#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"
#include "progress.h"
#include "list-objects.h"

struct connectivity_progress {
        struct progress *progress;
        unsigned long count;
};

static void update_progress(struct connectivity_progress *cp)
{
        cp->count++;
        if ((cp->count & 1023) == 0)
                display_progress(cp->progress, cp->count);
}

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

        add_pending_object(revs, object, "");

        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++) {
                struct blob *blob;

                /*
                 * 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(active_cache[i]->ce_mode))
                        continue;

                blob = lookup_blob(active_cache[i]->sha1);
                if (blob)
                        blob->object.flags |= SEEN;

                /*
                 * 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);
}

/*
 * The traversal will have already marked us as SEEN, so we
 * only need to handle any progress reporting here.
 */
static void mark_object(struct object *obj, const struct name_path *path,
                        const char *name, void *data)
{
        update_progress(data);
}

static void mark_commit(struct commit *c, void *data)
{
        mark_object(&c->object, NULL, NULL, data);
}

struct recent_data {
        struct rev_info *revs;
        unsigned long timestamp;
};

static void add_recent_object(const unsigned char *sha1,
                              unsigned long mtime,
                              struct recent_data *data)
{
        struct object *obj;
        enum object_type type;

        if (mtime <= data->timestamp)
                return;

        /*
         * We do not want to call parse_object here, because
         * inflating blobs and trees could be very expensive.
         * However, we do need to know the correct type for
         * later processing, and the revision machinery expects
         * commits and tags to have been parsed.
         */
        type = sha1_object_info(sha1, NULL);
        if (type < 0)
                die("unable to get object info for %s", sha1_to_hex(sha1));

        switch (type) {
        case OBJ_TAG:
        case OBJ_COMMIT:
                obj = parse_object_or_die(sha1, NULL);
                break;
        case OBJ_TREE:
                obj = (struct object *)lookup_tree(sha1);
                break;
        case OBJ_BLOB:
                obj = (struct object *)lookup_blob(sha1);
                break;
        default:
                die("unknown object type for %s: %s",
                    sha1_to_hex(sha1), typename(type));
        }

        if (!obj)
                die("unable to lookup %s", sha1_to_hex(sha1));

        add_pending_object(data->revs, obj, "");
}

static int add_recent_loose(const unsigned char *sha1,
                            const char *path, void *data)
{
        struct stat st;
        struct object *obj = lookup_object(sha1);

        if (obj && obj->flags & SEEN)
                return 0;

        if (stat(path, &st) < 0) {
                /*
                 * It's OK if an object went away during our iteration; this
                 * could be due to a simultaneous repack. But anything else
                 * we should abort, since we might then fail to mark objects
                 * which should not be pruned.
                 */
                if (errno == ENOENT)
                        return 0;
                return error("unable to stat %s: %s",
                             sha1_to_hex(sha1), strerror(errno));
        }

        add_recent_object(sha1, st.st_mtime, data);
        return 0;
}

static int add_recent_packed(const unsigned char *sha1,
                             struct packed_git *p, uint32_t pos,
                             void *data)
{
        struct object *obj = lookup_object(sha1);

        if (obj && obj->flags & SEEN)
                return 0;
        add_recent_object(sha1, p->mtime, data);
        return 0;
}

static int add_unseen_recent_objects_to_traversal(struct rev_info *revs,
                                                  unsigned long timestamp)
{
        struct recent_data data;
        int r;

        data.revs = revs;
        data.timestamp = timestamp;

        r = for_each_loose_object(add_recent_loose, &data);
        if (r)
                return r;
        return for_each_packed_object(add_recent_packed, &data);
}

void mark_reachable_objects(struct rev_info *revs, int mark_reflog,
                            unsigned long mark_recent,
                            struct progress *progress)
{
        struct connectivity_progress cp;

        /*
         * 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);

        /* detached HEAD is not included in the list above */
        head_ref(add_one_ref, revs);

        /* Add all reflog info */
        if (mark_reflog)
                add_reflogs_to_pending(revs, 0);

        cp.progress = progress;
        cp.count = 0;

        /*
         * Set up the revision walk - this will move all commits
         * from the pending list to the commit walking list.
         */
        if (prepare_revision_walk(revs))
                die("revision walk setup failed");
        traverse_commit_list(revs, mark_commit, mark_object, &cp);

        if (mark_recent) {
                revs->ignore_missing_links = 1;
                if (add_unseen_recent_objects_to_traversal(revs, mark_recent))
                        die("unable to mark recent objects");
                if (prepare_revision_walk(revs))
                        die("revision walk setup failed");
                traverse_commit_list(revs, mark_commit, mark_object, &cp);
        }

        display_progress(cp.progress, cp.count);
}