/*!
   \file gk.c

   \brief OGSF library - setting and manipulating keyframes animation (lower level functions)

   GRASS OpenGL gsurf OGSF Library 

   (C) 1999-2008 by the GRASS Development Team

   This program is free software under the 
   GNU General Public License (>=v2). 
   Read the file COPYING that comes with GRASS
   for details.

   \author Bill Brown USACERL, GMSL/University of Illinois
   \author Doxygenized by Martin Landa <landa.martin gmail.com> (May 2008)
 */

#include <stdlib.h>
#include <math.h>

#include <grass/gis.h>
#include <grass/glocale.h>
#include <grass/ogsf.h>

static float spl3(float, double, double, double, double, double, double,
		  double);

static float spl3(float tension, double data0, double data1, double x,
		  double x2, double x3, double lderiv, double rderiv)
{
    return ((float)
	    (data0 * (2 * x3 - 3 * x2 + 1) + data1 * (-2 * x3 + 3 * x2) +
	     (double)tension * lderiv * (x3 - 2 * x2 + x) +
	     (double)tension * rderiv * (x3 - x2)));
}

/*!
   \brief Copy keyframes

   \param k source keyframes

   \return pointer to Keylist struct (target)
 */
Keylist *gk_copy_key(Keylist * k)
{
    Keylist *newk;
    int i;

    newk = (Keylist *) G_malloc(sizeof(Keylist));	/* G_fatal_error */
    if (!newk) {
	return (NULL);
    }

    for (i = 0; i < KF_NUMFIELDS; i++) {
	newk->fields[i] = k->fields[i];
    }

    newk->pos = k->pos;
    newk->look_ahead = k->look_ahead;
    newk->fieldmask = k->fieldmask;
    newk->next = newk->prior = NULL;

    return (newk);
}

/*!
   \brief Get mask value

   Get begin & end pos, AND all masks in keys <= pos

   Time must be between 0.0 & 1.0

   \param time timestamp
   \param keys list of keyframes

   \return mask value
 */
unsigned long gk_get_mask_sofar(float time, Keylist * keys)
{
    Keylist *k;
    float startpos, endpos, curpos;
    unsigned long mask = 0xFFFFFFFF;

    if (keys) {
	/* find end key */
	for (k = keys; k->next; k = k->next) ;

	startpos = keys->pos;
	endpos = k->pos;
	curpos = startpos + time * (endpos - startpos);

	for (k = keys; k->next; k = k->next) {
	    if (k->pos <= curpos) {
		mask &= k->fieldmask;	/* (else break) */
	    }
	}
    }

    return (mask);
}

/*!
   \brief ADD

   \param mask mask value
   \param keys list of keyframes
   \param[out] keyret output list of keyframes

   \return number of output keyframes
 */
int gk_viable_keys_for_mask(unsigned long mask, Keylist * keys,
			    Keylist ** keyret)
{
    Keylist *k;
    int cnt = 0;

    for (k = keys; k; k = k->next) {
	if ((mask & k->fieldmask) == mask) {
	    keyret[cnt++] = k;
	}
    }

    return (cnt);
}

/*!
   \brief Checks key masks

   Because if they're masked up until the current position,
   pre-existing (or current) field should be used.

   \param view pointer to Viewmode struct
   \param numsteps number of steps
   \param keys list of keyframes
   \param step step value
   \param onestep
   \param render
   \param mode
 */
void gk_follow_frames(Viewnode * view, int numsteps, Keylist * keys, int step,
		      int onestep, int render, unsigned long mode)
{
    Viewnode *v;
    int frame;			/* frame is index into viewnode array */
    float tmp[3];
    float x, y, z;
    int num, w;
    unsigned long mask;

    for (frame = step - 1; frame < numsteps; frame++) {

	v = &view[frame];
	mask = gk_get_mask_sofar((float)frame / numsteps, keys);

	/* TODO?: set view field to current settings if not set,
	   thereby keeping view structure up to date for easier saving of
	   animation? */

