// Doorbell: a button that tells Alexa when it is pressed (Alexa.DoorbellEventSource).
//
// The button connects the pin to ground; the internal pull-up makes the pin high while it is released. A level has
// to hold for 50 ms before it counts. Every press publishes a DoorbellPress event on <root>/event. A press while
// there is no session with the broker is lost: the library prints why it was not sent.
//
// This event has not been tried with Alexa yet.
#include <Arduino.h>
#include <ESP8266WiFi.h>
#include <Alex2ESP.h>

// Wi-Fi and the credentials of your Alex2MQTT account
const char *WIFI_SSID = "";
const char *WIFI_PASSWORD = "";

const char *ALEXA_USERNAME = "";
const char *ALEXA_PASSWORD = "";
const char *ALEXA_ROOT_TOPIC = "";

const uint8_t BUTTON_PIN = 14; // D5 on a Wemos D1 mini
const unsigned long DEBOUNCE_MS = 50;

Alex2ESP alexa;
AlexaDevice *doorbell;

bool pressed = false;
bool lastLevel = false;
unsigned long lastEdge = 0;

// Joins the Wi-Fi network and returns after 30 s at the latest. Without a connection the sketch carries on: the
// ESP8266 keeps trying, and alexa.loop() opens the MQTT session once Wi-Fi is up.
void connectWiFi()
{
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  Serial.printf("\n[WIFI] Connecting to \"%s\"\n", WIFI_SSID);

  unsigned long started = millis();
  while (WiFi.status() != WL_CONNECTED && millis() - started < 30000)
  {
    delay(100);
  }

  if (WiFi.status() == WL_CONNECTED)
  {
    Serial.printf("[WIFI] Connected, IP address %s\n", WiFi.localIP().toString().c_str());
  }
  else
  {
    Serial.printf("[WIFI] No connection after 30 s (status %d): check WIFI_SSID and WIFI_PASSWORD. Still trying.\n",
                  WiFi.status());
  }
}

void onDirective(AlexaDirective &directive)
{
  if (directive.isReportState())
  {
    directive.stateReport().addHealthProp(EndpointHealth::OK).send();
    return;
  }

  directive.error(AlexaErrorType::INVALID_DIRECTIVE, "A doorbell takes no directives").send();
}

void setup()
{
  Serial.begin(74880);
  pinMode(BUTTON_PIN, INPUT_PULLUP);

  connectWiFi();

  // MQTT user name, MQTT password, root topic
  alexa.begin(ALEXA_USERNAME, ALEXA_PASSWORD, ALEXA_ROOT_TOPIC);

  // The name Alexa shows, and the id of the endpoint: every device of an account has its own
  doorbell = alexa.getDevice("Front Door Bell", "esp-doorbell");
  doorbell->setDisplayCategory(DisplayCategory::DOORBELL);
  doorbell->addCapability(AlexaInterfaces::DoorbellEventSource);
  doorbell->addCapability(AlexaInterfaces::EndpointHealth);
  doorbell->onDirective(onDirective);
}

void loop()
{
  alexa.loop();

  bool level = digitalRead(BUTTON_PIN) == LOW;
  if (level != lastLevel)
  {
    lastLevel = level;
    lastEdge = millis();
  }

  if (level != pressed && millis() - lastEdge >= DEBOUNCE_MS)
  {
    pressed = level;
    if (pressed)
    {
      Serial.println("[DOORBELL] pressed");
      doorbell->doorbellPress().send();
    }
  }
}