#include "cache.h"
#include "builtin.h"
#include "dir.h"
#include "parse-options.h"

static const char * const worktree_usage[] = {
	N_("git worktree prune [<options>]"),
	NULL
};

static int show_only;
static int verbose;
static unsigned long expire;

static int prune_worktree(const char *id, struct strbuf *reason)
{
	struct stat st;
	char *path;
	int fd, len;

	if (!is_directory(git_path("worktrees/%s", id))) {
		strbuf_addf(reason, _("Removing worktrees/%s: not a valid directory"), id);
		return 1;
	}
	if (file_exists(git_path("worktrees/%s/locked", id)))
		return 0;
	if (stat(git_path("worktrees/%s/gitdir", id), &st)) {
		strbuf_addf(reason, _("Removing worktrees/%s: gitdir file does not exist"), id);
		return 1;
	}
	fd = open(git_path("worktrees/%s/gitdir", id), O_RDONLY);
	if (fd < 0) {
		strbuf_addf(reason, _("Removing worktrees/%s: unable to read gitdir file (%s)"),
			    id, strerror(errno));
		return 1;
	}
	len = st.st_size;
	path = xmalloc(len + 1);
	read_in_full(fd, path, len);
	close(fd);
	while (len && (path[len - 1] == '\n' || path[len - 1] == '\r'))
		len--;
	if (!len) {
		strbuf_addf(reason, _("Removing worktrees/%s: invalid gitdir file"), id);
		free(path);
		return 1;
	}
	path[len] = '\0';
	if (!file_exists(path)) {
		struct stat st_link;
		free(path);
		/*
		 * the repo is moved manually and has not been
		 * accessed since?
		 */
		if (!stat(git_path("worktrees/%s/link", id), &st_link) &&
		    st_link.st_nlink > 1)
			return 0;
		if (st.st_mtime <= expire) {
			strbuf_addf(reason, _("Removing worktrees/%s: gitdir file points to non-existent location"), id);
			return 1;
		} else {
			return 0;
		}
	}
	free(path);
	return 0;
}

static void prune_worktrees(void)
{
	struct strbuf reason = STRBUF_INIT;
	struct strbuf path = STRBUF_INIT;
	DIR *dir = opendir(git_path("worktrees"));
	struct dirent *d;
	int ret;
	if (!dir)
		return;
	while ((d = readdir(dir)) != NULL) {
		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
			continue;
		strbuf_reset(&reason);
		if (!prune_worktree(d->d_name, &reason))
			continue;
		if (show_only || verbose)
			printf("%s\n", reason.buf);
		if (show_only)
			continue;
		strbuf_reset(&path);
		strbuf_addstr(&path, git_path("worktrees/%s", d->d_name));
		ret = remove_dir_recursively(&path, 0);
		if (ret < 0 && errno == ENOTDIR)
			ret = unlink(path.buf);
		if (ret)
			error(_("failed to remove: %s"), strerror(errno));
	}
	closedir(dir);
	if (!show_only)
		rmdir(git_path("worktrees"));
	strbuf_release(&reason);
	strbuf_release(&path);
}

static int prune(int ac, const char **av, const char *prefix)
{
	struct option options[] = {
		OPT__DRY_RUN(&show_only, N_("do not remove, show only")),
		OPT__VERBOSE(&verbose, N_("report pruned objects")),
		OPT_EXPIRY_DATE(0, "expire", &expire,
				N_("expire objects older than <time>")),
		OPT_END()
	};

	expire = ULONG_MAX;
	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
	if (ac)
		usage_with_options(worktree_usage, options);
	prune_worktrees();
	return 0;
}

int cmd_worktree(int ac, const char **av, const char *prefix)
{
	struct option options[] = {
		OPT_END()
	};

	if (ac < 2)
		usage_with_options(worktree_usage, options);
	if (!strcmp(av[1], "prune"))
		return prune(ac - 1, av + 1, prefix);
	usage_with_options(worktree_usage, options);
}