#!/usr/bin/env escript
-mode(compile).

% --- Part 1 Code
part1(Input) -> io:format("Part 1: ~b~n", [code_interp_diff(Input, 0)]).

interp_length([]) -> 0;
interp_length([$\\, $\\ | Rest]) -> 1 + interp_length(Rest);
interp_length([$\\, $" | Rest]) -> 1 + interp_length(Rest);
interp_length([$\\, $x, _, _ | Rest]) -> 1 + interp_length(Rest);
interp_length([_ | Rest]) -> 1 + interp_length(Rest).

code_interp_diff([], Acc) ->
    Acc;
code_interp_diff([Line | Rest], Acc) ->
    code_interp_diff(Rest, Acc + (string:length(Line) - (interp_length(Line) - 2))).

% --- Part 2 Code
part2(Input) -> io:format("Part 2: ~b~n", [escape_code_diff(Input, 0)]).

escape_length([]) -> 0;
escape_length([$\\ | Rest]) -> 2 + escape_length(Rest);
escape_length([$" | Rest]) -> 2 + escape_length(Rest);
escape_length([_Char | Rest]) -> 1 + escape_length(Rest).

escape_code_diff([], Acc) ->
    Acc;
escape_code_diff([Line | Rest], Acc) ->
    escape_code_diff(Rest, Acc + ((escape_length(Line) + 2) - string:length(Line))).

% --- Read Input
read_input() -> read_input("").
read_input(Prev) ->
    case io:get_line("") of
        eof -> Prev;
        {error, _} -> halt(1);
        Data when Prev == "" -> read_input([Data]);
        Data -> read_input(Prev ++ [Data])
    end.

main(Args) ->
    Input = read_input(),
    case Args of
        ["1"] ->
            part1(Input);
        ["2"] ->
            part2(Input);
        _ ->
            part1(Input),
            part2(Input)
    end.