TESL Pack opening simulator

COST = [50, 100, 400, 1200, 1200]
DUST = [5, 20, 100, 400, 400]
ODDS = [688, 923, 985, 990, 1000] # cumulative odds out of 1000
MAX = [3, 3, 3, 3, 1] # number you want of each card
CARDS_PER_TYPE = [57, 45, 22, 10, 20]

got = [{}, {}, {}, {}, {}] # card ID => number of them

rng = Random.new

total_dust_reqd = 0
total_dust_earnt = 0

(0..4).each do |i|
  total_dust_reqd += (CARDS_PER_TYPE[i] * MAX[i] * COST[i])
end

got_counts = [0, 0, 0, 0, 0]
packs = 0

while total_dust_earnt < total_dust_reqd
  packs += 1

  6.times do # 6 cards in a pack
    card_type_number = rng.rand(1000)
    card_type = 0
    while ODDS[card_type] < card_type_number
      card_type += 1
    end

    raise "wtf?" if card_type >= 5

    card = rng.rand(CARDS_PER_TYPE[card_type])

    if !got[card_type].has_key?(card)
      got[card_type][card] = 1
      total_dust_reqd -= COST[card_type]
      got_counts[card_type] += 1
    elsif got[card_type][card] < MAX[card_type]
      got[card_type][card] += 1
      total_dust_reqd -= COST[card_type]
      got_counts[card_type] += 1
    else
      total_dust_earnt += DUST[card_type]
    end
  end

  puts "After #{packs} packs, got #{got_counts[0]} C, #{got_counts[1]} R, #{got_counts[2]} E, #{got_counts[3]} L, #{got_counts[4]} UL, #{total_dust_earnt} dust, need #{total_dust_reqd} dust"
end

puts "Done"