#include <grass/config.h>

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include <grass/gis.h>
#include <grass/glocale.h>
#include <grass/edit.h>
#include "local_proto.h"


/*
*******************************************************************
*
* MODULE:        modhead (etc/support) for r.support
*
* AUTHOR(S):     Original by Michael Shapiro - CERL
*                Port to 6.x by Brad Douglas
*
* PURPOSE:       r.support module that allows editing of raster
*                file header.
*
* COPYRIGHT:     (C) 2000-2005 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.
*
********************************************************************/

int main (int argc, char *argv[])
{
    char buffer[256];
    struct Cell_head cellhd;
    int cellhd_ok;
    int compressed_old;
    int compressed_new;
    int fd;
    off_t filesize;
    off_t offset;
    off_t prev_offset = 0;
    int rows_old = 0;
    int rows_new = 0;
    int quiet = 0;
    char *rname   = NULL;
    char *rmapset = NULL;
    char *mapset;
    char name[64];


    /* Initialize GIS engine */
    G_gisinit(argv[0]);

    if (argc == 3) {
        if (strcmp(argv[1], "-") == 0) {
            argv++;
            argc--;
            quiet = 1;
        }
    }

    if (argc >= 2) {
        strncpy(name, argv[1], sizeof(name));
        G_message(_("Edit header for [%s]\n"), name);

        if ((mapset = G_find_cell(name, "")) == NULL)
            G_fatal_error(_("[%s] cannot be found!"), name);
    } else {
        mapset = G_ask_cell_in_mapset(_("For what layer shall the "
                 "header file be edited? "), name);

        if (mapset == NULL)
            return EXIT_SUCCESS;
    }

    /* Make sure map is not reclassed */
    if (G_is_reclass(name, mapset, rname, rmapset) > 0) {
        if (strcmp(mapset, rmapset) == 0)
            G_fatal_error(_("[%s] is a reclass of [%s] - cannot edit header! Run support on [%s]."),
                          name, rname, rname);

        /* ELSE */
        G_fatal_error(_("[%s] is a reclass of [%s in %s] - cannot edit header!"),
                      name, rname, rmapset);
    }

    /* Open cell file */
    if ((fd = G_open_cell_old(name, mapset)) < 0)
        G_fatal_error(_("Cannot open raster file [%s]!"), name);

    /* Determine file size */
    filesize = lseek(fd, 0L, 2);
    if (filesize == 0)
        G_fatal_error(_("Raster file [%s] is empty."), name);
    else if (filesize < 0)
        G_fatal_error(_("Error reading raster file [%s]."), name);

    G_suppress_warnings(quiet);
    cellhd_ok = (G_get_cellhd(name, mapset, &cellhd) >= 0);
    G_suppress_warnings(0);
    if (!cellhd_ok) {
        G_zero(&cellhd, (int)sizeof(cellhd));
        cellhd.proj = G_projection();
        cellhd.zone = G_zone();
    } else
        cellhd.format++;    /* set to number of bytes per cell (for now) */

/*
 * Determine compression type, if any, without consulting cellhd
 *
 * In a compressed file, there is an array of row addresses at the
 * beginning of the file.  Try to read the address array.
 * If the file really is compressed, the addresses will increase,
 * the last one will be the same as the filesize, and the number of
 * row addresses will be one more than the number of rows in the file.
 *
 * If the file matches these conditions, it is probably compressed.
 * The probability of this being wrong is very small.
 * So we will take a safe route that doesn't annoy the user:
 *  If the cellhd wasn't valid, verify the compression with the user.
 *  else if the cellhd says something different, ask the user.
 *  else don't bother the user about it.
 *
 * note: 3.0 address are in machine independent format
 *       pre 3.0 are true longs
 */

    /* Look for pre3.0 compression */
    compressed_old = 0;
    lseek(fd, 0L, 0);
    if (read(fd, buffer, (size_t)3) == 3 && buffer[0] == (char)251 &&
        buffer[1] == (char)255   && buffer[2] == (char)251) {

        rows_old = 0;
        offset = -1;

        while ((next_row_addr(fd, &offset, 0)) == EXIT_SUCCESS)
        {
            if (rows_old > 0 && offset <= prev_offset)
                break;
            if (offset >= filesize)
                break;
            prev_offset = offset;
            rows_old++;
        }

        if (offset == filesize)
            /* It is old format compressed */
            compressed_old = 1; 
    }

