO_TICKS(100);
    const TickType_t slow = pdMS_TO_TICKS(500);
    for(;;){
        uint8_t mode = self-&gt;ledMode;
        if(mode == 0){ // Fast blink (Initial/Connection attempt)
            digitalWrite(LED_PIN, HIGH);
            vTaskDelay(fast);
            digitalWrite(LED_PIN, LOW);
            vTaskDelay(fast);
        } else if(mode == 1){ // Solid ON (AP Mode)
            digitalWrite(LED_PIN, HIGH);
            vTaskDelay(pdMS_TO_TICKS(200));
        } else if(mode == 2){ // Slow blink (STA connection attempt)
            digitalWrite(LED_PIN, HIGH);
            vTaskDelay(slow);
            digitalWrite(LED_PIN, LOW);
            vTaskDelay(slow);
        } else { // OFF (Connection successful)
            digitalWrite(LED_PIN, LOW);
            vTaskDelay(pdMS_TO_TICKS(5000));
        }
    }
}

/**
 * @brief FreeRTOS task to check for and execute a device restart.
 * Waits a short period after configuration save before restarting the ESP.
 * @param param Pointer to the WiFiConfig class instance.
 */
void WiFiConfig::restartCheckTask(void* param){
    WiFiConfig* self = (WiFiConfig*)param;
    const TickType_t period = pdMS_TO_TICKS(200);
    for(;;){
        if(self-&gt;restartRequested){
            unsigned long now = millis();
            // Check if at least 2000ms have passed since restart was requested.
            if(now &gt;= self-&gt;restartAt &amp;&amp; (now - self-&gt;restartAt) &gt;= 2000){
                Serial.println("RestartCheckTask: conditions met -&gt; restarting now.");
                vTaskDelay(pdMS_TO_TICKS(50));
                ESP.restart();
            }
        }
        vTaskDelay(period);
    }
}

/**
 * @brief Initiates the Wi-Fi configuration process.
 * Checks the reset pin, loads config, and decides whether to start STA or AP mode.
 */
void WiFiConfig::begin(){
    pinMode(resetButtonPin, INPUT_PULLUP);
    pinMode(LED_PIN, OUTPUT);

    // Start LED Task with default mode (fast blink).
    ledMode = 0;
    xTaskCreatePinnedToCore(WiFiConfig::ledTask, "ledTask", 2048, this, 1, &amp;ledTaskHandle, 1);

    // Initialize LittleFS.
    if(!LittleFS.begin()){
        Serial.println("LittleFS mount failed, formatting...");
        LittleFS.format();
        if(!LittleFS.begin()){
            Serial.println("LittleFS re-mount failed!");
        } else {
            Serial.println("LittleFS mounted after format.");
        }
    } else {
        Serial.println("LittleFS mounted.");
    }

    // Load saved configuration.
    loadConfig();
    vTaskDelay(pdMS_TO_TICKS(900));

    // Check if reset pin is held to force config portal.
    bool forceConfig = (digitalRead(resetButtonPin) == LOW);
    if(forceConfig){
        Serial.println("Reset pin held: forcing config portal (reset config file).");
        resetConfigFile();
    }

    // If no config is available or force config is requested, enter AP Mode.
    if(!isConfigAvailable() || forceConfig){
        Serial.println("Entering Config Portal mode (AP).");
        startConfigPortal();

        ledMode = 1; // Change LED mode to Solid ON (AP Mode).

        // Start the restart check task if not running.
        if(restartTaskHandle == NULL){
            xTaskCreatePinnedToCore(WiFiConfig::restartCheckTask, "restartChk", 2048, this, 1, &amp;restartTaskHandle, 1);
        }

        // Block execution in AP Mode until restart happens.
        while(true){
            vTaskDelay(pdMS_TO_TICKS(200));
        }
    }

    // Config found, attempt to connect as Station (STA).
    Serial.println("Config found: attempting to connect as station.");
    ledMode = 2; // Change LED mode to Slow blink (STA attempt).
    if(!connectSTA()){
        // STA connection failed, fall back to AP Mode.
        Serial.println("Could not connect as station; starting Config Portal as fallback.");
        startConfigPortal();
        ledMode = 1; // Change LED mode to Solid ON (AP Mode).
        if(restartTaskHandle == NULL){
            xTaskCreatePinnedToCore(WiFiConfig::restartCheckTask, "restartChk", 2048, this, 1, &amp;restartTaskHandle, 1);
        }
        while(true){
            vTaskDelay(pdMS_TO_TICKS(200));
        }
    }

    // STA connection successful, delete LED Task and turn off LED.
    if(ledTaskHandle != NULL){
        vTaskDelete(ledTaskHandle);
        ledTaskHandle = NULL;
    }
    digitalWrite(LED_PIN, LOW);
    ledMode = 3; // Set LED mode to OFF.
    Serial.println("Wi-Fi ready; continuing with main application.");
}

