#include "cache.h"
#include "refs.h"
#include "tag.h"
#include "commit.h"
#include "blob.h"
#include "diff.h"
#include "revision.h"
#include "reachable.h"
#include "cache-tree.h"

static void process_blob(struct blob *blob,
                         struct object_array *p,
                         struct name_path *path,
                         const char *name)
{
        struct object *obj = &blob->object;

        if (obj->flags & SEEN)
                return;
        obj->flags |= SEEN;
        /* Nothing to do, really .. The blob lookup was the important part */
}

static void process_gitlink(const unsigned char *sha1,
                            struct object_array *p,
                            struct name_path *path,
                            const char *name)
{
        /* I don't think we want to recurse into this, really. */
}

static void process_tree(struct tree *tree,
                         struct object_array *p,
                         struct name_path *path,
                         const char *name)
{
        struct object *obj = &tree->object;
        struct tree_desc desc;
        struct name_entry entry;
        struct name_path me;

        if (obj->flags & SEEN)
                return;
        obj->flags |= SEEN;
        if (parse_tree(tree) < 0)
                die("bad tree object %s", sha1_to_hex(obj->sha1));
        name = xstrdup(name);
        add_object(obj, p, path, name);
        me.up = path;
        me.elem = name;
        me.elem_len = strlen(name);

        init_tree_desc(&desc, tree->buffer, tree->size);

        while (tree_entry(&desc, &entry)) {
                if (S_ISDIR(entry.mode))
                        process_tree(lookup_tree(entry.sha1), p, &me, entry.path);
                else if (S_ISGITLINK(entry.mode))
                        process_gitlink(entry.sha1, p, &me, entry.path);
                else
                        process_blob(lookup_blob(entry.sha1), p, &me, entry.path);
        }
        free(tree->buffer);
        tree->buffer = NULL;
}

static void process_tag(struct tag *tag, struct object_array *p, const char *name)
{
        struct object *obj = &tag->object;
        struct name_path me;

        if (obj->flags & SEEN)
                return;
        obj->flags |= SEEN;

        me.up = NULL;
        me.elem = "tag:/";
        me.elem_len = 5;

        if (parse_tag(tag) < 0)
                die("bad tag object %s", sha1_to_hex(obj->sha1));
        if (tag->tagged)
                add_object(tag->tagged, p, NULL, name);
}

static void walk_commit_list(struct rev_info *revs)
{
        int i;
        struct commit *commit;
        struct object_array objects = { 0, 0, NULL };

        /* Walk all commits, process their trees */
        while ((commit = get_revision(revs)) != NULL)
                process_tree(commit->tree, &objects, NULL, "");

        /* Then walk all the pending objects, recursively processing them too */
        for (i = 0; i < revs->pending.nr; i++) {
                struct object_array_entry *pending = revs->pending.objects + i;
                struct object *obj = pending->item;
                const char *name = pending->name;
                if (obj->type == OBJ_TAG) {
                        process_tag((struct tag *) obj, &objects, name);
                        continue;
                }
                if (obj->type == OBJ_TREE) {
                        process_tree((struct tree *)obj, &objects, NULL, name);
                        continue;
                }
                if (obj->type == OBJ_BLOB) {
                        process_blob((struct blob *)obj, &objects, NULL, name);
                        continue;
                }
                die("unknown pending object %s (%s)", sha1_to_hex(obj->sha1), name);
        }
}

static int add_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
                const char *email, unsigned long timestamp, int tz,
                const char *message, void *cb_data)
{
        struct object *object;
        struct rev_info *revs = (struct rev_info *)cb_data;

        object = parse_object(osha1);
        if (object)
                add_pending_object(revs, object, "");
        object = parse_object(nsha1);
        if (object)
                add_pending_object(revs, object, "");
        return 0;
}

static int add_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
{
        struct object *object = parse_object(sha1);
        struct rev_info *revs = (struct rev_info *)cb_data;

        if (!object)
                die("bad object ref: %s:%s", path, sha1_to_hex(sha1));
        add_pending_object(revs, object, "");

        return 0;
}

static int add_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
{
        for_each_reflog_ent(path, add_one_reflog_ent, cb_data);
        return 0;
}

static void add_one_tree(const unsigned char *sha1, struct rev_info *revs)
{
        struct tree *tree = lookup_tree(sha1);
        if (tree)
                add_pending_object(revs, &tree->object, "");
}

static void add_cache_tree(struct cache_tree *it, struct rev_info *revs)
{
        int i;

        if (it->entry_count >= 0)
                add_one_tree(it->sha1, revs);
        for (i = 0; i < it->subtree_nr; i++)
                add_cache_tree(it->down[i]->cache_tree, revs);
}

static void add_cache_refs(struct rev_info *revs)
{
        int i;

        read_cache();
        for (i = 0; i < active_nr; i++) {
                /*
                 * The index can contain blobs and GITLINKs, GITLINKs are hashes
                 * that don't actually point to objects in the repository, it's
                 * almost guaranteed that they are NOT blobs, so we don't call
                 * lookup_blob() on them, to avoid populating the hash table
                 * with invalid information
                 */
                if (S_ISGITLINK(ntohl(active_cache[i]->ce_mode)))
                        continue;

                lookup_blob(active_cache[i]->sha1);
                /*
                 * We could add the blobs to the pending list, but quite
                 * frankly, we don't care. Once we've looked them up, and
                 * added them as objects, we've really done everything
                 * there is to do for a blob
                 */
        }
        if (active_cache_tree)
                add_cache_tree(active_cache_tree, revs);
}

void mark_reachable_objects(struct rev_info *revs, int mark_reflog)
{
        /*
         * Set up revision parsing, and mark us as being interested
         * in all object types, not just commits.
         */
        revs->tag_objects = 1;
        revs->blob_objects = 1;
        revs->tree_objects = 1;

        /* Add all refs from the index file */
        add_cache_refs(revs);

        /* Add all external refs */
        for_each_ref(add_one_ref, revs);

        /* Add all reflog info */
        if (mark_reflog)
                for_each_reflog(add_one_reflog, revs);

        /*
         * Set up the revision walk - this will move all commits
         * from the pending list to the commit walking list.
         */
        prepare_revision_walk(revs);
        walk_commit_list(revs);
}