#include "cache.h"
#include "object.h"
#include "blob.h"
#include "tree.h"
#include "tree-walk.h"
#include "commit.h"
#include "tag.h"
#include "fsck.h"

static int fsck_walk_tree(struct tree *tree, fsck_walk_func walk, void *data)
{
        struct tree_desc desc;
        struct name_entry entry;
        int res = 0;

        if (parse_tree(tree))
                return -1;

        init_tree_desc(&desc, tree->buffer, tree->size);
        while (tree_entry(&desc, &entry)) {
                int result;

                if (S_ISGITLINK(entry.mode))
                        continue;
                if (S_ISDIR(entry.mode))
                        result = walk(&lookup_tree(entry.sha1)->object, OBJ_TREE, data);
                else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode))
                        result = walk(&lookup_blob(entry.sha1)->object, OBJ_BLOB, data);
                else {
                        result = error("in tree %s: entry %s has bad mode %.6o\n",
                                        sha1_to_hex(tree->object.sha1), entry.path, entry.mode);
                }
                if (result < 0)
                        return result;
                if (!res)
                        res = result;
        }
        return res;
}

static int fsck_walk_commit(struct commit *commit, fsck_walk_func walk, void *data)
{
        struct commit_list *parents;
        int res;
        int result;

        if (parse_commit(commit))
                return -1;

        result = walk((struct object *)commit->tree, OBJ_TREE, data);
        if (result < 0)
                return result;
        res = result;

        parents = commit->parents;
        while (parents) {
                result = walk((struct object *)parents->item, OBJ_COMMIT, data);
                if (result < 0)
                        return result;
                if (!res)
                        res = result;
                parents = parents->next;
        }
        return res;
}

static int fsck_walk_tag(struct tag *tag, fsck_walk_func walk, void *data)
{
        if (parse_tag(tag))
                return -1;
        return walk(tag->tagged, OBJ_ANY, data);
}

int fsck_walk(struct object *obj, fsck_walk_func walk, void *data)
{
        if (!obj)
                return -1;
        switch (obj->type) {
        case OBJ_BLOB:
                return 0;
        case OBJ_TREE:
                return fsck_walk_tree((struct tree *)obj, walk, data);
        case OBJ_COMMIT:
                return fsck_walk_commit((struct commit *)obj, walk, data);
        case OBJ_TAG:
                return fsck_walk_tag((struct tag *)obj, walk, data);
        default:
                error("Unknown object type for %s", sha1_to_hex(obj->sha1));
                return -1;
        }
}

/*
 * The entries in a tree are ordered in the _path_ order,
 * which means that a directory entry is ordered by adding
 * a slash to the end of it.
 *
 * So a directory called "a" is ordered _after_ a file
 * called "a.c", because "a/" sorts after "a.c".
 */
#define TREE_UNORDERED (-1)
#define TREE_HAS_DUPS  (-2)

static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
{
        int len1 = strlen(name1);
        int len2 = strlen(name2);
        int len = len1 < len2 ? len1 : len2;
        unsigned char c1, c2;
        int cmp;

        cmp = memcmp(name1, name2, len);
        if (cmp < 0)
                return 0;
        if (cmp > 0)
                return TREE_UNORDERED;

        /*
         * Ok, the first <len> characters are the same.
         * Now we need to order the next one, but turn
         * a '\0' into a '/' for a directory entry.
         */
        c1 = name1[len];
        c2 = name2[len];
        if (!c1 && !c2)
                /*
                 * git-write-tree used to write out a nonsense tree that has
                 * entries with the same name, one blob and one tree.  Make
                 * sure we do not have duplicate entries.
                 */
                return TREE_HAS_DUPS;
        if (!c1 && S_ISDIR(mode1))
                c1 = '/';
        if (!c2 && S_ISDIR(mode2))
                c2 = '/';
        return c1 < c2 ? 0 : TREE_UNORDERED;
}

static int fsck_tree(struct tree *item, int strict, fsck_error error_func)
{
        int retval;
        int has_full_path = 0;
        int has_empty_name = 0;
        int has_zero_pad = 0;
        int has_bad_modes = 0;
        int has_dup_entries = 0;
        int not_properly_sorted = 0;
        struct tree_desc desc;
        unsigned o_mode;
        const char *o_name;
        const unsigned char *o_sha1;

        init_tree_desc(&desc, item->buffer, item->size);

        o_mode = 0;
        o_name = NULL;
        o_sha1 = NULL;
        if (!desc.size)
                return error_func(&item->object, FSCK_ERROR, "empty tree");

        while (desc.size) {
                unsigned mode;
                const char *name;
                const unsigned char *sha1;

                sha1 = tree_entry_extract(&desc, &name, &mode);

                if (strchr(name, '/'))
                        has_full_path = 1;
                if (!*name)
                        has_empty_name = 1;
                has_zero_pad |= *(char *)desc.buffer == '0';
                update_tree_entry(&desc);

