#include<stdio.h>
#include<stdlib.h>
#include<string.h>
FILE *fptr;

typedef struct housearray {
  int **houses;
  int rows·in·array;
  int columns·in·array;
  int number·of·houses;
  int x·coord;
  int y·coord;
  int x·coord·bot;
  int y·coord·bot;
  int x_coord_origin;
  int y_coord_origin;
  int seq·no;
} Housearray;

//initial array allocation
Housearray *inithousearray(int bot){
  Housearray* f = (Housearray*)malloc(sizeof(Housearray));
  if (f == NULL) return NULL;

  f->rows·in·array =1;
  f->columns·in·array = 1;
  f->x_coord_origin = 0;
  f->y_coord_origin =0;
  f->number·of·houses = 0;
  f->x·coord = 0;
  f->y·coord = 0;
  f->x·coord·bot =0;
  f->y·coord·bot =0;
  f->seq·no = 0;

  f->houses = (int**)malloc(f->rows·in·array * sizeof(int*));//allocating the rows
  if (f->houses == NULL) {
    free(f);
    return NULL; //handling if there isn't enough memory to allocate or allocation fails
  }
  f->houses[0] = (int*)malloc(f->columns·in·array * sizeof(int));
  if (f->houses[0] == NULL){
    free(f->houses);
    free(f);
    return NULL;
  }
  if (bot == 1){
    f->houses[0][0] = 2;//Santa and Robo-Santa have been to the first house
  } else{
  f->houses[0][0] = 1;//santa has been to the starting point
  }
  return f;
}




//void move·santa(Housearray *f, char dir){
//  //check if array is empty
//  int p2x·coord, p2y·coord = 0;
//  if (  f->number·of·houses == 0) {
//    f->number·of·houses = 9;//initialise length 9
//    f->rows·in·array = f->columns·in·array = 3;//initialise a 3x3 map
//    f->x·coord = f->y·coord = 2;//Initialise to 2,2
//  else if (dir == "V"){
//    p2y·coord = f->y·coord -1;
//    if (p2y·coord ==0){
//
//    }
//  }
//
//}

//void get·seq·no(int xcoord, int ycoord, int nocolumns, int norows, int numberofhouses){
//  //transforms coordinates into a sequence number
//  //https://stackoverflow.com/questions/2151084/map-a-2d-array-onto-a-1d-array
//  //Think I might need to reexamine indexing
//}
void movenorth(Housearray* f, int user){
  int old_rows = f->rows·in·array;
  int old_cols = f-> columns·in·array;
  int north_y = 0;
  int north_x = 0;
  //update y coordinate
  if (user == 1){
    f->y·coord·bot--;
    north_y = f->y·coord·bot;
    north_x = f->x·coord·bot;
  } else{
    f->y·coord--;
    north_y = f->y·coord;
    north_x = f->x·coord;
  }
  //check if expansion needed
  if (north_y - f->y_coord_origin < 0){
    //Expand north
    int new_rows = old_rows +1;
    int new_cols = old_cols;
    //creates an array of pointers to point to my rows of integers
    int** new_grid = (int**)malloc(new_rows * sizeof(int*));
    if (new_grid == NULL){
      return;
    }
    for (int i = 0; i< old_rows; ++i){
      new_grid[i+1] = f->houses[i];//repeat without the plus one for the southward add row
    }
    new_grid[0] = (int*)calloc(new_cols, sizeof(int));//Initialising the new row to empty
    free(f->houses);
    f->houses = new_grid;
    f->rows·in·array = new_rows;
    f->columns·in·array = new_cols;
    f->y_coord_origin--;
  }
  //updating the visit count
  int grid_x = north_x - f->x_coord_origin;
  int grid_y = north_y - f->y_coord_origin;
  f->houses[grid_y][grid_x]++;
  //comment
}

void movesouth(Housearray* f, int user){
  int old_rows = f->rows·in·array;
  int old_cols = f-> columns·in·array;
  int south_y = 0;
  int south_x = 0;
  //update y coordinate
  if (user == 1){
    f->y·coord·bot++;
    south_x = f->x·coord·bot;
    south_y = f->y·coord·bot;
  } else{
    f->y·coord++;
    south_x = f->x·coord;
    south_y = f->y·coord;
  }

