#include <stdlib.h>
#include <string.h>

#include "common.h"
#include "env.h"

#include "hashtable.h"
#include "value.h"

struct env {
    hashtable_t table;

    struct env *parent;
    size_t refs;

    env_destroy_func destroy_func;
};

#include "mempool.h"
MEMPOOL_GENERATE(env, struct env, 64)

#define ENV_TABLE_CAP (1 << 3)

static unsigned long str_hash(char *str)
{
    unsigned long hash = 5381;
    int c;

    while ((c = *str++))
        hash = ((hash << 5) + hash) + c; /* hash * 33 + c */

    return hash;
}

static size_t hash(void *key)
{
    return str_hash((char*)key);
}

static bool equal(void *key1, void *key2)
{
    if(strcmp((char *)key1, (char*)key2) == 0) {
        return true;
    }

    return false;
}

env_t env_create(env_t parent, env_destroy_func destroy_func)
{
    // env_t env = malloc(sizeof(*env));
    env_t env = env_mempool_allocate();
    env->destroy_func = destroy_func;
    env->parent = parent;
    env->refs = 1;

    ERR_Z(env->table = hashtable_create(ENV_TABLE_CAP, hash, equal),
          env_destroy(env));

    return env;
}

void env_destroy(env_t env)
{
    if(!env) return;

    env->refs--;
    env_destroy(env->parent);

    if(env->refs > 0) return;

    hashtable_for_each_item(env->table, item, i) {
        env->destroy_func((char *)item->key, (value_t)item->data);
    }

    hashtable_destroy(env->table);
    // free(env);
    env_mempool_free(env);
}

int env_insert(env_t env, char *key, value_t data,
                     char **prevkey, value_t *prevdata)
{
    return hashtable_insert(env->table, (void *)key, (void *)data, (void **)prevkey, (void **)prevdata);
}

int env_query(env_t env, char *key, value_t *data)
{
    return hashtable_query(env->table, (void *)key, (void **)data);
}

env_t env_copy(env_t env)
{
    if(env == ENV_EMPTY) return ENV_EMPTY;

    env->refs++;
    env_copy(env->parent);

    return env;
}

env_t env_parent(env_t env)
{
    return env->parent;
}