#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#include <util/delay.h>
#include <stdlib.h> // for NULL

#include "lights.h"

#define WAKEUP_LIMIT	5	// times 100 ms
#define SHORT_PRESS_MIN 2       // in jiffies (16 Hz ticks)
#define SHORT_PRESS_MAX 5
#define LONG_PRESS_MIN  10
#define SETUP_TIMEOUT	255	// 15 seconds in jiffies
// #define USER_PARAMS_WRAPPING 1

static uint16_t button_start[3];
union {
	unsigned char all;
	struct {
		unsigned char btn1 : 1;
		unsigned char btn2 : 1;
		unsigned char brake : 1;
		unsigned char brake_working : 1;
		unsigned char brake_reported : 1;
	};
} button_state, prev_state;

/*
 * How does the user_params setup mode work:
 *
 * There is an array of user-settable parameters user_params[N_USER_PARAMS],
 * each of which has its own maximum value (user_params_max[N_USER_PARAMS].
 * These parameters can be modified in the following way:
 *
 * Long press of button 1 enters the setup mode.
 * In the setup mode, status and illumination LEDs both blink in inversion
 * number mode.
 * The # of blinks of the illumination LED shows which user_param is
 * being modified now,
 * and the # of blinks of the status LED shows the value of this particular
 * user_param.
 *
 * Long press of button 1 selects the next user_param,
 * short press of button 0 decrements this particular user_param value,
 * short press of button 1 increments this particular user_param value.
 *
 * If USER_PARAMS_WRAPPING is #defined, decrementing the zero leads to
 * the maximum value - 1, and incrementing the maximum value - 1 leads
 * to zero.
 *
 * After the SETUP_TIMEOUT with no button press, the system leaves the setup
 * mode.
 */
static unsigned char user_params[N_USER_PARAMS] = { 0, 0, 0 };
static unsigned char user_params_max[N_USER_PARAMS] = {
	N_AMBIENT_ZONES+1, 2, 2
};

static unsigned char user_params_state = 0;
	/*
	 * Here 0 means "no setup currently in progress",
	 * 1 .. N_USER_PARAMS means "now short presses increase or decrease
	 *           the value of user_params[user_params_state-1]"
	 */

static unsigned char user_params_timeout;

static void inline set_status_led(unsigned char n, pattern_t *pattern)
{
	led_set_pattern(n + 1, pattern);
}

unsigned char buttons_setup_in_progress()
{
	if (user_params_state) // setup in progress ...
		return 1;
	return 0;
}

pattern_t *buttons_setup_status1_pattern_select()
{
	if (user_params_state) // Setup in progress
		return number_pattern(user_params_state, 1);
	else
		return NULL;
}

pattern_t *buttons_setup_status0_pattern_select()
{
	if (user_params_state) // Setup in progress
		return number_pattern(
			1 + user_params[user_params_state-1],
			1
		);
	else
		return NULL;
}

unsigned char get_user_param(unsigned char param)
{
	if (param < N_USER_PARAMS)
		return user_params[param];
	return 0; // FIXME: internal error?
}

static inline void short_press(unsigned char button)
{
	unsigned char param;

	if (user_params_state == 0) {
		if (button == 0)
			toggle_dim_mode();
		else
			set_panic_mode();
		return;
	}

	param = user_params_state-1;

	if (button == 0) {
		if (user_params[param])
			--user_params[param];
#if SETUP_VALUES_WRAPPING
		else
			user_params[param] = user_params_max[param]-1;
#endif
	} else {
		++user_params[param];

		if (user_params[param] >= user_params_max[param])
#if SETUP_VALUES_WRAPPING
			user_params[param] = 0;
#else
			user_params[param] = user_params_max[param]-1;
#endif
	}
	// FIXME: notify somebody about user_params change?

	set_status_led(1, buttons_setup_status1_pattern_select());

	user_params_timeout = SETUP_TIMEOUT;
}

static inline void long_press(unsigned char button)
{
	if (button == 0) {
		power_down(0);
		return;
	}

	// button 1 - cycle through states
	user_params_state++;

	if (user_params_state > N_USER_PARAMS)
		user_params_state = 1;

	set_status_led(0, buttons_setup_status0_pattern_select());
	set_status_led(1, buttons_setup_status1_pattern_select());
	user_params_timeout = SETUP_TIMEOUT;
}

void init_buttons()
{
	DDRA &= ~_BV(PA4); // set as input
	DDRA |= _BV(PA3); // output
	PORTA &= ~(_BV(PA3) | _BV(PA4));  // PA4 disable internal pull-up
					// PA3 set to zero

