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

const char *tag_type = "tag";

static int run_gpg_verify(const char *buf, unsigned long size, unsigned flags)
{
        struct signature_check sigc;
        size_t payload_size;
        int ret;

        memset(&sigc, 0, sizeof(sigc));

        payload_size = parse_signature(buf, size);

        if (size == payload_size) {
                if (flags & GPG_VERIFY_VERBOSE)
                        write_in_full(1, buf, payload_size);
                return error("no signature found");
        }

        ret = check_signature(buf, payload_size, buf + payload_size,
                                size - payload_size, &sigc);
        print_signature_buffer(&sigc, flags);

        signature_check_clear(&sigc);
        return ret;
}

int gpg_verify_tag(const unsigned char *sha1, const char *name_to_report,
                unsigned flags)
{
        enum object_type type;
        char *buf;
        unsigned long size;
        int ret;

        type = sha1_object_info(sha1, NULL);
        if (type != OBJ_TAG)
                return error("%s: cannot verify a non-tag object of type %s.",
                                name_to_report ?
                                name_to_report :
                                find_unique_abbrev(sha1, DEFAULT_ABBREV),
                                typename(type));

        buf = read_sha1_file(sha1, &type, &size);
        if (!buf)
                return error("%s: unable to read file.",
                                name_to_report ?
                                name_to_report :
                                find_unique_abbrev(sha1, DEFAULT_ABBREV));

        ret = run_gpg_verify(buf, size, flags);

        free(buf);
        return ret;
}

struct object *deref_tag(struct object *o, const char *warn, int warnlen)
{
        while (o && o->type == OBJ_TAG)
                if (((struct tag *)o)->tagged)
                        o = parse_object(((struct tag *)o)->tagged->oid.hash);
                else
                        o = NULL;
        if (!o && warn) {
                if (!warnlen)
                        warnlen = strlen(warn);
                error("missing object referenced by '%.*s'", warnlen, warn);
        }
        return o;
}

struct object *deref_tag_noverify(struct object *o)
{
        while (o && o->type == OBJ_TAG) {
                o = parse_object(o->oid.hash);
                if (o && o->type == OBJ_TAG && ((struct tag *)o)->tagged)
                        o = ((struct tag *)o)->tagged;
                else
                        o = NULL;
        }
        return o;
}

struct tag *lookup_tag(const unsigned char *sha1)
{
        struct object *obj = lookup_object(sha1);
        if (!obj)
                return create_object(sha1, alloc_tag_node());
        return object_as_type(obj, OBJ_TAG, 0);
}

static unsigned long parse_tag_date(const char *buf, const char *tail)
{
        const char *dateptr;

        while (buf < tail && *buf++ != '>')
                /* nada */;
        if (buf >= tail)
                return 0;
        dateptr = buf;
        while (buf < tail && *buf++ != '\n')
                /* nada */;
        if (buf >= tail)
                return 0;
        /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
        return strtoul(dateptr, NULL, 10);
}

int parse_tag_buffer(struct tag *item, const void *data, unsigned long size)
{
        unsigned char sha1[20];
        char type[20];
        const char *bufptr = data;
        const char *tail = bufptr + size;
        const char *nl;

        if (item->object.parsed)
                return 0;
        item->object.parsed = 1;

        if (size < 64)
                return -1;
        if (memcmp("object ", bufptr, 7) || get_sha1_hex(bufptr + 7, sha1) || bufptr[47] != '\n')
                return -1;
        bufptr += 48; /* "object " + sha1 + "\n" */

        if (!starts_with(bufptr, "type "))
                return -1;
        bufptr += 5;
        nl = memchr(bufptr, '\n', tail - bufptr);
        if (!nl || sizeof(type) <= (nl - bufptr))
                return -1;
        memcpy(type, bufptr, nl - bufptr);
        type[nl - bufptr] = '\0';
        bufptr = nl + 1;

        if (!strcmp(type, blob_type)) {
                item->tagged = &lookup_blob(sha1)->object;
        } else if (!strcmp(type, tree_type)) {
                item->tagged = &lookup_tree(sha1)->object;
        } else if (!strcmp(type, commit_type)) {
                item->tagged = &lookup_commit(sha1)->object;
        } else if (!strcmp(type, tag_type)) {
                item->tagged = &lookup_tag(sha1)->object;
        } else {
                error("Unknown type %s", type);
                item->tagged = NULL;
        }

        if (bufptr + 4 < tail && starts_with(bufptr, "tag "))
                ;               /* good */
        else
                return -1;
        bufptr += 4;
        nl = memchr(bufptr, '\n', tail - bufptr);
        if (!nl)
                return -1;
        item->tag = xmemdupz(bufptr, nl - bufptr);
        bufptr = nl + 1;

        if (bufptr + 7 < tail && starts_with(bufptr, "tagger "))
                item->date = parse_tag_date(bufptr, tail);
        else
                item->date = 0;

        return 0;
}

int parse_tag(struct tag *item)
{
        enum object_type type;
        void *data;
        unsigned long size;
        int ret;

        if (item->object.parsed)
                return 0;
        data = read_sha1_file(item->object.oid.hash, &type, &size);
        if (!data)
                return error("Could not read %s",
                             oid_to_hex(&item->object.oid));
        if (type != OBJ_TAG) {
                free(data);
                return error("Object %s not a tag",
                             oid_to_hex(&item->object.oid));
        }
        ret = parse_tag_buffer(item, data, size);
        free(data);
        return ret;
}