/*
 * IGC parser
 * @brief parse IGC file, get all data points, compute average horizontal/vertical speed, print to STDOUT
 *
 * As per standard: https://xp-soaring.github.io/igc_file_format/igc_format_2008.html
 *                  https://xp-soaring.github.io/igc_file_format/igc_fr_specification_with_al8_2023-2-1_0.pdf
 *
 * @author xamidev <xamidev@riseup.net>
 * @license GNU GPL v3
 */

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include "igc.h"

struct IGC_DataPoint* parse_datapoint(char* line)
{
	// There probably exists a better and/or prettier way
	struct IGC_DataPoint* dp = (struct IGC_DataPoint*)malloc(sizeof(struct IGC_DataPoint));	
	char hour[3], min[3], sec[3] = {0};
	char lat_d[3], lat_m[3], lat_s[4] = {0};
	char lon_d[4], lon_m[3], lon_s[4] = {0};
	char baro_alt[6], gps_alt[6] = {0};

	memcpy(hour, line+1, 2);
	memcpy(min, line+3, 2);
	memcpy(sec, line+5, 2);
	memcpy(lat_d, line+7, 2);
	memcpy(lat_m, line+9, 2);
	memcpy(lat_s, line+11, 3);
	memcpy(lon_d, line+15, 3);
	memcpy(lon_m, line+18, 2);	
	memcpy(lon_s, line+20, 3);
	memcpy(baro_alt, line+25, 5);
	memcpy(gps_alt, line+30, 5);

	dp->hour = atoi(hour);
	dp->minute = atoi(min);
	dp->second = atoi(sec);
	dp->lat.deg = atoi(lat_d);
	dp->lat.min = atoi(lat_m);
	dp->lat.sec = atoi(lat_s);
	dp->lat.cardinal = line[14] == NORTH ? NORTH : SOUTH;
	dp->lon.deg = atoi(lon_d);
	dp->lon.min = atoi(lon_m);
	dp->lon.sec = atoi(lon_s);
	dp->lon.cardinal = line[23] == EAST ? EAST : WEST;
	dp->baro_alt = atoi(baro_alt);
	dp->gps_alt = atoi(gps_alt);

	printf("Data point: %d:%d:%d | %d°%d'%d\"%c %d°%d'%d\"%c | Baro: %dm GPS: %dm\n", dp->hour, dp->minute, dp->second, dp->lat.deg, dp->lat.min, dp->lat.sec, dp->lat.cardinal, dp->lon.deg, dp->lon.min, dp->lon.sec, dp->lon.cardinal, dp->baro_alt, dp->gps_alt);
	
	return dp;
}

void parse_header_record(char* line)
{
	if (strncmp(line, "HFDTEDATE", 9) == 0)
	{
			
	}
}

void parse_igc_file(FILE* fp)
{
	size_t len = 0;
	char* line = NULL;

	while (getline(&line, &len, fp)	!= -1)
	{
		switch(line[0])
		{
			case DATAPOINT:
				struct IGC_DataPoint* dp = parse_datapoint(line);
				// Doubly linked list of points (so theyre joined in chronological order; opens possibilities for analysis later)
				// append_datapoint(dp);
				break;
			case HEADER:
				parse_header_record(line);
				break;			
			default:
				printf("Unrecognized record type '%c'\n", line[0]);
				break;
		}
	}
}

int main(int argc, char* argv[])
{
	if (argc < 2)
	{
		printf("Usage: %s <file>\n", argv[0]);
		return -EINVAL;
	}

	char filename[NAME_MAX] = {0};
	strncpy(filename, argv[1], NAME_MAX-1);

	FILE* fp = fopen(filename, "r");

	if (!fp)
	{
		printf("Couldn't open file %s\n", filename);
		return -EINVAL;
	}

	parse_igc_file(fp);

	return EXIT_SUCCESS;
}