include("utils.jl")

function parse_input(filename)
    input_lines = collect(non_empty_lines(filename))
    width = length(input_lines[1])
    integers = map(x->parse(Int, x, base = 2), input_lines)
    (integers, width)
end

function most_common_bit(integers, width)
    score = zeros(Int, width)
    for int in integers
        for index in 1:width
            score[index] += ((int >> (index-1) & 1) - 0.5) * 2
        end
    end
    map(map(sign, score)) do x
        if x == 0
            1
        else
            x
        end
    end
end

function solution3_1()
    integers, width = parse_input("3.data")

    score = most_common_bit(integers, width)

    result = 0
    cresult = 0
    for i in 1:width
        result += ((score[i] + 1) >> 1) << (i - 1)
        cresult += (((score[i] * -1) + 1) >> 1) << (i - 1)
    end
    (result, cresult, result * cresult)
end

function filterdata(integers, width, score_factor)
    ints = copy(integers)
    for i in reverse(1:width)
        score = most_common_bit(ints, width) * score_factor
        ints = filter(ints) do x
            (x & (1 << (i - 1))) >> (i - 1) == (score[i] + 1) >> 1
        end
        if length(ints) == 1
            break
        end
    end
    ints[1]
end

function solution3_2()
    integers, width = parse_input("3.data")
    oxy = filterdata(integers, width, 1)
    co2 = filterdata(integers, width, -1)
    (oxy, co2, oxy * co2)
end

solution3_2()