#include "cache.h"
#include "repository.h"
#include "refs.h"
#include "strbuf.h"
#include "worktree.h"
#include "dir.h"
#include "wt-status.h"

void free_worktrees(struct worktree **worktrees)
{
        int i = 0;

        for (i = 0; worktrees[i]; i++) {
                free(worktrees[i]->path);
                free(worktrees[i]->id);
                free(worktrees[i]->head_ref);
                free(worktrees[i]->lock_reason);
                free(worktrees[i]);
        }
        free (worktrees);
}

/**
 * Update head_sha1, head_ref and is_detached of the given worktree
 */
static void add_head_info(struct worktree *wt)
{
        int flags;
        const char *target;

        target = refs_resolve_ref_unsafe(get_worktree_ref_store(wt),
                                         "HEAD",
                                         0,
                                         &wt->head_oid, &flags);
        if (!target)
                return;

        if (flags & REF_ISSYMREF)
                wt->head_ref = xstrdup(target);
        else
                wt->is_detached = 1;
}

/**
 * get the main worktree
 */
static struct worktree *get_main_worktree(void)
{
        struct worktree *worktree = NULL;
        struct strbuf path = STRBUF_INIT;
        struct strbuf worktree_path = STRBUF_INIT;

        strbuf_add_absolute_path(&worktree_path, get_git_common_dir());
        if (!strbuf_strip_suffix(&worktree_path, "/.git"))
                strbuf_strip_suffix(&worktree_path, "/.");

        strbuf_addf(&path, "%s/HEAD", get_git_common_dir());

        worktree = xcalloc(1, sizeof(*worktree));
        worktree->path = strbuf_detach(&worktree_path, NULL);
        /*
         * NEEDSWORK: If this function is called from a secondary worktree and
         * config.worktree is present, is_bare_repository_cfg will reflect the
         * contents of config.worktree, not the contents of the main worktree.
         * This means that worktree->is_bare may be set to 0 even if the main
         * worktree is configured to be bare.
         */
        worktree->is_bare = (is_bare_repository_cfg == 1) ||
                is_bare_repository();
        add_head_info(worktree);

        strbuf_release(&path);
        strbuf_release(&worktree_path);
        return worktree;
}

static struct worktree *get_linked_worktree(const char *id)
{
        struct worktree *worktree = NULL;
        struct strbuf path = STRBUF_INIT;
        struct strbuf worktree_path = STRBUF_INIT;

        if (!id)
                die("Missing linked worktree name");

        strbuf_git_common_path(&path, the_repository, "worktrees/%s/gitdir", id);
        if (strbuf_read_file(&worktree_path, path.buf, 0) <= 0)
                /* invalid gitdir file */
                goto done;

        strbuf_rtrim(&worktree_path);
        if (!strbuf_strip_suffix(&worktree_path, "/.git")) {
                strbuf_reset(&worktree_path);
                strbuf_add_absolute_path(&worktree_path, ".");
                strbuf_strip_suffix(&worktree_path, "/.");
        }

        strbuf_reset(&path);
        strbuf_addf(&path, "%s/worktrees/%s/HEAD", get_git_common_dir(), id);

        worktree = xcalloc(1, sizeof(*worktree));
        worktree->path = strbuf_detach(&worktree_path, NULL);
        worktree->id = xstrdup(id);
        add_head_info(worktree);

done:
        strbuf_release(&path);
        strbuf_release(&worktree_path);
        return worktree;
}

static void mark_current_worktree(struct worktree **worktrees)
{
        char *git_dir = absolute_pathdup(get_git_dir());
        int i;

        for (i = 0; worktrees[i]; i++) {
                struct worktree *wt = worktrees[i];
                const char *wt_git_dir = get_worktree_git_dir(wt);

                if (!fspathcmp(git_dir, absolute_path(wt_git_dir))) {
                        wt->is_current = 1;
                        break;
                }
        }
        free(git_dir);
}

static int compare_worktree(const void *a_, const void *b_)
{
        const struct worktree *const *a = a_;
        const struct worktree *const *b = b_;
        return fspathcmp((*a)->path, (*b)->path);
}

struct worktree **get_worktrees(unsigned flags)
{
        struct worktree **list = NULL;
        struct strbuf path = STRBUF_INIT;
        DIR *dir;
        struct dirent *d;
        int counter = 0, alloc = 2;

