#include "cache.h"
#include "tag.h"
#include "commit.h"
#include "tree.h"
#include "blob.h"
#include "diff.h"
#include "tree-walk.h"
#include "revision.h"
#include "list-objects.h"
#include "list-objects-filter.h"
#include "list-objects-filter-options.h"
#include "packfile.h"
#include "object-store.h"
#include "trace.h"

struct traversal_context {
        struct rev_info *revs;
        show_object_fn show_object;
        show_commit_fn show_commit;
        void *show_data;
        filter_object_fn filter_fn;
        void *filter_data;
};

static void process_blob(struct traversal_context *ctx,
                         struct blob *blob,
                         struct strbuf *path,
                         const char *name)
{
        struct object *obj = &blob->object;
        size_t pathlen;
        enum list_objects_filter_result r = LOFR_MARK_SEEN | LOFR_DO_SHOW;

        if (!ctx->revs->blob_objects)
                return;
        if (!obj)
                die("bad blob object");
        if (obj->flags & (UNINTERESTING | SEEN))
                return;

        /*
         * Pre-filter known-missing objects when explicitly requested.
         * Otherwise, a missing object error message may be reported
         * later (depending on other filtering criteria).
         *
         * Note that this "--exclude-promisor-objects" pre-filtering
         * may cause the actual filter to report an incomplete list
         * of missing objects.
         */
        if (ctx->revs->exclude_promisor_objects &&
            !has_object_file(&obj->oid) &&
            is_promisor_object(&obj->oid))
                return;

        pathlen = path->len;
        strbuf_addstr(path, name);
        if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn)
                r = ctx->filter_fn(LOFS_BLOB, obj,
                                   path->buf, &path->buf[pathlen],
                                   ctx->filter_data);
        if (r & LOFR_MARK_SEEN)
                obj->flags |= SEEN;
        if (r & LOFR_DO_SHOW)
                ctx->show_object(obj, path->buf, ctx->show_data);
        strbuf_setlen(path, pathlen);
}

/*
 * Processing a gitlink entry currently does nothing, since
 * we do not recurse into the subproject.
 *
 * We *could* eventually add a flag that actually does that,
 * which would involve:
 *  - is the subproject actually checked out?
 *  - if so, see if the subproject has already been added
 *    to the alternates list, and add it if not.
 *  - process the commit (or tag) the gitlink points to
 *    recursively.
 *
 * However, it's unclear whether there is really ever any
 * reason to see superprojects and subprojects as such a
 * "unified" object pool (potentially resulting in a totally
 * humongous pack - avoiding which was the whole point of
 * having gitlinks in the first place!).
 *
 * So for now, there is just a note that we *could* follow
 * the link, and how to do it. Whether it necessarily makes
 * any sense what-so-ever to ever do that is another issue.
 */
static void process_gitlink(struct traversal_context *ctx,
                            const unsigned char *sha1,
                            struct strbuf *path,
                            const char *name)
{
        /* Nothing to do */
}

static void process_tree(struct traversal_context *ctx,
                         struct tree *tree,
                         struct strbuf *base,
                         const char *name);

static void process_tree_contents(struct traversal_context *ctx,
                                  struct tree *tree,
                                  struct strbuf *base)
{
        struct tree_desc desc;
        struct name_entry entry;
        enum interesting match = ctx->revs->diffopt.pathspec.nr == 0 ?
                all_entries_interesting : entry_not_interesting;

