Door Opener

door_opener.ino

#include <ESP8266WiFi.h>

const int BUZZER_INPUT_IO = 5;
const int DOOR_OUTPUT_IO = 4;
const int LED_IO = 0;

enum { STARTING, READY, NOTIFYING, OPENING };

void setup() {
  Serial.begin(115200);
  Serial.write("starting up\n");
  WiFi.begin("redacted", "redacted");
  pinMode(LED_IO, OUTPUT);
  pinMode(BUZZER_INPUT_IO, INPUT);
  pinMode(DOOR_OUTPUT_IO, OUTPUT);  
}

int last_val = LOW;
boolean check_button_pressed() {
  int val = digitalRead(5);
  boolean pressed = (val == HIGH && last_val == LOW);
  last_val = val;
  return pressed;
}

void client_loop(int &main_state) {
  enum { BEGIN, CONNECTING, CONNECTED, RECEIVING, ERROR, DONE };
  static int state = BEGIN;
  static WiFiClient client;
  const char * domain = "iot.example.com";
  int port = 80;
  String content;
  
  switch(state) {
  case BEGIN:
    if (!client.connect(domain, port)) {
      Serial.println("connection failed");
      state = ERROR;
      return;
    }
    state = CONNECTED;
  case CONNECTED:
    client.print("GET /button HTTP/1.1\r\nUser-Agent:door\r\nHost: iot.example.com\r\n\r\n");
    state = RECEIVING;
  case RECEIVING:
    if (!client.connected()) {
      Serial.println("server disconnected\r\n");
      main_state = READY;
      state = BEGIN;
      return;
    }
    else if (!client.available()) {
      return;
    }
    
    content = client.readString();
    Serial.print(">>> ");
    Serial.print(content);

    state = BEGIN;
    main_state = (content.indexOf("\nopen") > 0) ? OPENING : READY;
    Serial.println(content.indexOf("\nopen"));
    client.stop();
    digitalWrite(0, LOW);          
  }
}

void _blink(int counter, int cycles) {
  if (counter % cycles == 0) digitalWrite(LED_IO, (counter / cycles) % 2);
}
  
void open_door(int & main_state) {
  Serial.print("Opening door\r\n");
  digitalWrite(DOOR_OUTPUT_IO, HIGH);
  delay(5000);
  digitalWrite(DOOR_OUTPUT_IO, LOW);
  main_state = READY;
}

void loop() {
  static int state = STARTING, counter = 0, status = 0;
  counter++;
  
  switch(state) {
  case STARTING: // STARTING
    _blink(counter, 10000);    
    status = WiFi.status();
    if (status == WL_CONNECTED) {
      state = READY;
      digitalWrite(0, LOW);
    }
  case READY:
    if (check_button_pressed()) {
      digitalWrite(0, HIGH);
      Serial.println("button pressed");
      state = NOTIFYING;
    }
    break;
  case NOTIFYING: // send request and read response
    client_loop(state);
    break;
  case OPENING: // open door request
    open_door(state);
    break;
  }
}