#include	"dda.h"

#include	<string.h>

#include	"timer.h"
#include	"serial.h"
#include	"sermsg.h"

#ifndef	ABS
#define	ABS(v)		(((v) >= 0)?(v):(-(v)))
#endif

#ifndef	ABSDELTA
#define	ABSDELTA(a, b)	(((a) >= (b))?((a) - (b)):((b) - (a)))
#endif

#ifndef	DEBUG
#define	DEBUG 0
#endif

/*
	step timeout
*/

uint8_t	steptimeout = 0;

/*
	move queue
*/

uint8_t	mb_head = 0;
uint8_t	mb_tail = 0;
DDA movebuffer[MOVEBUFFER_SIZE];

/*
	position tracking
*/

TARGET startpoint = { 0, 0, 0, 0, 0 };
TARGET current_position = { 0, 0, 0, 0, 0 };

uint8_t queue_full() {
	if (mb_tail == 0)
		return mb_head == (MOVEBUFFER_SIZE - 1);
	else
		return mb_head == (mb_tail - 1);
}

uint8_t queue_empty() {
	return ((mb_tail == mb_head) && (movebuffer[mb_tail].live == 0))?255:0;
}

void enqueue(TARGET *t) {
	while (queue_full())
		delay(WAITING_DELAY);

	uint8_t h = mb_head;
	h++;
	if (h == MOVEBUFFER_SIZE)
		h = 0;
	dda_create(t, &movebuffer[h]);
	mb_head = h;

	// fire up in case we're not running yet
	enableTimerInterrupt();
}

void next_move() {
	if (queue_empty()) {
		// queue is empty
// 		disable_steppers();
// 		setTimer(DEFAULT_TICK);
		disableTimerInterrupt();
	}
	else {
		uint8_t t = mb_tail;
		t++;
		if (t == MOVEBUFFER_SIZE)
			t = 0;
		dda_start(&movebuffer[t]);
		mb_tail = t;
	}
}

/*
	utility functions
*/

// courtesy of http://www.oroboro.com/rafael/docserv.php/index/programming/article/distance
uint32_t approx_distance( uint32_t dx, uint32_t dy )
{
	uint32_t min, max, approx;

	if ( dx < dy )
	{
		min = dx;
		max = dy;
	} else {
		min = dy;
		max = dx;
	}

	approx = ( max * 1007 ) + ( min * 441 );
	if ( max < ( min << 4 ))
		approx -= ( max * 40 );

	// add 512 for proper rounding
	return (( approx + 512 ) >> 10 );
}

// courtesy of http://www.oroboro.com/rafael/docserv.php/index/programming/article/distance
uint32_t approx_distance_3( uint32_t dx, uint32_t dy, uint32_t dz )
{
	uint32_t min, med, max, approx;

	if ( dx < dy )
	{
		min = dy;
		med = dx;
	} else {
		min = dx;
		med = dy;
	}

	if ( dz < min )
	{
		max = med;
		med = min;
		min = dz;
	} else if ( dz < med ) {
		max = med;
		med = dz;
	} else {
		max = dz;
	}

	approx = ( max * 860 ) + ( med * 851 ) + ( min * 520 );
	if ( max < ( med << 1 )) approx -= ( max * 294 );
	if ( max < ( min << 2 )) approx -= ( max * 113 );
	if ( med < ( min << 2 )) approx -= ( med *  40 );

	// add 512 for proper rounding
	return (( approx + 512 ) >> 10 );
}

uint32_t abs32(int32_t v) {
	if (v < 0)
		return (uint32_t) (-v);
	return (uint32_t) (v);
}


void print_queue() {
	serial_writechar('Q');
	serwrite_uint8(mb_tail);
	serial_writechar('/');
	serwrite_uint8(mb_head);
	if (queue_full())
		serial_writechar('F');
	if (queue_empty())
		serial_writechar('E');
	serial_writechar('\n');
}

/*
	CREATE
*/

void dda_create(TARGET *target, DDA *dda) {
	uint32_t	distance;

	// initialise DDA to a known state
	dda->move_duration = 0;
	dda->live = 0;
	dda->total_steps = 0;

	if (DEBUG)
		serial_writestr_P(PSTR("\n{DDA_CREATE: ["));

	// we end at the passed target
	memcpy(&(dda->endpoint), target, sizeof(TARGET));

	dda->x_delta = abs32(target->X - startpoint.X);
	dda->y_delta = abs32(target->Y - startpoint.Y);
	dda->z_delta = abs32(target->Z - startpoint.Z);
	dda->e_delta = abs32(target->E - startpoint.E);
	dda->f_delta = abs32(target->F - startpoint.F);

	if (DEBUG) {
		serwrite_uint32(dda->x_delta); serial_writechar(',');
		serwrite_uint32(dda->y_delta); serial_writechar(',');
		serwrite_uint32(dda->z_delta); serial_writechar(',');
		serwrite_uint32(dda->e_delta); serial_writechar(',');
		serwrite_uint32(dda->f_delta); serial_writestr_P(PSTR("] ["));
	}

