#include "cache.h"
#include "object.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "exec_cmd.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++) {
                int 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)) {
                        warn("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;
}

/* if in && *in >= 0, take that as input file descriptor instead */
static int fork_with_pipe(const char **argv, int *in, int *out)
{
        int needs_in, needs_out;
        int fdin[2], fdout[2], pid;

        needs_in = in && *in < 0;
        if (needs_in) {
                if (pipe(fdin) < 0)
                        return error("could not setup pipe");
                *in = fdin[1];
        }

        needs_out = out && *out < 0;
        if (needs_out) {
                if (pipe(fdout) < 0)
                        return error("could not setup pipe");
                *out = fdout[0];
        }

        if ((pid = fork()) < 0) {
                if (needs_in) {
                        close(fdin[0]);
                        close(fdin[1]);
                }
                if (needs_out) {
                        close(fdout[0]);
                        close(fdout[1]);
                }
                return error("could not fork");
        }
        if (!pid) {
                if (needs_in) {
                        dup2(fdin[0], 0);
                        close(fdin[0]);
                        close(fdin[1]);
                } else if (in) {
                        dup2(*in, 0);
                        close(*in);
                }
                if (needs_out) {
                        dup2(fdout[1], 1);
                        close(fdout[0]);
                        close(fdout[1]);
                } else if (out) {
                        dup2(*out, 1);
                        close(*out);
                }
                exit(execv_git_cmd(argv));
        }
        if (needs_in)
                close(fdin[0]);
        else if (in)
                close(*in);
        if (needs_out)
                close(fdout[1]);
        else if (out)
                close(*out);
        return pid;
}

#define PREREQ_MARK (1u<<16)

static int verify_bundle(struct bundle_header *header)
{
        /*
         * 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 == 0)
                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);

        return ret;
}

static int list_heads(struct bundle_header *header, int argc, const char **argv)
{
        int i;
        struct ref_list *r = &header->references;

        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;
}

static void show_commit(struct commit *commit)
{
        write_or_die(1, sha1_to_hex(commit->object.sha1), 40);
        write_or_die(1, "\n", 1);
        if (commit->parents) {
                free_commit_list(commit->parents);
                commit->parents = NULL;
        }
}

static void show_object(struct object_array_entry *p)
{
        /* An object with name "foo\n0000000..." can be used to
         * confuse downstream git-pack-objects very badly.
         */
        const char *ep = strchr(p->name, '\n');
        int len = ep ? ep - p->name : strlen(p->name);
        write_or_die(1, sha1_to_hex(p->item->sha1), 40);
        write_or_die(1, " ", 1);
        if (len)
                write_or_die(1, p->name, len);
        write_or_die(1, "\n", 1);
}

static void show_edge(struct commit *commit)
{
        ; /* nothing to do */
}

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(4 * sizeof(const char *));
        int pid, in, out, i, status;
        char buffer[1024];
        struct rev_info revs;

        bundle_fd = (!strcmp(path, "-") ? 1 :
                        open(path, O_CREAT | O_WRONLY, 0666));
        if (bundle_fd < 0)
                return error("Could not write to '%s'", path);

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

        /* 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;
        out = -1;
        pid = fork_with_pipe(argv_boundary, NULL, &out);
        if (pid < 0)
                return -1;
        while ((i = read_string(out, buffer, sizeof(buffer))) > 0)
                if (buffer[0] == '-')
                        write_or_die(bundle_fd, buffer, i);
        while ((i = waitpid(pid, &status, 0)) < 0)
                if (errno != EINTR)
                        return error("rev-list died");
        if (!WIFEXITED(status) || WEXITSTATUS(status))
                return error("rev-list died %d", WEXITSTATUS(status));

        /* write references */
        save_commit_buffer = 0;
        init_revisions(&revs, NULL);
        revs.tag_objects = 1;
        revs.tree_objects = 1;
        revs.blob_objects = 1;
        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;
                if (!(e->item->flags & UNINTERESTING)) {
                        unsigned char sha1[20];
                        char *ref;
                        if (dwim_ref(e->name, strlen(e->name), sha1, &ref) != 1)
                                continue;
                        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);
                }
        }

        /* 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] = NULL;
        in = -1;
        out = bundle_fd;
        pid = fork_with_pipe(argv_pack, &in, &out);
        if (pid < 0)
                return error("Could not spawn pack-objects");
        close(1);
        dup2(in, 1);
        close(in);
        prepare_revision_walk(&revs);
        mark_edges_uninteresting(revs.commits, &revs, show_edge);
        traverse_commit_list(&revs, show_commit, show_object);
        close(1);
        while (waitpid(pid, &status, 0) < 0)
                if (errno != EINTR)
                        return -1;
        if (!WIFEXITED(status) || WEXITSTATUS(status))
                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", "--stdin", NULL};
        int pid, status, dev_null;

        if (verify_bundle(header))
                return -1;
        dev_null = open("/dev/null", O_WRONLY);
        pid = fork_with_pipe(argv_index_pack, &bundle_fd, &dev_null);
        if (pid < 0)
                return error("Could not spawn index-pack");
        while (waitpid(pid, &status, 0) < 0)
                if (errno != EINTR)
                        return error("index-pack died");
        if (!WIFEXITED(status) || WEXITSTATUS(status))
                return error("index-pack exited with status %d",
                                WEXITSTATUS(status));
        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)))
                return 1;

        if (!strcmp(cmd, "verify")) {
                close(bundle_fd);
                if (verify_bundle(&header))
                        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);
}