{-# LANGUAGE NoMonomorphismRestriction, FlexibleContexts, TypeFamilies, PartialTypeSignatures, ScopedTypeVariables #-}

module Rendering (
  renderDrawing,
  customLayoutParams,
  renderIngSyntaxGraph
) where

import Diagrams.Core.Names(Name(..))
import Diagrams.Prelude hiding ((#), (&))
import Diagrams.TwoD.GraphViz(mkGraph, getGraph, layoutGraph')
--import Diagrams.Backend.SVG(B)

import qualified Data.GraphViz as GV
import qualified Data.GraphViz.Attributes.Complete as GVA
import qualified Data.Map as Map
import Data.Maybe(isJust)

import Control.Arrow(second)
import Data.Function(on)
import qualified Data.Graph.Inductive as ING
import Data.Graph.Inductive.PatriciaTree (Gr)
import Data.List(minimumBy)
import Data.Typeable(Typeable)

--import qualified Data.GraphViz.Types
--import Data.GraphViz.Commands
--import qualified Debug.Trace
--import Data.Word(Word16)

import Icons(colorScheme, iconToDiagram, nameDiagram, defaultLineWidth, ColorStyle(..), TransformableDia)
import TranslateCore(nodeToIcon)
import Types(Edge(..), Icon, EdgeOption(..), Connection, Drawing(..), EdgeEnd(..),
  NameAndPort(..), SpecialQDiagram, SpecialBackend, SyntaxNode)
import Util(fromMaybeError)

-- If the inferred types for these functions becomes unweildy,
-- try using PartialTypeSignitures.

-- CONSTANT
graphvizScaleFactor :: (Fractional a) => a

-- For Neato
graphvizScaleFactor = 0.12

-- For Fdp
--scaleFactor = 0.09

--scaleFactor = 0.04

drawingToGraphvizScaleFactor :: Double
-- For Neato, ScaleOverlaps
--drawingToGraphvizScaleFactor = 0.08

-- For Neato, PrismOverlap
drawingToGraphvizScaleFactor = 0.15

-- CONVERTING Edges AND Icons TO DIAGRAMS --
makeNamedMapFromGraph :: (SpecialBackend b, ING.Graph gr) =>
  gr (d, Icon) e -> [(d, Icons.TransformableDia b)]
makeNamedMapFromGraph graph = (second iconToDiagram . snd) <$> ING.labNodes graph

-- Note that the name type alias is different from the Name constructor.
getTopLevelName :: Name -> Name
getTopLevelName (Name []) = Name []
getTopLevelName (Name (x:_)) = Name [x]

-- TODO Refactor with syntaxGraphToFglGraph in TranslateCore
drawingToIconGraph :: Drawing -> Gr (Name, Icon) Edge
drawingToIconGraph (Drawing nodes edges) =
  mkGraph nodes labeledEdges where
    labeledEdges = fmap makeLabeledEdge edges
    makeLabeledEdge e@(Edge _ _ (NameAndPort n1 _, NameAndPort n2 _)) =
      let name1 = getTopLevelName n1
          name2 = getTopLevelName n2
      in
      ((name1, lookupInNodes name1), (name2, lookupInNodes name2), e) where
        lookupInNodes name = fromMaybeError errorString (lookup name nodes) where
          errorString =
            "syntaxGraphToFglGraph edge connects to non-existent node. Node Name ="
            ++ show name ++ " Edge=" ++ show e


-- | Custom arrow tail for the arg1 result circle.
-- The ArrowHT type does not seem to be documented.
arg1ResT :: (RealFloat n) => ArrowHT n
arg1ResT len _ = (alignR $ circle (len / 2), mempty)

