#include <stdio.h>
#include <string.h>
#include <stdbool.h>

typedef struct {
  int number;
  int x;
  int y;
  int w;
  int h;
} Claim;

bool read_claim(FILE *input, Claim *claim) {
  return fscanf(input, "#%d @ %d,%d: %dx%d\n", &claim->number, &claim->x, &claim->y, &claim->w, &claim->h) > 0;
}

typedef int Fabric[1000][1000];
bool overlapped(Claim *claim, Fabric *fabric) {
  for(int x = claim->x; x < (claim->x + claim->w); x++) {
    for(int y = claim->y; y < (claim->y + claim->h); y++) {
      if ((*fabric)[x][y] > 1) return true;
    }
  }
  return false;
}

void apply_claim(const Claim *claim, Fabric *fabric) {
  for(int x = claim->x; x < (claim->x + claim->w); x++) {
    for(int y = claim->y; y < (claim->y + claim->h); y++) {
      int *col = (*fabric)[x];
      col[y]++;
    }
  }
}

int part_1(FILE *input) {
  rewind(input);
  Fabric fabric = {0};

  Claim claim = {0};
  while(read_claim(input, &claim)) apply_claim(&claim, &fabric);

  int double_claimed = 0;
  for(int x = 0; x < 1000; x++) {
    for(int y = 0; y < 1000; y++) {
      if (fabric[x][y] > 1) double_claimed++;
    }
  }
  
  return double_claimed;
}

int part_2(FILE *input) {
  rewind(input);
  Fabric fabric = {0};

  Claim claims[1401] = {0};
  Claim *claim = claims;
  while(read_claim(input, claim)) {
    apply_claim(claim, &fabric);
    claim++;
  }

  for(int i = 0; i < 1401; i++) {
    if(!overlapped(&(claims[i]), &fabric)) {
      return claims[i].number;
    }
  }
  return -1;
}

int main() {
  char *input_file_path = "../data/2018/3/input.txt";
  FILE *input = fopen(input_file_path, "r");
  if (input == NULL) {
    printf("Can't open file %s\n", input_file_path);
    return 1;
  }

  printf("Part 1: %d\n", part_1(input));
  printf("Part 2: %d\n", part_2(input));
  fclose(input);
}