#include <errno.h>

#include "readstat.h"

#include "readstat_iconv.h"

#include "readstat_convert.h"

readstat_error_t readstat_convert(char *dst, size_t dst_len, const char *src, size_t src_len, iconv_t converter) {

    /* strip off spaces from the input because the programs use ASCII space

     * padding even with non-ASCII encoding. */

    while (src_len && (src[src_len-1] == ' ' || src[src_len-1] == '\0')) {

        src_len--;

    }

    if (dst_len == 0) {

        return READSTAT_ERROR_CONVERT_LONG_STRING;

    } else if (converter) {

        size_t dst_left = dst_len - 1;

        char *dst_end = dst;

        size_t status = iconv(converter, (readstat_iconv_inbuf_t)&src, &src_len, &dst_end, &dst_left);

        if (status == (size_t)-1) {

            if (errno == E2BIG) {

                return READSTAT_ERROR_CONVERT_LONG_STRING;

            } else if (errno == EILSEQ) {

                return READSTAT_ERROR_CONVERT_BAD_STRING;

            } else if (errno != EINVAL) { /* EINVAL indicates improper truncation; accept it */

                return READSTAT_ERROR_CONVERT;

            }

        }

        dst[dst_len - dst_left - 1] = '\0';

    } else if (src_len + 1 > dst_len) {

        return READSTAT_ERROR_CONVERT_LONG_STRING;

    } else {

        memcpy(dst, src, src_len);

        dst[src_len] = '\0';

    }

    return READSTAT_OK;

}