/**
 * @brief Checks if a valid Wi-Fi configuration (SSID and Password) is stored.
 * @retval true If SSID and Password fields have non-zero length.
 * @retval false Otherwise.
 */
bool WiFiConfig::isConfigAvailable(){
    return (strlen(cfg.ssid) &gt; 0 &amp;&amp; strlen(cfg.password) &gt; 0);
}

/**
 * @brief Resets the Wi-Fi configuration file to empty defaults in LittleFS.
 */
void WiFiConfig::resetConfigFile(){
    Serial.println("Resetting config file to empty defaults.");
    memset(&amp;cfg, 0, sizeof(cfg));
    StaticJsonDocument doc;
    doc["ssid"] = "";
    doc["password"] = "";
    doc["ip"] = "";
    doc["gateway"] = "";
    File f = LittleFS.open(CONFIG_FILE, "w");
    if(f){
        serializeJson(doc, f);
        f.close();
        Serial.println("Empty config written to LittleFS.");
    } else {
        Serial.println("Failed to write empty config to LittleFS.");
    }
}

/**
 * @brief Loads the Wi-Fi configuration from the JSON file in LittleFS.
 * Resets the config if the file is not found or fails to parse.
 */
void WiFiConfig::loadConfig(){
    if(!LittleFS.exists(CONFIG_FILE)){
        Serial.println("Config file not found, creating default.");
        resetConfigFile();
        return;
    }

    File f = LittleFS.open(CONFIG_FILE, "r");
    if(!f){
        Serial.println("Failed to open config file for read, resetting.");
        resetConfigFile();
        return;
    }

    StaticJsonDocument doc;
    DeserializationError err = deserializeJson(doc, f);
    f.close();
    if(err){
        Serial.print("Config parse error: ");
        Serial.println(err.c_str());
        resetConfigFile();
        return;
    }

    // Load values with fallback to empty strings.
    strlcpy(cfg.ssid, doc["ssid"] | "", sizeof(cfg.ssid));
    strlcpy(cfg.password, doc["password"] | "", sizeof(cfg.password));
    strlcpy(cfg.ip, doc["ip"] | "", sizeof(cfg.ip));
    strlcpy(cfg.gateway, doc["gateway"] | "", sizeof(cfg.gateway));

    Serial.printf("Loaded Wi-Fi config: SSID=%s, IP=%s, Gateway=%s\n", cfg.ssid, cfg.ip, cfg.gateway);
}

/**
 * @brief Saves the current Wi-Fi configuration to a JSON file in LittleFS.
 */
void WiFiConfig::saveConfig(){
    StaticJsonDocument doc;
    doc["ssid"] = cfg.ssid;
    doc["password"] = cfg.password;
    doc["ip"] = cfg.ip;
    doc["gateway"] = cfg.gateway;

    File f = LittleFS.open(CONFIG_FILE, "w");
    if(f){
        serializeJson(doc, f);
        f.close();
        Serial.println("Wi-Fi config saved to LittleFS.");
    } else {
        Serial.println("Failed to open config file for write!");
    }
}

/**
 * @brief Attempts to connect to the configured Wi-Fi network as a Station (STA).
 * Supports both DHCP and static IP configuration.
 * @retval true If connection is successful.
 * @retval false If connection times out after 15 seconds or no SSID is configured.
 */
bool WiFiConfig::connectSTA(){
    if(strlen(cfg.ssid) == 0){
        Serial.println("No SSID configured.");
        return false;
    }

    Serial.printf("Attempting to connect to SSID: %s\n", cfg.ssid);

    WiFi.mode(WIFI_STA);

    IPAddress localIP, gw;
    IPAddress dns1(8,8,8,8);
    IPAddress dns2(1,1,1,1);

    // Check for valid static IP configuration.
    bool useStaticIP = (strlen(cfg.ip) &gt; 0 &amp;&amp; strlen(cfg.gateway) &gt; 0 &amp;&amp;
                         localIP.fromString(cfg.ip) &amp;&amp; gw.fromString(cfg.gateway));

    if(useStaticIP){
        IPAddress subnet(255,255,255,0);
        bool ok = WiFi.config(localIP, gw, subnet, dns1, dns2);
        if(ok){
            Serial.println("Static IP and DNS configured.");
            Serial.printf("Static IP: %s, Gateway: %s, DNS1: %s, DNS2: %s\n",
                localIP.toString().c_str(), gw.toString().c_str(), dns1.toString().c_str(), dns2.toString().c_str());
        } else {
            Serial.println("WiFi.config failed; will try DHCP.");
        }
    } else {
        Serial.println("No static IP provided; using DHCP (DNS via DHCP).");
    }