        ALLOC_ARRAY(list, alloc);

        list[counter++] = get_main_worktree();

        strbuf_addf(&path, "%s/worktrees", get_git_common_dir());
        dir = opendir(path.buf);
        strbuf_release(&path);
        if (dir) {
                while ((d = readdir(dir)) != NULL) {
                        struct worktree *linked = NULL;
                        if (is_dot_or_dotdot(d->d_name))
                                continue;

                        if ((linked = get_linked_worktree(d->d_name))) {
                                ALLOC_GROW(list, counter + 1, alloc);
                                list[counter++] = linked;
                        }
                }
                closedir(dir);
        }
        ALLOC_GROW(list, counter + 1, alloc);
        list[counter] = NULL;

        if (flags & GWT_SORT_LINKED)
                /*
                 * don't sort the first item (main worktree), which will
                 * always be the first
                 */
                QSORT(list + 1, counter - 1, compare_worktree);

        mark_current_worktree(list);
        return list;
}

const char *get_worktree_git_dir(const struct worktree *wt)
{
        if (!wt)
                return get_git_dir();
        else if (!wt->id)
                return get_git_common_dir();
        else
                return git_common_path("worktrees/%s", wt->id);
}

static struct worktree *find_worktree_by_suffix(struct worktree **list,
                                                const char *suffix)
{
        struct worktree *found = NULL;
        int nr_found = 0, suffixlen;

        suffixlen = strlen(suffix);
        if (!suffixlen)
                return NULL;

        for (; *list && nr_found < 2; list++) {
                const char      *path    = (*list)->path;
                int              pathlen = strlen(path);
                int              start   = pathlen - suffixlen;

                /* suffix must start at directory boundary */
                if ((!start || (start > 0 && is_dir_sep(path[start - 1]))) &&
                    !fspathcmp(suffix, path + start)) {
                        found = *list;
                        nr_found++;
                }
        }
        return nr_found == 1 ? found : NULL;
}

struct worktree *find_worktree(struct worktree **list,
                               const char *prefix,
                               const char *arg)
{
        struct worktree *wt;
        char *path;
        char *to_free = NULL;

        if ((wt = find_worktree_by_suffix(list, arg)))
                return wt;

        if (prefix)
                arg = to_free = prefix_filename(prefix, arg);
        path = real_pathdup(arg, 0);
        if (!path) {
                free(to_free);
                return NULL;
        }
        for (; *list; list++)
                if (!fspathcmp(path, real_path((*list)->path)))
                        break;
        free(path);
        free(to_free);
        return *list;
}

int is_main_worktree(const struct worktree *wt)
{
        return !wt->id;
}

const char *worktree_lock_reason(struct worktree *wt)
{
        assert(!is_main_worktree(wt));

        if (!wt->lock_reason_valid) {
                struct strbuf path = STRBUF_INIT;

                strbuf_addstr(&path, worktree_git_path(wt, "locked"));
                if (file_exists(path.buf)) {
                        struct strbuf lock_reason = STRBUF_INIT;
                        if (strbuf_read_file(&lock_reason, path.buf, 0) < 0)
                                die_errno(_("failed to read '%s'"), path.buf);
                        strbuf_trim(&lock_reason);
                        wt->lock_reason = strbuf_detach(&lock_reason, NULL);
                } else
                        wt->lock_reason = NULL;
                wt->lock_reason_valid = 1;
                strbuf_release(&path);
        }

        return wt->lock_reason;
}

/* convenient wrapper to deal with NULL strbuf */
static void strbuf_addf_gently(struct strbuf *buf, const char *fmt, ...)
{
        va_list params;

        if (!buf)
                return;

        va_start(params, fmt);
        strbuf_vaddf(buf, fmt, params);
        va_end(params);
}

int validate_worktree(const struct worktree *wt, struct strbuf *errmsg,
                      unsigned flags)
{
        struct strbuf wt_path = STRBUF_INIT;
        char *path = NULL;
        int err, ret = -1;

        strbuf_addf(&wt_path, "%s/.git", wt->path);

        if (is_main_worktree(wt)) {
                if (is_directory(wt_path.buf)) {
                        ret = 0;
                        goto done;
                }
                /*
                 * Main worktree using .git file to point to the
                 * repository would make it impossible to know where
                 * the actual worktree is if this function is executed
                 * from another worktree. No .git file support for now.
                 */
                strbuf_addf_gently(errmsg,
                                   _("'%s' at main working tree is not the repository directory"),
                                   wt_path.buf);
                goto done;
        }

