#include "cache.h"
#include "bundle.h"
#include "object.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "run-command.h"
#include "refs.h"

static const char bundle_signature[] = "# v2 git bundle\n";

static void add_to_ref_list(const unsigned char *sha1, const char *name,
                struct ref_list *list)
{
        if (list->nr + 1 >= list->alloc) {
                list->alloc = alloc_nr(list->nr + 1);
                list->list = xrealloc(list->list,
                                list->alloc * sizeof(list->list[0]));
        }
        memcpy(list->list[list->nr].sha1, sha1, 20);
        list->list[list->nr].name = xstrdup(name);
        list->nr++;
}

/* Eventually this should go to strbuf.[ch] */
static int strbuf_readline_fd(struct strbuf *sb, int fd)
{
        strbuf_reset(sb);

        while (1) {
                char ch;
                ssize_t len = xread(fd, &ch, 1);
                if (len < 0)
                        return -1;
                strbuf_addch(sb, ch);
                if (ch == '\n')
                        break;
        }
        return 0;
}

int read_bundle_header(const char *path, struct bundle_header *header)
{
        struct strbuf buf = STRBUF_INIT;
        int fd = open(path, O_RDONLY);
        int status = 0;

        if (fd < 0)
                return error("could not open '%s'", path);

        /* The bundle header begins with the signature */
        if (strbuf_readline_fd(&buf, fd) ||
            strcmp(buf.buf, bundle_signature)) {
                error("'%s' does not look like a v2 bundle file", path);
                status = -1;
                goto abort;
        }

        /* The bundle header ends with an empty line */
        while (!strbuf_readline_fd(&buf, fd) &&
               buf.len && buf.buf[0] != '\n') {
                unsigned char sha1[20];
                int is_prereq = 0;

                if (*buf.buf == '-') {
                        is_prereq = 1;
                        strbuf_remove(&buf, 0, 1);
                }
                strbuf_rtrim(&buf);

                /*
                 * Tip lines have object name, SP, and refname.
                 * Prerequisites have object name that is optionally
                 * followed by SP and subject line.
                 */
                if (get_sha1_hex(buf.buf, sha1) ||
                    (40 <= buf.len && !isspace(buf.buf[40])) ||
                    (!is_prereq && buf.len <= 40)) {
                        error("unrecognized header: %s%s (%d)",
                              (is_prereq ? "-" : ""), buf.buf, (int)buf.len);
                        status = -1;
                        break;
                } else {
                        if (is_prereq)
                                add_to_ref_list(sha1, "", &header->prerequisites);
                        else
                                add_to_ref_list(sha1, buf.buf + 41, &header->references);
                }
        }

 abort:
        if (status) {
                close(fd);
                fd = -1;
        }
        strbuf_release(&buf);
        return fd;
}

static int list_refs(struct ref_list *r, int argc, const char **argv)
{
        int i;

        for (i = 0; i < r->nr; i++) {
                if (argc > 1) {
                        int j;
                        for (j = 1; j < argc; j++)
                                if (!strcmp(r->list[i].name, argv[j]))
                                        break;
                        if (j == argc)
                                continue;
                }
                printf("%s %s\n", sha1_to_hex(r->list[i].sha1),
                                r->list[i].name);
        }
        return 0;
}

#define PREREQ_MARK (1u<<16)

int verify_bundle(struct bundle_header *header, int verbose)
{
        /*
         * Do fast check, then if any prereqs are missing then go line by line
         * to be verbose about the errors
         */
        struct ref_list *p = &header->prerequisites;
        struct rev_info revs;
        const char *argv[] = {NULL, "--all", NULL};
        struct object_array refs;
        struct commit *commit;
        int i, ret = 0, req_nr;
        const char *message = "Repository lacks these prerequisite commits:";

        init_revisions(&revs, NULL);
        for (i = 0; i < p->nr; i++) {
                struct ref_list_entry *e = p->list + i;
                struct object *o = parse_object(e->sha1);
                if (o) {
                        o->flags |= PREREQ_MARK;
                        add_pending_object(&revs, o, e->name);
                        continue;
                }
                if (++ret == 1)
                        error("%s", message);
                error("%s %s", sha1_to_hex(e->sha1), e->name);
        }
        if (revs.pending.nr != p->nr)
                return ret;
        req_nr = revs.pending.nr;
        setup_revisions(2, argv, &revs, NULL);

        memset(&refs, 0, sizeof(struct object_array));
        for (i = 0; i < revs.pending.nr; i++) {
                struct object_array_entry *e = revs.pending.objects + i;
                add_object_array(e->item, e->name, &refs);
        }

