#define USE_THE_REPOSITORY_VARIABLE

#include "git-compat-util.h"

#include "default.h"

#include "../commit.h"

#include "../fetch-negotiator.h"

#include "../prio-queue.h"

#include "../refs.h"

#include "../repository.h"

#include "../tag.h"

/* Remember to update object flag allocation in object.h */

#define COMMON    (1U << 2)

#define COMMON_REF  (1U << 3)

#define SEEN    (1U << 4)

#define POPPED    (1U << 5)

static int marked;

struct negotiation_state {

  struct prio_queue rev_list;

  int non_common_revs;

};

static void rev_list_push(struct negotiation_state *ns,

        struct commit *commit, int mark)

{

  if (!(commit->object.flags & mark)) {

    commit->object.flags |= mark;

    if (repo_parse_commit(the_repository, commit))

      return;

    prio_queue_put(&ns->rev_list, commit);

    if (!(commit->object.flags & COMMON))

      ns->non_common_revs++;

  }

}

static int clear_marks(const struct reference *ref, void *cb_data UNUSED)

{

  struct object *o = deref_tag(the_repository, parse_object(the_repository, ref->oid),

             ref->name, 0);

  if (o && o->type == OBJ_COMMIT)

    clear_commit_marks((struct commit *)o,

           COMMON | COMMON_REF | SEEN | POPPED);

  return 0;

}

/*

 * This function marks a rev and its ancestors as common.

 * In some cases, it is desirable to mark only the ancestors (for example

 * when only the server does not yet know that they are common).

 */

static void mark_common(struct negotiation_state *ns, struct commit *commit,

    int ancestors_only, int dont_parse)

{

  struct prio_queue queue = { NULL };

  if (!commit || (commit->object.flags & COMMON))

    return;

  prio_queue_put(&queue, commit);

  if (!ancestors_only) {

    commit->object.flags |= COMMON;

    if ((commit->object.flags & SEEN) && !(commit->object.flags & POPPED))

      ns->non_common_revs--;

  }

  while ((commit = prio_queue_get(&queue))) {

    struct object *o = (struct object *)commit;

    if (!(o->flags & SEEN))

      rev_list_push(ns, commit, SEEN);

    else {

      struct commit_list *parents;

      if (!o->parsed && !dont_parse)

        if (repo_parse_commit(the_repository, commit))

          continue;

      for (parents = commit->parents;

          parents;

          parents = parents->next) {

        struct commit *p = parents->item;

        if (p->object.flags & COMMON)

          continue;

        p->object.flags |= COMMON;

        if ((p->object.flags & SEEN) && !(p->object.flags & POPPED))

          ns->non_common_revs--;

        prio_queue_put(&queue, parents->item);

      }

    }

  }

  clear_prio_queue(&queue);

}

/*

 * Get the next rev to send, ignoring the common.

 */

static const struct object_id *get_rev(struct negotiation_state *ns)

{

  struct commit *commit = NULL;

  while (commit == NULL) {

    unsigned int mark;

    struct commit_list *parents;

    if (ns->rev_list.nr == 0 || ns->non_common_revs == 0)

      return NULL;

    commit = prio_queue_get(&ns->rev_list);

    repo_parse_commit(the_repository, commit);

    parents = commit->parents;

    commit->object.flags |= POPPED;

    if (!(commit->object.flags & COMMON))

      ns->non_common_revs--;

    if (commit->object.flags & COMMON) {

      /* do not send "have", and ignore ancestors */

      commit = NULL;

      mark = COMMON | SEEN;

    } else if (commit->object.flags & COMMON_REF)

      /* send "have", and ignore ancestors */

      mark = COMMON | SEEN;

    else

      /* send "have", also for its ancestors */

      mark = SEEN;

    while (parents) {

      if (!(parents->item->object.flags & SEEN))

        rev_list_push(ns, parents->item, mark);

      if (mark & COMMON)

        mark_common(ns, parents->item, 1, 0);

      parents = parents->next;

    }

  }

  return &commit->object.oid;

}

static void known_common(struct fetch_negotiator *n, struct commit *c)

{

  if (!(c->object.flags & SEEN)) {

    rev_list_push(n->data, c, COMMON_REF | SEEN);

    mark_common(n->data, c, 1, 1);

  }

}

static void add_tip(struct fetch_negotiator *n, struct commit *c)

{

  n->known_common = NULL;

  rev_list_push(n->data, c, SEEN);

}

static const struct object_id *next(struct fetch_negotiator *n)

{

  n->known_common = NULL;

  n->add_tip = NULL;

  return get_rev(n->data);

}

static int ack(struct fetch_negotiator *n, struct commit *c)

{

  int known_to_be_common = !!(c->object.flags & COMMON);

  mark_common(n->data, c, 0, 1);

  return known_to_be_common;

}

static void release(struct fetch_negotiator *n)

{

  clear_prio_queue(&((struct negotiation_state *)n->data)->rev_list);

  FREE_AND_NULL(n->data);

}

void default_negotiator_init(struct fetch_negotiator *negotiator)

{

  struct negotiation_state *ns;

  negotiator->known_common = known_common;

  negotiator->add_tip = add_tip;

  negotiator->next = next;

  negotiator->ack = ack;

  negotiator->release = release;

  negotiator->data = CALLOC_ARRAY(ns, 1);

  ns->rev_list.compare = compare_commits_by_commit_date;

  if (marked)

    refs_for_each_ref(get_main_ref_store(the_repository),

          clear_marks, NULL);

  marked = 1;

}