@roundHalfDown = (number) ->
  Math.ceil(number - .5)

@typeEffectiveness = (userType, againstTypes, options = {}) ->
  userType = Type[userType]
  effectiveness = 1
  for subtype in againstTypes
    targetType = Type[subtype]
    multiplier = typeChart[userType][targetType]
    multiplier = 1  if multiplier == 0 && options.ignoreImmunities
    multiplier = 2  if options.superEffectiveAgainst == subtype
    effectiveness *= multiplier
  effectiveness

@Type = Type =
  Normal   : 0
  Fire     : 1
  Water    : 2
  Electric : 3
  Grass    : 4
  Ice      : 5
  Fighting : 6
  Poison   : 7
  Ground   : 8
  Flying   : 9
  Psychic  : 10
  Bug      : 11
  Rock     : 12
  Ghost    : 13
  Dragon   : 14
  Dark     : 15
  Steel    : 16
  "???"    : 17

typeChart = [
  # Nor Fir Wat Ele Gra Ice Fig Poi Gro Fly Psy Bug Roc Gho Dra Dar Ste ???
  [  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1, .5,  0,  1,  1, .5,  1 ], # Nor
  [  1, .5, .5,  1,  2,  2,  1,  1,  1,  1,  1,  2, .5,  1, .5,  1,  2,  1 ], # Fir
  [  1,  2, .5,  1, .5,  1,  1,  1,  2,  1,  1,  1,  2,  1, .5,  1,  1,  1 ], # Wat
  [  1,  1,  2, .5, .5,  1,  1,  1,  0,  2,  1,  1,  1,  1, .5,  1,  1,  1 ], # Ele
  [  1, .5,  2,  1, .5,  1,  1, .5,  2, .5,  1, .5,  2,  1, .5,  1, .5,  1 ], # Gra
  [  1, .5, .5,  1,  2, .5,  1,  1,  2,  2,  1,  1,  1,  1,  2,  1, .5,  1 ], # Ice
  [  2,  1,  1,  1,  1,  2,  1, .5,  1, .5, .5, .5,  2,  0,  1,  2,  2,  1 ], # Fig
  [  1,  1,  1,  1,  2,  1,  1, .5, .5,  1,  1,  1, .5, .5,  1,  1,  0,  1 ], # Poi
  [  1,  2,  1,  2, .5,  1,  1,  2,  1,  0,  1, .5,  2,  1,  1,  1,  2,  1 ], # Gro
  [  1,  1,  1, .5,  2,  1,  2,  1,  1,  1,  1,  2, .5,  1,  1,  1, .5,  1 ], # Fly
  [  1,  1,  1,  1,  1,  1,  2,  2,  1,  1, .5,  1,  1,  1,  1,  0, .5,  1 ], # Psy
  [  1, .5,  1,  1,  2,  1, .5, .5,  1, .5,  2,  1,  1, .5,  1,  2, .5,  1 ], # Bug
  [  1,  2,  1,  1,  1,  2, .5,  1, .5,  2,  1,  2,  1,  1,  1,  1, .5,  1 ], # Roc
  [  0,  1,  1,  1,  1,  1,  1,  1,  1,  1,  2,  1,  1,  2,  1, .5, .5,  1 ], # Gho
  [  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  2,  1, .5,  1 ], # Dra
  [  1,  1,  1,  1,  1,  1, .5,  1,  1,  1,  2,  1,  1,  2,  1, .5, .5,  1 ], # Dar
  [  1, .5, .5, .5,  1,  2,  1,  1,  1,  1,  1,  1,  2,  1,  1,  1, .5,  1 ], # Ste
  [  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1 ]  # ???
]