{-# OPTIONS_GHC -Wall #-}

module Main where

import Physics.Learn
import Vis
import SpatialMath
    ( Euler(..)
    )

drawFunction :: SimpleState -> VisObject Double
drawFunction (_t,r,_v)
    = RotEulerDeg (Euler 270 0 0) $ RotEulerDeg (Euler 0 180 0) $
      VisObjects [ Axes (0.5, 15)
                 , Trans (xyzFromPos r) (Sphere 0.1 Solid red)
                 ]

statePropagationFunction :: Float -> SimpleState -> SimpleState
statePropagationFunction t' (t,r,v) = rungeKutta4 newton2 (realToFrac t' - t) (t,r,v)

-- Newton's Second Law
newton2 :: SimpleState -> Diff SimpleState
newton2 (t,r,v) = (1,v,force (t,r,v) ^/ m)

-- Lorentz Force Law
force :: SimpleState -> Vec
force (_t,r,v) = q *^ (electricField r ^+^ v >< magneticField r)

main :: IO ()
main = simulate
       Nothing
       "Particle Experiencing Electromagnetic Force"
       0.01
       (0,initialPosition,initialVelocity)
       drawFunction
       statePropagationFunction

-- particle mass
m :: Double
m = 1

-- particle charge
q :: Double
q = 1

-- Electric Field
electricField :: VectorField
electricField r = vec 0 2 0
    where
      (x,y,z) = cartesianCoordinates r

-- Magnetic Field
magneticField :: VectorField
magneticField r = vec 0 0 4
    where
      (x,y,z) = cartesianCoordinates r

-- Initial displacement
initialPosition :: Position
initialPosition = cart 0 0 0

-- Initial velocity
initialVelocity :: Vec
initialVelocity = vec 0 0 0