  //check if expansion needed
  if (south_y - f->y_coord_origin >= f->rows·in·array){
    //Expand south
    int new_rows = old_rows +1;
    int new_cols = old_cols;
    //creates an array of pointers to point to my rows of integers
    int** new_grid = (int**)malloc(new_rows * sizeof(int*));
    for (int i = 0; i< old_rows; ++i){
      new_grid[i] = f->houses[i];
    }
    new_grid[new_rows - 1] = (int*)calloc(new_cols, sizeof(int));//Initialising the new row to empty
    free(f->houses);
    f->houses = new_grid;
    f->rows·in·array = new_rows;
    f->columns·in·array = new_cols;

  }
  //updating the visit count
  int grid_x = south_x - f->x_coord_origin;
  int grid_y = south_y - f->y_coord_origin;
  f->houses[grid_y][grid_x]++;
}

void moveeast(Housearray* f, int user){
  int old_rows = f->rows·in·array;
  int old_cols = f-> columns·in·array;
  int east_y = 0;
  int east_x = 0;
  //update x coordinate
  //f->x·coord++;
  if (user ==1){
    f->x·coord·bot++;
    east_x = f->x·coord·bot;
    east_y = f->y·coord·bot;
  } else{
    f->x·coord++;
    east_x = f->x·coord;
    east_y = f->y·coord;
  }
  //check if expansion needed
  if (east_x - f->x_coord_origin >= f->columns·in·array){
    //Expand east
    int new_rows = old_rows;
    int new_cols = old_cols + 1;
    //creates an array of pointers to point to my rows of integers
    int** new_grid = (int**)malloc(new_rows * sizeof(int*));
    for (int i = 0; i< old_rows; ++i){
      int *new_row = malloc((new_cols) * sizeof(int));//allocating the new row
      //new_row[0] = 0;//initialising the leftmost element
      memcpy(&new_row[0], f->houses[i], old_cols * sizeof(int));//copying the rest of the elements over
      new_row[old_cols] = 0;//Initially was lacking this line, because it wasn't set to zero, some extra values showed up there and increased the count of houses which recieved gifts
      free(f->houses[i]);
      new_grid[i] = new_row;
      
      //new_grid[i] = f->houses[i];
    }
    free(f->houses);
    f->houses = new_grid;
    f->rows·in·array = new_rows;
    f->columns·in·array = new_cols;

  }
  //updating the visit count
  int grid_x = east_x - f->x_coord_origin;
  int grid_y = east_y - f->y_coord_origin;
  f->houses[grid_y][grid_x]++;
}

void movewest(Housearray* f, int user){
  int old_rows = f->rows·in·array;
  int old_cols = f-> columns·in·array;
  int west_y = 0;
  int west_x =0;
  //update x coordinate
  //f->x·coord--;
  if (user ==1){
    f->x·coord·bot--;
    west_x = f->x·coord·bot;
    west_y = f->y·coord·bot;
  } else{
    f->x·coord--;
    west_x = f->x·coord;
    west_y = f->y·coord;
  }
  //check if expansion needed
  if (west_x- f->x_coord_origin < 0){
    //Expand south
    int new_rows = old_rows;
    int new_cols = old_cols +1;
    //creates an array of pointers to point to my rows of integers
    int** new_grid = (int**)malloc(new_rows * sizeof(int*));
    for (int i = 0; i< old_rows; ++i){
      int *new_row = malloc((new_cols) * sizeof(int));//allocating the new row
      new_row[0] = 0;//initialising the leftmost element
      memcpy(&new_row[1], f->houses[i], old_cols * sizeof(int));//copying the rest of the elements over
      free(f->houses[i]);
      new_grid[i] = new_row;
      //new_grid[i] = f->houses[i];
    }
    free(f->houses);
    f->houses = new_grid;
    f->rows·in·array = new_rows;
    f->columns·in·array = new_cols;
    f->x_coord_origin--;

