{-# LANGUAGE Arrows #-}
{-# LANGUAGE CPP    #-}
-- |
-- Description : Test cases for signal functions working with events
-- Copyright   : (c) Antony Courtney and Henrik Nilsson, Yale University, 2003-2004
-- Authors     : Antony Courtney, Henrik Nilsson

-- Notes pertaining to regression tests:
-- - Add test cases for Yampa. There should be at least one test case for each
--   "non-trivial" entity exported from Yampa.
--
-- - Make tests cases for after and repeatedly more robust.  Must not
--   fail due to small discrepancies in floating point implementation.
--
--   01-May-2002:  evsrc_t7 currently fails in hugs.
module Test.FRP.Yampa.EventS
    ( tests
    )
  where

#if __GLASGOW_HASKELL__ < 710
import Control.Applicative ((<*>))
import Data.Functor        ((<$>))
#endif
import Test.QuickCheck hiding (once, sample)
import Test.Tasty (TestTree, testGroup)
import Test.Tasty.QuickCheck (testProperty)

import FRP.Yampa as Yampa
import FRP.Yampa.EventS (snap, sampleWindow, recur, andThen, snapAfter, sample)
import FRP.Yampa.Stream
import FRP.Yampa.QuickCheck
import FRP.Yampa.LTLFuture

import TestsCommon

tests :: TestTree
tests = testGroup "Regression tests for FRP.Yampa.EventS"
  [ testProperty "never (0, fixed)"         (property $ evsrc_t0 ~= evsrc_t0r)
  , testProperty "Events > No event"        prop_event_noevent
  , testProperty "eventS (1, fixed)"        (property $ evsrc_t1 ~= evsrc_t1r)
  , testProperty "Events > Now"             prop_event_now
  , testProperty "eventS (2, fixed)"        (property $ evsrc_t2 ~= evsrc_t2r)
  , testProperty "Events > After 0.0"       prop_event_after_0
  , testProperty "eventS (3, fixed)"        (property $ evsrc_t3 ~= evsrc_t3r)
  , testProperty "eventS (4, fixed)"        (property $ evsrc_t4 ~= evsrc_t4r)
  , testProperty "eventS (5, fixed)"        (property $ evsrc_t5 ~= evsrc_t5r)
  , testProperty "eventS (6, fixed)"        (property $ evsrc_t6 ~= evsrc_t6r)
  , testProperty "eventS (7, fixed)"        (property $ evsrc_t7 ~= evsrc_t7r)
  , testProperty "eventS (8, fixed)"        (property $ evsrc_t8 ~= evsrc_t8r)
  , testProperty "eventS (9, fixed)"        (property $ evsrc_t9 ~= evsrc_t9r)
  , testProperty "eventS (10, fixed)"       (property $ evsrc_t10 ~= evsrc_t10r)
  , testProperty "eventS (11, fixed)"       (property $ evsrc_t11 ~= evsrc_t11r)
  , testProperty "eventS (28, fixed)"       (property $ evsrc_t28 ~= evsrc_t28r)
  , testProperty "delayEvent (0, fixed)"    (property $ evsrc_t30 ~= evsrc_t30r)
  , testProperty "delayEvent (1, qc)"       propDelayEvent
  , testProperty "delayEventCat (0, fixed)" (property $ evsrc_t29 ~= evsrc_t29r)
  , testProperty "eventS (12, fixed)"       (property $ evsrc_t12 ~= evsrc_t12r)
  , testProperty "eventS (13, fixed)"       (property $ evsrc_t13 ~= evsrc_t13r)
  , testProperty "iEdge (0, qc)"            propIEdge
  , testProperty "edgeTag (0, qc)"          propEdgeTag
  , testProperty "edgeJust (0, qc)"         propEdgeJust
  , testProperty "eventS (14, fixed)"       (property $ evsrc_t14 ~= evsrc_t14r)
  , testProperty "eventS (15, fixed)"       (property $ evsrc_t15 ~= evsrc_t15r)
  , testProperty "eventS (16, fixed)"       (property $ evsrc_t16 ~= evsrc_t16r)
  , testProperty "notYet (0, qc)"           propNotYet
  , testProperty "eventS (17, fixed)"       (property $ evsrc_t17 ~= evsrc_t17r)
  , testProperty "eventS (18, fixed)"       (property $ evsrc_t18 ~= evsrc_t18r)
  , testProperty "eventS (19, fixed)"       (property $ evsrc_t19 ~= evsrc_t19r)
  , testProperty "eventS (20, fixed)"       (property $ evsrc_t20 ~= evsrc_t20r)
  , testProperty "eventS (21, fixed)"       (property $ evsrc_t21 ~= evsrc_t21r)
  , testProperty "eventS (22, fixed)"       (property $ evsrc_t22 ~= evsrc_t22r)
  , testProperty "eventS (23, fixed)"       (property $ evsrc_t23 ~= evsrc_t23r)
  , testProperty "eventS (24, fixed)"       (property $ evsrc_t24 ~= evsrc_t24r)
  , testProperty "eventS (25, fixed)"       (property $ evsrc_t25 ~= evsrc_t25r)
  , testProperty "eventS (26, fixed)"       (property $ evsrc_t26 ~= evsrc_t26r)
  , testProperty "eventS (27, fixed)"       (property $ evsrc_t27 ~= evsrc_t27r)
  , testProperty "snap (fixed)"             (property $ utils_t10 ~= utils_t10r)
  , testProperty "snapAfter (fixed)"        (property $ utils_t11 ~= utils_t11r)
  , testProperty "sample (fixed)"           (property $ utils_t12 ~= utils_t12r)
  , testProperty "sampleWindow (0, fixed)"  (property $ utils_t15 ~= utils_t15r)
  , testProperty "sampleWindow (1, fixed)"  (property $ utils_t16 ~= utils_t16r)
  , testProperty "after (0, fixed)"         (property $ utils_t13 ~= utils_t13r)
  , testProperty "after (1, fixed)"         (property $ utils_t14 ~= utils_t14r)
  ]

