/* Generic GPIO Control by HTTP REST interface                     */
/* Modify GPIO by accessing DEVICE_IP/gpio?gpio=[GPIO]&value=[0|1] */
/* At first boot it creates a WiFi access point                    */
/*  and provide a web server on it, so you can configure Wifi ssid */
/*  Wifi passwd, and a mDNS hostname                               */
/* In this mode, device will be available at 192.168.4.1           */
/* Device can also be put in OTA Mode: In this case, if you have   */
/*  a little flash (512K), it better to disable SPIFFS in          */
/*  "Flash Size" Menu. Use espota.py to upload OTA                 */
/* After passing in OTA mode, next boot will be in setup mode      */


#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266mDNS.h>
#include <EEPROM.h>
#include <ArduinoOTA.h>
#include <errno.h>

#define EEPROM_SIZE 512
char eeprom[EEPROM_SIZE];

#define BOOTMODE_SETUP  0
#define BOOTMODE_NORMAL 1
#define BOOTMODE_OTA    2

/*  EEPROM LAYOUT
                  "BOOTMODE;SSID;PASSWORD;HOSTNAME;"
    BOOTMODE could be 0 for Setup, 1 for normal use, 2 for OTA
    Setup mode is trigger by setting GPIO3 to ground or at first boot
*/


/* Set these to your desired credentials. */
const char *ssid = "ESPConfigurator";

ESP8266WebServer server(80);

/* Just a little test message.  Go to http://192.168.4.1 in a web browser
   connected to this access point to see it.
*/
void handleRoot() {
  server.send(200, "text/html", "<h1>You are connected</h1><br/>"
              "<a href=\"/setup\">Setup</a><br/>"
              "<a href=\"/gpio?gpio=2&amp;value=1\">ON</a><br/>"
              "<a href=\"/gpio?gpio=2&value=0\">OFF</a><br/>"
             );
}

void handleSetup() {
  server.send(200, "text/html", "<form action=\"/save\" method=\"get\">"
              "<div><label for=\"ssid\">Wifi SSID :</label> <input type=\"text\" name=\"ssid\" /></div>"
              "<div><label for=\"password\">Wifi Password :</label><input type=\"password\" name=\"password\" /> </div>"
              "<div><label for=\"host\">Hostname :</label><input type=\"text\" name=\"host\" /> </div>"
              "<div class=\"button\"> <button type=\"submit\">Save</button></div>"
              "</form>");
}

void handleGpio() {
  if (!server.hasArg("gpio") || !server.hasArg("value")) {
    server.send(500, "text/plain", "Bad arguments\r\n");
    return;
  }

  digitalWrite(server.arg("gpio").toInt(), server.arg("value").toInt());
  pinMode(server.arg("gpio").toInt(), OUTPUT);
  server.send(200, "text/html", "<h1>GPIO" + server.arg("gpio") + " changed to " + server.arg("value") + "</h1>");
}

int saveConfig(int bootMode, String ssid, String password, String host ) {
  String eeprom;

  eeprom = String(bootMode) + ";" + ssid + ";" + password + ";" + host + ";";

  if (eeprom.length() > EEPROM_SIZE )
    return -EMSGSIZE;

  Serial.println("Saving " + eeprom);

  for (int i = 0; i < eeprom.length() && i < EEPROM_SIZE; i++) {
    EEPROM.write(i, eeprom.charAt(i));
  }

  EEPROM.commit();
  delay(100);

  return 0;
}

void handleSave() {
  String password;
  String ssid;
  String hostName;

  if (!server.hasArg("ssid") || !server.hasArg("password") || !server.hasArg("host")) {
    server.send(500, "text/plain", "Bad arguments\r\n");
    return;
  }

  if (saveConfig(BOOTMODE_NORMAL, server.arg("ssid"), server.arg("password"), server.arg("host")) < 0) {
    server.send(500, "text/plain", "Cannot Save Credentials (Too long ?Contains \";\"?)\r\n");
    return;
  }

