// Features

// #define FEAT_UNDERVOLTSLEEP
// Activates VLM Feature of Tiny10 (Voltage Level Monitoring) and sets it to the lowest value Vcc=2.5V
// In 3V supply scenarios (2 AG13/LR44 button cells in serial) this makes no sense because Vcc almost immediately drops below 2.5V

#define FEAT_STANDBY
// Activates PB1 and PB2. PB2 is the standby button, pull it to ground to activate deep sleep or wake up. Its pullup resistor is enabled.
// PB1 is set to high when awake and low when asleep. Can be used to disable external hardware during sleep mode

// Color values
#define R_STATIC  110 //80
#define G_HIGH     55 //40
#define B_STATIC    0 // 0
#define G_BURN     46 //34
#define G_FLICKER  43 //31
#define G_FLUTTER  35 //49 //25

// Timings
#define T_ON      5
#define T_BURN    4
#define T_FLICKER 3
#define T_FLUTTER 2

#ifndef F_CPU
  #define F_CPU 8000000UL
#endif

#include <avr/io.h>
#include <avr/sleep.h>
#include <avr/interrupt.h>

extern "C" {
  #include "ws2812_config.h"
  #include "light_ws2812.h"
}

struct cRGB led[1];

volatile uint8_t timertick = 0;

void delayms(uint16_t ms);


#ifdef FEAT_STANDBY
	void buttonrelease() {
		while ((PINB & (1<<PB2)) == 0) {	// Wait 50ms per check until PB2 goes up again (pulled low by pressed button)
			delayms(50);
		}
		delayms(50);						// Wait additional 50ms to skip released button bouncing
	}

	void checksleep() {
		if ((EIMSK & (1<<INT0)) == 0) {
			uint8_t tempr = led[0].r;
			uint8_t tempg = led[0].g;
			uint8_t tempb = led[0].b;
			
			led[0].r = 0; led[0].g = 0; led[0].b = 0;
			ws2812_setleds(led,1);
			PORTB &= ~(1<<DDB1);				// Deactivate LED Power supply

			buttonrelease();					// Wait for button release
			EIMSK |= (1<<INT0);					// Reenable INT0 for wakeup
			set_sleep_mode(SLEEP_MODE_PWR_DOWN); // Prepare sleep mode
			sleep_enable();
			sleep_mode();					 // Go down until PB2 gets low (by pressed button
			sleep_disable();
			PORTB |= (1<<DDB1);				// Activate LED Power supply
			buttonrelease();				// Wait for button release

			led[0].r = tempr; led[0].g = tempg; led[0].b = tempb;
			ws2812_setleds(led,1);			// Restore previous colors
			EIMSK |= (1<<INT0);					// Reenable INT0 for next shutdown
		}
	}
#endif

void fire(uint8_t g_low, uint8_t g_high, uint8_t gdelay) {
  for (led[0].g = g_high; led[0].g > g_low; led[0].g--) {
    ws2812_setleds(led,1);
    delayms(gdelay);
  }
  for (led[0].g = g_low; led[0].g < g_high; led[0].g++) {
    ws2812_setleds(led,1);
    delayms(gdelay);
  }
  #ifdef FEAT_STANDBY
	checksleep();
  #endif
}

void on(uint8_t f) {
  led[0].g = G_HIGH;
  ws2812_setleds(led,1);
  for (uint8_t t = f<<4; t > 0; t--) {	// f*16
    delayms(62);
	#ifdef FEAT_STANDBY
		checksleep();
	#endif
  }
}

void burn(uint8_t f) {
  for(uint8_t var = f<<4; var > 0; var--) {	// f*16
    fire(G_BURN, G_HIGH, T_BURN);
  }
}

void flicker(uint8_t f) {
  fire(G_BURN,G_HIGH,T_BURN);
  for(uint8_t var = f<<4; var > 0; var--) {	// f*16
    fire(G_FLICKER,G_HIGH,T_FLICKER);
  }
  fire(G_BURN,G_HIGH,T_BURN);
  fire(G_BURN,G_HIGH,T_BURN);
  fire(G_BURN,G_HIGH,T_BURN);
}

void flutter(uint8_t f) {
  fire(G_BURN,G_HIGH,T_BURN);
  fire(G_FLICKER,G_HIGH,T_FLICKER);
  for(uint8_t var = f<<4; var > 0; var--) {	// f*16
    fire(G_FLUTTER,G_HIGH,T_FLUTTER);
  }
  fire(G_FLICKER,G_HIGH,T_FLICKER);
  fire(G_BURN,G_HIGH,T_BURN);
  fire(G_BURN,G_HIGH,T_BURN);
}

