#include <stdlib.h>
#include <stdio.h>
#include <err.h>
#include <string.h>
#include "input.h"

#define INPUT "input/02.txt"

enum direction { forward, up, down };

struct submarine_move {
	enum direction dir;
	int length;
};

void parse_move(char* string, struct submarine_move* move) {
	if(*string == 'f')
		move->dir = forward;
	else if(*string == 'u')
		move->dir = up;
	else if(*string == 'd')
		move->dir = down;
	else
		err(1, "direction inconnue %c", *string);

	size_t stringLength = strlen(string);
	char digit = string[stringLength - 2];
	if(digit < '0' || digit > '9')
		err(1, "longueur inconnue %c", digit);
	move->length = digit - '0';
}

int main() {
	// lecture du fichier d'entree
	FILE* file=fopen(INPUT,"r");
	if(file == NULL)
		err(1, "Le fichier %s n'existe pas\n", INPUT);
	
	size_t lineCount = count_lines(file);
	char** input = malloc(lineCount * sizeof(char*));
	read_lines_as_string(file, input, lineCount);
	// fermeture du fichier
	fclose(file);

	// l'algo
	struct submarine_move currentMove;
	long forwardDst = 0;
	long downDst = 0;
	long aim = 0;
	for(size_t i = 0; i < lineCount; i++) {
		parse_move(input[i], &currentMove);
		switch(currentMove.dir) {
			case forward:
				forwardDst += currentMove.length;
				downDst += currentMove.length * aim;
				continue;
			case up:
				aim -= currentMove.length;
				continue;
			case down:
				aim += currentMove.length;
				continue;
		}
	}
	printf("%ld\n", forwardDst * downDst);

	free_strings(input, lineCount);
	return 0;
}