	if (dda->x_delta > dda->total_steps)
		dda->total_steps = dda->x_delta;
	if (dda->y_delta > dda->total_steps)
		dda->total_steps = dda->y_delta;
	if (dda->z_delta > dda->total_steps)
		dda->total_steps = dda->z_delta;
	if (dda->e_delta > dda->total_steps)
		dda->total_steps = dda->e_delta;

	if (dda->total_steps == 0) {
		dda->nullmove = 1;
	}
	else {

		if (DEBUG) {
			serwrite_uint32(dda->total_steps); serial_writechar(',');
		}

	// 	if (dda->f_delta > dda->total_steps) {
	// 		dda->f_scale = dda->f_delta / dda->total_steps;
	// 		if (dda->f_scale > 3) {
	// 			dda->f_delta = dda->total_steps;
	// 		}
	// 		else {
	// 			// if we boost the number of steps here, many will only be F-steps which take no time- maybe we should calculate move_distance first?
	// 			dda->f_scale = 1;
	// 			dda->total_steps = dda->f_delta;
	// 		}
	// 	}
	// 	else {
	// 		dda->f_scale = 1;
	// 	}
	//
	// 	if (DEBUG) {
	// 		serwrite_uint32(dda->total_steps); serial_writechar(',');
	// 	}

		dda->x_direction = (target->X >= startpoint.X)?1:0;
		dda->y_direction = (target->Y >= startpoint.Y)?1:0;
		dda->z_direction = (target->Z >= startpoint.Z)?1:0;
		dda->e_direction = (target->E >= startpoint.E)?1:0;
		dda->f_direction = (target->F >= startpoint.F)?1:0;

		dda->x_counter = dda->y_counter = dda->z_counter = dda->e_counter = dda->f_counter =
			-(dda->total_steps >> 1);

		// since it's unusual to combine X, Y and Z changes in a single move on reprap, check if we can use simpler approximations before trying the full 3d approximation.
		if (dda->z_delta == 0)
			distance = approx_distance(dda->x_delta * UM_PER_STEP_X, dda->y_delta * UM_PER_STEP_Y);
		else if (dda->x_delta == 0 && dda->y_delta == 0)
			distance = dda->z_delta * UM_PER_STEP_Z;
		else
			distance = approx_distance_3(dda->x_delta * UM_PER_STEP_X, dda->y_delta * UM_PER_STEP_Y, dda->z_delta * UM_PER_STEP_Z);

		if (distance < 2)
			distance = dda->e_delta * UM_PER_STEP_E;
	// 	if (distance < 2)
	// 		distance = dda->f_delta;

		// pre-calculate move speed in millimeter microseconds per step minute for less math in interrupt context
		// mm (distance) * 60000000 us/min / step (total_steps) = mm.us per step.min
		//   note: um (distance) * 60000 == mm * 60000000
		// so in the interrupt we must simply calculate
		// mm.us per step.min / mm per min (F) = us per step
		dda->move_duration = distance * 60000 / dda->total_steps;

		if (DEBUG)
			serwrite_uint32(dda->move_duration);
	}

	if (DEBUG)
		serial_writestr_P(PSTR("] }\n"));

	// next dda starts where we finish
	memcpy(&startpoint, target, sizeof(TARGET));

	// get steppers ready to go
	steptimeout = 0;
	enable_steppers();
}

/*
	START
*/

void dda_start(DDA *dda) {
	// called from interrupt context: keep it simple!
	if (
			(current_position.X == dda->endpoint.X) &&
			(current_position.Y == dda->endpoint.Y) &&
			(current_position.Z == dda->endpoint.Z) &&
			(current_position.E == dda->endpoint.E)
		 ) {
// 	if (dda->nullmove) {
		// just change speed?
		current_position.F = dda->endpoint.F;
		return;
	}

	// ensure steppers are ready to go
	steptimeout = 0;
	enable_steppers();

	// set direction outputs
	x_direction(dda->x_direction);
	y_direction(dda->y_direction);
	z_direction(dda->z_direction);
	e_direction(dda->e_direction);

	// ensure this dda starts
	dda->live = 1;

	// set timeout for first step
	setTimer(dda->move_duration / current_position.F);
}

/*
	CAN STEP
*/

uint8_t	can_step(uint8_t min, uint8_t max, int32_t current, int32_t target, uint8_t dir) {
	if (current == target)
		return 0;

	if (dir) {
		// forwards/positive
		if (max)
			return 0;
		if (current > target)
			return 0;
	}
	else {
		// backwards/negative
		if (min)
			return 0;
		if (target > current)
			return 0;
	}

	return 255;
}

/*
	STEP
*/

void dda_step(DDA *dda) {
	uint8_t	step_option = 0;
#define	X_CAN_STEP	1
#define	Y_CAN_STEP	2
#define	Z_CAN_STEP	4
#define	E_CAN_STEP	8
#define	F_CAN_STEP	16
#define	REAL_MOVE		32
#define	F_REAL_STEP	64

	serial_writechar('!');