    WiFi.begin(cfg.ssid, cfg.password);

    unsigned long start = millis();
    // Wait loop for Wi-Fi connection.
    while(WiFi.status() != WL_CONNECTED){
        vTaskDelay(pdMS_TO_TICKS(500));
        Serial.print(".");
        if(millis() - start &gt; 15000){
            Serial.println("\nConnection timed out (15s).");
            return false;
        }
    }

    Serial.println("\nConnected to Wi-Fi.");
    Serial.printf("SSID: %s\n", cfg.ssid);
    Serial.printf("IP Address: %s\n", WiFi.localIP().toString().c_str());
    Serial.printf("Gateway: %s\n", WiFi.gatewayIP().toString().c_str());

    if(useStaticIP){
        Serial.println("DNS1: 8.8.8.8");
        Serial.println("DNS2: 1.1.1.1");
    } else {
        Serial.println("DNS set by DHCP (if DHCP provided DNS).");
    }

    return true;
}

/**
 * @brief Starts the Wi-Fi configuration portal in Access Point (AP) mode.
 * Configures the AP with predefined SSID/Password and sets up the web server routes.
 */
void WiFiConfig::startConfigPortal(){
    Serial.println("Starting Config Portal (AP mode)...");
    WiFi.mode(WIFI_AP);
    WiFi.softAPConfig(AP_IP, AP_IP, AP_NETMASK);
    WiFi.softAP(AP_SSID, AP_PASS);
    Serial.printf("AP started. SSID: %s, PASS: %s, IP: %s\n", AP_SSID, AP_PASS, AP_IP.toString().c_str());

    setupServerRoutes();
    server.begin();
    Serial.println("HTTP server started for portal on port 80.");
}

/**
 * @brief Sets up the HTTP routes for the configuration portal.
 * Handles the index page ("/") and the configuration submission page ("/save").
 */
void WiFiConfig::setupServerRoutes(){
    // Root route: serve the configuration form.
    server.on("/", HTTP_GET, [this](AsyncWebServerRequest* req){
        req-&gt;send(200, "text/html; charset=utf-8", htmlIndex);
    });

    // Save route: process submitted configuration data.
    server.on("/save", HTTP_POST, [this](AsyncWebServerRequest* req){
        String ssid = req-&gt;arg("ssid");
        String pass = req-&gt;arg("password");
        String ip_str = req-&gt;arg("ip");
        String gateway_str = req-&gt;arg("gateway");

        // Validate SSID.
        if(ssid.length() == 0){
            String tmp = htmlError;
            tmp.replace("%%ERROR_MESSAGE%%", "نام شبکه (SSID) نمی‌تواند خالی باشد.");
            req-&gt;send(400, "text/html; charset=utf-8", tmp);
            return;
        }
        
        // Validate IP Address format.
        IPAddress test;
        if(ip_str.length() &gt; 0 &amp;&amp; !test.fromString(ip_str)){
            String tmp = htmlError;
            tmp.replace("%%ERROR_MESSAGE%%", "آدرس IP وارد شده نامعتبر است.");
            req-&gt;send(400, "text/html; charset=utf-8", tmp);
            return;
        }
        // Validate Gateway format.
        if(gateway_str.length() &gt; 0 &amp;&amp; !test.fromString(gateway_str)){
            String tmp = htmlError;
            tmp.replace("%%ERROR_MESSAGE%%", "آدرس Gateway وارد شده نامعتبر است.");
            req-&gt;send(400, "text/html; charset=utf-8", tmp);
            return;
        }

        // Copy valid data to the configuration structure.
        strlcpy(cfg.ssid, ssid.c_str(), sizeof(cfg.ssid));
        strlcpy(cfg.password, pass.c_str(), sizeof(cfg.password));
        strlcpy(cfg.ip, ip_str.c_str(), sizeof(cfg.ip));
        strlcpy(cfg.gateway, gateway_str.c_str(), sizeof(cfg.gateway));

        saveConfig();

        // Determine the target IP for the success link.
        String targetIp = ip_str;
        if(targetIp.length() == 0){
            if(gateway_str.length() &gt; 0) targetIp = gateway_str;
            else targetIp = String("192.168.1.1"); // Default assumption if no static IP/Gateway.
        }
        
        // Send success page and set restart flags.
        String out = htmlSuccess;
        out.replace("%%IP_ADDRESS%%", targetIp);
        req-&gt;send(200, "text/html; charset=utf-8", out);

        restartAt = millis();
        restartRequested = true;
        Serial.println("Config saved. restartRequested set = true; restartCheckTask will perform restart after 2s.");
    });
    
    // Not Found handler: redirect to the configuration form.
    server.onNotFound([](AsyncWebServerRequest* req){
        req-&gt;redirect("/");
    });
}