-- | Arrow head version of arg1ResT
arg1ResH :: (RealFloat n) => ArrowHT n
arg1ResH len _ = (alignL $ circle (len / 2), mempty)

bezierShaft :: (V t ~ V2, TrailLike t) => Angle (N t) -> Angle (N t) -> t
bezierShaft angle1 angle2 = fromSegments [bezier3 c1 c2 x] where
  scaleFactor = 0.5
  x = r2 (1,0)
  c1 = rotate angle1 (scale scaleFactor unitX)
  c2 = rotate angle2 (scale scaleFactor unitX) ^+^ x

getArrowOpts :: (RealFloat n, Typeable n) => (EdgeEnd, EdgeEnd) -> [EdgeOption]-> ArrowOpts n
getArrowOpts (t, h) opts = arrowOptions
  where
    shaftColor = if EdgeInPattern `elem` opts then patternC else lineC
    ap1ArgTexture = solid (backgroundC colorScheme)
    ap1ArgStyle = lwG defaultLineWidth . lc (apply1C colorScheme)
    ap1ResultTexture = solid (apply1C colorScheme)

    lookupTail EndNone = id
    lookupTail EndAp1Arg = (arrowTail .~ dart')
      . (tailTexture .~ ap1ArgTexture) . (tailStyle %~  ap1ArgStyle)
    lookupTail EndAp1Result = (arrowTail .~ arg1ResT) . (tailTexture .~ ap1ResultTexture)

    lookupHead EndNone = id
    lookupHead EndAp1Arg = (arrowHead .~ dart)
      . (headTexture .~ ap1ArgTexture) . (headStyle %~ ap1ArgStyle)
    lookupHead EndAp1Result = (arrowHead .~ arg1ResH) . (headTexture .~ ap1ResultTexture)

    arrowOptions =
      arrowHead .~ noHead $
      arrowTail .~ noTail $
      lengths .~ global 0.75 $
      shaftStyle %~ (lwG defaultLineWidth . lc (shaftColor colorScheme)) $
      lookupHead h $ lookupTail t with

-- | Given an Edge, return a transformation on Diagrams that will draw a line.
connectMaybePorts :: SpecialBackend b =>
  Edge -> SpecialQDiagram b -> SpecialQDiagram b
connectMaybePorts (Edge opts ends (NameAndPort icon0 (Just port0), NameAndPort icon1 (Just port1))) =
  connect'
  (getArrowOpts ends opts)
  (icon0 .> port0)
  (icon1 .> port1)
connectMaybePorts (Edge opts ends (NameAndPort icon0 Nothing, NameAndPort icon1 (Just port1))) =
  connectOutside' (getArrowOpts ends opts) icon0 (icon1 .> port1)
connectMaybePorts (Edge opts ends (NameAndPort icon0 (Just port0), NameAndPort icon1 Nothing)) =
  connectOutside' (getArrowOpts ends opts) (icon0 .> port0) icon1
connectMaybePorts (Edge opts ends (NameAndPort icon0 Nothing, NameAndPort icon1 Nothing)) =
  connectOutside' (getArrowOpts ends opts) icon0 icon1

makeConnections :: SpecialBackend b =>
  [Edge] -> SpecialQDiagram b -> SpecialQDiagram b
makeConnections edges = applyAll connections
  where
    connections = map connectMaybePorts edges

-- ROTATING/FLIPPING ICONS --

--printSelf :: (Show a) => a -> a
--printSelf a = Debug.Trace.trace (show a ++ "/n") a

{-# ANN totalLenghtOfLines "HLint: ignore Redundant bracket" #-}
{-# ANN totalLenghtOfLines "HLint: ignore Move brackets to avoid $" #-}
-- | For a specific icon, given its angle, location, and a list of pairs of locations
-- of (this icon's port, icon that connects to this port), return the sum of the
-- distances (possibly squared) between the ports and the icons they connect to.
-- This function is used to find that angle that minimizes the sum of distances.
totalLenghtOfLines :: Double -> P2 Double -> [(P2 Double, P2 Double)] -> Double
totalLenghtOfLines angle myLocation edges = sum $ map edgeDist edges
  where
    edgeDist :: (P2 Double, P2 Double) -> Double
    edgeDist (relativePortLocation, iconLocation) =
      -- The squaring here is arbitrary. Distance should be replaced with angle diff.
      (norm $  absPortVec ^-^ iconLocationVec) ** 2
      where
        P relPortVec = relativePortLocation
        P iconLocationVec = iconLocation
        P myLocVec = myLocation
        absPortVec = myLocVec ^+^ (rotateBy angle relPortVec)

