#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>

#define COUNT_DECK_PARAMS 32
#define PROGRAM_NAME "wasureta"

/* wasureta: Anki on the terminal.
 * Anki decks (.apkg) are found in:
 * - $XDG_DATA_HOME/wasureta, or $HOME/.local/share/wasureta
 * - passed in via the -d argument.
 *
 * When you run `wasureta`, the program will check for any decks, if any
 * revision needs to be done. If so, it will give a choice of deck to select.
 * On selecting the deck, the practice will begin.
 * This only displays the text, not audio or images.
 */

/* ******************************** Types ********************************** */
enum error_t {
	err_copyfailed = 0,
};

/* **************************** Function Decls ***************************** */
void die(const char*, ...);
void usage(void);
void version(void);
int run(void);
enum error_t copy_decks(const char* decks[], size_t decks_len);

/* **************************** Function Impls ***************************** */
void 
die(const char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	vfprintf(stderr, fmt, ap);
	va_end(ap);

	if (fmt[0] && fmt[strlen(fmt) - 1] == ':') {
		fputc(' ', stderr);
		perror(NULL);
	} else {
		fputc('\n', stderr);
	}

	exit(1);
}

void 
usage(void)
{
	printf(
		PROGRAM_NAME ": Anki on the terminal.\n"
		"\tSource:  https://gabbott.dev/git/" PROGRAM_NAME "\n"
		"\tLicense: BSD 3-Clause\n"
		"\n"
		"Usage:\n"
		"\t" PROGRAM_NAME " FLAGS\n"
		"\t-d DECK   Copy a deck to $XDG_DATA_HOME/" PROGRAM_NAME " for use.\n"
		"\t-h        Display this help message.\n"
		"\t-v        Display version information.\n"
	);
}

void 
version(void) 
{
	printf(PROGRAM_NAME ": ver 0.1.0\n");
}

enum error_t 
copy_decks(const char* decks[], size_t decks_len) 
{
	const char xdgpath[] = "/.local/share";
	const char dir[] = "/" PROGRAM_NAME;
	const char *xdg = getenv("XDG_DATA_HOME");
	const char *home = getenv("HOME");
	if (!xdg && !home) {
		die("Both HOME AND XDG_DATA_HOME envvars unset - this is bad!");
	}
	
	char* target;
	if (xdg) {
		target = malloc(strlen(xdg) + strlen(dir));
		strcpy(target, xdg);
		strcat(target, dir);
	} else {
		target = malloc(strlen(home) + strlen(xdgpath));
		strcpy(target, home);
		strcat(target, xdgpath);
	}

	printf("target: %s\n", target);

	for (size_t i = 0; i < decks_len; ++i) {
		printf("decks: %s", decks[i]);
	}

/* cleanup:*/	free(target);

	return err_copyfailed;
}

int 
run(void)
{
	return 0;
	
}

int 
main(int argc, char* argv[])
{
	const char* decks[COUNT_DECK_PARAMS] = {0};
	size_t decks_index = 0; // used for setting decks values
	
	for (int i = 0; i < argc; ++i) {
		if (argv[i][0] == '-') {
			switch (argv[i][1]) {
				case 'h':
					usage();
					exit(0);
				case 'v':
					version();
					exit(0);
				case 'd':
					decks[decks_index++] = argv[++i];
					break;
				default:
					die("Unsupported flag -%c; run " PROGRAM_NAME " -h for usage information.", argv[i][1]);
			}
		}
	}

	// If we have any decks, copy them into the appropriate location.
	if (decks_index) {
		enum error_t err = copy_decks(decks, decks_index);
		die("Failed to copy for -d flag. Error: %d", (int)err);
	} else {
		return run();
	}
}