Add ESP8266 code

ESP8266/.gitignore

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+.pio
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch

ESP8266/.vscode/extensions.json

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+{
+    // See http://go.microsoft.com/fwlink/?LinkId=827846
+    // for the documentation about the extensions.json format
+    "recommendations": [
+        "platformio.platformio-ide"
+    ],
+    "unwantedRecommendations": [
+        "ms-vscode.cpptools-extension-pack"
+    ]
+}

ESP8266/.vscode/settings.json

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+{
+    "C_Cpp.clang_format_fallbackStyle": "Visual Studio",
+    "C_Cpp.clang_format_style": "{ BasedOnStyle: LLVM, UseTab: Never, IndentWidth: 4, TabWidth: 4}"
+}

ESP8266/include/.gitignore

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+credentials.hpp

ESP8266/include/README

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+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with `.h'.
+It is most portable to use only letters, digits, dashes, and underscores in
+header file names, and at most one dot.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

ESP8266/lib/README

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+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into executable file.
+
+The source code of each library should be placed in a an own separate directory
+("lib/your_library_name/[here are source files]").
+
+For example, see a structure of the following two libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional, custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+and a contents of `src/main.c`:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+PlatformIO Library Dependency Finder will find automatically dependent
+libraries scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

ESP8266/platformio.ini

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+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:esp12e]
+platform = espressif8266
+board = esp12e
+framework = arduino
+lib_deps = knolleary/PubSubClient@^2.8
+monitor_speed = 921600
+upload_speed = 921600

