#include "cache.h"
#include "cache-tree.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_opt(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage, int opt)
{
        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(stage);
        ce->ce_namelen = baselen + len;
        memcpy(ce->name, base, baselen);
        memcpy(ce->name + baselen, pathname, len+1);
        hashcpy(ce->sha1, sha1);
        return add_cache_entry(ce, opt);
}

static int read_one_entry(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage, void *context)
{
        return read_one_entry_opt(sha1, base, baselen, pathname, mode, stage,
                                  ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
}

/*
 * This is used when the caller knows there is no existing entries at
 * the stage that will conflict with the entry being added.
 */
static int read_one_entry_quick(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage, void *context)
{
        return read_one_entry_opt(sha1, base, baselen, pathname, mode, stage,
                                  ADD_CACHE_JUST_APPEND);
}

static int read_tree_1(struct tree *tree, struct strbuf *base,
                       int stage, const struct pathspec *pathspec,
                       read_tree_fn_t fn, void *context)
{
        struct tree_desc desc;
        struct name_entry entry;
        unsigned char sha1[20];
        int len, oldlen = base->len;
        enum interesting retval = entry_not_interesting;

        if (parse_tree(tree))
                return -1;

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

        while (tree_entry(&desc, &entry)) {
                if (retval != all_entries_interesting) {
                        retval = tree_entry_interesting(&entry, base, 0, pathspec);
                        if (retval == all_entries_not_interesting)
                                break;
                        if (retval == entry_not_interesting)
                                continue;
                }

                switch (fn(entry.sha1, base->buf, base->len,
                           entry.path, entry.mode, stage, context)) {
                case 0:
                        continue;
                case READ_TREE_RECURSIVE:
                        break;
                default:
                        return -1;
                }

                if (S_ISDIR(entry.mode))
                        hashcpy(sha1, entry.sha1);
                else if (S_ISGITLINK(entry.mode)) {
                        struct commit *commit;

                        commit = lookup_commit(entry.sha1);
                        if (!commit)
                                die("Commit %s in submodule path %s%s not found",
                                    sha1_to_hex(entry.sha1),
                                    base->buf, entry.path);

                        if (parse_commit(commit))
                                die("Invalid commit %s in submodule path %s%s",
                                    sha1_to_hex(entry.sha1),
                                    base->buf, entry.path);

                        hashcpy(sha1, commit->tree->object.sha1);
                }
                else
                        continue;

                len = tree_entry_len(&entry);
                strbuf_add(base, entry.path, len);
                strbuf_addch(base, '/');
                retval = read_tree_1(lookup_tree(sha1),
                                     base, stage, pathspec,
                                     fn, context);
                strbuf_setlen(base, oldlen);
                if (retval)
                        return -1;
        }
        return 0;
}

int read_tree_recursive(struct tree *tree,
                        const char *base, int baselen,
                        int stage, const struct pathspec *pathspec,
                        read_tree_fn_t fn, void *context)
{
        struct strbuf sb = STRBUF_INIT;
        int ret;

        strbuf_add(&sb, base, baselen);
        ret = read_tree_1(tree, &sb, stage, pathspec, fn, context);
        strbuf_release(&sb);
        return ret;
}

static int cmp_cache_name_compare(const void *a_, const void *b_)
{
        const struct cache_entry *ce1, *ce2;

        ce1 = *((const struct cache_entry **)a_);
        ce2 = *((const struct cache_entry **)b_);
        return cache_name_stage_compare(ce1->name, ce1->ce_namelen, ce_stage(ce1),
                                  ce2->name, ce2->ce_namelen, ce_stage(ce2));
}

int read_tree(struct tree *tree, int stage, struct pathspec *match)
{
        read_tree_fn_t fn = NULL;
        int i, err;

        /*
         * Currently the only existing callers of this function all
         * call it with stage=1 and after making sure there is nothing
         * at that stage; we could always use read_one_entry_quick().
         *
         * But when we decide to straighten out git-read-tree not to
         * use unpack_trees() in some cases, this will probably start
         * to matter.
         */

        /*
         * See if we have cache entry at the stage.  If so,
         * do it the original slow way, otherwise, append and then
         * sort at the end.
         */
        for (i = 0; !fn && i < active_nr; i++) {
                const struct cache_entry *ce = active_cache[i];
                if (ce_stage(ce) == stage)
                        fn = read_one_entry;
        }

        if (!fn)
                fn = read_one_entry_quick;
        err = read_tree_recursive(tree, "", 0, stage, match, fn, NULL);
        if (fn == read_one_entry || err)
                return err;

        /*
         * Sort the cache entry -- we need to nuke the cache tree, though.
         */
        cache_tree_free(&active_cache_tree);
        qsort(active_cache, active_nr, sizeof(active_cache[0]),
              cmp_cache_name_compare);
        return 0;
}

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;
}

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;

        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);
}