/* init.c                                                               */
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <grass/gis.h>
#include <grass/raster.h>
#include <grass/glocale.h>

#include "ransurf.h"
#include "local_proto.h"

/* function prototypes */
static int comp_array(const void *p1, const void *p2);

void Init()
{
    struct Cell_head Region;
    int Count;
    int FD, row, col;
    double MinRes;

    G_debug(2, "Init()");

    Rs = Rast_window_rows();
    Cs = Rast_window_cols();
    G_get_set_window(&Region);
    EW = Region.ew_res;
    NS = Region.ns_res;
    if (EW < NS)
	MinRes = EW;
    else
	MinRes = NS;
    CellBuffer = Rast_allocate_c_buf();

    /* Out = FlagCreate( Rs, Cs); */
    Out = (CELL **) G_malloc(sizeof(CELL *) * Rs);
    for (row = 0; row < Rs; row++) {
	Out[row] = Rast_allocate_c_buf();
	Rast_zero_buf(Out[row], CELL_TYPE);
    }

    Cells = FlagCreate(Rs, Cs);
    CellCount = 0;
    if (G_find_raster2("MASK", G_mapset())) {
	FD = Rast_open_old("MASK", G_mapset());
	{
	    for (row = 0; row < Rs; row++) {
		Rast_get_c_row_nomask(FD, CellBuffer, row);
		for (col = 0; col < Cs; col++) {
		    if (CellBuffer[col] && !Rast_is_c_null_value(&CellBuffer[col])) {
			FLAG_SET(Cells, row, col);
			CellCount++;
		    }
		}
	    }
	    Rast_close(FD);
	}
    }
    else {
	for (row = 0; row < Rs; row++) {
	    for (col = 0; col < Cs; col++) {
		FLAG_SET(Cells, row, col);
	    }
	}
	CellCount = Rs * Cs;
    }

    /* cut down num of cells if requested */
    if (MaxCells->answer)
        sscanf(MaxCells->answer, "%d", &MaxCellsNum);
    else
        MaxCellsNum = CellCount;
    G_debug(1, "(CellCount):%d", CellCount);

    sscanf(Distance->answer, "%lf", &MaxDist);
    if (MaxDist < 0.0)
	G_fatal_error(_("Distance must be >= 0.0"));
    
    G_debug(3, "(MaxDist):%.12lf", MaxDist);
    MaxDistSq = MaxDist * MaxDist;
    if (!SeedStuff->answer) {
	Seed = -1;
    }
    else {
	sscanf(SeedStuff->answer, "%d", &(Seed));
    }

    if (Seed < 0)
	G_srand48_auto();
    else
	G_srand48(Seed);

    G_message(_("Generating raster map <%s>..."),
	      Output->answer);

    DoNext = (CELLSORTER *) G_malloc(CellCount * sizeof(CELLSORTER));
    Count = 0;
    for (row = 0; row < Rs; row++) {
	G_percent(row, Rs, 2);
	for (col = 0; col < Cs; col++) {
	    if (0 != FlagGet(Cells, row, col)) {
		DoNext[Count].R = row;
		DoNext[Count].C = col;
		DoNext[Count].Value = GasDev();
		if (++Count == CellCount) {
		    row = Rs;
		    col = Cs;
		}
	    }
	}
    }
    G_percent(1, 1, 1);
    
    qsort(DoNext, CellCount, sizeof(CELLSORTER), comp_array);
}


static int comp_array(const void *q1, const void *q2)
{
    const CELLSORTER *p1 = q1;
    const CELLSORTER *p2 = q2;

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

