#include <ctype.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/* TODO: sysexits.h */

#define PROGRAM_NAME "wordle"
#define DEFAULT_DICTIONARY_FILENAME "/usr/share/" PROGRAM_NAME "/dictionary.txt"
#define DEFAULT_SOLUTIONS_FILENAME "/usr/share/" PROGRAM_NAME "/solutions.txt"
#define WORD_LENGTH 5
#define GUESSES 6

int
dictionary_has(char *s, int fd){
	char buf[WORD_LENGTH + 2];
	if(lseek(fd, 0, SEEK_SET) != 0){
		fprintf(stderr, "%s: Could not seek to the start of the"
			" dictionary (errno %d).\n", PROGRAM_NAME, errno
		);
		close(fd);
		exit(1);
	}
	/* unused, but just in case */
	buf[WORD_LENGTH + 1] = '\0';

	if(read(fd, buf, WORD_LENGTH + 1) < WORD_LENGTH)
		return 1;
}

int
strisuint(char *s){
	while(*s != '\0')
		if(!isdigit(*(s++)))
			return 0;
	return 1;
}

void
usage(char *name){
	fprintf(stderr, "Usage: %s [index] (-d [dictionary file])"
		" (-s [solutions file])\n", name
	);
	exit(1);
}

int main(int argc, char *argv[]){
	int c;
	int dictionary_fd;
	size_t i;
	size_t index;
	size_t j;
	FILE *solutions_file;
	char word[WORD_LENGTH + 1];

	/* arg parse */
	if(argc < 2)
		usage(argv[0] != NULL ? argv[0] : PROGRAM_NAME);
	while((c = getopt(argc, argv, "d:hs:")) != -1)
		switch(c){
		case 'd':
			dictionary_filename = optarg;
			break;
		case 's':
			solutions_filename = optarg;
			break;
		case 'h':
			usage(argv[0] != NULL ? argv[0] : PROGRAM_NAME);
		}
	if(!strisuint(argv[optind])){
		fprintf(stderr, "%s: index must be a number.\n",
			argv[0] != NULL ? argv[0] : PROGRAM_NAME
		);
		exit(1);
	}
	index = (size_t)atoi(argv[optind]);

	/* get word */
	if((solutions_file = fopen(solutions_filename, "rb")) == NULL){
		fprintf(stderr, "%s: %s: Error opening solutions file.\n",
			argv[0] != NULL ? argv[0] : PROGRAM_NAME, solutions_filename
		);
		exit(1);
	}
	i = j = 0;
	while((c = getc(solutions_file)) != EOF)
		if(i == index){
			if(j == WORD_LENGTH){
				word[WORD_LENGTH] = '\0';
				j = 0;
				break;
			}else
				word[j++] = c;
		}else
			i += c == '\n';
	if(j != '\0'){
		word[j] = '\0';
		fprintf(stderr, "%s: %s: Word is too few characters.\n",
			argv[0] != NULL ? argv[0] : PROGRAM_NAME, word
		);
		exit(1);
	}
	fclose(solutions_file);

	if(dictionary_fd = open(dictionary_filename, O_RDONLY) == NULL){
		fprintf(stderr, "%s: %s: Error opening dictionary file.\n",
			argv[0] != NULL ? argv[0] : PROGRAM_NAME, dictionary_filename
		);
		exit(1);
	}

	close(dictionary_fd);
	exit(0);
}