#include "aoc.h"

const int dx[] = {0, 1, 0, -1};
const int dy[] = {-1, 0, 1, 0};

static inline bool
inside(Grid *grid, int x, int y) {
    return x >= 0 && y >= 0 && x < grid->width && y < grid->height;
}

static inline bool
unequal_or_outside(Grid *grid, int x, int y, char type) {
    if (inside(grid, x, y)) {
        return grid->grid[y * grid->width + x] != type;
    }
    else {
        return true;
    }
}

static void
flood_fill(Grid *grid, bool *visited, int x, int y, int *area, int *perimeter, int *sides) {
    if (visited[y * grid->width + x]) {
        return;
    }

    char type = grid->grid[y * grid->width + x];

    (*area)++;
    visited[y * grid->width + x] = true;
    for (int i = 0; i < 4; i++) {
        int nx = x + dx[i];
        int ny = y + dy[i];

        if (unequal_or_outside(grid, nx, ny, type)) {
            (*perimeter)++;
        }
        else {
            flood_fill(grid, visited, nx, ny, area, perimeter, sides);
        }
    }


    // convex corners
    *sides += (unequal_or_outside(grid, x - 1, y, type) && unequal_or_outside(grid, x, y - 1, type)); // top left corner
    *sides += (unequal_or_outside(grid, x + 1, y, type) && unequal_or_outside(grid, x, y - 1, type)); // top right corner
    *sides += (unequal_or_outside(grid, x - 1, y, type) && unequal_or_outside(grid, x, y + 1, type)); // bottom left corner
    *sides += (unequal_or_outside(grid, x + 1, y, type) && unequal_or_outside(grid, x, y + 1, type)); // bottom right corner

    // concave corners
    *sides += (!unequal_or_outside(grid, x - 1, y, type) && !unequal_or_outside(grid, x - 1, y - 1, type) && unequal_or_outside(grid, x, y - 1, type)); // top left corner
    *sides += (!unequal_or_outside(grid, x + 1, y, type) && !unequal_or_outside(grid, x + 1, y - 1, type) && unequal_or_outside(grid, x, y - 1, type)); // top right corner
    *sides += (!unequal_or_outside(grid, x - 1, y, type) && !unequal_or_outside(grid, x - 1, y + 1, type) && unequal_or_outside(grid, x, y + 1, type)); // bottom left corner
    *sides += (!unequal_or_outside(grid, x + 1, y, type) && !unequal_or_outside(grid, x + 1, y + 1, type) && unequal_or_outside(grid, x, y + 1, type)); // bottom right corner
}

int main(int argc, char **argv) {
    Arena *arena = make_arena(Megabytes(1));
    str input = read_file(arena, argv[1]);
    Grid grid = parse_grid(input, arena);

    bool *visited = ARENA_ALLOC_ARRAY(arena, bool, grid.width * grid.height);

    i64 part_1 = 0;
    i64 part_2 = 0;
    for (int y = 0; y < grid.height; y++) {
        for (int x = 0; x < grid.width; x++) {
            if (!visited[y * grid.width + x]) {
                int area = 0;
                int perimeter = 0;
                int sides = 0;
                flood_fill(&grid, visited, x, y, &area, &perimeter, &sides);
                char type = grid.grid[y * grid.width + x];
                /* printf("type = %c, area = %d, perimeter = %d, sides = %d\n", type, area, perimeter, sides); */
                part_1 += area * perimeter;
                part_2 += area * sides;
            }
        }
    }
    printf("%ld\n", part_1);
    printf("%ld\n", part_2);
}