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

        while (tree_entry(&desc, &entry)) {
                if (match != all_entries_interesting) {
                        match = tree_entry_interesting(&entry, base, 0,
                                                       &ctx->revs->diffopt.pathspec);
                        if (match == all_entries_not_interesting)
                                break;
                        if (match == entry_not_interesting)
                                continue;
                }

                if (S_ISDIR(entry.mode)) {
                        struct tree *t = lookup_tree(the_repository, entry.oid);
                        t->object.flags |= NOT_USER_GIVEN;
                        process_tree(ctx, t, base, entry.path);
                }
                else if (S_ISGITLINK(entry.mode))
                        process_gitlink(ctx, entry.oid->hash,
                                        base, entry.path);
                else {
                        struct blob *b = lookup_blob(the_repository, entry.oid);
                        b->object.flags |= NOT_USER_GIVEN;
                        process_blob(ctx, b, base, entry.path);
                }
        }
}

static void process_tree(struct traversal_context *ctx,
                         struct tree *tree,
                         struct strbuf *base,
                         const char *name)
{
        struct object *obj = &tree->object;
        struct rev_info *revs = ctx->revs;
        int baselen = base->len;
        enum list_objects_filter_result r = LOFR_MARK_SEEN | LOFR_DO_SHOW;
        int failed_parse;

        if (!revs->tree_objects)
                return;
        if (!obj)
                die("bad tree object");
        if (obj->flags & (UNINTERESTING | SEEN))
                return;

        failed_parse = parse_tree_gently(tree, 1);
        if (failed_parse) {
                if (revs->ignore_missing_links)
                        return;

                /*
                 * Pre-filter known-missing tree objects when explicitly
                 * requested.  This may cause the actual filter to report
                 * an incomplete list of missing objects.
                 */
                if (revs->exclude_promisor_objects &&
                    is_promisor_object(&obj->oid))
                        return;

                if (!revs->do_not_die_on_missing_tree)
                        die("bad tree object %s", oid_to_hex(&obj->oid));
        }

        strbuf_addstr(base, name);
        if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn)
                r = ctx->filter_fn(LOFS_BEGIN_TREE, obj,
                                   base->buf, &base->buf[baselen],
                                   ctx->filter_data);
        if (r & LOFR_MARK_SEEN)
                obj->flags |= SEEN;
        if (r & LOFR_DO_SHOW)
                ctx->show_object(obj, base->buf, ctx->show_data);
        if (base->len)
                strbuf_addch(base, '/');

        if (r & LOFR_SKIP_TREE)
                trace_printf("Skipping contents of tree %s...\n", base->buf);
        else if (!failed_parse)
                process_tree_contents(ctx, tree, base);

        if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn) {
                r = ctx->filter_fn(LOFS_END_TREE, obj,
                                   base->buf, &base->buf[baselen],
                                   ctx->filter_data);
                if (r & LOFR_MARK_SEEN)
                        obj->flags |= SEEN;
                if (r & LOFR_DO_SHOW)
                        ctx->show_object(obj, base->buf, ctx->show_data);
        }

        strbuf_setlen(base, baselen);
        free_tree_buffer(tree);
}

static void mark_edge_parents_uninteresting(struct commit *commit,
                                            struct rev_info *revs,
                                            show_edge_fn show_edge)
{
        struct commit_list *parents;

        for (parents = commit->parents; parents; parents = parents->next) {
                struct commit *parent = parents->item;
                if (!(parent->object.flags & UNINTERESTING))
                        continue;
                mark_tree_uninteresting(revs->repo, get_commit_tree(parent));
                if (revs->edge_hint && !(parent->object.flags & SHOWN)) {
                        parent->object.flags |= SHOWN;
                        show_edge(parent);
                }
        }
}

void mark_edges_uninteresting(struct rev_info *revs, show_edge_fn show_edge)
{
        struct commit_list *list;
        int i;

        for (list = revs->commits; list; list = list->next) {
                struct commit *commit = list->item;

                if (commit->object.flags & UNINTERESTING) {
                        mark_tree_uninteresting(revs->repo,
                                                get_commit_tree(commit));
                        if (revs->edge_hint_aggressive && !(commit->object.flags & SHOWN)) {
                                commit->object.flags |= SHOWN;
                                show_edge(commit);
                        }
                        continue;
                }
                mark_edge_parents_uninteresting(commit, revs, show_edge);
        }
        if (revs->edge_hint_aggressive) {
                for (i = 0; i < revs->cmdline.nr; i++) {
                        struct object *obj = revs->cmdline.rev[i].item;
                        struct commit *commit = (struct commit *)obj;
                        if (obj->type != OBJ_COMMIT || !(obj->flags & UNINTERESTING))
                                continue;
                        mark_tree_uninteresting(revs->repo,
                                                get_commit_tree(commit));
                        if (!(obj->flags & SHOWN)) {
                                obj->flags |= SHOWN;
                                show_edge(commit);
                        }
                }
        }
}

