/*
 * Code is heavily inspired from pg-currency
 *
 * -- ms
 */

#include "language.h"
#include "language_forward.h"
#include "language_reverse.h"

#include "access/hash.h"
#include "funcapi.h"
#include "libpq/pqformat.h"

PG_MODULE_MAGIC;

PG_FUNCTION_INFO_V1(language_in);
PG_FUNCTION_INFO_V1(language_out);
PG_FUNCTION_INFO_V1(language_recv);
PG_FUNCTION_INFO_V1(language_send);
PG_FUNCTION_INFO_V1(supported_languages);

Datum language_in(PG_FUNCTION_ARGS)
{
    char *str = PG_GETARG_CSTRING(0);

    if (strlen(str) != 2)
        elog(ERROR, "invalid language input string %s", str);

    PG_RETURN_LANGUAGE(lang_from_str(str));
}

Datum language_out(PG_FUNCTION_ARGS)
{
    const language_code curr = PG_GETARG_CHAR(0);

    PG_RETURN_CSTRING(language_to_str(curr));
}

Datum language_recv(PG_FUNCTION_ARGS)
{
    StringInfo    buf    = (StringInfo) PG_GETARG_POINTER(0);
    language_code result = pq_getmsgbyte(buf);
    PG_RETURN_LANGUAGE(result);
}

Datum language_send(PG_FUNCTION_ARGS)
{
    const language_code a = PG_GETARG_LANGUAGE(0);
    StringInfoData      buf;

    pq_begintypsend(&buf);
    pq_sendbyte(&buf, a);
    PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}

Datum supported_languages(PG_FUNCTION_ARGS)
{
    FuncCallContext *funcctx;

    /* stuff done only on the first call of the function */
    if (SRF_IS_FIRSTCALL())
    {
        /* create a function context for cross-call persistence */
        funcctx = SRF_FIRSTCALL_INIT();
    }

    /* stuff done on every call of the function */
    funcctx = SRF_PERCALL_SETUP();

    if (funcctx->call_cntr + 1 < LANG_MAX)
    {
        Datum lang = LanguageGetDatum(funcctx->call_cntr + 1);

        /* do when there is more left to send */
        SRF_RETURN_NEXT(funcctx, lang);
    }
    else
    {
        /* do when there is no more left */
        SRF_RETURN_DONE(funcctx);
    }
}