module Here4.Bounding
    exposing
        ( Bounding
        , Methods
        , Motion
        , inside
        , outside
        , emplace
        , bounce
        , bump
        )

import Math.Vector3 as V3 exposing (Vec3)
import Time exposing (Time)
import Here4.Body exposing (..)


type alias Motion =
    { position : Vec3, velocity : Vec3 }


type alias Methods a =
    { inside : a -> Vec3 -> Bool
    , emplace : a -> Float -> Vec3 -> Vec3
    , bounce : a -> Float -> Time -> Motion -> Motion
    , bump : a -> Float -> Time -> Motion -> Motion
    }


type alias Bounding a =
    { methods : Methods a
    , model : a
    }


inside : Bounding a -> Vec3 -> Bool
inside a pos =
    a.methods.inside a.model pos


outside : Bounding a -> Vec3 -> Bool
outside a pos =
    not (a.methods.inside a.model pos)


emplace : Bounding a -> Float -> Vec3 -> Vec3
emplace a radius pos =
    a.methods.emplace a.model radius pos


bounce : Bounding a -> Time -> Spherical (Moving b) -> Spherical (Moving b)
bounce a dt body =
    let
        motion =
            { position = body.position, velocity = body.velocity }

        { position, velocity } =
            a.methods.bounce a.model body.radius dt motion
    in
        { body | position = position, velocity = velocity }



-- bump : Bounding a -> Time -> Spherical (Moving b) -> Spherical (Moving b)


bump a dt body =
    let
        motion =
            { position = body.position, velocity = body.velocity }

        { position, velocity } =
            a.methods.bump a.model body.radius dt motion
    in
        { body | position = position, velocity = velocity }