	GS_get_from(tmp);
	if ((mask & KF_FROMX_MASK)) {
	    tmp[X] = v->fields[KF_FROMX];
	}
	if ((mask & KF_FROMY_MASK)) {
	    tmp[Y] = v->fields[KF_FROMY];
	}
	if ((mask & KF_FROMZ_MASK)) {
	    tmp[Z] = v->fields[KF_FROMZ];
	}

	GS_moveto(tmp);

	GS_get_from(tmp);
	G_debug(3, "gk_follow_frames():");
	G_debug(3, "  MASK: %lx", mask);
	G_debug(3, "  FROM: %f %f %f", tmp[X], tmp[Y], tmp[Z]);

	/* ACS 1 line: was      GS_get_focus(tmp);
	   with this kanimator works also for flythrough navigation
	   also changed in GK2.c
	 */
	GS_get_viewdir(tmp);
	if ((mask & KF_DIRX_MASK)) {
	    tmp[X] = v->fields[KF_DIRX];
	}
	if ((mask & KF_DIRY_MASK)) {
	    tmp[Y] = v->fields[KF_DIRY];
	}
	if ((mask & KF_DIRZ_MASK)) {
	    tmp[Z] = v->fields[KF_DIRZ];
	}
	/* ACS 1 line: was      GS_set_focus(tmp);
	   with this kanimator works also for flythrough navigation
	   also changed in GK2.c
	 */
	GS_set_viewdir(tmp);

	G_debug(3, "gk_follow_frames():");
	GS_get_viewdir(tmp);
	G_debug(3, "  DIR: %f %f %f\n", tmp[X], tmp[Y], tmp[Z]);

	if ((mask & KF_TWIST_MASK)) {
	    GS_set_twist((int)v->fields[KF_TWIST]);
	}

	if ((mask & KF_FOV_MASK)) {
	    GS_set_fov((int)v->fields[KF_FOV]);
	}

	/* Initilaize lights before drawing */
	num = 1;
	GS_getlight_position(num, &x, &y, &z, &w);
	GS_setlight_position(num, x, y, z, w);
	num = 2;		/* Top light */
	GS_setlight_position(num, 0., 0., 1., 0);

	if (render) {
	    GS_set_draw(GSD_FRONT);
	}
	else {
	    GS_set_draw(GSD_BACK);
	}

	GS_ready_draw();
	GS_clear(GS_background_color());

	if (render) {
	    GS_alldraw_surf();
	}
	else {
	    GS_alldraw_wire();
	}

	GS_alldraw_cplane_fences();

	if (mode & FM_PATH) {
	    gk_draw_path(view, numsteps, keys);
	}

	if (mode & FM_VECT) {
	    GV_alldraw_vect();
	}

	if (mode & FM_SITE) {
	    GP_alldraw_site();
	}

	if (mode & FM_VOL) {
	    GVL_alldraw_vol();
	}

	GS_done_draw();

	if (mode & FM_LABEL) {
	    GS_draw_all_list();	/* draw labels and legend */
	}

	if (onestep) {
	    return;
	}
    }

    return;
}

/*!
   \brief Free keyframe list

   \param ok pointer to Keylist struct
 */
void gk_free_key(Keylist * ok)
{
    Keylist *k, *prev;

    if (ok) {
	k = ok;
	while (k) {
	    prev = k;
	    k = k->next;
	    G_free(prev);
	}
    }

    return;
}

/*!
   \brief Generate viewnode from keyframes

   Here we use a cardinal cubic spline

   \param keys list of keyframes
   \param keysteps keyframe step
   \param newsteps new step value
   \param loop loop indicator
   \param t

   \return pointer to Viewnode
   \return NULL on failure
 */
Viewnode *gk_make_framesfromkeys(Keylist * keys, int keysteps, int newsteps,
				 int loop, float t)
{
    int i;
    Viewnode *v, *newview;
    Keylist *k, *kp1, *kp2, *km1, **tkeys;
    float startpos, endpos;
    double dt1, dt2, x, x2, x3, range, time, time_step, len, rderiv, lderiv;

