#include <stdlib.h>
#include <grass/gis.h>
#include <grass/vector.h>
#include <grass/dbmi.h>
#include <grass/glocale.h>

#include "local_proto.h"

static int srch(const void *, const void *);

/*!
   \brief transform 3d vector features to 2d (z-coordinate is omitted)

   \param In input vector
   \param Out output vector
   \param type feature type to be transformed
   \param field layer number
   \param zcolumn attribute column where to store height
 */
void trans3d(struct Map_info *In, struct Map_info *Out, int type,
	    const char *field_name, const char *zcolumn)
{
    int ltype, line;
    int ctype;
    int field;
    
    struct line_pnts *Points;
    struct line_cats *Cats;

    struct field_info *Fi;
    dbDriver *driver;
    dbString stmt;
    char buf[2000];
    int ncats, *cats, cat, *cex;

    Points = Vect_new_line_struct();
    Cats = Vect_new_cats_struct();

    db_init_string(&stmt);

    field = Vect_get_field_number(In, field_name);

    if (zcolumn) {
        if (field == -1) {
            G_warning(_("Invalid layer number %d, assuming 1"), field);
            field = 1;
        }

	Fi = Vect_get_field(Out, field);
	if (!Fi) {
	    G_fatal_error(_("Database connection not defined for layer <%s>"),
                          field_name);
	}

	driver = db_start_driver_open_database(Fi->driver, Fi->database);
	if (!driver) {
	    G_fatal_error(_("Unable to open database <%s> by driver <%s>"),
                          Fi->database, Fi->driver);
	}
        db_set_error_handler_driver(driver);
        
	/* column type must numeric */
	ctype = db_column_Ctype(driver, Fi->table, zcolumn);
	if (ctype == -1) {
	    G_fatal_error(_("Column <%s> not found in table <%s>"),
                          zcolumn, Fi->table);
	}
	if (ctype != DB_C_TYPE_INT && ctype != DB_C_TYPE_DOUBLE) {
	    G_fatal_error(_("Column must be numeric"));
	}

	db_begin_transaction(driver);

	/* select existing categories (layer) to array (array is sorted) */
        G_message(_("Reading categories..."));
	ncats = db_select_int(driver, Fi->table, Fi->key, NULL, &cats);
	G_debug(3, "Existing categories: %d", ncats);
    }

    G_message(_("Transforming features..."));
    line = 1;
    while (1) {
	ltype = Vect_read_next_line(In, Points, Cats);
	if (ltype == -1) {
	    G_fatal_error(_("Unable to read vector map"));
	}
	if (ltype == -2) {	/* EOF */
	    break;
	}

        G_progress(line, 1000);

	if (!(ltype & type))
	    continue;

	if (field != -1 && !Vect_cat_get(Cats, field, &cat))
	    continue;

	/* get first cat */
	if (cat == -1) {
	    G_warning(_("Feature id %d has no category - skipping"), line);
	}
	else if (Cats->n_cats > 1) {
	    G_warning(_("Feature id %d has more categories. "
			"Using category %d."), line, cat);
	}

	if (zcolumn && ltype & (GV_POINT | GV_LINE) && cat > -1) {
	    /* category exist in table ? */
	    cex = (int *)bsearch((void *)&cat, cats, ncats, sizeof(int),
				 srch);

	    /* store height to the attribute table */
	    if (ctype == DB_C_TYPE_INT)
		sprintf(buf, "update %s set %s = %d where cat = %d",
			Fi->table, zcolumn, (int)Points->z[0], cat);
	    else		/* double */
		sprintf(buf, "update %s set %s = %.8f where cat = %d",
			Fi->table, zcolumn, Points->z[0], cat);

	    G_debug(3, "SQL: %s", buf);
	    db_set_string(&stmt, buf);

	    if (cex) {
		if (db_execute_immediate(driver, &stmt) == DB_OK) {
		    /* TODO */
		}
	    }
	    else {		/* cat does not exist in table */
		G_warning(_("Record (cat %d) does not exist (not updated)"),
			  cat);
	    }
	}

	Vect_write_line(Out, ltype, Points, Cats);
	line++;
    }
    G_progress(1, 1);

    if (zcolumn) {
	db_commit_transaction(driver);

	G_free(cats);

	db_close_database_shutdown_driver(driver);
	db_free_string(&stmt);
    }

    Vect_destroy_line_struct(Points);
    Vect_destroy_cats_struct(Cats);
}

int srch(const void *pa, const void *pb)
{
    int *p1 = (int *)pa;

    int *p2 = (int *)pb;

    if (*p1 < *p2)
	return -1;
    if (*p1 > *p2)
	return 1;
    return 0;
}