{- ORMOLU_DISABLE -}
{-|
Everything below this line in this file was taken verbatim from the Monomer source code, commit e49a79357653f171efe4a2e93a273ac9504d029f.

Module      : Monomer.TestUtil
Copyright   : (c) 2018 Francisco Vallarino
License     : BSD-3-Clause (see the LICENSE file)
Maintainer  : fjvallarino@gmail.com
Stability   : experimental
Portability : non-portable

Helper functions for testing Monomer widgets.
-}
{-# LANGUAGE FlexibleContexts #-}

module Monomer.TestUtil where

import Control.Concurrent (newMVar)
import Control.Concurrent.STM.TChan (newTChanIO)
import Control.Lens ((&), (^.), (.~), (.=))
import Control.Monad.State
import Data.Default
import Data.Maybe
import Data.Text (Text)
import Data.Sequence (Seq)
import System.Environment (lookupEnv)
import System.IO.Unsafe (unsafePerformIO)
import Test.Hspec (Expectation, pendingWith)

import qualified Data.ByteString as BS
import qualified Data.Map.Strict as M
import qualified Data.Text as T
import qualified Data.Sequence as Seq

import Monomer.Core
import Monomer.Event
import Monomer.Graphics
import Monomer.Main.Handlers
import Monomer.Main.Types
import Monomer.Main.Util

import qualified Monomer.Lens as L

data InitWidget
  = WInit
  | WInitKeepFirst
  | WNoInit
  deriving (Eq, Show)

testW :: Double
testW = 640

testH :: Double
testH = 480

testWindowSize :: Size
testWindowSize = Size testW testH

testWindowRect :: Rect
testWindowRect = Rect 0 0 testW testH

mockTextMetrics :: Double -> Font -> FontSize -> TextMetrics
mockTextMetrics scale font fontSize = TextMetrics {
  _txmAsc = 15,
  _txmDesc = 5,
  _txmLineH = 20,
  _txmLowerX = 10
}

mockTextSize
  :: Maybe Double -> Double -> Font -> FontSize -> FontSpace -> Text -> Size
mockTextSize mw scale font (FontSize fs) spaceH text = Size width height where
  w = fromMaybe fs mw + unFontSpace spaceH
  width = fromIntegral (T.length text) * w
  height = 20

mockGlyphsPos
  :: Maybe Double
  -> Double
  -> Font
  -> FontSize
  -> FontSpace
  -> Text
  -> Seq GlyphPos
mockGlyphsPos mw scale font (FontSize fs) spaceH text = glyphs where
  w = fromMaybe fs mw + unFontSpace spaceH
  chars = Seq.fromList $ T.unpack text
  mkGlyph idx chr = GlyphPos {
    _glpGlyph = chr,
    _glpX = fromIntegral idx * w,
    _glpXMin = fromIntegral idx * w,
    _glpXMax = (fromIntegral idx + 1) * w,
    _glpYMin = 0,
    _glpYMax = 10,
    _glpW = w,
    _glpH = 10
  }
  glyphs = Seq.mapWithIndex mkGlyph chars

mockRenderText :: Point -> Font -> FontSize -> FontSpace -> Text -> IO ()
mockRenderText point font size spaceH text = return ()

