#include "cache.h"

#include <sys/types.h>
#include <dirent.h>

#include "revision.h"

static int show_unreachable = 0;
static unsigned char head_sha1[20];

static void check_connectivity(void)
{
        int i;

        /* Look up all the requirements, warn about missing objects.. */
        for (i = 0; i < nr_revs; i++) {
                struct revision *rev = revs[i];

                if (show_unreachable && !(rev->flags & REACHABLE)) {
                        printf("unreachable %s %s\n", rev->tag, sha1_to_hex(rev->sha1));
                        continue;
                }

                switch (rev->flags & (SEEN | USED)) {
                case 0:
                        printf("bad %s %s\n", rev->tag, sha1_to_hex(rev->sha1));
                        break;
                case USED:
                        printf("missing %s, %s\n", rev->tag, sha1_to_hex(rev->sha1));
                        break;
                case SEEN:
                        printf("dangling %s %s\n", rev->tag, sha1_to_hex(rev->sha1));
                        break;
                }
        }
}

static void mark_needs_sha1(unsigned char *parent, const char *ptag, unsigned char *child, const char *ctag)
{
        struct revision * child_rev = add_relationship(lookup_rev(parent, ptag), child, ctag);
        child_rev->flags |= USED;
}

static int mark_sha1_seen(unsigned char *sha1, const char *tag)
{
        struct revision *rev = lookup_rev(sha1, tag);

        rev->flags |= SEEN;
        return 0;
}

static int fsck_tree(unsigned char *sha1, void *data, unsigned long size)
{
        int warn_old_tree = 1;

        while (size) {
                int len = 1+strlen(data);
                unsigned char *file_sha1 = data + len;
                char *path = strchr(data, ' ');
                unsigned int mode;
                if (size < len + 20 || !path || sscanf(data, "%o", &mode) != 1)
                        return -1;

                /* Warn about trees that don't do the recursive thing.. */
                if (warn_old_tree && strchr(path, '/')) {
                        fprintf(stderr, "warning: fsck-cache: tree %s has full pathnames in it\n", sha1_to_hex(sha1));
                        warn_old_tree = 0;
                }

                data += len + 20;
                size -= len + 20;
                mark_needs_sha1(sha1, "tree", file_sha1, S_ISDIR(mode) ? "tree" : "blob");
        }
        return 0;
}

static int fsck_commit(unsigned char *sha1, void *data, unsigned long size)
{
        int parents;
        unsigned char tree_sha1[20];
        unsigned char parent_sha1[20];

        if (memcmp(data, "tree ", 5))
                return -1;
        if (get_sha1_hex(data + 5, tree_sha1) < 0)
                return -1;
        mark_needs_sha1(sha1, "commit", tree_sha1, "tree");
        data += 5 + 40 + 1;     /* "tree " + <hex sha1> + '\n' */
        parents = 0;
        while (!memcmp(data, "parent ", 7)) {
                if (get_sha1_hex(data + 7, parent_sha1) < 0)
                        return -1;
                mark_needs_sha1(sha1, "commit", parent_sha1, "commit");
                data += 7 + 40 + 1;     /* "parent " + <hex sha1> + '\n' */
                parents++;
        }
        if (!parents)
                printf("root %s\n", sha1_to_hex(sha1));
        return 0;
}

static int fsck_entry(unsigned char *sha1, char *tag, void *data, unsigned long size)
{
        if (!strcmp(tag, "blob")) {
                /* Nothing to check */;
        } else if (!strcmp(tag, "tree")) {
                if (fsck_tree(sha1, data, size) < 0)
                        return -1;
        } else if (!strcmp(tag, "commit")) {
                if (fsck_commit(sha1, data, size) < 0)
                        return -1;
        } else
                return -1;
        return mark_sha1_seen(sha1, tag);
}

static int fsck_name(char *hex)
{
        unsigned char sha1[20];
        if (!get_sha1_hex(hex, sha1)) {
                unsigned long mapsize;
                void *map = map_sha1_file(sha1, &mapsize);
                if (map) {
                        char type[100];
                        unsigned long size;
                        void *buffer = NULL;
                        if (!check_sha1_signature(sha1, map, mapsize))
                                buffer = unpack_sha1_file(map, mapsize, type, &size);
                        munmap(map, mapsize);
                        if (buffer && !fsck_entry(sha1, type, buffer, size))
                                return 0;
                }
        }
        return -1;
}

static int fsck_dir(int i, char *path)
{
        DIR *dir = opendir(path);
        struct dirent *de;

        if (!dir) {
                return error("missing sha1 directory '%s'", path);
        }

        while ((de = readdir(dir)) != NULL) {
                char name[100];
                int len = strlen(de->d_name);

                switch (len) {
                case 2:
                        if (de->d_name[1] != '.')
                                break;
                case 1:
                        if (de->d_name[0] != '.')
                                break;
                        continue;
                case 38:
                        sprintf(name, "%02x", i);
                        memcpy(name+2, de->d_name, len+1);
                        if (!fsck_name(name))
                                continue;
                }
                fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
        }
        closedir(dir);
        return 0;
}

int main(int argc, char **argv)
{
        int i, heads;
        char *sha1_dir;

        sha1_dir = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
        for (i = 0; i < 256; i++) {
                static char dir[4096];
                sprintf(dir, "%s/%02x", sha1_dir, i);
                fsck_dir(i, dir);
        }

        heads = 0;
        for (i = 1; i < argc; i++) {
                if (!strcmp(argv[i], "--unreachable")) {
                        show_unreachable = 1;
                        continue;
                }
                if (!get_sha1_hex(argv[i], head_sha1)) {
                        mark_reachable(lookup_rev(head_sha1, "commit"), REACHABLE);
                        heads++;
                        continue;
                }
                error("fsck-cache [[--unreachable] <head-sha1>*]");
        }

        if (!heads) {
                if (show_unreachable) {
                        fprintf(stderr, "unable to do reachability without a head\n");
                        show_unreachable = 0; 
                }
                fprintf(stderr, "expect dangling commits - potential heads - due to lack of head information\n");
        }

        check_connectivity();
        return 0;
}