#!/bin/env ruby

slopes = {
    :one => { :right => 1, :down => 1},
    :two => { :right => 3, :down => 1},
    :three => { :right => 5, :down => 1},
    :four => { :right => 7, :down => 1},
    :five => { :right => 1, :down => 2}
}

input = Array.new
File.readlines('./input').each.with_index do |line, i|
    line.strip!
    input[i] = line.split('')
end

input.each do |x|
    x.map! do |y|
        y == '#' ? true : false
    end
end

collisions = Array.new
slopes.each do |num, slope|
    i = 0
    trees = 0
    len = input[0].length
    input.each.with_index do |row, row_num|
        next if (slope[:down] == 2 and row_num.odd?)
        trees += 1 if row[i]
        i +=slope[:right]
        i = i - len if i >= len
    end
    collisions.push(trees)
    puts "On slope #{num.to_s} We hit #{trees} trees"
end

puts "Multiplied together we get: #{collisions.inject(:*)}"