#include "object.h"
#include "blob.h"
#include "tree.h"
#include "commit.h"
#include "cache.h"
#include "tag.h"

struct object **objs;
int nr_objs;
static int obj_allocs;

static int find_object(const unsigned char *sha1)
{
        int first = 0, last = nr_objs;

        while (first < last) {
                int next = (first + last) / 2;
                struct object *obj = objs[next];
                int cmp;

                cmp = memcmp(sha1, obj->sha1, 20);
                if (!cmp)
                        return next;
                if (cmp < 0) {
                        last = next;
                        continue;
                }
                first = next+1;
        }
        return -first-1;
}

struct object *lookup_object(const unsigned char *sha1)
{
        int pos = find_object(sha1);
        if (pos >= 0)
                return objs[pos];
        return NULL;
}

void created_object(const unsigned char *sha1, struct object *obj)
{
        int pos = find_object(sha1);

        obj->parsed = 0;
        memcpy(obj->sha1, sha1, 20);
        obj->type = NULL;
        obj->refs = NULL;
        obj->used = 0;

        if (pos >= 0)
                die("Inserting %s twice\n", sha1_to_hex(sha1));
        pos = -pos-1;

        if (obj_allocs == nr_objs) {
                obj_allocs = alloc_nr(obj_allocs);
                objs = xrealloc(objs, obj_allocs * sizeof(struct object *));
        }

        /* Insert it into the right place */
        memmove(objs + pos + 1, objs + pos, (nr_objs - pos) * 
                sizeof(struct object *));

        objs[pos] = obj;
        nr_objs++;
}

void add_ref(struct object *refer, struct object *target)
{
        struct object_list **pp = &refer->refs;
        struct object_list *p;
        
        while ((p = *pp) != NULL) {
                if (p->item == target)
                        return;
                pp = &p->next;
        }

        target->used = 1;
        p = xmalloc(sizeof(*p));
        p->item = target;
        p->next = NULL;
        *pp = p;
}

void mark_reachable(struct object *obj, unsigned int mask)
{
        struct object_list *p = obj->refs;

        /* If we've been here already, don't bother */
        if (obj->flags & mask)
                return;
        obj->flags |= mask;
        while (p) {
                mark_reachable(p->item, mask);
                p = p->next;
        }
}

struct object *lookup_object_type(const unsigned char *sha1, const char *type)
{
        if (!type) {
                return lookup_unknown_object(sha1);
        } else if (!strcmp(type, blob_type)) {
                return &lookup_blob(sha1)->object;
        } else if (!strcmp(type, tree_type)) {
                return &lookup_tree(sha1)->object;
        } else if (!strcmp(type, commit_type)) {
                return &lookup_commit(sha1)->object;
        } else if (!strcmp(type, tag_type)) {
                return &lookup_tag(sha1)->object;
        } else {
                error("Unknown type %s", type);
                return NULL;
        }
}

union any_object {
        struct object object;
        struct commit commit;
        struct tree tree;
        struct blob blob;
        struct tag tag;
};

struct object *lookup_unknown_object(const unsigned char *sha1)
{
        struct object *obj = lookup_object(sha1);
        if (!obj) {
                union any_object *ret = xmalloc(sizeof(*ret));
                memset(ret, 0, sizeof(*ret));
                created_object(sha1, &ret->object);
                ret->object.type = NULL;
                return &ret->object;
        }
        return obj;
}

struct object *parse_object(const unsigned char *sha1)
{
        unsigned long size;
        char type[20];
        void *buffer = read_sha1_file(sha1, type, &size);
        if (buffer) {
                struct object *obj;
                if (check_sha1_signature(sha1, buffer, size, type) < 0)
                        printf("sha1 mismatch %s\n", sha1_to_hex(sha1));
                if (!strcmp(type, "blob")) {
                        struct blob *blob = lookup_blob(sha1);
                        parse_blob_buffer(blob, buffer, size);
                        obj = &blob->object;
                } else if (!strcmp(type, "tree")) {
                        struct tree *tree = lookup_tree(sha1);
                        parse_tree_buffer(tree, buffer, size);
                        obj = &tree->object;
                } else if (!strcmp(type, "commit")) {
                        struct commit *commit = lookup_commit(sha1);
                        parse_commit_buffer(commit, buffer, size);
                        if (!commit->buffer) {
                                commit->buffer = buffer;
                                buffer = NULL;
                        }
                        obj = &commit->object;
                } else if (!strcmp(type, "tag")) {
                        struct tag *tag = lookup_tag(sha1);
                        parse_tag_buffer(tag, buffer, size);
                        obj = &tag->object;
                } else {
                        obj = NULL;
                }
                free(buffer);
                return obj;
        }
        return NULL;
}

struct object_list *object_list_insert(struct object *item,
                                       struct object_list **list_p)
{
        struct object_list *new_list = xmalloc(sizeof(struct object_list));
        new_list->item = item;
        new_list->next = *list_p;
        *list_p = new_list;
        return new_list;
}

unsigned object_list_length(struct object_list *list)
{
        unsigned ret = 0;
        while (list) {
                list = list->next;
                ret++;
        }
        return ret;
}

int object_list_contains(struct object_list *list, struct object *obj)
{
        while (list) {
                if (list->item == obj)
                        return 1;
                list = list->next;
        }
        return 0;
}