    /* allocate tmp keys to hold valid keys for fields */
    tkeys = (Keylist **) G_malloc(keysteps * sizeof(Keylist *));	/* G_fatal_error */
    if (!tkeys) {
	return (NULL);
    }

    correct_twist(keys);

    if (keys && keysteps) {
	if (keysteps < 3) {
	    G_warning(_("Need at least 3 keyframes for spline"));
	    G_free(tkeys);
	    return (NULL);
	}

	/* find end key */
	for (k = keys; k->next; k = k->next) ;

	startpos = keys->pos;
	endpos = k->pos;
	range = endpos - startpos;
	time_step = range / (newsteps - 1);

	newview = (Viewnode *) G_malloc(newsteps * sizeof(Viewnode));	/* G_fatal_error */
	if (!newview) {		/* not used */
	    G_free(tkeys);
	    return (NULL);
	}

	for (i = 0; i < newsteps; i++) {
	    int field = 0;

	    v = &newview[i];

	    time = startpos + i * time_step;

	    if (i == newsteps - 1) {
		time = endpos;	/*to ensure no roundoff errors */
	    }

	    for (field = 0; field < KF_NUMFIELDS; field++) {
		int nvk = 0;	/* number of viable keyframes for this field */

		/* now need to do for each field to look at mask */
		k = kp1 = kp2 = km1 = NULL;
		nvk = gk_viable_keys_for_mask((unsigned long)(1 << field),
					      keys, tkeys);
		if (nvk) {
		    len = get_key_neighbors(nvk, time, range,
					    loop, tkeys, &k, &kp1, &kp2, &km1,
					    &dt1, &dt2);
		}

		/* ACS 1 line: was      if (len == 0.0) {
		   when disabling a channel no calculation must be made at all (otherwise core dump)
		 */
		if (len == 0.0 || nvk == 0) {
		    if (!k) {
			/* none valid - use first.
			   (when showing , will be ignored anyway) */
			v->fields[field] = keys->fields[field];
		    }
		    else if (!kp1) {
			/* none on right - use left */
			v->fields[field] = k->fields[field];
		    }

		    continue;
		}
		else if (!km1 && !kp2) {
		    /* only two valid - use linear */
		    v->fields[field] = lin_interp((time - k->pos) / len,
						  k->fields[field],
						  kp1->fields[field]);
		    continue;
		}

		x = (time - k->pos) / len;
		x2 = x * x;
		x3 = x2 * x;

		if (!km1) {
		    /* leftmost interval */
		    rderiv = (kp2->fields[field] - k->fields[field]) / dt2;
		    lderiv = (3 * (kp1->fields[field] -
				   k->fields[field]) / dt1 - rderiv) / 2.0;
		    v->fields[field] = spl3(t, k->fields[field],
					    kp1->fields[field], x, x2, x3,
					    lderiv, rderiv);
		}
		else if (!kp2) {
		    /* rightmost interval */
		    lderiv = (kp1->fields[field] - km1->fields[field]) / dt1;
		    rderiv = (3 * (kp1->fields[field] -
				   k->fields[field]) / dt2 - lderiv) / 2.0;
		    v->fields[field] = spl3(t, k->fields[field],
					    kp1->fields[field], x, x2, x3,
					    lderiv, rderiv);
		}
		else {
		    /* not on ends */
		    lderiv = (kp1->fields[field] - km1->fields[field]) / dt1;
		    rderiv = (kp2->fields[field] - k->fields[field]) / dt2;
		    v->fields[field] = spl3(t, k->fields[field],
					    kp1->fields[field], x, x2, x3,
					    lderiv, rderiv);
		}
	    }
	}

	G_free(tkeys);
	return (newview);
    }
    else {
	G_free(tkeys);
	return (NULL);
    }
}

/*!
   \brief Find interval containing time

   Changed June 94 to handle masks - now need to have called get_viable_keys
   for appropriate mask first to build the ARRAY of viable keyframes.

