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

static struct object **obj_hash;
static int nr_objs, obj_hash_size;

unsigned int get_max_object_index(void)
{
        return obj_hash_size;
}

struct object *get_indexed_object(unsigned int idx)
{
        return obj_hash[idx];
}

static const char *object_type_strings[] = {
        NULL,           /* OBJ_NONE = 0 */
        "commit",       /* OBJ_COMMIT = 1 */
        "tree",         /* OBJ_TREE = 2 */
        "blob",         /* OBJ_BLOB = 3 */
        "tag",          /* OBJ_TAG = 4 */
};

const char *typename(unsigned int type)
{
        if (type >= ARRAY_SIZE(object_type_strings))
                return NULL;
        return object_type_strings[type];
}

int type_from_string(const char *str)
{
        int i;

        for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
                if (!strcmp(str, object_type_strings[i]))
                        return i;
        die("invalid object type \"%s\"", str);
}

static unsigned int hash_obj(struct object *obj, unsigned int n)
{
        unsigned int hash = *(unsigned int *)obj->sha1;
        return hash % n;
}

static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
{
        int j = hash_obj(obj, size);

        while (hash[j]) {
                j++;
                if (j >= size)
                        j = 0;
        }
        hash[j] = obj;
}

static int hashtable_index(const unsigned char *sha1)
{
        unsigned int i;
        memcpy(&i, sha1, sizeof(unsigned int));
        return (int)(i % obj_hash_size);
}

struct object *lookup_object(const unsigned char *sha1)
{
        int i;
        struct object *obj;

        if (!obj_hash)
                return NULL;

        i = hashtable_index(sha1);
        while ((obj = obj_hash[i]) != NULL) {
                if (!hashcmp(sha1, obj->sha1))
                        break;
                i++;
                if (i == obj_hash_size)
                        i = 0;
        }
        return obj;
}

static void grow_object_hash(void)
{
        int i;
        int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
        struct object **new_hash;

        new_hash = xcalloc(new_hash_size, sizeof(struct object *));
        for (i = 0; i < obj_hash_size; i++) {
                struct object *obj = obj_hash[i];
                if (!obj)
                        continue;
                insert_obj_hash(obj, new_hash, new_hash_size);
        }
        free(obj_hash);
        obj_hash = new_hash;
        obj_hash_size = new_hash_size;
}

void created_object(const unsigned char *sha1, struct object *obj)
{
        obj->parsed = 0;
        obj->used = 0;
        obj->type = OBJ_NONE;
        obj->flags = 0;
        hashcpy(obj->sha1, sha1);

        if (obj_hash_size - 1 <= nr_objs * 2)
                grow_object_hash();

        insert_obj_hash(obj, obj_hash, obj_hash_size);
        nr_objs++;
}

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 = xcalloc(1, sizeof(*ret));
                created_object(sha1, &ret->object);
                ret->object.type = OBJ_NONE;
                return &ret->object;
        }
        return obj;
}

struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
{
        struct object *obj;
        int eaten = 0;

        if (type == OBJ_BLOB) {
                struct blob *blob = lookup_blob(sha1);
                parse_blob_buffer(blob, buffer, size);
                obj = &blob->object;
        } else if (type == OBJ_TREE) {
                struct tree *tree = lookup_tree(sha1);
                obj = &tree->object;
                if (!tree->object.parsed) {
                        parse_tree_buffer(tree, buffer, size);
                        eaten = 1;
                }
        } else if (type == OBJ_COMMIT) {
                struct commit *commit = lookup_commit(sha1);
                parse_commit_buffer(commit, buffer, size);
                if (!commit->buffer) {
                        commit->buffer = buffer;
                        eaten = 1;
                }
                obj = &commit->object;
        } else if (type == OBJ_TAG) {
                struct tag *tag = lookup_tag(sha1);
                parse_tag_buffer(tag, buffer, size);
                obj = &tag->object;
        } else {
                obj = NULL;
        }
        *eaten_p = eaten;
        return obj;
}

struct object *parse_object(const unsigned char *sha1)
{
        unsigned long size;
        enum object_type type;
        int eaten;
        void *buffer = read_sha1_file(sha1, &type, &size);

        if (buffer) {
                struct object *obj;
                if (check_sha1_signature(sha1, buffer, size, typename(type)) < 0)
                        printf("sha1 mismatch %s\n", sha1_to_hex(sha1));

                obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
                if (!eaten)
                        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;
}

void object_list_append(struct object *item,
                        struct object_list **list_p)
{
        while (*list_p) {
                list_p = &((*list_p)->next);
        }
        *list_p = xmalloc(sizeof(struct object_list));
        (*list_p)->next = NULL;
        (*list_p)->item = item;
}

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;
}

void add_object_array(struct object *obj, const char *name, struct object_array *array)
{
        unsigned nr = array->nr;
        unsigned alloc = array->alloc;
        struct object_array_entry *objects = array->objects;

        if (nr >= alloc) {
                alloc = (alloc + 32) * 2;
                objects = xrealloc(objects, alloc * sizeof(*objects));
                array->alloc = alloc;
                array->objects = objects;
        }
        objects[nr].item = obj;
        objects[nr].name = name;
        array->nr = ++nr;
}