module Model.Vec2 exposing
  ( Vec2
  , add
  , sub
  , mul
  , div
  , norm
  , clockwiseRotate90
  , isNull
  , originVec
  )

type alias Vec2 =
  { x : Float
  , y : Float
  }

add : Vec2 -> Vec2 -> Vec2
add v1 v2 =
  { x = v1.x + v2.x
  , y = v1.y + v2.y
  }

sub : Vec2 -> Vec2 -> Vec2
sub v1 v2 =
  { x = v1.x - v2.x
  , y = v1.y - v2.y
  }

mul : Float -> Vec2 -> Vec2
mul m v =
  { x = m * v.x
  , y = m * v.y
  }

div : Vec2 -> Float -> Vec2
div v d =
  { x = v.x / d
  , y = v.y / d
  }

norm : Vec2 -> Float
norm v = sqrt(v.x ^ 2 + v.y ^ 2)

clockwiseRotate90 : Vec2 -> Vec2
clockwiseRotate90 v =
  { x = -v.y
  , y = v.x
  }

isNull : Vec2 -> Bool
isNull v = (v.x == 0) && (v.y == 0)

originVec : Vec2
originVec = { x = 0, y = 0 }