 -- | For a specific icon, given its location, and a list of pairs of locations
-- of (this icon's port, icon that connects to this port), find the angle that
-- minimizes the the sum of the distances (possibly squared) between the ports
-- and the icons they connect to. Returns (angle, sum of distances).
-- todo: Return 0 immediatly if edges == [].
angleWithMinDist :: P2 Double -> [(P2 Double, P2 Double)] -> (Double, Double)
angleWithMinDist myLocation edges =
  minimumBy (compare `on` snd) $ map totalLength [0,(1/40)..1]
  where
    totalLength angle = (angle, totalLenghtOfLines angle myLocation edges)

getFromMapAndScale :: (Fractional a, Functor f, Ord k) => Map.Map k (f a) -> k -> f a
getFromMapAndScale posMap name = graphvizScaleFactor *^ (posMap Map.! name)

-- | Returns [(myport, other node, maybe other node's port)]
connectedPorts :: [Connection] -> Name -> [(Int, Name, Maybe Int)]
connectedPorts edges name = map edgeToPort $ filter nameInEdge edges
  where
    isPort = isJust
    nameInEdge (NameAndPort name1 port1, NameAndPort name2 port2) = (name == name1 && isPort port1) || (name == name2 && isPort port2)
    edgeToPort (NameAndPort name1 port1, NameAndPort name2 port2) =
      if name == name1
        then (fromMaybeError "connectedPorts: port is Nothing" port1, name2, port2)
        else (fromMaybeError "connectedPorts: port is Nothing" port2, name1, port1)

-- | rotateNodes rotates the nodes such that the distance of its connecting lines
-- are minimized.
-- Precondition: the diagrams are already centered
-- todo: confirm precondition (or use a newtype)
rotateNodes ::
  Map.Map Name (Point V2 Double)
  -> [(Name, Bool -> Double -> SpecialQDiagram b)]
  -> [Connection]
  -> [(Name, SpecialQDiagram b)]
rotateNodes positionMap nameDiagramMap edges = map rotateDiagram nameDiagramMap
  where
    rotateDiagram (name, originalDia) = (name, nameDiagram name transformedDia)
      where
        transformedDia = if flippedDist < unflippedDist
          then rotateBy flippedAngle . reflectX $ originalDia True flippedAngle
          else rotateBy unflippedAngle $ originalDia False unflippedAngle
        (unflippedAngle, unflippedDist) = minAngleForDia (originalDia False 0)
        (flippedAngle, flippedDist) = minAngleForDia (reflectX $ originalDia True 0)
        --minAngleForDia :: QDiagram b V2 Double m -> (Double, Double)
        minAngleForDia dia = minAngle where
        --ports = Debug.Trace.trace ((show $ names dia) ++ "\n") $ names dia
          ports = names dia
          namesOfPortsWithLines = connectedPorts edges name

          iconInMap :: (Int, Name, Maybe Int) -> Bool
          iconInMap (_, otherIconName, _) = Map.member otherIconName positionMap

          getPortPoint :: Int -> P2 Double
          getPortPoint x =
            -- TODO remove partial function head.
            head $ fromMaybeError
              ("rotateNodes: port not found. Port: " ++ show x ++ ". Valid ports: " ++ show ports)
              (lookup (toName x) ports)

          makePortEdge :: (Int, Name, Maybe Int) -> (P2 Double, P2 Double)
          makePortEdge (portInt, otherIconName, _) =
            (getPortPoint portInt, getFromMapAndScale positionMap otherIconName)

          portEdges = map makePortEdge $ filter iconInMap namesOfPortsWithLines

          minAngle = angleWithMinDist (getFromMapAndScale positionMap name) portEdges


type LayoutResult a b = Gr (GV.AttributeNode (Name, b)) (GV.AttributeNode a)

