#include <avr/io.h>

#include "lights.h"

static uint16_t pwm_vals[N_PWMLEDS*N_PWMLED_MODES];
static uint16_t pwm_max[N_PWMLEDS] = { 0x70, 0x70, 0xF0 };
static uint16_t adc_max[N_PWMLEDS] = { 0x70, 0x70, 0xF0 };
static uint16_t adc_vals[N_PWMLEDS*N_PWMLED_MODES] = {
	/* pwmled0 */
	0x04, 0x14, 0x24, 0x38,
	/* pwmled1 */
	0x04, 0x14, 0x24, 0x38,
	/* pwmled2 */
	0x0c, 0x24, 0x48, 0x90,
};

// TODO: maybe convert this to bitmask to simplify pwmled_needs_adc() ?
static unsigned char pwmled_state[N_PWMLEDS];
#define ST_DISABLED 0
#define ST_PROBING  1
#define ST_OFF      2
#define ST_ON       3

static unsigned char pwmled_mode[N_PWMLEDS];
static unsigned char pwmled_mode_set[N_PWMLEDS];

static uint16_t pwm_probes[N_PWMLEDS];

static void start_probing(unsigned char n)
{
	pwmled_state[n] = ST_PROBING;
	pwm_set(n, 0);
	pwm_probes[n] = 0;
}

void pwmled_init()
{
	unsigned char i;

	for (i = 0; i < N_PWMLEDS*N_PWMLED_MODES; i++) {
		pwm_vals[i] = 0;
		pwmled_mode[i] = 0;
		pwmled_mode_set[i] = 0;
	}

	for (i = 0; i < N_PWMLEDS; i++) {
		start_probing(i);
	}
}

unsigned char pwmled_needs_adc(unsigned char n)
{
	unsigned char st = pwmled_state[n];
	if (st == ST_PROBING || st == ST_ON)
		return 1;
	else
		return 0;
}

unsigned char pwmled_enabled(unsigned char n)
{
	unsigned char st = pwmled_state[n];
	if (st == ST_OFF || st == ST_ON)
		return 1;
	else
		return 0;
}

void pwmled_set_mode(unsigned char n, unsigned char mode)
{
	if (!pwmled_enabled(n))
		return;

#if 0
	log_byte(0xF8);
	log_byte(n);
	log_byte(mode);
#endif

	if (mode == 0) {
		pwm_off(n);
		pwmled_state[n] = ST_OFF;
		return;
	}

	if (mode <= N_PWMLED_MODES) {
		uint16_t pwmval;
		mode--;
		pwmval = pwm_vals[n*N_PWMLED_MODES+mode];
		pwm_set(n, pwmval);
#if 0
		log_byte(pwmval);
#endif
		pwmled_state[n] = ST_ON;
		pwmled_mode[n] = mode;
		pwmled_mode_set[n] = 1;
	}
}

static void inline probing_adc(unsigned char n, uint16_t adcval)
{
	unsigned char need_bigger = 0, i;
	uint16_t *pwm_p = &pwm_vals[n*N_PWMLED_MODES];
	uint16_t *adc_p = &adc_vals[n*N_PWMLED_MODES];
	uint16_t pwm = pwm_probes[n];

#if 0
	log_byte(0xF4);
	log_byte(n);
	log_word(adcval);
#endif

	if (adcval > adc_max[n] // Too high
		|| (pwm == 0 && adcval > 0) // non-zero voltage with zero PWM
		) {
		pwm_off(n);
		pwmled_state[n] = ST_DISABLED;
		log_byte(0xF0);
		log_byte(n);
		log_word(adcval);
		return;
	}

	for (i = 0; i < N_PWMLED_MODES; i++, pwm_p++, adc_p++) {
		uint16_t adc = *adc_p;
		if (adc >= adcval) {
			*pwm_p = pwm;
			need_bigger = 1;
		}
	}

#if 0
	if ((n == 1 && pwm > 0x35) || adcval != 0) {
		log_byte(n);
		log_byte(0xF3);
		log_byte(pwm);
		log_word(adcval);
	}
#endif

	if (!need_bigger) { // successfully probed
		pwm_off(n);
		// pwm_set(n, 0);
		pwmled_state[n] = ST_OFF;
		log_byte(0xF1);
		log_byte(n);

		return;
	}

	if (pwm >= pwm_max[n]) { // over the maximum!
		pwm_off(n);
		pwmled_state[n] = ST_DISABLED;
		log_byte(0xF2);
		log_byte(n);
		// pwm_set(n, 0);
		return;
	}

	// try to increase
	pwm++;
	pwm_probes[n] = pwm;
	pwm_set(n, pwm);
}

// Feedback loop
static void inline on_adc(unsigned char n, uint16_t adcval)
{
	unsigned char mode = pwmled_mode[n];
	uint16_t adc_exp     =  adc_vals[n*N_PWMLED_MODES+mode];
	uint16_t *pwm_p      = &pwm_vals[n*N_PWMLED_MODES+mode];
	uint16_t old_pwm     = *pwm_p;
	uint16_t new_pwm = old_pwm;

#if 0
	log_byte(0xF5);
	log_byte(n);
	log_word(adcval);
#endif

	if (pwmled_mode_set[n]) { // ignore the first reading
		pwmled_mode_set[n] = 0;
		return;
	}

	// FIXME: running average?
	if (2*adcval > 5*adc_exp) { // >2.5x expected, lower significantly
		new_pwm = 2*old_pwm/3;
	} else if (3*adcval > 4*adc_exp) { // >1.33x expected, lower a bit
		new_pwm = old_pwm - 1;
	} else if (4*adcval < 3*adc_exp) { // 0.75x expected, raise a bit
		new_pwm = old_pwm + 1;
	}

	// FIXME: better disconnect detection
	if (new_pwm > pwm_max[n]) { // FIXME: disconnected?
		new_pwm = pwm_max[n];
	}
	if (new_pwm < 2) { // short-circuit?
		new_pwm = 2;
	}

	if (new_pwm != old_pwm) {
		*pwm_p = new_pwm;
		pwm_set(n, new_pwm);
#if 0
		log_byte(0xF9);
		log_byte(new_pwm);
#endif
	}
}

void pwmled_adc(unsigned char n, uint16_t adcval)
{
	unsigned char i, probing;
	switch (pwmled_state[n]) {
	case ST_PROBING:
		probing_adc(n, adcval);

#if 1
		probing = 0;
		for (i = 0; i < N_PWMLEDS; i++)
			if (pwmled_state[i] == ST_PROBING)
				probing = 1;

		if (!probing) {
			for (i = 0; i < N_PWMLEDS; i++)
				log_byte(pwmled_state[i]);
				
			for (i = 0; i < N_PWMLEDS*N_PWMLED_MODES; i++)
				log_word(pwm_vals[i]);
			log_flush();
			log_set_state(4);
		}
#endif
		
		return;
	case ST_ON:
		on_adc(n, adcval);
		return;
	// WTF am I doing in this function then? Maybe recently switched off?
	}
}