// SPDX-License-Identifier: BSD-3-Clause
/* Generate C project
 *
 * Copyright (C) 2025, GCK.
 * Written by vx-clutch (vx-clutch)
 */

#include <config.h>
#include <errno.h>
#include <getopt.h>
#include <pwd.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include <lib/err.h>
#include <lib/fs.h>
#include <lib/proginfo.h>
#include <lib/say.h>
#include <lib/textc.h>

#include "license.h"

typedef enum { MIT, GPL, BSD, UNL } license_t;

static const struct option longopts[] = {
	{ "author", required_argument, 0, 'a' },
	{ "license", required_argument, 0, 'l' },
	{ 0, 0, 0, 0 }
};

static int exit_status;

static void print_help();
static void print_version();

static char *get_name()
{
	int fds[2];
	if (pipe(fds) == -1)
		goto sysuser;

	pid_t pid = fork();
	if (pid == -1) {
		close(fds[0]);
		close(fds[1]);
		goto sysuser;
	}

	if (pid == 0) {
		dup2(fds[1], STDOUT_FILENO);
		close(fds[0]);
		close(fds[1]);
		execlp("git", "git", "config", "--get", "user.name",
		       (char *)NULL);
		_exit(127);
	}

	close(fds[1]);
	char buf[256];
	ssize_t n = read(fds[0], buf, sizeof buf - 1);
	close(fds[0]);
	int status;
	waitpid(pid, &status, 0);
	if (n > 0 && WIFEXITED(status) && WEXITSTATUS(status) == 0) {
		buf[n] = 0;
		buf[strcspn(buf, "\n")] = 0;
		return str_dup(buf);
	}

sysuser: {
	char *name = getlogin();
	if (name)
		return str_dup(name);
	struct passwd *pw = getpwuid(getuid());
	if (pw && pw->pw_name)
		return str_dup(pw->pw_name);
}
	return str_dup("author");
}

static int get_year()
{
	time_t now = time(NULL);
	struct tm *t = localtime(&now);

	return t->tm_year + 1900;
}

int main(int argc, char **argv)
{
	int optc;
	int lose = 0;
	char *m = str_dup("Does a thing"), *package;
	bool shell = false;
	char *author = get_name();
	exit_status = EXIT_SUCCESS;
	int year = get_year();
	license_t license = BSD;
	char *license_str = "BSD-3-Clause";
	set_prog_name(argv[0]);

	parse_standard_options(argc, argv, print_help, print_version);

	while ((optc = getopt_long(argc, argv, "a:l:m:EqfS", longopts, NULL)) !=
	       -1)
		switch (optc) {
		case 'a':
			if (optarg) {
				if (author)
					free(author);
				author = str_dup(optarg);
			}
			break;
		case 'm':
			if (optarg) {
				if (m)
					free(m);
				m = str_dup(optarg);
			}
			break;
		case 'l':
			if (!strcmp(optarg, "list")) {
				puts("BSD\nGPL\nMIT\nUNL");
				exit(EXIT_SUCCESS);
			}
			if (!strcmp(optarg, "GPL")) {
				license = GPL;
				license_str = "GPL-3.0-only";
			} else if (!strcmp(optarg, "MIT")) {
				license = MIT;
				license_str = "MIT";
			} else if (!strcmp(optarg, "BSD")) {
				license = BSD;
				license_str = "BSD-3-Clause";
			} else if (!strcmp(optarg, "UNL")) {
				license = UNL;
				license_str = "Unlicense";
			} else {
				puts("BSD\nGPL\nMIT\nUNL");
				exit(EXIT_FAILURE);
			}
			break;
		case 'S':
			shell = true;
			break;
		default:
			lose = 1;
		}
	if (lose) {
		emit_try_help();
	}

	if (optind >= argc) {
		fatalf("no input name");
	}

	if (optind + 1 < argc) {
		errorf("extra operand: %s", argv[optind + 1]);
		emit_try_help();
	}

	package = str_dup(argv[optind]);

	if (shell) {
		fs_write(package, "\
#!/bin/sh\n\
# SPDX-License-Identifier: %s\n\
#\n\
# %s\n\
\n\
me=$0\n\
scriptversion=\"1.0.0\"\n\
\n\
version=\"$me $scriptversion\n\
\n\
Copyright (C) %d %s\n\
This is free software; you are free to change and redistribute it.\n\
There is NO WARRANTY, to  the textent permitted by law.\"\n\
\n\
usage=\"\\\n\
Usage: $me [OPTION]...\n\
%s\n\
\n\
Options:\n\
\n\
   --help     print this help and exit\n\
   --version  output version information\"\n\
\n\
while [ $# -gt 0 ]; do\n\
  case $1 in\n\
    --help) echo \"$usage\"; exit 0;;\n\
    --version) echo \"$version\"; exit 0;;\n\
    -*)\n\
      echo \"$0: Unknwon option '$1'.\" >&2\n\
      echo \"$0: Try '--help' for more information.\" >&2\n\
      exit 1 ;;\n\
  esac\n\
  shift\n\
done\n\
\n\
echo \"$0: done.\"\n\
\n\
# End: %s\
",
			 license_str, m, year, author, m, package);
		struct stat st;

		if (stat(package, &st) != 0) {
			fatalfa(errno);
		}

		mode_t mode = st.st_mode | S_IXUSR;

		if (chmod(package, mode) != 0) {
			fatalfa(errno);
		}
		return exit_status;
	}

	return exit_status;
}

static void print_help()
{
	printf("Usage: %s [OPTION]... [project-name]...\n", PROGRAM);
	fputs("\
Generates an opinionated C project.\n",
	      stdout);
	puts("");
	fputs("\
      --help                  display this help and exit\n\
      --version               display version information and exit\n",
	      stdout);
	puts("");
	fputs("\
      --author=NAME           Set the program author (default git username|system username)\n\
      --license=LICENSE       Set the program license (default BSD)\n",
	      stdout);
	exit(exit_status);
}

static void print_version()
{
	printf("%s %s %d\n", prog_name, VERSION, COMMIT);

	printf("Copyright (C) %d GCK.\n", YEAR);

	puts("This is free software: you are free to change and redistribute it.");
	puts("There is NO WARRANTY, to the extent permitted by law.");
	exit(exit_status);
}

/* end of file yait.c */