  }
  //updating the visit count
  int grid_x = west_x - f->x_coord_origin;
  int grid_y = west_y- f->y_coord_origin;
  f->houses[grid_y][grid_x]++;
}




int main(){
  int counter_r, counter_e =0;
  Housearray* my_house_array = inithousearray(0);
  if (my_house_array == NULL){
    fprintf(stderr, "ERROR:initialisation of struct failed\n");
    return 1;
  }
//  char c;
  char up = '^';
  char down = 'v';
  char left = '<';
  char right = '>';

  char ch, zh;
  fptr = fopen("2015_day_3_input.txt", "r");  
  if(fptr == NULL) {
    printf("Not able to open the file.");
    return 1;
  }
  //https://www.geeksforgeeks.org/c-program-to-read-contents-of-whole-file/
  while ((ch = fgetc(fptr)) != EOF) {
      printf("%c", ch);
      if (ch == up){
        printf("\nUP");
        movenorth(my_house_array, 0);
      }else if (ch == down){
        printf("\nDOWN");
        movesouth(my_house_array,0);        
      }else if (ch == left){
        printf("\nWEST");
        movewest(my_house_array, 0);
      }else if (ch == right){
        moveeast(my_house_array,0);
      }

      ++my_house_array->seq·no;
      printf("\n%d ycoordinate\n",my_house_array->y·coord);
      printf("\n%d rows in array\n",my_house_array->rows·in·array);
      printf("\n%d cols in array\n",my_house_array->columns·in·array);


  }
  for (int i = 0; i < my_house_array->rows·in·array; ++i){
    for (int x = 0; x< my_house_array->columns·in·array; ++x){
      printf("%d",my_house_array->houses[i][x]);
      if (my_house_array->houses[i][x] > 0){
        ++counter_r;
      }
  }
  }

  printf("\n\n%d houses recieved at least one gift", counter_r);
  printf("\nEND PART ONE\n");
  Housearray* robo_house_array = inithousearray(1);
  if (robo_house_array == NULL){
    fprintf(stderr, "ERROR:initialisation of struct failed\n");
    return 1;
  }
  fptr = fopen("2015_day_3_input.txt", "r");  
  if(fptr == NULL) {
    printf("Not able to open the file.");
    return 1;
  }
  while ((zh = fgetc(fptr)) != EOF) {//every other char goes to robo-santa
    printf("\n%c", zh);
    if(robo_house_array->seq·no % 2 == 0){
      if (zh == up){
        printf("\nUP");
        movenorth(robo_house_array, 0);
      }else if (zh == down){
        printf("\nDOWN");
        movesouth(robo_house_array,0);        
      }else if (zh == left){
        printf("\nWEST");
        movewest(robo_house_array, 0);
      }else if (zh == right){
        moveeast(robo_house_array,0);
      }
    } else{
      if (zh == up){
        printf("\nUP");
        movenorth(robo_house_array, 1);
      }else if (zh == down){
        printf("\nDOWN");
        movesouth(robo_house_array,1);        
      }else if (zh == left){
        printf("\nWEST");
        movewest(robo_house_array, 1);
      }else if (zh == right){
        moveeast(robo_house_array,1);
      }
    }


    ++robo_house_array->seq·no;
  }
  for (int i = 0; i < robo_house_array->rows·in·array; ++i){
    for (int x = 0; x< robo_house_array->columns·in·array; ++x){
      printf("%d",robo_house_array->houses[i][x]);
      if (robo_house_array->houses[i][x] > 0){
        ++counter_e;
      }
  }
  }

  printf("\n\n%d houses recieved at least one gift", counter_e);
}