	GIMSK &= ~(_BV(PCIE0) | _BV(PCIE1)); // disable pin-change IRQs
	PCMSK0 = 0; // disable pin-change IRQs on all pins of port A
	PCMSK1 = 0; // disable pin-change IRQs on all pins of port B

	button_start[0] = 0;
	button_start[1] = 0;
	button_start[2] = 0;

	prev_state.all    = 0;
	button_state.all  = 0;
	user_params_state = 0;
}

void susp_buttons()
{
	DDRA &= ~(_BV(PA3) | _BV(PA4)); // set as input
	PORTA |= _BV(PA4);  // enable internal pull-up
	PORTA &= ~_BV(PA3); // disable pull-up

	GIMSK &= ~_BV(PCIE0);
	GIMSK |= _BV(PCIE1);

	PCMSK0 = _BV(PCINT4);
		// disable pin-change IRQs on all pins except PA4
	PCMSK1 = 0; // disable pin-change IRQs on all pins of port B
}

static void handle_button(unsigned char button, unsigned char cur,
	unsigned char prev)
{
	if (cur && !prev) {                   // --- just pressed ---
		button_start[button] = jiffies;
		if (!user_params_state)
			set_status_led(button, NULL);

	} else if (cur && prev) {           // --- is still pressed ---
		uint16_t duration = jiffies - button_start[button];

		if (duration >= LONG_PRESS_MIN) {
			set_status_led(button, on_pattern);
				// acknowledge long press
		}
	} else if (!cur && prev) {            // --- just released ---
		uint16_t duration = jiffies - button_start[button];

		if (duration >= SHORT_PRESS_MIN && duration < SHORT_PRESS_MAX) {
			short_press(button);
		} else if (duration > LONG_PRESS_MIN) {
			set_status_led(button, NULL);
			long_press(button);
		}
		// ignore other button-press durations
	}
}

static void handle_brake(unsigned char cur, unsigned char prev)
{
	uint16_t duration;

	if (cur && !prev) {                   // --- just pressed ---
		button_start[2] = jiffies;
		return;
	} else if (!cur && prev) {            // --- just released ---
		button_start[2] = jiffies;
		return;
	}
				              // --- no change ---
	duration = jiffies - button_start[2];

	if (duration == 0) // at least two jiffies
		return;

	if (cur) {
		if (button_state.brake_working) {
			static unsigned int brake_time;
			if (button_state.brake_reported) {
				if (brake_time) {
					brake_time--;
				} else {
					brake_off();
					button_state.brake_working = 0;
					button_state.brake_reported = 0;
				}
			} else {
				button_state.brake_reported = 1;
				brake_on();
				brake_time = 255; // avoid longer than ~16s
			}
		}
	} else {
		button_state.brake_working = 1;
		if (button_state.brake_reported) {
			button_state.brake_reported = 0;
			brake_off();
		}
	}

	button_start[2] = jiffies - 7; // avoid overflow
}

void timer_check_buttons()
{
	handle_button(0, button_state.btn1, prev_state.btn1);

	// when button 1 is on, all other states are unreadable
	if (button_state.btn1) {
		prev_state.btn1 = button_state.btn1;
	} else {
		handle_button(1, button_state.btn2, prev_state.btn2);
		handle_brake(button_state.brake, prev_state.brake);
		prev_state.all = button_state.all;
	}

	if (user_params_timeout)
		--user_params_timeout;

	if (user_params_state && !user_params_timeout) {
		user_params_state = 0;
		set_status_led(0, buttons_setup_status0_pattern_select());
		set_status_led(1, buttons_setup_status1_pattern_select());
	}
}

unsigned char buttons_wait_for_release()
{
	uint16_t wake_count = 0;
	unsigned char pin;

	do {
		if (wake_count++ > WAKEUP_LIMIT)
			gpio_set(0, 1); // inform the user

		_delay_ms(100);

		pin = PINA & _BV(PA4);
	} while (!(pin & _BV(PA4)));

	gpio_set(0, 0);

	return wake_count > WAKEUP_LIMIT;
}

void button_adc(uint16_t adcval)
{
#if 0
	static unsigned char count=250;
#endif
	PORTA &= ~_BV(PA3); // disable +5V to the hall probe
		// adc.c will re-enable it again

	button_state.btn1 = 0;
	button_state.btn2 = 0;
	button_state.brake = 0;

	if (adcval == 0x3FF) {
		button_state.brake = 1;
	} else if (adcval > 0x240) {
		button_state.brake = 1;
		button_state.btn2 = 1;
	} else if (adcval > 0x180) {
		// nothing
	} else if (adcval > 0xc0) {
		button_state.btn2 = 1;
	} else {
		button_state.btn1 = 1;
	}

#if 0
	if (--count)
		return;

	count = 250;
	log_word(adcval);
	log_flush();
#endif
}

ISR(PCINT_vect)
{
	// empty - let it wake us from sleep, but do nothing else
}