ESP8266/src/main.cpp

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+#include <ENC28J60lwIP.h>
+#include <ESP8266WiFi.h>
+#include <PubSubClient.h>
+
+#include <credentials.hpp>
+
+/* C:\Users\Gabriel\.platformio\packages\framework-arduinoespressif8266\libraries\lwIP_enc28j60\src\utility\enc28j60.cpp
+ * Set DEBUG 0 or 1 for enc28j60 debug printf
+ */
+
+ENC28J60lwIP ethernet(16);
+WiFiClientSecure espClient;
+PubSubClient client(espClient);
+
+void mqttCallback(char *topic, byte *payload, unsigned int length) {
+    uint8_t message[256];
+    memcpy(message, payload, length);
+    Serial.printf("Message arrived: topic=%s, length=%d , message=%.*s\n",
+                  topic, length, length, message);
+    if (!strcmp(topic, ROOT_TOPIC "/ledBuiltin/set")) {
+        if (length > 1) {
+            Serial.printf("Payload length = %d > 1", length);
+            return;
+        }
+        if (message[0] == '0') {
+            // builtin led is active low
+            digitalWrite(LED_BUILTIN, 1);
+        } else if (message[0] == '1') {
+            digitalWrite(LED_BUILTIN, 0);
+        } else {
+            Serial.printf("Undefined payload value\n");
+        }
+    } else {
+        // If topic is not recognized, exit without publishing to /get
+        Serial.printf("Unrecognized topic %s\n", topic);
+        return;
+    }
+    // Publish payload to /get if topic ends with /set
+    if (strlen(topic) > 4) {
+        if (!strcmp(topic + (strlen(topic) - 4), "/set")) {
+            char gettopic[256];
+            strcpy(gettopic, topic);
+            gettopic[strlen(topic) - 3] = 'g';
+            /* This function changes original callback payload parameter,
+             * because PubSubClient uses same buffer for send and receive */
+            client.publish(gettopic, message, length, false);
+        }
+    }
+}
+
+void setClock() {
+    configTime(3 * 3600, 0, "pool.ntp.org", "time.nist.gov");
+    Serial.print("Waiting for NTP time sync: ");
+    time_t now = time(nullptr);
+    while (now < 8 * 3600 * 2) {
+        delay(500);
+        Serial.print(".");
+        now = time(nullptr);
+    }
+    Serial.println("");
+    struct tm timeinfo;
+    gmtime_r(&now, &timeinfo);
+    Serial.print("Current time: ");
+    Serial.print(asctime(&timeinfo));
+}
+
+void setClockOffline() {
+    time_t epoch_t = 1665619602;
+    timeval tv = {epoch_t, 0};
+    settimeofday(&tv, nullptr);
+    time_t now = time(nullptr);
+    struct tm timeinfo;
+    gmtime_r(&now, &timeinfo);
+    Serial.print("Current time: ");
+    Serial.print(asctime(&timeinfo));
+}
+
+void connectWiFi() {
+    WiFi.begin(ssid, password);
+    Serial.print("Connecting to WiFi..");
+    while (WiFi.status() != WL_CONNECTED) {
+        Serial.println(".");
+        delay(500);
+    }
+    Serial.println();
+    Serial.println("Connected to WiFi");
+    Serial.print("WiFi SSID: ");
+    Serial.print(WiFi.SSID());
+    Serial.print(" RSSI: ");
+    Serial.println(WiFi.RSSI());
+    Serial.print("WiFi IP address: ");
+    Serial.println(WiFi.localIP());
+    Serial.print("WiFi subnet mask: ");
+    Serial.println(WiFi.subnetMask());
+    Serial.print("WiFi default gateway: ");
+    Serial.println(WiFi.gatewayIP());
+    Serial.print("WiFi DNS server: ");
+    Serial.println(WiFi.dnsIP());
+}
+
+void connectEthernet() {
+    SPI.begin();
+    SPI.setBitOrder(MSBFIRST);
+    SPI.setDataMode(SPI_MODE0);
+    SPI.setFrequency(4000000);
+    uint8_t macaddr[6];
+    int present = ethernet.begin(WiFi.macAddress(macaddr));
+    if (!present) {
+        Serial.println("FATAL: No ethernet hardware present");
+        while (1) {
+        }
+    }
+    Serial.print("Connecting to Ethernet");
+    while (!ethernet.connected()) {
+        Serial.print(".");
+        delay(500);
+    }
+    Serial.println();
+    Serial.println("Connected to Ethernet");
+    Serial.print("Ethernet IP address: ");
+    Serial.println(ethernet.localIP());
+    Serial.print("Ethernet subnet mask: ");
+    Serial.println(ethernet.subnetMask());
+    Serial.print("Ethernet default gateway: ");
+    Serial.println(ethernet.gatewayIP());
+}
+
+void setup() {
+    pinMode(LED_BUILTIN, OUTPUT);
+    Serial.begin(921600);
+    Serial.println();
+    BearSSL::X509List *serverTrustedCA =
+        new BearSSL::X509List(ca_cert);
+    BearSSL::X509List *serverCertList =
+        new BearSSL::X509List(client_cert);
+    BearSSL::PrivateKey *serverPrivKey =
+        new BearSSL::PrivateKey(client_private_key);
+    espClient.setTrustAnchors(serverTrustedCA);
+    espClient.setClientRSACert(serverCertList, serverPrivKey);
+    ethernet.setDefault();
+    connectEthernet();
+    // setClockOffline();
+    // connectWiFi();
+    setClock();
+    /*  Por um bug na biblioteca ENC28J60lwIP ou na WifiClientSecure, o DNS não
+     * funciona quando ambas são usadas em conjunto. Assim, é necessário colocar
+     * o DNS em cache usando o WiFiClient antes de finalmente conectar ao
+     * servidor devidamente usando o WiFiClientSecure.
+     */
+    WiFiClient wifi_test;
+    wifi_test.connect(mqttBroker, mqttPort);
+    wifi_test.stop();
+    espClient.setInsecure();
+    client.setServer(mqttBroker, mqttPort);
+    client.setCallback(mqttCallback);
+    char err_buf[256];
+    while (!client.connected()) {
+        String client_id = "esp8266-client-";
+        client_id += String(WiFi.macAddress());
+        Serial.printf("%s Connecting to MQTT broker %s\n", client_id.c_str(), mqttBroker);
+        if (client.connect(client_id.c_str())) {
+            Serial.printf("Connected to MQTT broker %s\n", mqttBroker);
+        } else {
+            Serial.print("Connection failed with state ");
+            Serial.println(client.state());
+            espClient.getLastSSLError(err_buf, sizeof(err_buf));
+            Serial.print("SSL error: ");
+            Serial.println(err_buf);
+            delay(2000);
+        }
+    }
+    // TODO: Support set topic with more than one level
+    char settopic[64];
+    strcpy(settopic, ROOT_TOPIC);
+    strcat(settopic, "/+/set");
+    client.subscribe(settopic);
+    Serial.print("Subscribed to topic: ");
+    Serial.println(settopic);
+}
+
+void loop() { client.loop(); }

ESP8266/test/README

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+
+This directory is intended for PlatformIO Test Runner and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PlatformIO Unit Testing:
+- https://docs.platformio.org/en/latest/advanced/unit-testing/index.html