        if (prepare_revision_walk(&revs))
                die("revision walk setup failed");

        i = req_nr;
        while (i && (commit = get_revision(&revs)))
                if (commit->object.flags & PREREQ_MARK)
                        i--;

        for (i = 0; i < req_nr; i++)
                if (!(refs.objects[i].item->flags & SHOWN)) {
                        if (++ret == 1)
                                error("%s", message);
                        error("%s %s", sha1_to_hex(refs.objects[i].item->sha1),
                                refs.objects[i].name);
                }

        for (i = 0; i < refs.nr; i++)
                clear_commit_marks((struct commit *)refs.objects[i].item, -1);

        if (verbose) {
                struct ref_list *r;

                r = &header->references;
                printf("The bundle contains %d ref%s\n",
                       r->nr, (1 < r->nr) ? "s" : "");
                list_refs(r, 0, NULL);
                r = &header->prerequisites;
                printf("The bundle requires these %d ref%s\n",
                       r->nr, (1 < r->nr) ? "s" : "");
                list_refs(r, 0, NULL);
        }
        return ret;
}

int list_bundle_refs(struct bundle_header *header, int argc, const char **argv)
{
        return list_refs(&header->references, argc, argv);
}

static int is_tag_in_date_range(struct object *tag, struct rev_info *revs)
{
        unsigned long size;
        enum object_type type;
        char *buf, *line, *lineend;
        unsigned long date;

        if (revs->max_age == -1 && revs->min_age == -1)
                return 1;

        buf = read_sha1_file(tag->sha1, &type, &size);
        if (!buf)
                return 1;
        line = memmem(buf, size, "\ntagger ", 8);
        if (!line++)
                return 1;
        lineend = memchr(line, buf + size - line, '\n');
        line = memchr(line, lineend ? lineend - line : buf + size - line, '>');
        if (!line++)
                return 1;
        date = strtoul(line, NULL, 10);
        free(buf);
        return (revs->max_age == -1 || revs->max_age < date) &&
                (revs->min_age == -1 || revs->min_age > date);
}

int create_bundle(struct bundle_header *header, const char *path,
                int argc, const char **argv)
{
        static struct lock_file lock;
        int bundle_fd = -1;
        int bundle_to_stdout;
        const char **argv_boundary = xmalloc((argc + 4) * sizeof(const char *));
        const char **argv_pack = xmalloc(6 * sizeof(const char *));
        int i, ref_count = 0;
        char buffer[1024];
        struct rev_info revs;
        struct child_process rls;
        FILE *rls_fout;

        bundle_to_stdout = !strcmp(path, "-");
        if (bundle_to_stdout)
                bundle_fd = 1;
        else
                bundle_fd = hold_lock_file_for_update(&lock, path,
                                                      LOCK_DIE_ON_ERROR);

        /* write signature */
        write_or_die(bundle_fd, bundle_signature, strlen(bundle_signature));

        /* init revs to list objects for pack-objects later */
        save_commit_buffer = 0;
        init_revisions(&revs, NULL);

        /* write prerequisites */
        memcpy(argv_boundary + 3, argv + 1, argc * sizeof(const char *));
        argv_boundary[0] = "rev-list";
        argv_boundary[1] = "--boundary";
        argv_boundary[2] = "--pretty=oneline";
        argv_boundary[argc + 2] = NULL;
        memset(&rls, 0, sizeof(rls));
        rls.argv = argv_boundary;
        rls.out = -1;
        rls.git_cmd = 1;
        if (start_command(&rls))
                return -1;
        rls_fout = xfdopen(rls.out, "r");
        while (fgets(buffer, sizeof(buffer), rls_fout)) {
                unsigned char sha1[20];
                if (buffer[0] == '-') {
                        write_or_die(bundle_fd, buffer, strlen(buffer));
                        if (!get_sha1_hex(buffer + 1, sha1)) {
                                struct object *object = parse_object(sha1);
                                object->flags |= UNINTERESTING;
                                add_pending_object(&revs, object, buffer);
                        }
                } else if (!get_sha1_hex(buffer, sha1)) {
                        struct object *object = parse_object(sha1);
                        object->flags |= SHOWN;
                }
        }
        fclose(rls_fout);
        if (finish_command(&rls))
                return error("rev-list died");