static void add_pending_tree(struct rev_info *revs, struct tree *tree)
{
        add_pending_object(revs, &tree->object, "");
}

static void traverse_trees_and_blobs(struct traversal_context *ctx,
                                     struct strbuf *base)
{
        int i;

        assert(base->len == 0);

        for (i = 0; i < ctx->revs->pending.nr; i++) {
                struct object_array_entry *pending = ctx->revs->pending.objects + i;
                struct object *obj = pending->item;
                const char *name = pending->name;
                const char *path = pending->path;
                if (obj->flags & (UNINTERESTING | SEEN))
                        continue;
                if (obj->type == OBJ_TAG) {
                        obj->flags |= SEEN;
                        ctx->show_object(obj, name, ctx->show_data);
                        continue;
                }
                if (!path)
                        path = "";
                if (obj->type == OBJ_TREE) {
                        process_tree(ctx, (struct tree *)obj, base, path);
                        continue;
                }
                if (obj->type == OBJ_BLOB) {
                        process_blob(ctx, (struct blob *)obj, base, path);
                        continue;
                }
                die("unknown pending object %s (%s)",
                    oid_to_hex(&obj->oid), name);
        }
        object_array_clear(&ctx->revs->pending);
}

static void do_traverse(struct traversal_context *ctx)
{
        struct commit *commit;
        struct strbuf csp; /* callee's scratch pad */
        strbuf_init(&csp, PATH_MAX);

        while ((commit = get_revision(ctx->revs)) != NULL) {
                /*
                 * an uninteresting boundary commit may not have its tree
                 * parsed yet, but we are not going to show them anyway
                 */
                if (get_commit_tree(commit)) {
                        struct tree *tree = get_commit_tree(commit);
                        tree->object.flags |= NOT_USER_GIVEN;
                        add_pending_tree(ctx->revs, tree);
                }
                ctx->show_commit(commit, ctx->show_data);

                if (ctx->revs->tree_blobs_in_commit_order)
                        /*
                         * NEEDSWORK: Adding the tree and then flushing it here
                         * needs a reallocation for each commit. Can we pass the
                         * tree directory without allocation churn?
                         */
                        traverse_trees_and_blobs(ctx, &csp);
        }
        traverse_trees_and_blobs(ctx, &csp);
        strbuf_release(&csp);
}

void traverse_commit_list(struct rev_info *revs,
                          show_commit_fn show_commit,
                          show_object_fn show_object,
                          void *show_data)
{
        struct traversal_context ctx;
        ctx.revs = revs;
        ctx.show_commit = show_commit;
        ctx.show_object = show_object;
        ctx.show_data = show_data;
        ctx.filter_fn = NULL;
        ctx.filter_data = NULL;
        do_traverse(&ctx);
}

void traverse_commit_list_filtered(
        struct list_objects_filter_options *filter_options,
        struct rev_info *revs,
        show_commit_fn show_commit,
        show_object_fn show_object,
        void *show_data,
        struct oidset *omitted)
{
        struct traversal_context ctx;
        filter_free_fn filter_free_fn = NULL;

        ctx.revs = revs;
        ctx.show_object = show_object;
        ctx.show_commit = show_commit;
        ctx.show_data = show_data;
        ctx.filter_fn = NULL;

        ctx.filter_data = list_objects_filter__init(omitted, filter_options,
                                                    &ctx.filter_fn, &filter_free_fn);
        do_traverse(&ctx);
        if (ctx.filter_data && filter_free_fn)
                filter_free_fn(ctx.filter_data);
}