#include "cache.h"
#include "tree.h"
#include "blob.h"
#include "commit.h"
#include "tag.h"
#include "tree-walk.h"
#include <stdlib.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);
        memcpy(ce->sha1, sha1, 20);
        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;

        if (parse_tree(tree))
                return -1;

        desc.buf = tree->buffer;
        desc.size = tree->size;

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

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

                if (!match_tree_entry(base, baselen, name, mode, match))
                        continue;

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

                        newbase = xmalloc(baselen + 1 + pathlen);
                        memcpy(newbase, base, baselen);
                        memcpy(newbase + baselen, name, pathlen);
                        newbase[baselen + pathlen] = '/';
                        retval = read_tree_recursive(lookup_tree(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) {
                struct tree *ret = xcalloc(1, sizeof(struct tree));
                created_object(sha1, &ret->object);
                ret->object.type = tree_type;
                return ret;
        }
        if (!obj->type)
                obj->type = tree_type;
        if (obj->type != tree_type) {
                error("Object %s is a %s, not a tree", 
                      sha1_to_hex(sha1), obj->type);
                return NULL;
        }
        return (struct tree *) obj;
}

int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)
{
        struct tree_desc desc;
        struct tree_entry_list **list_p;
        int n_refs = 0;

        if (item->object.parsed)
                return 0;
        item->object.parsed = 1;
        item->buffer = buffer;
        item->size = size;

        desc.buf = buffer;
        desc.size = size;

        list_p = &item->entries;
        while (desc.size) {
                unsigned mode;
                const char *path;
                const unsigned char *sha1;
                struct tree_entry_list *entry;

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

                entry = xmalloc(sizeof(struct tree_entry_list));
                entry->name = path;
                entry->sha1 = sha1;
                entry->mode = mode;
                entry->directory = S_ISDIR(mode) != 0;
                entry->executable = (mode & S_IXUSR) != 0;
                entry->symlink = S_ISLNK(mode) != 0;
                entry->zeropad = *(const char *)(desc.buf) == '0';
                entry->next = NULL;

                update_tree_entry(&desc);
                n_refs++;
                *list_p = entry;
                list_p = &entry->next;
        }

        if (track_object_refs) {
                struct tree_entry_list *entry;
                unsigned i = 0;
                struct object_refs *refs = alloc_object_refs(n_refs);
                for (entry = item->entries; entry; entry = entry->next) {
                        struct object *obj;

                        if (entry->directory)
                                obj = &lookup_tree(entry->sha1)->object;
                        else
                                obj = &lookup_blob(entry->sha1)->object;
                        refs->ref[i++] = obj;
                }

                set_object_refs(&item->object, refs);
        }

        return 0;
}

int parse_tree(struct tree *item)
{
         char type[20];
         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 (strcmp(type, tree_type)) {
                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 == tree_type)
                        return (struct tree *) obj;
                else if (obj->type == commit_type)
                        obj = &(((struct commit *) obj)->tree->object);
                else if (obj->type == tag_type)
                        obj = ((struct tag *) obj)->tagged;
                else
                        return NULL;
                if (!obj->parsed)
                        parse_object(obj->sha1);
        } while (1);
}