   Putting left (or equal) key
   at km1, right at kp1, 2nd to right at kp2, and second to left at km2.
   dt1 is given the length of the current + left intervals
   dt2 is given the length of the current + right intervals

   \param nvk
   \param time
   \param range
   \param loop
   \param karray
   \param km1
   \param kp1
   \param kp2
   \param km2
   \param dt1
   \param dt2

   \return the length of the current interval
   \return 0 on error
 */
double get_key_neighbors(int nvk, double time, double range, int loop,
			 Keylist * karray[], Keylist ** km1, Keylist ** kp1,
			 Keylist ** kp2, Keylist ** km2, double *dt1,
			 double *dt2)
{
    int i;
    double len;

    *km1 = *kp1 = *kp2 = *km2 = NULL;
    *dt1 = *dt2 = 0.0;

    for (i = 0; i < nvk; i++) {
	if (time < karray[i]->pos) {
	    break;
	}
    }

    if (!i) {
	return (0.0);		/* before first keyframe or nvk == 0 */
    }

    if (i == nvk) {
	/* past or == last keyframe! */
	*km1 = karray[nvk - 1];
	return (0.0);
    }

    /* there's at least 2 */
    *km1 = karray[i - 1];
    *kp1 = karray[i];
    len = karray[i]->pos - karray[i - 1]->pos;

    if (i == 1) {
	/* first interval */
	if (loop) {
	    *km2 = karray[nvk - 2];
	    *kp2 = karray[(i + 1) % nvk];
	}
	else {
	    if (nvk > 2) {
		*kp2 = karray[i + 1];
	    }
	}
    }
    else if (i == nvk - 1) {
	/* last interval */
	if (loop) {
	    *km2 = nvk > 2 ? karray[i - 2] : karray[1];
	    *kp2 = karray[1];
	}
	else {
	    if (nvk > 2) {
		*km2 = karray[i - 2];
	    }
	}
    }
    else {
	*km2 = karray[i - 2];
	*kp2 = karray[i + 1];
    }

    *dt1 = (*km2) ? (*kp1)->pos - (*km2)->pos : len;
    *dt2 = (*kp2) ? (*kp2)->pos - (*km1)->pos : len;

    if (i == 1 && loop) {
	*dt1 += range;
    }

    if (i == nvk - 1 && loop) {
	*dt2 += range;
    }

    return (len);
}

/*!
   \brief Linear interpolation

   \param dt coeficient
   \param val2 value 2
   \param val1 value 1

   \return val1 + dt * (val2 - val1)
 */
double lin_interp(float dt, float val1, float val2)
{
    return ((double)(val1 + dt * (val2 - val1)));
}

/*!
   \brief Finds interval containing time, putting left (or equal) key
   at km1, right at kp1

   \param nvk
   \param time
   \param range
   \param loop
   \param karray
   \param km1
   \param km2

   \return interval value
 */
double get_2key_neighbors(int nvk, float time, float range, int loop,
			  Keylist * karray[], Keylist ** km1, Keylist ** kp1)
{
    int i;
    double len;

    *km1 = *kp1 = NULL;

    for (i = 0; i < nvk; i++) {
	if (time < karray[i]->pos) {
	    break;
	}
    }

    if (!i) {
	return (0.0);		/* before first keyframe or nvk == 0 */
    }

    if (i == nvk) {
	/* past or == last keyframe! */
	*km1 = karray[nvk - 1];
	return (0.0);
    }

    /* there's at least 2 */
    *km1 = karray[i - 1];
    *kp1 = karray[i];
    len = karray[i]->pos - karray[i - 1]->pos;

    return (len);
}

/*!
   \brief Generate viewnode from keyframe list (linear interpolation)

   Here we use linear interpolation. Loop variable isn't used, but left
   in for use in possible "linear interp with smoothing" version.

   \param kesy keyframe list
   \param keysteps step value
   \param newsteps new step value
   \param loop loop indicator

   \param pointer to viewnode struct
   \param NULL on failure
 */
Viewnode *gk_make_linear_framesfromkeys(Keylist * keys, int keysteps,
					int newsteps, int loop)
{
    int i, nvk;
    Viewnode *v, *newview;
    Keylist *k, *k1, *k2, **tkeys;
    float startpos, endpos, dt, range, time, time_step, len;

    /* allocate tmp keys to hold valid keys for fields */
    tkeys = (Keylist **) G_malloc(keysteps * sizeof(Keylist *));	/* G_fatal_error */
    if (!tkeys) {
	return (NULL);
    }

    correct_twist(keys);

    if (keys && keysteps) {
	if (keysteps < 2) {
	    G_warning(_("Need at least 2 keyframes for interpolation"));
	    G_free(tkeys);
	    return (NULL);
	}

