//
// Created by villuton on 20.03.25.
//
#include <stdbool.h>
#include <string.h>
#include "Nmea0183Parser_General.h"
#include "Nmea0183Parser_Private.h"
#define Nmea0183ParserEndDataPos(STR,LEN) strnstr((char *) STR, "*", LEN)

/**
 * Calculates the checksum of an NMEA 0183 XOR string of all bytes in the string
 * @param str
 * @param len
 * @return XOR checksum
 */
uint8_t uNmea0183CheckSum(const char *str, size_t len) {
    char *end = (char *) (str + len);

    unsigned char result;
    result = 0;

    while (str != end)
        result ^= *str++;
    return result;
}

/**
 * Checking string validity NMEA 0183
 * @param str
 * @param len
 * @return Checksum comparison result
 */
bool bNmea0183IsValidString(char *str, size_t len) {
    char *end = str + len;
    char *front = str;
    char *nextDivider = front - 1;

    char *dataStartPos = Nmea0183SkipToStartDelimiter(front,end);
    char *dataEndPos = Nmea0183SkipToStartCheckSumDelimiter(front,end);
    uint8_t checksumCalculated = uNmea0183CheckSum(dataStartPos, dataEndPos - dataStartPos);
    if(Nmea0183ParseCheckSumPosition(&front,&nextDivider,end) > 0){
        uint8_t checksumInString = Nmea0183ParseHexByte(nextDivider);
        return checksumCalculated == checksumInString;
    }
    return false;
}

#define NMEA_HourStrLen 2
#define NMEA_MinuteStrLen 2
#define NMEA_SecondStrLen 2

#define NMEA_HourStrOffset 0
#define NMEA_MinuteStrOffset (NMEA_HourStrOffset + NMEA_HourStrLen)
#define NMEA_SecondStrOffset (NMEA_MinuteStrOffset + NMEA_MinuteStrLen)
#define NMEA_UTC_PointStrOffset 1
#define NMEA_DecimalSecondStrOffset (NMEA_SecondStrOffset + NMEA_SecondStrLen + NMEA_UTC_PointStrOffset)

bool Nmea0183ParseTime(char *utcString, char const *utcStringEnd, tNmeaTime *time) {

    uint32_t len = utcStringEnd - utcString;
    uint8_t decimalPortion = len - NMEA_HourStrLen+NMEA_MinuteStrLen+NMEA_SecondStrLen+NMEA_UTC_PointStrOffset;

    if (len > 10 || len < 9) {
        return false;
    }

    if (utcString[6] != '.') {
        return false;
    }

    time->hour = Nmea0183ParseShortCharsDecimalNumber(utcString + NMEA_HourStrOffset, NMEA_HourStrLen);
    time->minute = Nmea0183ParseShortCharsDecimalNumber(utcString + NMEA_MinuteStrOffset, NMEA_MinuteStrLen);
    time->second = Nmea0183ParseShortCharsDecimalNumber(utcString + NMEA_SecondStrOffset, NMEA_SecondStrLen);

    time->millisecond = Nmea0183ParseShortCharsDecimalNumber(utcString + NMEA_DecimalSecondStrOffset, decimalPortion);
    while (decimalPortion) {
        time->millisecond *= 10;
        --decimalPortion;
    }

    return true;
}

bool Nmea0183ParseDate(char *utcString, char const *utcStringEnd, tNmeaDate *date) {

    uint32_t len = utcStringEnd - utcString;

    if (len != 6) {
        return false;
    }

    date->day = Nmea0183ParseShortCharsDecimalNumber(utcString + 0, 2);
    date->month = Nmea0183ParseShortCharsDecimalNumber(utcString + 2, 2);
    date->year = Nmea0183ParseShortCharsDecimalNumber(utcString + 4, 2);

    return true;
}