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

/*
 * Basic handler for bundle files to connect repositories via sneakernet.
 * Invocation must include action.
 * This function can create a bundle or provide information on an existing
 * bundle supporting git-fetch, git-pull, and git-ls-remote
 */

static const char *bundle_usage="git-bundle (create <bundle> <git-rev-list args> | verify <bundle> | list-heads <bundle> [refname]... | unbundle <bundle> [refname]... )";

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

struct ref_list {
        unsigned int nr, alloc;
        struct ref_list_entry {
                unsigned char sha1[20];
                char *name;
        } *list;
};

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++;
}

struct bundle_header {
        struct ref_list prerequisites;
        struct ref_list references;
};

/* this function returns the length of the string */
static int read_string(int fd, char *buffer, int size)
{
        int i;
        for (i = 0; i < size - 1; i++) {
                ssize_t count = xread(fd, buffer + i, 1);
                if (count < 0)
                        return error("Read error: %s", strerror(errno));
                if (count == 0) {
                        i--;
                        break;
                }
                if (buffer[i] == '\n')
                        break;
        }
        buffer[i + 1] = '\0';
        return i + 1;
}

/* returns an fd */
static int read_header(const char *path, struct bundle_header *header) {
        char buffer[1024];
        int fd = open(path, O_RDONLY);

        if (fd < 0)
                return error("could not open '%s'", path);
        if (read_string(fd, buffer, sizeof(buffer)) < 0 ||
                        strcmp(buffer, bundle_signature)) {
                close(fd);
                return error("'%s' does not look like a v2 bundle file", path);
        }
        while (read_string(fd, buffer, sizeof(buffer)) > 0
                        && buffer[0] != '\n') {
                int is_prereq = buffer[0] == '-';
                int offset = is_prereq ? 1 : 0;
                int len = strlen(buffer);
                unsigned char sha1[20];
                struct ref_list *list = is_prereq ? &header->prerequisites
                        : &header->references;
                char delim;

                if (buffer[len - 1] == '\n')
                        buffer[len - 1] = '\0';
                if (get_sha1_hex(buffer + offset, sha1)) {
                        warning("unrecognized header: %s", buffer);
                        continue;
                }
                delim = buffer[40 + offset];
                if (!isspace(delim) && (delim != '\0' || !is_prereq))
                        die ("invalid header: %s", buffer);
                add_to_ref_list(sha1, isspace(delim) ?
                                buffer + 41 + offset : "", list);
        }
        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)

static 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"};
        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(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);
        }

        prepare_revision_walk(&revs);

        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(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;
}

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

static int create_bundle(struct bundle_header *header, const char *path,
                int argc, const char **argv)
{
        int bundle_fd = -1;
        const char **argv_boundary = xmalloc((argc + 4) * sizeof(const char *));
        const char **argv_pack = xmalloc(5 * sizeof(const char *));
        int i, ref_count = 0;
        char buffer[1024];
        struct rev_info revs;
        struct child_process rls;
        FILE *rls_fout;

        /*
         * NEEDSWORK: this should use something like lock-file
         * to create temporary that is cleaned up upon error.
         */
        bundle_fd = (!strcmp(path, "-") ? 1 :
                        open(path, O_CREAT | O_EXCL | O_WRONLY, 0666));
        if (bundle_fd < 0)
                return error("Could not create '%s': %s", path, strerror(errno));

        /* 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 = fdopen(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]);

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

                if (e->item->flags & UNINTERESTING)
                        continue;
                if (dwim_ref(e->name, strlen(e->name), sha1, &ref) != 1)
                        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, ref, strlen(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";
        argv_pack[2] = "--stdout";
        argv_pack[3] = "--thin";
        argv_pack[4] = 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");
        for (i = 0; i < revs.pending.nr; i++) {
                struct object *object = revs.pending.objects[i].item;
                if (object->flags & UNINTERESTING)
                        write(rls.in, "^", 1);
                write(rls.in, sha1_to_hex(object->sha1), 40);
                write(rls.in, "\n", 1);
        }
        if (finish_command(&rls))
                return error ("pack-objects died");
        return 0;
}

static int unbundle(struct bundle_header *header, int bundle_fd,
                int argc, const char **argv)
{
        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 list_heads(header, argc, argv);
}

int cmd_bundle(int argc, const char **argv, const char *prefix)
{
        struct bundle_header header;
        int nongit = 0;
        const char *cmd, *bundle_file;
        int bundle_fd = -1;
        char buffer[PATH_MAX];

        if (argc < 3)
                usage(bundle_usage);

        cmd = argv[1];
        bundle_file = argv[2];
        argc -= 2;
        argv += 2;

        prefix = setup_git_directory_gently(&nongit);
        if (prefix && bundle_file[0] != '/') {
                snprintf(buffer, sizeof(buffer), "%s/%s", prefix, bundle_file);
                bundle_file = buffer;
        }

        memset(&header, 0, sizeof(header));
        if (strcmp(cmd, "create") &&
                        (bundle_fd = read_header(bundle_file, &header)) < 0)
                return 1;

        if (!strcmp(cmd, "verify")) {
                close(bundle_fd);
                if (verify_bundle(&header, 1))
                        return 1;
                fprintf(stderr, "%s is okay\n", bundle_file);
                return 0;
        }
        if (!strcmp(cmd, "list-heads")) {
                close(bundle_fd);
                return !!list_heads(&header, argc, argv);
        }
        if (!strcmp(cmd, "create")) {
                if (nongit)
                        die("Need a repository to create a bundle.");
                return !!create_bundle(&header, bundle_file, argc, argv);
        } else if (!strcmp(cmd, "unbundle")) {
                if (nongit)
                        die("Need a repository to unbundle.");
                return !!unbundle(&header, bundle_fd, argc, argv);
        } else
                usage(bundle_usage);
}