                switch (mode) {
                /*
                 * Standard modes..
                 */
                case S_IFREG | 0755:
                case S_IFREG | 0644:
                case S_IFLNK:
                case S_IFDIR:
                case S_IFGITLINK:
                        break;
                /*
                 * This is nonstandard, but we had a few of these
                 * early on when we honored the full set of mode
                 * bits..
                 */
                case S_IFREG | 0664:
                        if (!strict)
                                break;
                default:
                        has_bad_modes = 1;
                }

                if (o_name) {
                        switch (verify_ordered(o_mode, o_name, mode, name)) {
                        case TREE_UNORDERED:
                                not_properly_sorted = 1;
                                break;
                        case TREE_HAS_DUPS:
                                has_dup_entries = 1;
                                break;
                        default:
                                break;
                        }
                }

                o_mode = mode;
                o_name = name;
                o_sha1 = sha1;
        }

        retval = 0;
        if (has_full_path)
                retval += error_func(&item->object, FSCK_WARN, "contains full pathnames");
        if (has_empty_name)
                retval += error_func(&item->object, FSCK_WARN, "contains empty pathname");
        if (has_zero_pad)
                retval += error_func(&item->object, FSCK_WARN, "contains zero-padded file modes");
        if (has_bad_modes)
                retval += error_func(&item->object, FSCK_WARN, "contains bad file modes");
        if (has_dup_entries)
                retval += error_func(&item->object, FSCK_ERROR, "contains duplicate file entries");
        if (not_properly_sorted)
                retval += error_func(&item->object, FSCK_ERROR, "not properly sorted");
        return retval;
}

static int fsck_commit(struct commit *commit, fsck_error error_func)
{
        char *buffer = commit->buffer;
        unsigned char tree_sha1[20], sha1[20];
        struct commit_graft *graft;
        int parents = 0;

        if (!commit->date)
                return error_func(&commit->object, FSCK_ERROR, "invalid author/committer line");

        if (memcmp(buffer, "tree ", 5))
                return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'tree' line");
        if (get_sha1_hex(buffer+5, tree_sha1) || buffer[45] != '\n')
                return error_func(&commit->object, FSCK_ERROR, "invalid 'tree' line format - bad sha1");
        buffer += 46;
        while (!memcmp(buffer, "parent ", 7)) {
                if (get_sha1_hex(buffer+7, sha1) || buffer[47] != '\n')
                        return error_func(&commit->object, FSCK_ERROR, "invalid 'parent' line format - bad sha1");
                buffer += 48;
                parents++;
        }
        graft = lookup_commit_graft(commit->object.sha1);
        if (graft) {
                struct commit_list *p = commit->parents;
                parents = 0;
                while (p) {
                        p = p->next;
                        parents++;
                }
                if (graft->nr_parent == -1 && !parents)
                        ; /* shallow commit */
                else if (graft->nr_parent != parents)
                        return error_func(&commit->object, FSCK_ERROR, "graft objects missing");
        } else {
                struct commit_list *p = commit->parents;
                while (p && parents) {
                        p = p->next;
                        parents--;
                }
                if (p || parents)
                        return error_func(&commit->object, FSCK_ERROR, "parent objects missing");
        }
        if (memcmp(buffer, "author ", 7))
                return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'author' line");
        if (!commit->tree)
                return error_func(&commit->object, FSCK_ERROR, "could not load commit's tree %s", sha1_to_hex(tree_sha1));

        return 0;
}

static int fsck_tag(struct tag *tag, fsck_error error_func)
{
        struct object *tagged = tag->tagged;

        if (!tagged)
                return error_func(&tag->object, FSCK_ERROR, "could not load tagged object");
        return 0;
}

int fsck_object(struct object *obj, int strict, fsck_error error_func)
{
        if (!obj)
                return error_func(obj, FSCK_ERROR, "no valid object to fsck");

        if (obj->type == OBJ_BLOB)
                return 0;
        if (obj->type == OBJ_TREE)
                return fsck_tree((struct tree *) obj, strict, error_func);
        if (obj->type == OBJ_COMMIT)
                return fsck_commit((struct commit *) obj, error_func);
        if (obj->type == OBJ_TAG)
                return fsck_tag((struct tag *) obj, error_func);

        return error_func(obj, FSCK_ERROR, "unknown type '%d' (internal fsck error)",
                          obj->type);
}

int fsck_error_function(struct object *obj, int type, const char *fmt, ...)
{
        va_list ap;
        int len;
        struct strbuf sb;

        strbuf_init(&sb, 0);
        strbuf_addf(&sb, "object %s:", obj->sha1?sha1_to_hex(obj->sha1):"(null)");

        va_start(ap, fmt);
        len = vsnprintf(sb.buf + sb.len, strbuf_avail(&sb), fmt, ap);
        va_end(ap);

        if (len < 0)
                len = 0;
        if (len >= strbuf_avail(&sb)) {
                strbuf_grow(&sb, len + 2);
                va_start(ap, fmt);
                len = vsnprintf(sb.buf + sb.len, strbuf_avail(&sb), fmt, ap);
                va_end(ap);
                if (len >= strbuf_avail(&sb))
                        die("this should not happen, your snprintf is broken");
        }

        error(sb.buf);
        strbuf_release(&sb);
        return 1;
}