{-# LANGUAGE InstanceSigs #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE FunctionalDependencies #-}
{-# LANGUAGE FlexibleInstances #-}
{-|
Paths in 2D / 3D space.

This module defines functions that can be used with "Waterfall.Path" or "Waterfall.TwoD.Path2D".
Those modules both export monomorphized variants of the functions defined in this module
-}
module Waterfall.Path.Common 
( AnyPath ()
, line
, lineTo
, lineRelative
, arcVia
, arcViaTo
, arcViaRelative
, bezier
, bezierTo
, bezierRelative
, pathFrom
, pathFromTo
, pathEndpoints
, splice
, closeLoop
, reversePath
, splitPath
) where
import Data.Acquire
import qualified OpenCascade.TopoDS as TopoDS
import qualified OpenCascade.GP as GP
import Foreign.Ptr
import Waterfall.Internal.Path.Common (RawPath (..))
import Waterfall.Internal.Path (Path (..))
import Waterfall.TwoD.Internal.Path2D (Path2D (..))
import Waterfall.Internal.Finalizers (unsafeFromAcquire, toAcquire, unsafeFromAcquireT)
import Waterfall.Internal.FromOpenCascade (gpPntToV3)
import Waterfall.Internal.Edges (wireEndpoints, reverseWire, splitWires)
import Control.Arrow (second)
import Data.Foldable (foldl')
import qualified OpenCascade.BRepBuilderAPI.MakeWire as MakeWire
import Control.Monad.IO.Class (liftIO)
import qualified OpenCascade.BRepBuilderAPI.MakeEdge as MakeEdge
import qualified OpenCascade.GC.MakeArcOfCircle as MakeArcOfCircle
import OpenCascade.Inheritance (upcast, unsafeDowncast)
import qualified OpenCascade.NCollection.Array1 as NCollection.Array1
import qualified OpenCascade.Geom.BezierCurve as BezierCurve
import qualified OpenCascade.GP.Trsf as GP.Trsf
import qualified OpenCascade.GP.Vec as  GP.Vec
import qualified OpenCascade.BRepBuilderAPI.Transform as BRepBuilderAPI.Transform
import Data.Proxy (Proxy (..))
import Linear (V3 (..), V2 (..), _xy, Epsilon, nearZero)
import qualified OpenCascade.GP.Pnt as GP.Pnt
import Control.Lens ((^.))

-- | Class used to abstract over constructing `Path` and `Path2D` 
-- 
-- There are instances for @AnyPath (V3 Double) Path@
-- and for @AnyPath (V2 Double) Path2D@
class AnyPath point path | path -> point where
    reconstructPath :: RawPath -> path
    deconstructPath :: path -> RawPath
    pointToV3 :: Proxy path -> point -> V3 Double
    v3ToPoint :: Proxy path -> V3 Double -> point 

pointToGPPnt :: AnyPath point path => Proxy path -> point -> Acquire (Ptr GP.Pnt)
pointToGPPnt proxy pnt = 
    let (V3 x y z) = pointToV3 proxy pnt
    in GP.Pnt.new x y z 

fromWire :: AnyPath point path => Acquire (Ptr TopoDS.Wire) -> path
fromWire = reconstructPath . ComplexRawPath . unsafeFromAcquire

edgeToPath :: (AnyPath point path) => Acquire (Ptr TopoDS.Edge) -> path
edgeToPath es = fromWire $ do
    edge <- es
    builder <- MakeWire.new
    liftIO $ MakeWire.addEdge builder edge
    MakeWire.wire builder

-- | A straight line between two points
line :: forall point path. (AnyPath point path, Epsilon point) => point -> point -> path
line start end = 
    if nearZero (start - end)
        then reconstructPath . SinglePointRawPath . pointToV3 (Proxy :: Proxy path) $ start
        else edgeToPath $ do
            pt1 <- pointToGPPnt (Proxy :: Proxy path) start
            pt2 <- pointToGPPnt (Proxy :: Proxy path) end
            MakeEdge.fromPnts pt1 pt2

-- | Version of `line` designed to work with `pathFrom`
lineTo :: (AnyPath point path, Epsilon point) => point -> point -> (point, path)
lineTo end = \start -> (end, line start end) 

-- | Version of `line` designed to work with `pathFrom`
-- 
-- With relative points; specifying the distance of the endpoint
-- relative to the start of the line, rather than in absolute space.
lineRelative :: (AnyPath point path, Epsilon point) => point -> point -> (point, path)
lineRelative dEnd = do
    end <- (+ dEnd)
    lineTo end