	WRITE(SCK, 0);

	do {
// 		WRITE(SCK, 0);

		step_option = 0;
// 		step_option |= can_step(x_min(), x_max(), current_position.X, dda->endpoint.X, dda->x_direction) & X_CAN_STEP;
// 		step_option |= can_step(y_min(), y_max(), current_position.Y, dda->endpoint.Y, dda->y_direction) & Y_CAN_STEP;
// 		step_option |= can_step(z_min(), z_max(), current_position.Z, dda->endpoint.Z, dda->z_direction) & Z_CAN_STEP;
		step_option |= can_step(0      , 0      , current_position.X, dda->endpoint.X, dda->x_direction) & X_CAN_STEP;
		step_option |= can_step(0      , 0      , current_position.Y, dda->endpoint.Y, dda->y_direction) & Y_CAN_STEP;
		step_option |= can_step(0      , 0      , current_position.Z, dda->endpoint.Z, dda->z_direction) & Z_CAN_STEP;
		step_option |= can_step(0      , 0      , current_position.E, dda->endpoint.E, dda->e_direction) & E_CAN_STEP;
		step_option |= can_step(0      , 0      , current_position.F, dda->endpoint.F, dda->f_direction) & F_CAN_STEP;

		if (step_option & X_CAN_STEP) {
			dda->x_counter -= dda->x_delta;
			if (dda->x_counter < 0) {
				step_option |= REAL_MOVE;

				x_step();
				if (dda->x_direction)
					current_position.X++;
				else
					current_position.X--;

				dda->x_counter += dda->total_steps;
			}
		}

		if (step_option & Y_CAN_STEP) {
			dda->y_counter -= dda->y_delta;
			if (dda->y_counter < 0) {
				step_option |= REAL_MOVE;

				y_step();
				if (dda->y_direction)
					current_position.Y++;
				else
					current_position.Y--;

				dda->y_counter += dda->total_steps;
			}
		}

		if (step_option & Z_CAN_STEP) {
			dda->z_counter -= dda->z_delta;
			if (dda->z_counter < 0) {
				step_option |= REAL_MOVE;

				z_step();
				if (dda->z_direction)
					current_position.Z++;
				else
					current_position.Z--;

				dda->z_counter += dda->total_steps;
			}
		}

		if (step_option & E_CAN_STEP) {
			dda->e_counter -= dda->e_delta;
			if (dda->e_counter < 0) {
				step_option |= REAL_MOVE;

				e_step();
				if (dda->e_direction)
					current_position.E++;
				else
					current_position.E--;

				dda->e_counter += dda->total_steps;
			}
		}

		if (step_option & F_CAN_STEP) {
			dda->f_counter -= dda->f_delta;
			while (dda->f_counter < 0) {

				dda->f_counter += dda->total_steps;

// 				if (dda->f_scale == 0)
// 					dda->f_scale = 1;

				if (dda->f_direction) {
// 					current_position.F += dda->f_scale;
					current_position.F += 1;
					if (current_position.F > dda->endpoint.F)
						current_position.F = dda->endpoint.F;
				}
				else {
// 					current_position.F -= dda->f_scale;
					current_position.F -= 1;
					if (current_position.F < dda->endpoint.F)
						current_position.F = dda->endpoint.F;
				}

				step_option |= F_REAL_STEP;
			}
		}

		if (0 && DEBUG) {
			serial_writechar('[');
			serwrite_hex8(step_option);
			serial_writechar(':');
// 			serwrite_uint16(dda->f_scale);
// 			serial_writechar(',');
			serwrite_int32(current_position.F);
			serial_writechar('/');
			serwrite_int32(dda->endpoint.F);
			serial_writechar('#');
			serwrite_uint32(dda->move_duration);
			serial_writechar(']');
		}

// 		WRITE(SCK, 1);

	} while (	((step_option & REAL_MOVE ) == 0)	&&
						((step_option & F_CAN_STEP) != 0)	);

	// turn off step outputs, hopefully they've been on long enough by now to register with the drivers
	unstep();

	if (step_option & REAL_MOVE)
		// we stepped, reset timeout
		steptimeout = 0;

	// we have stepped in speed and now need to recalculate our delay
	// WARNING: this is a divide in interrupt context! (which unfortunately seems unavoidable)
	// we simply don't have the memory to precalculate this for each step,
	// can't use a simplified process because the denominator changes rather than the numerator so the curve is non-linear
	// and don't have a process framework to force it to be done outside interrupt context within a usable period of time
	if (step_option & F_REAL_STEP)
		setTimer(dda->move_duration / current_position.F);

	// if we could step, we're still running
// 	dda->live = (step_option & (X_CAN_STEP | Y_CAN_STEP | Z_CAN_STEP | E_CAN_STEP | F_CAN_STEP))?1:0;
	if (
			(current_position.X == dda->endpoint.X) &&
			(current_position.Y == dda->endpoint.Y) &&
			(current_position.Z == dda->endpoint.Z) &&
			(current_position.E == dda->endpoint.E) &&
			(current_position.F == dda->endpoint.F)
		 ) {
		dda->live = 0;
	}

	WRITE(SCK, 1);
}