    /* Look for 3.0 compression */
    compressed_new = 0;
    lseek(fd, 0L, 0);
    if (read(fd, buffer, (size_t)1) == 1 && buffer[0] > 0) {
        int nbytes;

        nbytes = buffer[0];
        rows_new = 0;
        offset = -1;

        while ((next_row_addr(fd, &offset, nbytes)) == EXIT_SUCCESS)
        {
            if (rows_new > 0 && offset <= prev_offset)
                break;
            if (offset >= filesize)
                break;

            prev_offset = offset;
            rows_new++;
	}
    }

    if (offset == filesize)
        compressed_new = 1;

    /*
     * now check these results against cellhd.compressed
     * cellhd.compressed values are
     * -1 pre 3.0 cellhd - compression unknown (by cellhd alone)
     *  0 not compressed (3.0)
     *  1 compressed (3.0)
     */

    G_message(_("cellhd compression: %d\n"), cellhd.compressed);
    G_message(_("3.0 compression %sindicated\n"), 
                compressed_new ? "" : "not ");
    G_message(_("Pre 3.0 compression %sindicated\n"), 
                compressed_old ? "" : "not ");
    hitreturn();

    /* If we create a new cell header, find out if file is compressed */
    if (!cellhd_ok) {
        G_snprintf(buffer, sizeof(buffer), _("[%s] appears to be compressed. Is it? "), name);
        cellhd.compressed = 0;

        if ((compressed_new || compressed_old) && G_yes(buffer, -1)) {
            if (compressed_new && compressed_old) {
                while (1)
                {
                    G_message(_("Please indicate the type of compression:\n"));
                    G_message(_("  1. Pre 3.0 compression\n"));
                    G_message(_("  2. 3.0 compression\n"));
                    if (!G_gets(buffer))
                        continue;

                    G_strip(buffer);
                    if (strcmp(buffer, "1") == 0)
                        break;
                    if (strcmp(buffer, "2") == 0)
                        break;
                }

                switch (*buffer)
                {
                case '1':
                    compressed_new = 0;
                    break;
                case '2':
                    compressed_old = 0;
                    break;
                }
            }

            if (compressed_new) {
                cellhd.compressed = 1;
                cellhd.rows = rows_new;
            } else {
                cellhd.compressed = -1;
                cellhd.rows = rows_old;
            }
        }
    } else {
        if ((cellhd.compressed < 0) && !compressed_old)
            cellhd.compressed = 0;

        if ((cellhd.compressed == 0) && compressed_new) {
            G_warning(_("The header for [%s] says the file is not compressed. "), name);
            G_warning(_("The file appears to be compressed.\n"));
            G_warning(_("Most likely the header is wrong, but I want you to decide.\n"));

            if (G_yes("Is the file compressed? ", -1))
                cellhd.compressed = 1;
        } else if ((cellhd.compressed != 0) && !compressed_new) {
            G_warning(_("The header for [%s] says the file is compressed. "), name);
            G_warning(_("The file does NOT appear to be compressed.\n"));
            G_warning(_("Most likely the header is wrong, but I want you to decide.\n"));

            if (!G_yes("Is the file really compressed? ", -1))
                cellhd.compressed = 0;
        }
    }

    if ((cellhd.compressed < 0 && rows_old != cellhd.rows) ||
        (cellhd.compressed > 0 && rows_new != cellhd.rows)) {

        int rows;

        rows = (cellhd.compressed > 0 ? rows_new : rows_old);

        G_warning(_("Header indicates %d row%s in the cell file, but "
                   "the actual file format indicates %d row%s"),
                   cellhd.rows, (cellhd.rows == 1) ? "" : "s",
                   rows, (rows == 1) ? "" : "s");

        if (G_yes("Should this discrepancy be corrected? ", -1))
            cellhd.rows = rows;
    }

    while (1)
    {
        ask_format(name, &cellhd, filesize);

        if (cellhd.compressed == 0) {
            if (check_uncompressed(&cellhd, filesize) == EXIT_SUCCESS)
                break;
        } else
            break;

        hitreturn();
    }

    if (E_edit_cellhd(&cellhd, 1) < 0)
        return EXIT_SUCCESS;

    /* adjust from nbytes to nbytes-1 */
    /* FP map should be back to -1 */
    /* if (cellhd.format > 0) */
        cellhd.format--;

    /* Write new header out */
    if (G_put_cellhd(name, &cellhd) == -1)
        G_fatal_error(_("Unable to write header for [%s]."), name);
    else
        G_message(_("Header for raster file [%s] updated."), name);

    /* Free resources */
    close(fd);

    return EXIT_SUCCESS;
}