-- | Section of a circle based on three arguments, the start point, a point on the arc, and the endpoint
arcVia :: forall point path. (AnyPath point path, Epsilon point) => point -> point -> point -> path
arcVia start mid end =
    if nearZero (start - end) && nearZero (start - mid) 
        then reconstructPath . SinglePointRawPath . pointToV3 (Proxy :: Proxy path) $ start
        else edgeToPath $ do
            s <- pointToGPPnt (Proxy :: Proxy path) start
            m <- pointToGPPnt (Proxy :: Proxy path) mid
            e <- pointToGPPnt (Proxy :: Proxy path) end
            theArc <- MakeArcOfCircle.from3Pnts s m e
            MakeEdge.fromCurve (upcast theArc)

-- | Version of `arcVia` designed to work with `pathFrom`
--
-- The first argument is a point on the arc
-- The second argument is the endpoint of the arc
arcViaTo :: (AnyPath point path, Epsilon point) => point -> point -> point -> (point, path)
arcViaTo mid end = \start -> (end, arcVia start mid end) 

-- | Version of `arcVia` designed to work with `pathFrom`
-- 
-- With relative points; specifying the distance of the midpoint and endpoint
-- relative to the start of the line, rather than in absolute space.
arcViaRelative :: (AnyPath point path, Epsilon point) => point -> point -> point -> (point, path)
arcViaRelative dMid dEnd = do
    mid <- (+ dMid) 
    end <- (+ dEnd) 
    arcViaTo mid end

-- | Bezier curve of order 3
-- 
-- The arguments are, the start of the curve, the two control points, and the end of the curve
bezier :: forall point path. (AnyPath point path, Epsilon point) => point -> point -> point -> point -> path
bezier start controlPoint1 controlPoint2 end = 
    if nearZero (start - end) && nearZero (start - controlPoint1) && nearZero (start - controlPoint2)
        then reconstructPath . SinglePointRawPath . pointToV3 (Proxy :: Proxy path) $ start
        else edgeToPath $ do
            s <- pointToGPPnt (Proxy :: Proxy path) start
            c1 <- pointToGPPnt (Proxy :: Proxy path) controlPoint1
            c2 <- pointToGPPnt (Proxy :: Proxy path) controlPoint2
            e <- pointToGPPnt (Proxy :: Proxy path) end
            arr <- NCollection.Array1.newGPPntArray 1 4
            liftIO $ do 
                NCollection.Array1.setValueGPPnt arr 1 s
                NCollection.Array1.setValueGPPnt arr 2 c1
                NCollection.Array1.setValueGPPnt arr 3 c2
                NCollection.Array1.setValueGPPnt arr 4 e
            b <- BezierCurve.toHandle =<< BezierCurve.fromPnts arr
            MakeEdge.fromCurve (upcast b)

-- | Version of `bezier` designed to work with `pathFrom`
bezierTo :: (AnyPath point path, Epsilon point) => point -> point -> point -> point -> (point, path)
bezierTo controlPoint1 controlPoint2 end = \start -> (end, bezier start controlPoint1 controlPoint2 end) 

-- | Version of `bezier` designed to work with `pathFrom`
-- 
-- With relative points; specifying the distance of the control points and the endpoint
-- relative to the start of the line, rather than in absolute space.
bezierRelative :: (AnyPath point path, Epsilon point) => point -> point -> point -> point -> (point, path)
bezierRelative dControlPoint1 dControlPoint2 dEnd = do
    controlPoint1 <- (+ dControlPoint1)
    controlPoint2 <- (+ dControlPoint2)
    end <- (+ dEnd)
    bezierTo controlPoint1 controlPoint2 end

-- | When combining paths, we're generally interested in pairs of paths that share a common endpoint.
--
-- Rather than having to repeat these common endpoints, `pathFrom` can be used to combine a list of path components.
-- 
-- Where a path component is a function from a start point, to a tuple of an end point, and a path; @V2 Double -> (V2 Double, Path2D)@. 
-- 
-- A typical use of `pathFrom` uses a list of functions with the suffix \"To\" or \"Relative\", e.g:
--
-- @
-- Path.pathFrom zero 
--    [ Path.bezierRelative (V3 0 0 0.5) (V3 0.5 0.5 0.5) (V3 0.5 0.5 1)
--    , Path.bezierRelative (V3 0 0 0.5) (V3 (-0.5) (-0.5) 0.5) (V3 (-0.5) (-0.5) 1)
--    , Path.arcViaRelative (V3 0 1 1) (V3 0 2 0)
--    , Path.lineTo (V3 0 2 0) 
--    ] @
pathFrom :: (Monoid path) => point -> [point -> (point, path)] -> path
pathFrom start commands = snd $ pathFromTo commands start 
     