mockRenderer :: Renderer
mockRenderer = Renderer {
  beginFrame = \w h -> return (),
  endFrame = return (),
  -- Path
  beginPath = return (),
  closePath = return (),
  -- Context management
  saveContext = return (),
  restoreContext = return (),
  -- Overlays
  createOverlay = \overlay -> return (),
  renderOverlays = return (),
  -- Raw tasks
  createRawTask = \task -> return (),
  renderRawTasks = return (),
  -- Raw overlays
  createRawOverlay = \overlay -> return (),
  renderRawOverlays = return (),
  -- Scissor operations
  intersectScissor = \rect -> return (),
  -- Translation
  setTranslation = \point -> return (),
  -- Scale
  setScale = \point -> return (),
  -- Rotation
  setRotation = \angle -> return (),
  -- Global Alpha
  setGlobalAlpha = \alpha -> return (),
  -- Path Winding
  setPathWinding = \winding -> return (),
  -- Strokes
  stroke = return (),
  setStrokeColor = \color -> return (),
  setStrokeWidth = \width -> return (),
  setStrokeLinearGradient = \p1 p2 c1 c2 -> return (),
  setStrokeRadialGradient = \p1 a1 a2 c1 c2 -> return (),
  setStrokeBoxGradient = \r1 r f c1 c2 -> return (),
  setStrokeImagePattern = \n1 p1 s1 w1 h1 -> return (),
  -- Fill
  fill = return (),
  setFillColor = \color -> return (),
  setFillLinearGradient = \p1 p2 c1 c2 -> return (),
  setFillRadialGradient = \p1 a1 a2 c1 c2 -> return (),
  setFillBoxGradient = \r1 r f c1 c2 -> return (),
  setFillImagePattern = \n1 p1 s1 w1 h1 -> return (),
  -- Drawing
  moveTo = \point -> return (),
  renderLine = \p1 p2 -> return (),
  renderLineTo = \point -> return (),
  renderRect = \rect -> return (),
  renderRoundedRect = \rect r1 r2 r3 r4 -> return (),
  renderArc = \center radius angleStart angleEnd winding -> return (),
  renderQuadTo = \p1 p2 -> return (),
  renderEllipse = \rect -> return (),
  renderBezierTo = \p1 p2 p3 -> return (),
  -- Text
  renderText = mockRenderText,

  -- Image
  getImage = const . return $ Just $ ImageDef "test" def BS.empty [],
  addImage = \name size imgData flags -> return (),
  updateImage = \name size imgData -> return (),
  deleteImage = \name -> return ()
}

mockFontManager :: FontManager
mockFontManager = FontManager {
  computeTextMetrics = mockTextMetrics 1,
  computeTextMetrics_ = mockTextMetrics,
  computeTextSize = mockTextSize (Just 10) 1,
  computeTextSize_ = mockTextSize (Just 10),
  computeGlyphsPos = mockGlyphsPos (Just 10) 1,
  computeGlyphsPos_ = mockGlyphsPos (Just 10)
}
mockWenv :: s -> WidgetEnv s e
mockWenv model = WidgetEnv {
  _weOs = "Mac OS X",
  _weDpr = 2,
  _weAppStartTs = 0,
  _weFontManager = mockFontManager,
  _weFindBranchByPath = const Seq.empty,
  _weMainButton = BtnLeft,
  _weContextButton = BtnRight,
  _weTheme = def,
  _weWindowSize = testWindowSize,
  _weWidgetShared = unsafePerformIO (newMVar M.empty),
  _weWidgetKeyMap = M.empty,
  _weHoveredPath = Nothing,
  _weFocusedPath = emptyPath,
  _weOverlayPath = Nothing,
  _weDragStatus = Nothing,
  _weMainBtnPress = Nothing,
  _weCursor = Nothing,
  _weModel = model,
  _weInputStatus = def,
  _weTimestamp = 0,
  _weThemeChanged = False,
  _weInTopLayer = const True,
  _weLayoutDirection = LayoutNone,
  _weViewport = Rect 0 0 testW testH,
  _weOffset = def,
  _weIsGhci = False
}

mockWenvEvtUnit :: s -> WidgetEnv s ()
mockWenvEvtUnit model = mockWenv model

nodeInit :: (Eq s) => WidgetEnv s e -> WidgetNode s e -> WidgetNode s e
nodeInit wenv node = nodeHandleEventRoot wenv [] node

nodeMerge :: WidgetEnv s e -> WidgetNode s e -> WidgetNode s e -> WidgetNode s e
nodeMerge wenv node oldNode = resNode where
  newNode = node
    & L.info . L.path .~ oldNode ^. L.info . L.path
  WidgetResult resNode _ = widgetMerge (newNode^. L.widget) wenv newNode oldNode