	/* find end key */
	for (k = keys; k->next; k = k->next) ;

	startpos = keys->pos;
	endpos = k->pos;
	range = endpos - startpos;
	time_step = range / (newsteps - 1);

	newview = (Viewnode *) G_malloc(newsteps * sizeof(Viewnode));	/* G_fatal_error */
	if (!newview) {		/* not used */
	    G_free(tkeys);
	    return (NULL);
	}

	for (i = 0; i < newsteps; i++) {
	    int field = 0;

	    v = &newview[i];

	    time = startpos + i * time_step;
	    if (i == newsteps - 1) {
		time = endpos;	/*to ensure no roundoff errors */
	    }

	    for (field = 0; field < KF_NUMFIELDS; field++) {

		nvk = gk_viable_keys_for_mask((unsigned long)(1 << field),
					      keys, tkeys);
		if (!nvk) {
		    v->fields[field] = keys->fields[field];	/*default-not used */
		}
		else {
		    len = get_2key_neighbors(nvk, time, range, loop,
					     tkeys, &k1, &k2);
		}

		/* ACS 1 line: was      if (len == 0.0) {
		   when disabling a channel no calculation must be made at all (otherwise core dump)
		 */
		if (len == 0.0 || nvk == 0) {
		    if (!k1) {
			/* none valid - use first.
			   (when showing , will be ignored anyway) */
			v->fields[field] = keys->fields[field];
		    }
		    else if (!k2) {
			/* none on right - use left */
			v->fields[field] = k1->fields[field];
		    }
		}
		else {
		    dt = (time - k1->pos) / len;
		    v->fields[field] = lin_interp(dt,
						  k1->fields[field],
						  k2->fields[field]);
		}
	    }
	}

	G_free(tkeys);
	return (newview);
    }
    else {
	G_free(tkeys);
	return (NULL);
    }
}

/*!
   \brief Correct twist value

   \param k keyframe list
 */
void correct_twist(Keylist * k)
{
    Keylist *c, *p, *t;
    int cnt, j;

    p = NULL;
    cnt = 0;
    for (c = k; c; c = c->next) {
	if (p) {
	    if ((c->fields[KF_TWIST] - p->fields[KF_TWIST]) > 1800.) {
		for (t = c; t; t = t->next) {
		    t->fields[KF_TWIST] -= 3600.;
		}
	    }
	    else if ((p->fields[KF_TWIST] - c->fields[KF_TWIST]) > 1800.) {
		for (t = k, j = 0; j < cnt; j++, t = t->next) {
		    t->fields[KF_TWIST] -= 3600.;
		}
	    }
	}

	p = c;
	++cnt;
    }

    return;
}

/*!
   \brief Draw path

   \param views Viewnode struct
   \param steps step value
   \param keys keyframe list

   \return 0 on failure
   \return 1 on success
 */
int gk_draw_path(Viewnode * views, int steps, Keylist * keys)
{
    Viewnode *v;
    Keylist *k;
    int frame;
    float siz, from[3];

    if (!views || !keys) {
	return (0);
    }

    GS_get_longdim(&siz);
    siz /= 200.;

    gsd_colormode(CM_COLOR);
    gsd_linewidth(2);
    gsd_color_func(GS_default_draw_color());
    gsd_zwritemask(0);

    gsd_bgnline();

    for (frame = 0; frame < steps; frame++) {
	v = &views[frame];
	gsd_vert_func(&(v->fields[KF_FROMX]));
    }

    gsd_endline();

    gsd_linewidth(1);


    for (k = keys; k; k = k->next) {
	gsd_x(NULL, &(k->fields[KF_FROMX]),
	      ~(GS_background_color() | 0xFF0000), siz);
    }

    /* draw viewer position for inset images */
    GS_get_from(from);
    gsd_x(NULL, from, ~(GS_default_draw_color() | 0xFFFF00), 3.0 * siz);

    gsd_zwritemask(0xffffffff);

    return (1);
}