/** @license 20xx Neil Edelman, distributed under the terms of the
 [GNU General Public License 3](https://opensource.org/licenses/GPL-3.0).
 @license 20xx Neil Edelman, distributed under the terms of the
 [MIT License](https://opensource.org/licenses/MIT).

 This is a standard C file.

 @std C89 */

#include "kjv.h"
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <errno.h>
#include <dirent.h> /* opendir readdir closedir */
#include <unistd.h> /* chdir (POSIX) (because I'm lazy) */

#define ARRAY_NAME char
#define ARRAY_TYPE char
#include "array.h"

/** Append a text file, `fn`, to `c`, and add a '\0'.
 @return Success. A partial read is failure. @throws[fopen, fread, malloc]
 @throws[EISEQ] The text file has embedded nulls.
 @throws[ERANGE] If the standard library does not follow POSIX. */
static int append_file(struct char_array *c, const char *const fn) {
	FILE *fp = 0;
	const size_t granularity = 1024;
	size_t nread;
	char *cursor;
	int success = 0;
	assert(c && fn);
	if(!(fp = fopen(fn, "r"))) goto catch;
	/* Read entire file in chunks. */
	do if(!(cursor = char_array_buffer(c, granularity))
		|| (nread = fread(cursor, 1, granularity, fp), ferror(fp))
		|| !char_array_append(c, nread)) goto catch;
	while(nread == granularity);
	/* File to `C` string. */
	if(!(cursor = char_array_new(c))) goto catch;
	*cursor = '\0';
	/* Binary files with embedded '\0' are not allowed. */
	if(strchr(c->data, '\0') != cursor) { errno = EILSEQ; goto catch; }
	{ success = 1; goto finally; }
catch:
	if(!errno) errno = EILSEQ; /* Will never be true on POSIX. */
finally:
	if(fp) fclose(fp);
	return success;
}

int main(void) {
	const char *const dir_name = "KJV";
	int success = EXIT_SUCCESS;
	DIR *dir = 0;
	struct dirent *de = 0;
	struct char_array book[KJV_BOOK_SIZE] = { 0 };
	unsigned i;
	errno = 0;

	/* Read all files in `dir_name`. */
	if(chdir(dir_name) == -1 || !(dir = opendir("."))) goto catch;
	while((de = readdir(dir))) {
		unsigned ordinal;
		enum kjv_book b;
		if(!kjv_filename(de->d_name, &ordinal))
			{ fprintf(stderr, "Ignored <%s>.\n", de->d_name); continue; }
		printf("<%s> ordinal: %u\n", de->d_name, ordinal);
		if(ordinal < 1 || ordinal > KJV_BOOK_SIZE)
			{ errno = ERANGE; goto catch; } /* Not in range. */
		if(book[b = ordinal - 1].data)
			{ errno = EDOM; goto catch; } /* Duplicate. */
		if(!append_file(book + b, de->d_name)) goto catch;
	}
	closedir(dir), de = 0, dir = 0;
	for(i = 0; i < KJV_BOOK_SIZE; i++)
		if(!book[i].data) { errno = EDOM; goto catch; } /* Not there. */

	/**/
	goto finally;
catch:
	success = EXIT_FAILURE;
	perror(de ? de->d_name : dir_name);
	if(dir && closedir(dir)) perror(dir_name);
finally:
	for(i = 0; i < KJV_BOOK_SIZE; i++) char_array_(&book[i]);
	return success;
}