#ifndef ISEA_H_
#define ISEA_H_ 1

#include "hex.h"

enum isea_poly { ISEA_NONE, ISEA_ICOSAHEDRON = 20 };
enum isea_topology { ISEA_HEXAGON=6, ISEA_TRIANGLE=3, ISEA_DIAMOND=4 };
enum isea_address_form { ISEA_GEO, ISEA_Q2DI, ISEA_SEQNUM, ISEA_INTERLEAVE,
	ISEA_PLANE, ISEA_Q2DD, ISEA_PROJTRI, ISEA_VERTEX2DD, ISEA_HEX
};

/* TODO calculate this */
#define ISEA_SCALE 0.8301572857837594396028083

struct isea_dgg {
	int	polyhedron; /* ignored, icosahedron */
	double	o_lat, o_lon, o_az; /* orientation, radians */
	int	pole; /* true if standard snyder */
	int	topology; /* ignored, hexagon */
	int	aperture; /* valid values depend on partitioning method */
	int	resolution;
	double	radius; /* radius of the earth in meters, ignored 1.0 */
	int	output; /* an isea_address_form */
	int	triangle; /* triangle of last transformed point */
	int	quad; /* quad of last transformed point */
	unsigned long serial;
};

struct isea_pt {
	double x, y;
};

struct isea_geo {
	double lon, lat;
};

extern struct isea_dgg isea_standard_dgg;

struct isea_address {
	int	type; /* enum isea_address_form */
	int	number;
	double	x,y; /* or i,j or lon,lat depending on type */
};

#if 0
struct isea_address {
	unsigned	validity; /* which are good */
	struct coord geo;
        struct point plane;
        unsigned long seqnum;
        unsigned quad;
        unsigned triangle;
        struct point quad_xy;
        struct point quad_ij;
        struct point triangle_xy;
        unsigned vertex;
};
#endif

/* set the orientation */
int isea_orient(struct isea_dgg *dgg, double lon, double lat, double az);
int isea_orient_isea(struct isea_dgg *d);
int isea_orient_pole(struct isea_dgg *d);
int isea_orient_dymax(struct isea_dgg *d);

/* set a clip region */
int isea_region(struct isea_dgg *dgg, double lon, double lat);

/* ensure validity */
int isea_valid(struct isea_dgg *dgg);

/* set the resolution by picking the nearest area */
int isea_resolution_area(struct isea_dgg *dgg, double area);

/* the characteristic length scale */
double isea_cell_cls(struct isea_dgg *dgg);

/* intercell distance as projected */
double isea_cell_width(struct isea_dgg *dgg);

double isea_cell_area(struct isea_dgg *dgg);

/* total number of cells */
double isea_cell_count(struct isea_dgg *dgg);

/* set the resolution by picking the nearest intercell distance */
int isea_resolution_distance(struct isea_dgg *dgg, double distance);

/* grid size in cells */
int isea_grid_size(struct isea_dgg *dgg);

int isea_grid_init(struct isea_dgg *d);

/* const? */
struct isea_dgg *isea_grid_standard(void);

/* coordinate projection */

/* returns triangle, out may be null */
int isea_transform(struct isea_dgg *dgg, struct isea_geo *in,
		struct isea_pt *out);

struct isea_pt isea_forward(struct isea_dgg *g, struct isea_geo *in);

/* returns seqnum */
int isea_readdress(struct isea_dgg *dgg, int input, struct isea_pt *in,
		int output, struct isea_pt *out);

struct isea_pt isea_triangle_xy(int triangle);
int isea_xy_triangle(struct isea_pt *p, double radius);

/* grid changes */
/*
 * the idea is that if you have a cartesian coordinate, and just want
 * to change the resolution, it's just a re-bin, not a new
 * projection.
 */
int isea_tranform_grid(void);

/* grid generation */

/* address conversion */
void isea_rotate(struct isea_pt *pt, double degrees);
int isea_dddi(struct isea_dgg *g, int quad, struct isea_pt *pt, struct isea_pt *di);
int isea_ptdd(int triangle, struct isea_pt *pt);
int isea_ptdi(struct isea_dgg *g, int tri, struct isea_pt *pt, struct isea_pt *di);
int isea_hex(struct isea_dgg *g, int tri, struct isea_pt *pt, struct isea_pt *di);
int isea_disn(struct isea_dgg *g, int quad, struct isea_pt *h);

/* binning point values */

/* presence/absence binning */
int isea_snyder_forward(struct isea_geo *ll, struct isea_pt *out);

#endif