        /* write references */
        argc = setup_revisions(argc, argv, &revs, NULL);

        if (argc > 1)
                return error("unrecognized argument: %s'", argv[1]);

        object_array_remove_duplicates(&revs.pending);

        for (i = 0; i < revs.pending.nr; i++) {
                struct object_array_entry *e = revs.pending.objects + i;
                unsigned char sha1[20];
                char *ref;
                const char *display_ref;
                int flag;

                if (e->item->flags & UNINTERESTING)
                        continue;
                if (dwim_ref(e->name, strlen(e->name), sha1, &ref) != 1)
                        continue;
                if (!resolve_ref(e->name, sha1, 1, &flag))
                        flag = 0;
                display_ref = (flag & REF_ISSYMREF) ? e->name : ref;

                if (e->item->type == OBJ_TAG &&
                                !is_tag_in_date_range(e->item, &revs)) {
                        e->item->flags |= UNINTERESTING;
                        continue;
                }

                /*
                 * Make sure the refs we wrote out is correct; --max-count and
                 * other limiting options could have prevented all the tips
                 * from getting output.
                 *
                 * Non commit objects such as tags and blobs do not have
                 * this issue as they are not affected by those extra
                 * constraints.
                 */
                if (!(e->item->flags & SHOWN) && e->item->type == OBJ_COMMIT) {
                        warning("ref '%s' is excluded by the rev-list options",
                                e->name);
                        free(ref);
                        continue;
                }
                /*
                 * If you run "git bundle create bndl v1.0..v2.0", the
                 * name of the positive ref is "v2.0" but that is the
                 * commit that is referenced by the tag, and not the tag
                 * itself.
                 */
                if (hashcmp(sha1, e->item->sha1)) {
                        /*
                         * Is this the positive end of a range expressed
                         * in terms of a tag (e.g. v2.0 from the range
                         * "v1.0..v2.0")?
                         */
                        struct commit *one = lookup_commit_reference(sha1);
                        struct object *obj;

                        if (e->item == &(one->object)) {
                                /*
                                 * Need to include e->name as an
                                 * independent ref to the pack-objects
                                 * input, so that the tag is included
                                 * in the output; otherwise we would
                                 * end up triggering "empty bundle"
                                 * error.
                                 */
                                obj = parse_object(sha1);
                                obj->flags |= SHOWN;
                                add_pending_object(&revs, obj, e->name);
                        }
                        free(ref);
                        continue;
                }

                ref_count++;
                write_or_die(bundle_fd, sha1_to_hex(e->item->sha1), 40);
                write_or_die(bundle_fd, " ", 1);
                write_or_die(bundle_fd, display_ref, strlen(display_ref));
                write_or_die(bundle_fd, "\n", 1);
                free(ref);
        }
        if (!ref_count)
                die ("Refusing to create empty bundle.");

        /* end header */
        write_or_die(bundle_fd, "\n", 1);

        /* write pack */
        argv_pack[0] = "pack-objects";
        argv_pack[1] = "--all-progress-implied";
        argv_pack[2] = "--stdout";
        argv_pack[3] = "--thin";
        argv_pack[4] = "--delta-base-offset";
        argv_pack[5] = NULL;
        memset(&rls, 0, sizeof(rls));
        rls.argv = argv_pack;
        rls.in = -1;
        rls.out = bundle_fd;
        rls.git_cmd = 1;
        if (start_command(&rls))
                return error("Could not spawn pack-objects");

        /*
         * start_command closed bundle_fd if it was > 1
         * so set the lock fd to -1 so commit_lock_file()
         * won't fail trying to close it.
         */
        lock.fd = -1;

        for (i = 0; i < revs.pending.nr; i++) {
                struct object *object = revs.pending.objects[i].item;
                if (object->flags & UNINTERESTING)
                        write_or_die(rls.in, "^", 1);
                write_or_die(rls.in, sha1_to_hex(object->sha1), 40);
                write_or_die(rls.in, "\n", 1);
        }
        close(rls.in);
        if (finish_command(&rls))
                return error ("pack-objects died");
        if (!bundle_to_stdout) {
                if (commit_lock_file(&lock))
                        die_errno("cannot create '%s'", path);
        }
        return 0;
}

int unbundle(struct bundle_header *header, int bundle_fd)
{
        const char *argv_index_pack[] = {"index-pack",
                "--fix-thin", "--stdin", NULL};
        struct child_process ip;

        if (verify_bundle(header, 0))
                return -1;
        memset(&ip, 0, sizeof(ip));
        ip.argv = argv_index_pack;
        ip.in = bundle_fd;
        ip.no_stdout = 1;
        ip.git_cmd = 1;
        if (run_command(&ip))
                return error("index-pack died");
        return 0;
}