#include "cache.h"
#include "builtin.h"
#include "dir.h"
#include "parse-options.h"
#include "argv-array.h"
#include "run-command.h"

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

static int add(int ac, const char **av, const char *prefix)
{
        struct child_process c;
        int force = 0, detach = 0;
        const char *path, *branch;
        struct argv_array cmd = ARGV_ARRAY_INIT;
        struct option options[] = {
                OPT__FORCE(&force, N_("checkout <branch> even if already checked out in other worktree")),
                OPT_BOOL(0, "detach", &detach, N_("detach HEAD at named commit")),
                OPT_END()
        };

        ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
        if (ac != 2)
                usage_with_options(worktree_usage, options);

        path = prefix ? prefix_filename(prefix, strlen(prefix), av[0]) : av[0];
        branch = av[1];

        argv_array_push(&cmd, "checkout");
        argv_array_pushl(&cmd, "--to", path, NULL);
        if (force)
                argv_array_push(&cmd, "--ignore-other-worktrees");
        if (detach)
                argv_array_push(&cmd, "--detach");
        argv_array_push(&cmd, branch);

        memset(&c, 0, sizeof(c));
        c.git_cmd = 1;
        c.argv = cmd.argv;
        return run_command(&c);
}

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