#include "LowPower.h"     //https://github.com/rocketscream/Low-Power

#define BUTTON_PIN 2      //the on-off button
#define LED_PIN 13        //low battery indicator
#define LOW_BATTERY 10    //the value at wich the battery is empty

#define AC_SENSOR A0      //analog 0-1.1v AC sensor
#define BATTERY_SENSOR A1 //analog 0-1.1v battery sensor

#define LED_RELAY 3       //12v LED relay
#define AC_RELAY 4        //220v AC relay

#define acIsPresent() analogRead(AC_SENSOR)
#define batteryHasCharge() analogRead(BATTERY_SENSOR) > LOW_BATTERY

volatile int OnOffStatus = 0;

void onButtonPressed()
{
  //function run when the button is pressed
}

void setup()
{
    analogReference(INTERNAL);    //set voltage reference to internal 1.1v
    pinMode(BUTTON_PIN, INPUT);
    pinMode(LED_PIN, OUTPUT);
}

void loop()
{
    attachInterrupt(digitalPinToInterrupt(BUTTON_PIN),onButtonPressed,LOW);
    LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF);
    detachInterrupt(digitalPinToInterrupt(BUTTON_PIN));

    if (OnOffStatus) {
        if (acIsPresent()) {
            //turn the AC lights on
            OnOffStatus != OnOffStatus;
            digitalWrite(AC_RELAY,HIGH);
        }
        else if (batteryHasCharge()) {
            //turn the LED ligjts on
            OnOffStatus != OnOffStatus;
            digitalWrite(AC_RELAY,HIGH);
        }
        else {
            //we can't turn the lights on!
            for (int i=0;i<5;i++) {
                digitalWrite(LED_PIN,HIGH);
                delay(50);
                digitalWrite(LED_PIN,LOW);
                delay(50);
            }
        }
        //start shutdown timer
        //TODO
    }
    else {
        //turn the lights off
        OnOffStatus != OnOffStatus;
        digitalWrite(LED_RELAY,LOW);
        digitalWrite(AC_RELAY,LOW);
    }
}