#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "grb2.h"
#include "wgrib2.h"
#include "fnlist.h"
/*
 * Write_sec.c
 *   routines that import/export sections of a grib message
 *   only support bin and bin with f77 header
 *
 * 11/2020: Public Domain, Wesley Ebisuzaki
 */

extern int header;
extern int file_append;
extern int flush_mode;

/*
 * HEADER:100:write_sec:output:2:write grib msessage section X (0-8) to binary file Y
 */

int f_write_sec(ARG2) {
    unsigned int size;
    int n;
    size_t j;
    struct seq_file *save;

    if (isdigit((unsigned char) arg1[0]) == 0) fatal_error("export_sec: illegal section %s", arg1);
    n = atoi(arg1);
    if (mode == -1) {
	*local = save = (struct seq_file *) malloc( sizeof(struct seq_file));
	if (save == NULL) fatal_error("export_sec: memory allocation","");
        if (fopen_file(save, arg2, file_append ? "ab" : "wb") != 0) fatal_error("Could not open %s", arg2);
        if (n < 0 || n > 8) fatal_error_i("export_sec: illegal section %d", n);
	return 0;
    }
    save = *local;
    if (mode == -2) {
	fclose_file(save);
	free(save);
	return 0;
    }
    if (sec[n] == NULL) size = 0;
    else if (n == 0) size = 16;
    else if (n == 8) size = 4;
    else size = uint4(sec[n]);

    if (header) {
	j = fwrite_file((void *) &size, sizeof(unsigned int), 1, save);
        if (j != 1) fatal_error_i("export_sec: sec %d writing header", n);
    }
    if (size > 0) {
        j = fwrite_file((void *) sec[n], 1, size, save);
        if (j != size) fatal_error_i("export_sec: sec %d error writing", n);
    }
    if (header) {
	j = fwrite_file((void *) &size, sizeof(unsigned int), 1, save);
        if (j != 1) fatal_error_i("export_sec: sec %d error writing trailer", n);
    }
    if (flush_mode) fflush_file(save);
    return 0;
}


/*
 * HEADER:100:read_sec:misc:2:read grib message section (0-8) X from binary file (Y)
 */

int f_read_sec(ARG2) {

    struct local_struct {
        struct seq_file in;
	int n;
	unsigned char *data[9];
	unsigned int data_size[9];
    };

    struct local_struct *save;

    unsigned int size, size2;
    int n, i;
    size_t j;
    unsigned char csize[4];

    if (mode == -1) {
        if (isdigit((unsigned char) arg1[0]) == 0) fatal_error("import_sec: illegal section %s", arg1);
	n  = atoi(arg1);
        if (n < 0 || n > 8) fatal_error_i("import_sec: illegal section %d", n);

        // allocate static variables
        *local = save = (struct local_struct *) malloc( sizeof(struct local_struct) );
        if (save == NULL) fatal_error("import_sec: memory allocation","");
        if (fopen_file(&(save->in), arg2, "rb") != 0) fatal_error("import_sec: Could not open %s", arg2);
	save->n = n;
	for (i = 0; i < 9; i++) {
	    save->data_size[i] =  0;
	    save->data[i] = NULL;
	}
        return 0;
    }
    save = (struct local_struct *) *local;
    if (mode == -2) {
        // close file, free static varaibles
        save = (struct local_struct *) *local;
        fclose_file(&(save->in));
	for (i = 0; i < 9;  i++) {
	    if (save->data_size[i] != 0) free(save->data[i]);
	}
        free(save);
	return 0;
    }

    n = save->n;
    if (header) {
	/* read header */
        if (fread_file((void *) &size, sizeof(unsigned int), 1, &(save->in)) != 1) fatal_error_i("import_sec: sec %d read header",n);

	/* read data */
	if (size != 0) {
	    if (size > save->data_size[n]) {
		if (save->data_size[n] != 0) free(save->data[n]);
		save->data[n] = malloc(size*sizeof(unsigned char));
		if (save->data[n] == NULL) fatal_error_i("import_sec: sec %d memory allocation",n);
		save->data_size[n] = size;
	    }
            j = fread_file(save->data[n], sizeof(char), size, &(save->in));
            if (size != j) fatal_error_i("import_sec: sec %d read with header failed",n);
	}

	/* read trailer */
        if (fread_file((void *) &size2, sizeof(unsigned int), 1, &(save->in)) != 1) fatal_error_i("import_sec: sec %d read trailer",n);
	if (size != size2) fatal_error_i("import_sec: sec %d trailer size mismatch",n);
    }

    /* no header, can stack only if sections are not missing */
    else {
	/* read fixed length sections */
        if (n == 0 || n == 8 ) {
	    size = n == 0 ? 16 : 4;
	    if (size > save->data_size[n]) {
		if (save->data_size[n] != 0) free(save->data[n]);
		save->data[n] = malloc(size*sizeof(unsigned char));
		if (save->data[n] == NULL) fatal_error_i("import_sec: sec %d memory allocation",n);
		save->data_size[n] = size;
	    }
            j = fread_file(save->data[n], sizeof(unsigned char), size, &(save->in));
	    if (size != j) fatal_error_i("import_sec: sec %d read failed",n);
	}
	else {
	    // size in in  bytes 1-4
            j = fread_file(csize, sizeof(unsigned char), 4, &(save->in));
	    if (j > 0 && j < 4) fatal_error_i("import_sec: sec %d read error",n);
	    if (j == 0)  size = 0;
	    else size = uint4(csize);

	    if (size > 0) {
	        if (size > save->data_size[n]) {
		    if (save->data_size[n] != 0) free(save->data[n]);
		    save->data[n] = malloc(size*sizeof(unsigned char));
		    if (save->data[n] == NULL) fatal_error_i("import_sec: sec %d memory allocation",n);
		    save->data_size[n] = size;
		}
                j = fread_file(save->data[n]+4, sizeof(char), size-4, &(save->in));
		if (j != size-4) fatal_error_i("import_sec: sec %d read error",n);
		save->data[n][0] = csize[0];
		save->data[n][1] = csize[1];
		save->data[n][2] = csize[2];
		save->data[n][3] = csize[3];
	    }
	}
    }
    /* now to replace section */
    sec[n] = size == 0 ? NULL : save->data[n];
    return 0;
}