        /*
         * Make sure "gitdir" file points to a real .git file and that
         * file points back here.
         */
        if (!is_absolute_path(wt->path)) {
                strbuf_addf_gently(errmsg,
                                   _("'%s' file does not contain absolute path to the working tree location"),
                                   git_common_path("worktrees/%s/gitdir", wt->id));
                goto done;
        }

        if (flags & WT_VALIDATE_WORKTREE_MISSING_OK &&
            !file_exists(wt->path)) {
                ret = 0;
                goto done;
        }

        if (!file_exists(wt_path.buf)) {
                strbuf_addf_gently(errmsg, _("'%s' does not exist"), wt_path.buf);
                goto done;
        }

        path = xstrdup_or_null(read_gitfile_gently(wt_path.buf, &err));
        if (!path) {
                strbuf_addf_gently(errmsg, _("'%s' is not a .git file, error code %d"),
                                   wt_path.buf, err);
                goto done;
        }

        ret = fspathcmp(path, real_path(git_common_path("worktrees/%s", wt->id)));

        if (ret)
                strbuf_addf_gently(errmsg, _("'%s' does not point back to '%s'"),
                                   wt->path, git_common_path("worktrees/%s", wt->id));
done:
        free(path);
        strbuf_release(&wt_path);
        return ret;
}

void update_worktree_location(struct worktree *wt, const char *path_)
{
        struct strbuf path = STRBUF_INIT;

        if (is_main_worktree(wt))
                BUG("can't relocate main worktree");

        strbuf_realpath(&path, path_, 1);
        if (fspathcmp(wt->path, path.buf)) {
                write_file(git_common_path("worktrees/%s/gitdir", wt->id),
                           "%s/.git", path.buf);
                free(wt->path);
                wt->path = strbuf_detach(&path, NULL);
        }
        strbuf_release(&path);
}

int is_worktree_being_rebased(const struct worktree *wt,
                              const char *target)
{
        struct wt_status_state state;
        int found_rebase;

        memset(&state, 0, sizeof(state));
        found_rebase = wt_status_check_rebase(wt, &state) &&
                ((state.rebase_in_progress ||
                  state.rebase_interactive_in_progress) &&
                 state.branch &&
                 starts_with(target, "refs/heads/") &&
                 !strcmp(state.branch, target + strlen("refs/heads/")));
        free(state.branch);
        free(state.onto);
        return found_rebase;
}

int is_worktree_being_bisected(const struct worktree *wt,
                               const char *target)
{
        struct wt_status_state state;
        int found_rebase;

        memset(&state, 0, sizeof(state));
        found_rebase = wt_status_check_bisect(wt, &state) &&
                state.branch &&
                starts_with(target, "refs/heads/") &&
                !strcmp(state.branch, target + strlen("refs/heads/"));
        free(state.branch);
        return found_rebase;
}

/*
 * note: this function should be able to detect shared symref even if
 * HEAD is temporarily detached (e.g. in the middle of rebase or
 * bisect). New commands that do similar things should update this
 * function as well.
 */
const struct worktree *find_shared_symref(const char *symref,
                                          const char *target)
{
        const struct worktree *existing = NULL;
        static struct worktree **worktrees;
        int i = 0;

        if (worktrees)
                free_worktrees(worktrees);
        worktrees = get_worktrees(0);

        for (i = 0; worktrees[i]; i++) {
                struct worktree *wt = worktrees[i];
                const char *symref_target;
                struct ref_store *refs;
                int flags;

                if (wt->is_bare)
                        continue;

                if (wt->is_detached && !strcmp(symref, "HEAD")) {
                        if (is_worktree_being_rebased(wt, target)) {
                                existing = wt;
                                break;
                        }
                        if (is_worktree_being_bisected(wt, target)) {
                                existing = wt;
                                break;
                        }
                }

                refs = get_worktree_ref_store(wt);
                symref_target = refs_resolve_ref_unsafe(refs, symref, 0,
                                                        NULL, &flags);
                if ((flags & REF_ISSYMREF) &&
                    symref_target && !strcmp(symref_target, target)) {
                        existing = wt;
                        break;
                }
        }

        return existing;
}

int submodule_uses_worktrees(const char *path)
{
        char *submodule_gitdir;
        struct strbuf sb = STRBUF_INIT;
        DIR *dir;
        struct dirent *d;
        int ret = 0;
        struct repository_format format = REPOSITORY_FORMAT_INIT;

        submodule_gitdir = git_pathdup_submodule(path, "%s", "");
        if (!submodule_gitdir)
                return 0;

