#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include "../lib/util.h"

#define PREAMBLE_LENGTH 25
#define MESSAGE_LENGTH 1000

bool has_valid_sum(unsigned long long message[MESSAGE_LENGTH], size_t index, unsigned long long number) {
  for (size_t x = index - PREAMBLE_LENGTH; x < index; x++) {
    for (size_t y = x + 1; y < index; y++) {
      if (message[x] + message[y] == number) {
	return true;
      }
    }
  }
  return false;
}
		   
int part_1() {
  char *data_buffer = load_input();
  unsigned long long message[MESSAGE_LENGTH] = {0};
  size_t index = 0;

  char *number_text = strtok(data_buffer, "\n");
  unsigned long long number;
  do {
    number = atoll(number_text);
    if (index >= PREAMBLE_LENGTH && !has_valid_sum(message, index, number)) {
      break;
    } else {
      message[index++] = number;
    }
  } while (number_text = strtok(NULL, "\n"));
  message[index] = number;

  free(data_buffer);
  return number;
}

int part_2() {
  char *data_buffer = load_input();
  unsigned long long message[MESSAGE_LENGTH] = {0};
  size_t index = 0;

  char *number_text = strtok(data_buffer, "\n");
  unsigned long long number;
  do {
    number = atoll(number_text);
    if (index >= PREAMBLE_LENGTH && !has_valid_sum(message, index, number)) {
      break;
    } else {
      message[index++] = number;
    }
  } while (number_text = strtok(NULL, "\n"));
  message[index] = number;

  unsigned long long sum;
  int highest, lowest;
  for (int x = 0; x < index - 1; x++) {
    sum = 0;
    highest = 0;
    lowest = number;
    bool just_right = false;

    for (int y = x; y < index - 1; y++) {
      if (message[y] > highest) highest = message[y];
      if (message[y] < lowest) lowest = message[y];
      sum += message[y];
      if (sum >= number) break;
    }
    if (sum == number) break;
  }
    
  free(data_buffer);
  return lowest + highest;
}

int main() {
  printf("Part 1: %d\n", part_1());
  printf("Part 2: %d\n", part_2());
}