-- | Combines a list of "path components", as used by `pathFrom`
pathFromTo :: (Monoid path) => [point -> (point, path)] -> point -> (point, path)
pathFromTo commands start = 
    let go (pos, paths) cmd = second (:paths) (cmd pos)
        (end, allPaths) = foldl' go (start, []) commands
     in (end, mconcat . reverse $ allPaths)

-- | Returns the start and end of a `Path`
pathEndpoints :: forall point path. (AnyPath point path) => path -> Maybe (point, point)
pathEndpoints path = 
    case deconstructPath path of 
        ComplexRawPath p -> 
            unsafeFromAcquire $ do
                wire <- toAcquire p
                (s, e) <- liftIO $ wireEndpoints wire
                return . Just $ (v3ToPoint (Proxy :: Proxy path) s, v3ToPoint (Proxy :: Proxy path) e)
        SinglePointRawPath p -> let x = v3ToPoint (Proxy :: Proxy path) p in Just (x, x)
        EmptyRawPath -> Nothing
            

-- | Convert a path into a function that can be used as an argument to `pathFrom`
--
-- Takes a path, and returns a function which takes a new start point for the path, and returns 
-- tupled, the path translated onto the new start point, and the new endpoint 
splice :: forall point path. (AnyPath point path, Num point) => path -> point -> (point, path)
splice path pnt =
    case deconstructPath path of
        ComplexRawPath unacquiredWire ->  
            let res = unsafeFromAcquire $ do
                    wire <- toAcquire unacquiredWire
                    (s, e) <- liftIO $ wireEndpoints wire
                    let s' = v3ToPoint (Proxy :: Proxy path) s
                        e' = v3ToPoint (Proxy :: Proxy path) e
                    gp <- pointToGPPnt (Proxy :: Proxy path) pnt
                    p <- liftIO $ gpPntToV3 gp
                    let (V3 x y z) = p - s
                    trsf <- GP.Trsf.new
                    vec <- GP.Vec.new x y z
                    liftIO $ GP.Trsf.setTranslation trsf vec
                    newWire <- (liftIO . unsafeDowncast) =<< BRepBuilderAPI.Transform.transform (upcast wire) trsf True 
                    return (pnt + e' - s', newWire)
            in (fst res, fromWire (fmap snd . toAcquire $ res))
        _ -> (pnt, reconstructPath EmptyRawPath)

-- | Given a path, return a new path with the endpoints joined by a straight line.
closeLoop :: (AnyPath point path, Monoid path, Epsilon point) => path -> path
closeLoop p = 
    case pathEndpoints p of
        Just (s, e) -> if nearZero (s - e) 
            then p
            else p <> line e s
        Nothing -> p

reversePath :: (AnyPath point path) => path -> path
reversePath p = 
    case deconstructPath p of
        ComplexRawPath r -> fromWire . reverseWire $ r
        _ -> p

-- | Break a path appart at any "non smooth" point
splitPath :: (AnyPath point path) => path -> [path]
splitPath p = 
    case deconstructPath p of 
        ComplexRawPath r -> fmap (reconstructPath . ComplexRawPath) . unsafeFromAcquireT . splitWires $ r
        _ -> [p]

instance AnyPath (V3 Double) Path where
    reconstructPath :: RawPath -> Path
    reconstructPath = Path 
    pointToV3 :: Proxy Path -> V3 Double -> V3 Double
    pointToV3 _ = id
    deconstructPath :: Path -> RawPath
    deconstructPath (Path path) = path
    v3ToPoint :: Proxy Path -> V3 Double -> V3 Double
    v3ToPoint _ = id

instance AnyPath (V2 Double) Path2D where
    reconstructPath :: RawPath -> Path2D
    reconstructPath = Path2D
    pointToV3 :: Proxy Path2D -> V2 Double -> V3 Double
    pointToV3 _ (V2 x y) = V3 x y 0
    deconstructPath :: Path2D -> RawPath
    deconstructPath (Path2D path) = path
    v3ToPoint :: Proxy Path2D -> V3 Double -> V2 Double
    v3ToPoint _  = (^. _xy)