  server.send(200, "text/html", "<h1>Configuration Saved</h1>");
}

void handleNotFound() {
  String message = "File Not Found\n\n";
  message += "URI: ";
  message += server.uri();
  message += "\nMethod: ";
  message += (server.method() == HTTP_GET) ? "GET" : "POST";
  message += "\nArguments: ";
  message += server.args();
  message += "\n";
  for (uint8_t i = 0; i < server.args(); i++) {
    message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
  }
  server.send(404, "text/plain", message);
}

void readEEPROM(int &bootMode, char **ssid, char **password, char **host) {

  int i = 2;

  int boot = EEPROM.read(0);

  if (boot == '1') {
    bootMode = BOOTMODE_NORMAL;
  } else if (boot == '2') {
    bootMode = BOOTMODE_OTA;
  } else {
    //Do not need to parse EEPROM when not configured
    bootMode = BOOTMODE_SETUP;
    return;
  }

  //Read SSID
  *ssid = &eeprom[2];
  do {
    eeprom[i] = EEPROM.read(i);
    i++;
  } while (i < EEPROM_SIZE && eeprom[i - 1] != ';');
  eeprom[i - 1] = '\0';

  //Read password
  *password = &eeprom[i];
  do {
    eeprom[i] = EEPROM.read(i);
    i++;
  } while (i < EEPROM_SIZE && eeprom[i - 1] != ';');
  eeprom[i - 1] = '\0';

  //Read HostName
  *host = &eeprom[i];
  do {
    eeprom[i] = EEPROM.read(i);
    i++;
  } while (i < EEPROM_SIZE && eeprom[i - 1] != ';');
  eeprom[i - 1] = '\0';

}

void setupWifi(int bootmode, int forceSetup, char *confSsid, char *confPassword, char *confHost) {
  IPAddress myIP;
  if (bootmode == BOOTMODE_SETUP || forceSetup) {
    Serial.println("Configuring access point...");
    /* You can set a password to the AP here */
    WiFi.softAP(ssid);
    myIP = WiFi.softAPIP();
  } else {
    Serial.println("Connecting to Wifi...");
    WiFi.begin(confSsid, confPassword);
    while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(".");
    }
    Serial.println("");
    Serial.println("WiFi connected");

    if (!MDNS.begin(confHost)) {
      Serial.println("Error setting up MDNS responder!");
      while (1) {
        delay(1000);
      }
    }
    Serial.println("mDNS responder started");
    myIP = WiFi.localIP();
  }

  Serial.print("My IP address: ");
  Serial.println(myIP);
}

void setup() {
  pinMode(3, OUTPUT);

  int bootMode;
  char *confSsid;
  char *confPassword;
  char *confHost;

  delay(1000);
  Serial.begin(115200);
  Serial.println();

  // Get GPIO 3 Status
  Serial.swap(); //Switch Serial on GPIO 13 & 15
  pinMode(3, INPUT_PULLUP);
  int txStatus = digitalRead(3);
  Serial.swap(); // Switch back

  EEPROM.begin(EEPROM_SIZE);
  readEEPROM(bootMode, &confSsid, &confPassword, &confHost);
  if (bootMode == BOOTMODE_NORMAL || bootMode == BOOTMODE_OTA) {
    Serial.println("Configuration Found !:");
    Serial.println(bootMode);
    Serial.println(confSsid);
    Serial.println(confPassword);
    Serial.println(confHost);
    Serial.println();
  } else {
    Serial.println("No configuration saved");
  }

  Serial.print("GPIO 3 status :");
  Serial.print(txStatus);
  Serial.println();

  setupWifi(bootMode, txStatus == 0, confSsid, confPassword, confHost);

  server.on("/", handleRoot);
  server.on("/setup", handleSetup);
  server.on("/save", handleSave);
  if (bootMode == BOOTMODE_NORMAL)
    server.on("/gpio", handleGpio);
  server.onNotFound(handleNotFound);
  server.begin();
  Serial.println("HTTP server started");
}

void loop() {
  server.handleClient();
}