#include <stdio.h>
#include <stdlib.h>

#include "aoc.h"

typedef struct {
	char you, opponent;
} Round;

typedef struct {
	Round *rounds;
	size_t count;
} day2_Data;

static void *day2_parse(char **lines, int line_count) {
	day2_Data *data = calloc(1, sizeof(day2_Data));
	data->count = line_count;
	data->rounds = calloc(line_count, sizeof(Round));

	for (int i = 0; i < line_count; i++) {
		data->rounds[i].opponent = lines[i][0];
		data->rounds[i].you = lines[i][2];
	}

	return data;
}

static int day2_part1(void *p) {
	day2_Data *data = (day2_Data*)p;
	int result = 0;
	for (int i = 0; i < data->count; i++) {
		Round *round = &data->rounds[i];
		char you = round->you;
		char opponent = round->opponent;

		if (you == 'X') {
			result += 1;
		} else if (you == 'Y') {
			result += 2;
		} else if (you == 'Z') {
			result += 3;
		}

		if ((you == 'X' && opponent == 'A') ||
				(you == 'Y' && opponent == 'B') ||
				(you == 'Z' && opponent == 'C')) {
			result += 3;
		} else if ((you == 'X' && opponent == 'C') ||
								(you == 'Y' && opponent == 'A') ||
								(you == 'Z' && opponent == 'B')) {
			result += 6;
		}
	}
	return result;
}

static int day2_part2(void *p) {
	day2_Data *data = (day2_Data*)p;
	int result = 0;
	for (int i = 0; i < data->count; i++) {
		Round *round = &data->rounds[i];
		char you = round->you;
		char opponent = round->opponent;

		if (you == 'X') { // lose
			if (opponent == 'A') result += 3; // opponent = rock    , me = scissors
			if (opponent == 'B') result += 1; // opponent = paper   , me = rock
			if (opponent == 'C') result += 2; // opponent = scissors, me = paper
		} else if (you == 'Y') { // draw
			if (opponent == 'A') result += 1;
			if (opponent == 'B') result += 2;
			if (opponent == 'C') result += 3;
		} else if (you == 'Z') { // win
			if (opponent == 'A') result += 2; // opponent = rock    , me = paper
			if (opponent == 'B') result += 3; // opponent = paper   , me = scissors
			if (opponent == 'C') result += 1; // opponent = scissors, me = rock
		}

		if (you == 'Y') {
			result += 3;
		} else if (you == 'Z') {
			result += 6;
		}
	}
	return result;
}

ADD_SOLUTION(2, day2_parse, day2_part1, day2_part2);