nodeGetSizeReq :: WidgetEnv s e -> WidgetNode s e -> (SizeReq, SizeReq)
nodeGetSizeReq wenv node = (sizeReqW,  sizeReqH) where
  WidgetResult node2 _ = widgetInit (node ^. L.widget) wenv node
  sizeReqW = node2 ^. L.info . L.sizeReqW
  sizeReqH = node2 ^. L.info . L.sizeReqH

nodeResize :: WidgetEnv s e -> WidgetNode s e -> Rect -> WidgetNode s e
nodeResize wenv node viewport = result ^. L.node where
  resizeCheck = const True
  widget = node ^. L.widget
  result = widgetResize widget wenv node viewport resizeCheck

nodeHandleEventCtx
  :: (Eq s)
  => WidgetEnv s e
  -> [SystemEvent]
  -> WidgetNode s e
  -> MonomerCtx s e
nodeHandleEventCtx wenv evts node = ctx where
  ctx = nodeHandleEventCtx_ wenv WInit evts node

nodeHandleEventCtx_
  :: (Eq s)
  => WidgetEnv s e
  -> InitWidget
  -> [SystemEvent]
  -> WidgetNode s e
  -> MonomerCtx s e
nodeHandleEventCtx_ wenv init evts node = ctx where
  ctx = snd $ nodeHandleEvents wenv init evts node

nodeHandleEventModel
  :: (Eq s)
  => WidgetEnv s e
  -> [SystemEvent]
  -> WidgetNode s e
  -> s
nodeHandleEventModel wenv evts node = model where
  model = nodeHandleEventModel_ wenv WInit evts node

nodeHandleEventModel_
  :: (Eq s)
  => WidgetEnv s e
  -> InitWidget
  -> [SystemEvent]
  -> WidgetNode s e
  -> s
nodeHandleEventModel_ wenv init evts node = _weModel wenv2 where
  (wenv2, _, _) = fst $ nodeHandleEvents wenv init evts node

nodeHandleEventRoot
  :: (Eq s)
  => WidgetEnv s e
  -> [SystemEvent]
  -> WidgetNode s e
  -> WidgetNode s e
nodeHandleEventRoot wenv evts node = newRoot where
  newRoot = nodeHandleEventRoot_ wenv WInit evts node

nodeHandleEventRoot_
  :: (Eq s)
  => WidgetEnv s e
  -> InitWidget
  -> [SystemEvent]
  -> WidgetNode s e
  -> WidgetNode s e
nodeHandleEventRoot_ wenv init evts node = newRoot where
  (_, newRoot, _) = fst $ nodeHandleEvents wenv init evts node

nodeHandleEventReqs
  :: (Eq s)
  => WidgetEnv s e
  -> [SystemEvent]
  -> WidgetNode s e
  -> Seq (WidgetRequest s e)
nodeHandleEventReqs wenv evts node = reqs where
  reqs = nodeHandleEventReqs_ wenv WInit evts node

nodeHandleEventReqs_
  :: (Eq s)
  => WidgetEnv s e
  -> InitWidget
  -> [SystemEvent]
  -> WidgetNode s e
  -> Seq (WidgetRequest s e)
nodeHandleEventReqs_ wenv init evts node = reqs where
  (_, _, reqs) = fst $ nodeHandleEvents wenv init evts node

nodeHandleEventEvts
  :: (Eq s)
  => WidgetEnv s e
  -> [SystemEvent]
  -> WidgetNode s e
  -> Seq e
nodeHandleEventEvts wenv evts node = newEvts where
  newEvts = nodeHandleEventEvts_ wenv WInit evts node

nodeHandleEventEvts_
  :: (Eq s)
  => WidgetEnv s e
  -> InitWidget
  -> [SystemEvent]
  -> WidgetNode s e
  -> Seq e
nodeHandleEventEvts_ wenv init evts node = eventsFromReqs reqs where
  (_, _, reqs) = fst $ nodeHandleEvents wenv init evts node

