#include <stdlib.h>
#include "cache.h"
#include "commit.h"
#include "tag.h"
#include "refs.h"

static const char name_rev_usage[] =
        "git-name-rev [--tags] ( --all | --stdin | commitish [commitish...] )\n";

typedef struct rev_name {
        const char *tip_name;
        int merge_traversals;
        int generation;
} rev_name;

static long cutoff = LONG_MAX;

static void name_rev(struct commit *commit,
                const char *tip_name, int merge_traversals, int generation,
                int deref)
{
        struct rev_name *name = (struct rev_name *)commit->object.util;
        struct commit_list *parents;
        int parent_number = 1;

        if (!commit->object.parsed)
                parse_commit(commit);

        if (commit->date < cutoff)
                return;

        if (deref) {
                char *new_name = xmalloc(strlen(tip_name)+3);
                strcpy(new_name, tip_name);
                strcat(new_name, "^0");
                tip_name = new_name;

                if (generation)
                        die("generation: %d, but deref?", generation);
        }

        if (name == NULL) {
                name = xmalloc(sizeof(rev_name));
                commit->object.util = name;
                goto copy_data;
        } else if (name->merge_traversals > merge_traversals ||
                        (name->merge_traversals == merge_traversals &&
                         name->generation > generation)) {
copy_data:
                name->tip_name = tip_name;
                name->merge_traversals = merge_traversals;
                name->generation = generation;
        } else
                return;

        for (parents = commit->parents;
                        parents;
                        parents = parents->next, parent_number++) {
                if (parent_number > 1) {
                        char *new_name = xmalloc(strlen(tip_name)+8);

                        if (generation > 0)
                                sprintf(new_name, "%s~%d^%d", tip_name,
                                                generation, parent_number);
                        else
                                sprintf(new_name, "%s^%d", tip_name, parent_number);

                        name_rev(parents->item, new_name,
                                merge_traversals + 1 , 0, 0);
                } else {
                        name_rev(parents->item, tip_name, merge_traversals,
                                generation + 1, 0);
                }
        }
}

static int tags_only = 0;

static int name_ref(const char *path, const unsigned char *sha1)
{
        struct object *o = parse_object(sha1);
        int deref = 0;

        if (tags_only && strncmp(path, "refs/tags/", 10))
                return 0;

        while (o && o->type == tag_type) {
                struct tag *t = (struct tag *) o;
                if (!t->tagged)
                        break; /* broken repository */
                o = parse_object(t->tagged->sha1);
                deref = 1;
        }
        if (o && o->type == commit_type) {
                struct commit *commit = (struct commit *)o;

                if (!strncmp(path, "refs/heads/", 11))
                        path = path + 11;
                else if (!strncmp(path, "refs/", 5))
                        path = path + 5;

                name_rev(commit, strdup(path), 0, 0, deref);
        }
        return 0;
}

/* returns a static buffer */
static const char* get_rev_name(struct object *o)
{
        static char buffer[1024];
        struct rev_name *n = (struct rev_name *)o->util;
        if (!n)
                return "undefined";

        if (!n->generation)
                return n->tip_name;

        snprintf(buffer, sizeof(buffer), "%s~%d", n->tip_name, n->generation);

        return buffer;
}
        
int main(int argc, char **argv)
{
        struct object_list *revs = NULL;
        struct object_list **walker = &revs;
        int as_is = 0, all = 0, transform_stdin = 0;

        setup_git_directory();
        git_config(git_default_config);

        if (argc < 2)
                usage(name_rev_usage);

        for (--argc, ++argv; argc; --argc, ++argv) {
                unsigned char sha1[20];
                struct object *o;
                struct commit *commit;

                if (!as_is && (*argv)[0] == '-') {
                        if (!strcmp(*argv, "--")) {
                                as_is = 1;
                                continue;
                        } else if (!strcmp(*argv, "--tags")) {
                                tags_only = 1;
                                continue;
                        } else if (!strcmp(*argv, "--all")) {
                                if (argc > 1)
                                        die("Specify either a list, or --all, not both!");
                                all = 1;
                                cutoff = 0;
                                continue;
                        } else if (!strcmp(*argv, "--stdin")) {
                                if (argc > 1)
                                        die("Specify either a list, or --stdin, not both!");
                                transform_stdin = 1;
                                cutoff = 0;
                                continue;
                        }
                        usage(name_rev_usage);
                }

                if (get_sha1(*argv, sha1)) {
                        fprintf(stderr, "Could not get sha1 for %s. Skipping.\n",
                                        *argv);
                        continue;
                }

                o = deref_tag(parse_object(sha1), *argv, 0);
                if (!o || o->type != commit_type) {
                        fprintf(stderr, "Could not get commit for %s. Skipping.\n",
                                        *argv);
                        continue;
                }

                commit = (struct commit *)o;

                if (cutoff > commit->date)
                        cutoff = commit->date;

                object_list_append((struct object *)commit, walker);
                (*walker)->name = *argv;
                walker = &((*walker)->next);
        }

        for_each_ref(name_ref);

        if (transform_stdin) {
                char buffer[2048];
                char *p, *p_start;

                while (!feof(stdin)) {
                        int forty = 0;
                        p = fgets(buffer, sizeof(buffer), stdin);
                        if (!p)
                                break;

                        for (p_start = p; *p; p++) {
#define ishex(x) (isdigit((x)) || ((x) >= 'a' && (x) <= 'f'))
                                if (!ishex(*p))
                                        forty = 0;
                                else if (++forty == 40 &&
                                                !ishex(*(p+1))) {
                                        unsigned char sha1[40];
                                        const char *name = "undefined";
                                        char c = *(p+1);

                                        forty = 0;

                                        *(p+1) = 0;
                                        if (!get_sha1(p - 39, sha1)) {
                                                struct object *o =
                                                        lookup_object(sha1);
                                                if (o)
                                                        name = get_rev_name(o);
                                        }
                                        *(p+1) = c;

                                        if (!strcmp(name, "undefined"))
                                                continue;

                                        fwrite(p_start, p - p_start + 1, 1,
                                               stdout);
                                        printf(" (%s)", name);
                                        p_start = p + 1;
                                }
                        }

                        /* flush */
                        if (p_start != p)
                                fwrite(p_start, p - p_start, 1, stdout);
                }
        } else if (all) {
                int i;

                for (i = 0; i < obj_allocs; i++)
                        if (objs[i])
                                printf("%s %s\n", sha1_to_hex(objs[i]->sha1),
                                                get_rev_name(objs[i]));
        } else
                for ( ; revs; revs = revs->next)
                        printf("%s %s\n", revs->name, get_rev_name(revs->item));

        return 0;
}