#include "tree.h"
#include "blob.h"
#include "cache.h"
#include <stdlib.h>

const char *tree_type = "tree";

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

        memset(ce, 0, 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);
}

static int read_tree_recursive(void *buffer, unsigned long size,
                               const char *base, int baselen, int stage)
{
        while (size) {
                int len = strlen(buffer)+1;
                unsigned char *sha1 = buffer + len;
                char *path = strchr(buffer, ' ')+1;
                unsigned int mode;

                if (size < len + 20 || sscanf(buffer, "%o", &mode) != 1)
                        return -1;

                buffer = sha1 + 20;
                size -= len + 20;

                if (S_ISDIR(mode)) {
                        int retval;
                        int pathlen = strlen(path);
                        char *newbase;
                        void *eltbuf;
                        char elttype[20];
                        unsigned long eltsize;

                        eltbuf = read_sha1_file(sha1, elttype, &eltsize);
                        if (!eltbuf || strcmp(elttype, "tree")) {
                                if (eltbuf) free(eltbuf);
                                return -1;
                        }
                        newbase = xmalloc(baselen + 1 + pathlen);
                        memcpy(newbase, base, baselen);
                        memcpy(newbase + baselen, path, pathlen);
                        newbase[baselen + pathlen] = '/';
                        retval = read_tree_recursive(eltbuf, eltsize,
                                                     newbase,
                                                     baselen + pathlen + 1, stage);
                        free(eltbuf);
                        free(newbase);
                        if (retval)
                                return -1;
                        continue;
                }
                if (read_one_entry(sha1, base, baselen, path, mode, stage) < 0)
                        return -1;
        }
        return 0;
}

int read_tree(void *buffer, unsigned long size, int stage)
{
        return read_tree_recursive(buffer, size, "", 0, stage);
}

struct tree *lookup_tree(const unsigned char *sha1)
{
        struct object *obj = lookup_object(sha1);
        if (!obj) {
                struct tree *ret = xmalloc(sizeof(struct tree));
                memset(ret, 0, 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)
{
        void *bufptr = buffer;
        struct tree_entry_list **list_p;

        if (item->object.parsed)
                return 0;
        item->object.parsed = 1;
        list_p = &item->entries;
        while (size) {
                struct object *obj;
                struct tree_entry_list *entry;
                int len = 1+strlen(bufptr);
                unsigned char *file_sha1 = bufptr + len;
                char *path = strchr(bufptr, ' ');
                unsigned int mode;
                if (size < len + 20 || !path || 
                    sscanf(bufptr, "%o", &mode) != 1)
                        return -1;

                entry = xmalloc(sizeof(struct tree_entry_list));
                entry->name = strdup(path + 1);
                entry->directory = S_ISDIR(mode) != 0;
                entry->executable = (mode & S_IXUSR) != 0;
                entry->symlink = S_ISLNK(mode) != 0;
                entry->mode = mode;
                entry->next = NULL;

                bufptr += len + 20;
                size -= len + 20;

                if (entry->directory) {
                        entry->item.tree = lookup_tree(file_sha1);
                        obj = &entry->item.tree->object;
                } else {
                        entry->item.blob = lookup_blob(file_sha1);
                        obj = &entry->item.blob->object;
                }
                if (obj)
                        add_ref(&item->object, obj);
                entry->parent = NULL; /* needs to be filled by the user */
                *list_p = entry;
                list_p = &entry->next;
        }
        return 0;
}

int parse_tree(struct tree *item)
{
         char type[20];
         void *buffer;
         unsigned long size;
         int ret;

        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));
        }
        ret = parse_tree_buffer(item, buffer, size);
        free(buffer);
        return ret;
}