nodeHandleEvents
  :: (Eq s)
  => WidgetEnv s e
  -> InitWidget
  -> [SystemEvent]
  -> WidgetNode s e
  -> (HandlerStep s e, MonomerCtx s e)
nodeHandleEvents wenv init evts node = result where
  steps = case init of
    WInit -> tail $ nodeHandleEvents_ wenv init [evts] node
    WInitKeepFirst -> nodeHandleEvents_ wenv WInit [evts] node
    _ -> nodeHandleEvents_ wenv init [evts] node
  result = foldl1 stepper steps
  stepper step1 step2 = result where
    ((_, _, reqs1), _) = step1
    ((wenv2, root2, reqs2), ctx2) = step2
    result = ((wenv2, root2, reqs1 <> reqs2), ctx2)

nodeHandleEvents_
  :: (Eq s)
  => WidgetEnv s e
  -> InitWidget
  -> [[SystemEvent]]
  -> WidgetNode s e
  -> [(HandlerStep s e, MonomerCtx s e)]
nodeHandleEvents_ wenv init evtsG node = unsafePerformIO $ do
  -- Do NOT test code involving SDL Window functions
  channel <- liftIO newTChanIO

  fmap fst $ flip runStateT (monomerCtx channel) $ do
    L.inputStatus .= wenv ^. L.inputStatus
    handleResourcesInit

    stepA <- if init == WInit
      then do
        handleWidgetInit wenv pathReadyRoot
      else
        return (wenv, pathReadyRoot, Seq.empty)

    ctxA <- get
    let (wenvA, nodeA, reqsA) = stepA
    let resizeCheck = const True
    let resizeRes = widgetResize (nodeA ^. L.widget) wenv nodeA vp resizeCheck
    step <- handleWidgetResult wenvA True resizeRes
    ctx <- get
    let (wenvr, rootr, reqsr) = step

    (_, _, steps) <- foldM runStep (wenvr, rootr, [(step, ctx)]) evtsG

    return $ if init == WInit
      then (stepA, ctxA) : reverse steps
      else reverse steps
  where
    winSize = _weWindowSize wenv
    vp = Rect 0 0 (_sW winSize) (_sH winSize)
    dpr = 1
    epr = 1
    model = _weModel wenv
    monomerCtx channel = initMonomerCtx undefined channel winSize dpr epr model
    pathReadyRoot = node
      & L.info . L.path .~ rootPath
      & L.info . L.widgetId .~ WidgetId (wenv ^. L.timestamp) rootPath
    runStep (wenv, root, accum) evts = do
      step <- handleSystemEvents wenv root evts
      ctx <- get
      let (wenv2, root2, reqs2) = step

      return (wenv2, root2, (step, ctx) : accum)

nodeHandleResult
  :: (Eq s)
  => WidgetEnv s e
  -> WidgetResult s e
  -> (HandlerStep s e, MonomerCtx s e)
nodeHandleResult wenv result = unsafePerformIO $ do
  channel <- liftIO newTChanIO

  let winSize = _weWindowSize wenv
  let dpr = 1
  let epr = 1
  let model = _weModel wenv
  -- Do NOT test code involving SDL Window functions
  let monomerCtx = initMonomerCtx undefined channel winSize dpr epr model

  flip runStateT monomerCtx $ do
    L.inputStatus .= wenv ^. L.inputStatus
    handleResourcesInit

    handleWidgetResult wenv True result

roundRectUnits :: Rect -> Rect
roundRectUnits (Rect x y w h) = Rect nx ny nw nh where
  nx = fromIntegral (round x)
  ny = fromIntegral (round y)
  nw = fromIntegral (round w)
  nh = fromIntegral (round h)

useVideoSubSystem :: IO Bool
useVideoSubSystem = do
  (== Just "1") <$> lookupEnv "USE_SDL_VIDEO_SUBSYSTEM"

testInVideoSubSystem :: Expectation -> Expectation
testInVideoSubSystem expectation = do
  useVideo <- useVideoSubSystem
  if useVideo then
    expectation
  else
    pendingWith "SDL Video sub system not initialized. Skipping."