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

const char *tree_type = "tree";

static int read_one_entry(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage)
{
        int len;
        unsigned int size;
        struct cache_entry *ce;

        if (S_ISDIR(mode))
                return READ_TREE_RECURSIVE;

        len = strlen(pathname);
        size = cache_entry_size(baselen + len);
        ce = xcalloc(1, size);

        ce->ce_mode = create_ce_mode(mode);
        ce->ce_flags = create_ce_flags(baselen + len, stage);
        memcpy(ce->name, base, baselen);
        memcpy(ce->name + baselen, pathname, len+1);
        hashcpy(ce->sha1, sha1);
        return add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
}

static int match_tree_entry(const char *base, int baselen, const char *path, unsigned int mode, const char **paths)
{
        const char *match;
        int pathlen;

        if (!paths)
                return 1;
        pathlen = strlen(path);
        while ((match = *paths++) != NULL) {
                int matchlen = strlen(match);

                if (baselen >= matchlen) {
                        /* If it doesn't match, move along... */
                        if (strncmp(base, match, matchlen))
                                continue;
                        /* The base is a subdirectory of a path which was specified. */
                        return 1;
                }

                /* Does the base match? */
                if (strncmp(base, match, baselen))
                        continue;

                match += baselen;
                matchlen -= baselen;

                if (pathlen > matchlen)
                        continue;

                if (matchlen > pathlen) {
                        if (match[pathlen] != '/')
                                continue;
                        if (!S_ISDIR(mode))
                                continue;
                }

                if (strncmp(path, match, pathlen))
                        continue;

                return 1;
        }
        return 0;
}

int read_tree_recursive(struct tree *tree,
                        const char *base, int baselen,
                        int stage, const char **match,
                        read_tree_fn_t fn)
{
        struct tree_desc desc;
        struct name_entry entry;

        if (parse_tree(tree))
                return -1;

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

        while (tree_entry(&desc, &entry)) {
                if (!match_tree_entry(base, baselen, entry.path, entry.mode, match))
                        continue;

                switch (fn(entry.sha1, base, baselen, entry.path, entry.mode, stage)) {
                case 0:
                        continue;
                case READ_TREE_RECURSIVE:
                        break;;
                default:
                        return -1;
                }
                if (S_ISDIR(entry.mode)) {
                        int retval;
                        char *newbase;
                        unsigned int pathlen = tree_entry_len(entry.path, entry.sha1);

                        newbase = xmalloc(baselen + 1 + pathlen);
                        memcpy(newbase, base, baselen);
                        memcpy(newbase + baselen, entry.path, pathlen);
                        newbase[baselen + pathlen] = '/';
                        retval = read_tree_recursive(lookup_tree(entry.sha1),
                                                     newbase,
                                                     baselen + pathlen + 1,
                                                     stage, match, fn);
                        free(newbase);
                        if (retval)
                                return -1;
                        continue;
                }
        }
        return 0;
}

int read_tree(struct tree *tree, int stage, const char **match)
{
        return read_tree_recursive(tree, "", 0, stage, match, read_one_entry);
}

struct tree *lookup_tree(const unsigned char *sha1)
{
        struct object *obj = lookup_object(sha1);
        if (!obj)
                return create_object(sha1, OBJ_TREE, alloc_tree_node());
        if (!obj->type)
                obj->type = OBJ_TREE;
        if (obj->type != OBJ_TREE) {
                error("Object %s is a %s, not a tree",
                      sha1_to_hex(sha1), typename(obj->type));
                return NULL;
        }
        return (struct tree *) obj;
}

/*
 * NOTE! Tree refs to external git repositories
 * (ie gitlinks) do not count as real references.
 *
 * You don't have to have those repositories
 * available at all, much less have the objects
 * accessible from the current repository.
 */
static void track_tree_refs(struct tree *item)
{
        int n_refs = 0, i;
        struct object_refs *refs;
        struct tree_desc desc;
        struct name_entry entry;

        /* Count how many entries there are.. */
        init_tree_desc(&desc, item->buffer, item->size);
        while (tree_entry(&desc, &entry)) {
                if (S_ISGITLINK(entry.mode))
                        continue;
                n_refs++;
        }

        /* Allocate object refs and walk it again.. */
        i = 0;
        refs = alloc_object_refs(n_refs);
        init_tree_desc(&desc, item->buffer, item->size);
        while (tree_entry(&desc, &entry)) {
                struct object *obj;

                if (S_ISGITLINK(entry.mode))
                        continue;
                if (S_ISDIR(entry.mode))
                        obj = &lookup_tree(entry.sha1)->object;
                else
                        obj = &lookup_blob(entry.sha1)->object;
                refs->ref[i++] = obj;
        }
        set_object_refs(&item->object, refs);
}

int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)
{
        if (item->object.parsed)
                return 0;
        item->object.parsed = 1;
        item->buffer = buffer;
        item->size = size;

        if (track_object_refs)
                track_tree_refs(item);
        return 0;
}

int parse_tree(struct tree *item)
{
         enum object_type type;
         void *buffer;
         unsigned long size;

        if (item->object.parsed)
                return 0;
        buffer = read_sha1_file(item->object.sha1, &type, &size);
        if (!buffer)
                return error("Could not read %s",
                             sha1_to_hex(item->object.sha1));
        if (type != OBJ_TREE) {
                free(buffer);
                return error("Object %s not a tree",
                             sha1_to_hex(item->object.sha1));
        }
        return parse_tree_buffer(item, buffer, size);
}

struct tree *parse_tree_indirect(const unsigned char *sha1)
{
        struct object *obj = parse_object(sha1);
        do {
                if (!obj)
                        return NULL;
                if (obj->type == OBJ_TREE)
                        return (struct tree *) obj;
                else if (obj->type == OBJ_COMMIT)
                        obj = &(((struct commit *) obj)->tree->object);
                else if (obj->type == OBJ_TAG)
                        obj = ((struct tag *) obj)->tagged;
                else
                        return NULL;
                if (!obj->parsed)
                        parse_object(obj->sha1);
        } while (1);
}