        /* The env would be set for the superproject. */
        get_common_dir_noenv(&sb, submodule_gitdir);
        free(submodule_gitdir);

        /*
         * The check below is only known to be good for repository format
         * version 0 at the time of writing this code.
         */
        strbuf_addstr(&sb, "/config");
        read_repository_format(&format, sb.buf);
        if (format.version != 0) {
                strbuf_release(&sb);
                clear_repository_format(&format);
                return 1;
        }
        clear_repository_format(&format);

        /* Replace config by worktrees. */
        strbuf_setlen(&sb, sb.len - strlen("config"));
        strbuf_addstr(&sb, "worktrees");

        /* See if there is any file inside the worktrees directory. */
        dir = opendir(sb.buf);
        strbuf_release(&sb);

        if (!dir)
                return 0;

        while ((d = readdir(dir)) != NULL) {
                if (is_dot_or_dotdot(d->d_name))
                        continue;

                ret = 1;
                break;
        }
        closedir(dir);
        return ret;
}

int parse_worktree_ref(const char *worktree_ref, const char **name,
                       int *name_length, const char **ref)
{
        if (skip_prefix(worktree_ref, "main-worktree/", &worktree_ref)) {
                if (!*worktree_ref)
                        return -1;
                if (name)
                        *name = NULL;
                if (name_length)
                        *name_length = 0;
                if (ref)
                        *ref = worktree_ref;
                return 0;
        }
        if (skip_prefix(worktree_ref, "worktrees/", &worktree_ref)) {
                const char *slash = strchr(worktree_ref, '/');

                if (!slash || slash == worktree_ref || !slash[1])
                        return -1;
                if (name)
                        *name = worktree_ref;
                if (name_length)
                        *name_length = slash - worktree_ref;
                if (ref)
                        *ref = slash + 1;
                return 0;
        }
        return -1;
}

void strbuf_worktree_ref(const struct worktree *wt,
                         struct strbuf *sb,
                         const char *refname)
{
        switch (ref_type(refname)) {
        case REF_TYPE_PSEUDOREF:
        case REF_TYPE_PER_WORKTREE:
                if (wt && !wt->is_current) {
                        if (is_main_worktree(wt))
                                strbuf_addstr(sb, "main-worktree/");
                        else
                                strbuf_addf(sb, "worktrees/%s/", wt->id);
                }
                break;

        case REF_TYPE_MAIN_PSEUDOREF:
        case REF_TYPE_OTHER_PSEUDOREF:
                break;

        case REF_TYPE_NORMAL:
                /*
                 * For shared refs, don't prefix worktrees/ or
                 * main-worktree/. It's not necessary and
                 * files-backend.c can't handle it anyway.
                 */
                break;
        }
        strbuf_addstr(sb, refname);
}

const char *worktree_ref(const struct worktree *wt, const char *refname)
{
        static struct strbuf sb = STRBUF_INIT;

        strbuf_reset(&sb);
        strbuf_worktree_ref(wt, &sb, refname);
        return sb.buf;
}

int other_head_refs(each_ref_fn fn, void *cb_data)
{
        struct worktree **worktrees, **p;
        int ret = 0;

        worktrees = get_worktrees(0);
        for (p = worktrees; *p; p++) {
                struct worktree *wt = *p;
                struct object_id oid;
                int flag;

                if (wt->is_current)
                        continue;

                if (!refs_read_ref_full(get_main_ref_store(the_repository),
                                        worktree_ref(wt, "HEAD"),
                                        RESOLVE_REF_READING,
                                        &oid, &flag))
                        ret = fn(worktree_ref(wt, "HEAD"), &oid, flag, cb_data);
                if (ret)
                        break;
        }
        free_worktrees(worktrees);
        return ret;
}