#include <avr/io.h>

#include "lights.h"

static uint16_t pwm_vals[N_PWMLEDS*N_PWMLED_MODES];
static uint16_t pwm_max[N_PWMLEDS] = {
	PWM_MAX/2,
	PWM_MAX - (PWM_MAX >> 4), // step-up
	PWM_MAX/2
};

#define PWMLED2_TESTING_WITH_350MA_LED

#define SENSE_MOHM	33	/* 0.033 Ohm */
#define MA_MOHM_GAIN_TO_ADC(ma, mohm, gain) (\
	((unsigned long)(ma))*(mohm) /* voltage at sensing resistor in uV */ \
	/(1100000UL/gain/1024UL)     /* voltage of ADC reading == 1 */ \
)
static uint16_t adc_max[N_PWMLEDS] = {
	MA_MOHM_GAIN_TO_ADC( 400, SENSE_MOHM, 20),
	MA_MOHM_GAIN_TO_ADC(  30, SENSE_MOHM, 20),
#ifdef PWMLED2_TESTING_WITH_350MA_LED
	MA_MOHM_GAIN_TO_ADC( 400, SENSE_MOHM,  1)
#else
	MA_MOHM_GAIN_TO_ADC(2500, SENSE_MOHM,  1)
#endif
};
static uint16_t adc_vals[N_PWMLEDS*N_PWMLED_MODES] = {
	/* pwmled0 */
	MA_MOHM_GAIN_TO_ADC(  20, SENSE_MOHM, 20),
	MA_MOHM_GAIN_TO_ADC(  50, SENSE_MOHM, 20),
	MA_MOHM_GAIN_TO_ADC( 100, SENSE_MOHM, 20),
	MA_MOHM_GAIN_TO_ADC( 350, SENSE_MOHM, 20),
	/* pwmled1 */
	MA_MOHM_GAIN_TO_ADC(   5, SENSE_MOHM, 20),
	MA_MOHM_GAIN_TO_ADC(  12, SENSE_MOHM, 20),
	MA_MOHM_GAIN_TO_ADC(  16, SENSE_MOHM, 20),
	MA_MOHM_GAIN_TO_ADC(  20, SENSE_MOHM, 20),
	/* pwmled2 */
#ifdef PWMLED2_TESTING_WITH_350MA_LED
	MA_MOHM_GAIN_TO_ADC( 100, SENSE_MOHM,  1),
	MA_MOHM_GAIN_TO_ADC( 140, SENSE_MOHM,  1),
	MA_MOHM_GAIN_TO_ADC( 250, SENSE_MOHM,  1),
	MA_MOHM_GAIN_TO_ADC( 350, SENSE_MOHM,  1),
#else
	MA_MOHM_GAIN_TO_ADC( 150, SENSE_MOHM,  1),
	MA_MOHM_GAIN_TO_ADC( 350, SENSE_MOHM,  1),
	MA_MOHM_GAIN_TO_ADC( 700, SENSE_MOHM,  1),
	MA_MOHM_GAIN_TO_ADC(2400, SENSE_MOHM,  1),
#endif
};

// 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 int16_t differences[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++) {
		differences[i] = 0;
		start_probing(i);
	}
}

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 && 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;
		differences[n] = 0;
	} else {
		pwm_off(n);
		pwmled_state[n] = ST_OFF;
	}
}

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];
	int16_t old_pwm    = *pwm_p;
	int16_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;
	}

	differences[n] += adcval;
	differences[n] -= adc_exp;

	if (differences[n] > 16)
		new_pwm -= 2;
	else if (differences[n] > 4)
		new_pwm--;
	else if (differences[n] < -16)
		new_pwm += 2;
	else if (differences[n] < -4)
		new_pwm++;
	// new_pwm -= differences[n] >> 3;

	if (new_pwm == old_pwm)
		return;

	differences[n] = 0;

	if (new_pwm > (int16_t)pwm_max[n]) {
		// FIXME: disconnected?
		new_pwm = pwm_max[n];
	}

	if (new_pwm < 1) {
		// FIXME: short-circuit?
		new_pwm = 1;
	}

	*pwm_p = new_pwm;
	pwm_set(n, new_pwm);

	if (jiffies > 500 && n == 1) {
		log_byte(adcval & 0xFF);
		log_byte(new_pwm);
	}
}

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?
	}
}