#include "environment.h"


// RAMdisk path for MDB volatile store.
#define MDB_RAMDISK_PATH TMPDIR "/lsup_mem_graph"


/**
 * Static handles.
 */
#define DEFAULT_CTX_LABEL "urn:lsup:default"


/** @brief Environment "singleton".
 */
LSUP_Env *LSUP_default_env = NULL;


LSUP_Env *
LSUP_env_new (
        const char *default_ctx, const char *mdb_path,
        const char *mdb_ramdisk_path, const LSUP_NSMap *nsmap)
{
    LSUP_Env *env;
    MALLOC_GUARD (env, NULL);

    // Default store context.
    LSUP_Term *default_ctx_uri = LSUP_uri_new (default_ctx);
    env->default_ctx = LSUP_buffer_new_from_term (default_ctx_uri);
    LSUP_term_free (default_ctx_uri);
    log_info ("Setting up default context.");

    // Permanent store.
    if (LSUP_mdbstore_setup (mdb_path, false) != LSUP_OK) return NULL;
    env->mdbstore = LSUP_mdbstore_new (mdb_path, env->default_ctx);
    if (UNLIKELY (!env->mdbstore)) return NULL;
    log_info ("Initialized persistent back end at %s.", mdb_path);

    // RAM disk store.
    if (LSUP_mdbstore_setup (mdb_ramdisk_path, true) != LSUP_OK)
        return NULL;
    env->mdbstore_ramdisk = LSUP_mdbstore_new (
            mdb_ramdisk_path, env->default_ctx);
    if (UNLIKELY (!env->mdbstore_ramdisk)) return NULL;
    log_info ("Initialized RAM disk back end at %s.", mdb_ramdisk_path);

    return env;
}


LSUP_rc
LSUP_init (void)
{
    LSUP_rc rc = LSUP_NOACTION;

    if (LSUP_default_env == NULL) {
#ifdef DEBUG
        // In debug mode, always use max logging.
        int loglevel = LOG_TRACE;
#else
        char *_loglevel = getenv ("LSUP_LOGLEVEL");
        int loglevel = (_loglevel == NULL) ? LOG_WARN : atoi (_loglevel);
#endif
        log_set_level (loglevel);

        // Default permanent store path.
        char *mdb_path = getenv ("LSUP_MDB_STORE_PATH");
        if (!mdb_path) {
            mdb_path = DEFAULT_ENV_PATH;
            log_warn (
                "`LSUP_MDB_STORE_PATH' environment variable is not "
                "set. The default location %s will be used as the graph "
                "store.", mdb_path
            );
        }
        LSUP_default_env = LSUP_env_new (
                DEFAULT_CTX_LABEL, mdb_path, MDB_RAMDISK_PATH, NULL);

        if (!LSUP_default_env) rc = LSUP_DB_ERR;

        atexit (LSUP_done);

        rc = LSUP_OK;
    }

    return rc;
}


void
LSUP_env_free (LSUP_Env *env)
{
    LSUP_mdbstore_free (env->mdbstore);
    LSUP_mdbstore_free (env->mdbstore_ramdisk);
    LSUP_buffer_free (env->default_ctx);
    LSUP_nsmap_free (env->nsm);
    free (env);
}


void
LSUP_done (void)
{ LSUP_env_free (LSUP_default_env); }