placeNodes :: Ord c =>
   LayoutResult a c
   -> [(Name, Bool -> Double -> SpecialQDiagram b)]
   -> [Connection]
   -> SpecialQDiagram b
placeNodes layoutResult nameDiagramMap edges = mconcat placedNodes
  where
    positionMap = Map.mapKeys fst $ fst $ getGraph layoutResult
    rotatedNameDiagramMap = rotateNodes positionMap nameDiagramMap edges
    placedNodes = map placeNode rotatedNameDiagramMap
    --placedNodes = map placeNode nameDiagramMap
    -- todo: Not sure if the diagrams should already be centered at this point.
    placeNode (name, diagram) = place (centerXY diagram) (graphvizScaleFactor *^ (positionMap Map.! name))

customLayoutParams :: GV.GraphvizParams n v e () v
customLayoutParams = GV.defaultParams{
  GV.globalAttributes = [
    GV.NodeAttrs [GVA.Shape GVA.BoxShape]
    --GV.NodeAttrs [GVA.Shape GVA.Circle]
    , GV.GraphAttrs
      [
      --GVA.Overlap GVA.KeepOverlaps,
      --GVA.Overlap GVA.ScaleOverlaps,
      GVA.Overlap $ GVA.PrismOverlap (Just 5000),
      GVA.Splines GVA.LineEdges,
      GVA.OverlapScaling 8,
      --GVA.OverlapScaling 4,
      GVA.OverlapShrink True
      ]
    ],
  GV.fmtEdge = const [GV.arrowTo GV.noArrow]
  }

doGraphLayout :: forall b e.
  SpecialBackend b =>
  Gr (Name, Icon) e
  -> [(Name, Bool -> Double -> SpecialQDiagram b)]
  -> [Connection]
  -> IO (SpecialQDiagram b)
doGraphLayout graph nameDiagramMap edges = do
  layoutResult <- layoutGraph' layoutParams GVA.Neato graph
  --  layoutResult <- layoutGraph' layoutParams GVA.Fdp graph
  return $ placeNodes layoutResult nameDiagramMap edges
  where
    layoutParams :: GV.GraphvizParams Int (Name,Icon) e () (Name,Icon)
    --layoutParams :: GV.GraphvizParams Int l el Int l
    layoutParams = customLayoutParams{
      GV.fmtNode = nodeAttribute
      }
    nodeAttribute :: (Int, (Name, Icon)) -> [GV.Attribute]
    nodeAttribute (_, (_, nodeIcon)) =
      -- GVA.Width and GVA.Height have a minimum of 0.01
      --[GVA.Width diaWidth, GVA.Height diaHeight]
      [GVA.Width circleDiameter, GVA.Height circleDiameter]
      where
        -- This type annotation (:: SpecialQDiagram b) requires Scoped Typed Variables, which only works if the function's
        -- type signiture has "forall b e."
        dia = iconToDiagram nodeIcon False 0 :: SpecialQDiagram b

        diaWidth = drawingToGraphvizScaleFactor * width dia
        diaHeight = drawingToGraphvizScaleFactor * height dia
        circleDiameter' = max diaWidth diaHeight
        circleDiameter = if circleDiameter' <= 0.01 then error ("circleDiameter too small: " ++ show circleDiameter') else circleDiameter'

-- | Given a Drawing, produce a Diagram complete with rotated/flipped icons and
-- lines connecting ports and icons. IO is needed for the GraphViz layout.
renderDrawing ::
  SpecialBackend b =>
  Drawing -> IO (SpecialQDiagram b)
renderDrawing = renderIconGraph . drawingToIconGraph

renderIngSyntaxGraph ::
  SpecialBackend b =>
  Gr (Name, SyntaxNode) Edge -> IO (SpecialQDiagram b)
renderIngSyntaxGraph = renderIconGraph . ING.nmap (Control.Arrow.second nodeToIcon)

renderIconGraph :: SpecialBackend b => Gr (Name, Icon) Edge -> IO (SpecialQDiagram b)
renderIconGraph iconGraph = diagramAction where
  edges = ING.edgeLabel <$> ING.labEdges iconGraph
  connections = fmap edgeConnection edges
  diagramAction = makeConnections edges <$>
    doGraphLayout iconGraph (makeNamedMapFromGraph iconGraph) connections