void delayms(uint16_t ms) {
	timertick = 0;
	cli();
	PRR &= ~(1<<PRTIM0);  // Power up Timer 0
	TCNT0 = 0; // Reset Timer to Zero
	sei();
	TIMSK0 = 2; // Set OCIE0A Flag, Compare Match Interrupt for OCR0A
	if ( ms < 525 ) { // At Prescaler /64 and CPU = 8MHz, 1ms = 125 ticks. TIMER0 can only handle 524 of those
		OCR0A = (ms<<7) - ms - ms - ms; // ms * 125
	} else { // TIMER0 can only count 16bit, 2^16 / 125 per ms = 524,28ms max
		OCR0A = 65535;
	}
//	TCCR0A = 0; // Ports OC0A and OC0B disconnected, Waveform Generation Mode: CTC OCR0A
	TCCR0B = 11; // CS0 = 011 = Prescaler clk/1024), Waveform Generation Mode: CTC OCR0A

	while (timertick == 0) {
		set_sleep_mode(SLEEP_MODE_IDLE); // While we wait for the timer to finish its delay, put the CPU in idle mode
		sleep_enable();
		sleep_mode();					 // Start idle mode. Timer interrupt will wake up the CPU again
		sleep_disable();
	}									// CPU could wake up due to Timer interrupt or INT0 low level. If latter, make sure to go to sleep again.

	TCCR0B = 0; // Timer0 off
	TIMSK0 = 0; // Disable Timer Interrupts
	PRR |= (1<<PRTIM0); // Power down Timer0
}

ISR(TIM0_COMPA_vect) {
	timertick = 1;
}

#ifdef FEAT_UNDERVOLTSLEEP
	ISR(VLM_vect) { // Battery below 2.5V, power down for safety
		cli();		// Disable interrupts so that nothing can wake up deep sleep
		VLMCSR = 0; // Disable VLM entirely, interrupts will be ignored anyway

		struct cRGB leds[1];
		leds[0].r=0; leds[0].g=0; leds[0].b=0;
		ws2812_setleds(leds,1); // Turn LEDs off

		set_sleep_mode(SLEEP_MODE_PWR_DOWN); // Prepare eternal sleep
		sleep_enable();
		sleep_mode();					 // Go down until someone changes the battery and resets the Tiny10
	}
#endif

#ifdef FEAT_STANDBY
	ISR(INT0_vect) {
	  EIMSK &= ~(1<<INT0);	// Disable INT0
	}
#endif

int __attribute__((OS_main))
main (void) {
  CCP = 0xD8;   // configuration change protection, write signature
  CLKPSR = 0;   // set cpu clock prescaler =1 (8Mhz)
  
  ADCSRA &= ~(1<<ADEN);       // Disable ADC
  PRR |= (1<<PRADC);		  // Power down ADC entirely
  PRR |= (1<<PRTIM0);		  // Power down Timer0 for now, we will enable it when needed
  
  #ifdef FEAT_UNDERVOLTSLEEP
	VLMCSR |= (1<<VLMIE) | (1<<VLM1) | (1<<VLM0); // Enable VLM Interrupt, set VLM Level to 2.5V
  #endif
  
  // Pin Setup:
  //   PB0 - LED Data (out)		Reset (PB3)
  //   GND						VCC
  //   PB1 - LED Power (out)	PB2 (INT0) - Sleep Button (in)
  // PB1 and PB2 are only used if FEAT_STANDBY is defined

  #ifdef FEAT_STANDBY
	DDRB |= (1<<DDB1);	// Set PB1 to output leave everything else at default (input)
	PUEB |= (1<<PUEB2);	// Activate internal Pullup resistor for PB2

	PORTB |= (1<<DDB1);	// Activate LED Power supply

	EICRA = 0;			// Set External Interrupt INT0 to low level interrupt request generation
	EIMSK |= (1<<INT0);	// Enable INT0
	sei();				// Make sure interrupts are coming through
  #endif

  led[0].r=R_STATIC; led[0].g=G_HIGH; led[0].b=B_STATIC;
  ws2812_setleds(led,1);
  delayms(100);

  while (1)
  {
    on(12);
    burn(3);
    on(10);
    burn(3);
    on(5);
    flicker(3);
    burn(2);
    on(12);
    flutter(1);
    burn(4);
    on(15);
    burn(3);
  }
  return(0);
}