sample :: #string END
..@@.@@@@.
@@@.@.@.@@
@@@@@.@.@@
@.@@@@..@.
@@.@@@@.@@
.@@@@@@@.@
.@.@.@.@@@
@.@@@.@@@@
.@@@@@@@@.
@.@.@@@.@.
END

main :: () {
    print("@: %\n", #char "@");
    print(".: %\n", #char ".");
    content := read_entire_file("day4.input");

    solve_first(content);
}

solve_first :: (input: string) {
    all_lines := split(input, #char "\n");
    lines: [..]string;
    for line: all_lines {
        if line.count == 0 continue;
        array_add(*lines, line);
    }
    assert(lines[0].count != 0);
    line_length := lines[0].count;
    removable := 0;
    for line, line_index: lines {
        if line.count == 0 continue;
        for char, char_index: line {
            if char == #char "." continue;
            surrounding_chars: [8]u8;
            surrounding_chars_index := 0;
            for dy: -1..1 {
                for dx: -1..1 {
                    if dx == 0 && dy == 0 continue;
                    defer surrounding_chars_index += 1;
                    x := char_index + dx;
                    if x < 0 || line.count <= x continue;
                    y := line_index + dy;
                    if y < 0 || lines.count <= y continue;
                    surrounding_chars[surrounding_chars_index] = lines[y][x];
                }
            }
            if array_count(surrounding_chars, (char: u8) -> bool { return char == #char "@"; }) < 4 {
                removable += 1;
            }
        }
    }
    print("%\n", removable);
}

array_count :: (arr: []$T, f: (t: T) -> bool) -> int {
    total := 0;
    for arr {
        if f(it) total += 1;
    }
    return total;
}

#import "Basic";
#import "File";
#import "String";