-- * Basic event sources

evsrc_t0 :: [Event ()]
evsrc_t0 = testSF1 never

evsrc_t0r =
  [ NoEvent, NoEvent, NoEvent, NoEvent  -- 0.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 1.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 2.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 3.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 4.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 5.0 s
  , NoEvent
  ]

prop_event_noevent =
    forAll myStream $ evalT $ Always $ prop (sfNever, const (== noEvent))

  where myStream :: Gen (SignalSampleStream Float)
        myStream = uniDistStream
        sfNever :: SF Float (Event Float)
        sfNever = never

evsrc_t1 :: [Event Int]
evsrc_t1 = testSF1 (now 42)

evsrc_t1r :: [Event Int]
evsrc_t1r =
  [ Event 42, NoEvent, NoEvent, NoEvent  -- 0.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 1.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 2.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 3.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 4.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 5.0 s
  , NoEvent
  ]

prop_event_now =
    forAll myStream $ evalT $
      -- (sf, p0) /\ O [] (sf, pn)
      And (prop (sf, p0))                 -- Initially
          (Next $ Always $ prop (sf, pn)) -- After first sample

  where sf = Yampa.now 42.0

        p0 x y = y == Event 42.0
        pn x y = y == noEvent

        myStream :: Gen (SignalSampleStream Float)
        myStream = uniDistStream

evsrc_t2 :: [Event Int]
evsrc_t2 = testSF1 (after 0.0 42)
evsrc_t2r :: [Event Int]
evsrc_t2r =
  [ Event 42, NoEvent, NoEvent, NoEvent  -- 0.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 1.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 2.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 3.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 4.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 5.0 s
  , NoEvent
  ]

prop_event_after_0 =
    forAll myStream $ evalT $
      -- (sf, p0) /\ O [] (sf, pn)
      And (prop (sf, p0))                 -- Initially
          (Next $ Always $ prop (sf, pn)) -- After first sample

  where sf = after 0.0 42.0

        p0 x y = y == Event 42.0
        pn x y = y == noEvent

        myStream :: Gen (SignalSampleStream Float)
        myStream = uniDistStream

evsrc_t3 :: [Event Int]
evsrc_t3 = testSF1 (after 3.0 42)

evsrc_t3r :: [Event Int]
evsrc_t3r =
  [ NoEvent,  NoEvent, NoEvent, NoEvent  -- 0.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 1.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 2.0 s
  , Event 42, NoEvent, NoEvent, NoEvent  -- 3.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 4.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t4 :: [Event Int]
evsrc_t4 = testSF1 (after 3.01 42)

evsrc_t4r :: [Event Int]
evsrc_t4r =
  [ NoEvent, NoEvent,  NoEvent, NoEvent  -- 0.0 s
  , NoEvent, NoEvent,  NoEvent, NoEvent  -- 1.0 s
  , NoEvent, NoEvent,  NoEvent, NoEvent  -- 2.0 s
  , NoEvent, Event 42, NoEvent, NoEvent  -- 3.0 s
  , NoEvent, NoEvent,  NoEvent, NoEvent  -- 4.0 s
  , NoEvent, NoEvent,  NoEvent, NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t5 :: [Event Int]
evsrc_t5 = testSF1 (repeatedly 0.795 42)

evsrc_t5r :: [Event Int]
evsrc_t5r =
  [ NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 0.0 s
  , Event 42, NoEvent,  NoEvent,  Event 42  -- 1.0 s
  , NoEvent,  NoEvent,  Event 42, NoEvent   -- 2.0 s
  , NoEvent,  Event 42, NoEvent,  NoEvent   -- 3.0 s
  , Event 42, NoEvent,  NoEvent,  NoEvent   -- 4.0 s
  , Event 42, NoEvent,  NoEvent,  Event 42  -- 5.0 s
  , NoEvent
  ]

evsrc_t6 :: [Event Int]
evsrc_t6 = testSF1 (repeatedly 0.29999 42)

evsrc_t6r :: [Event Int]
evsrc_t6r =
  [ NoEvent,  NoEvent,  Event 42, Event 42  -- 0.0 s
  , Event 42, Event 42, Event 42, NoEvent   -- 1.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 2.0 s
  , Event 42, NoEvent,  Event 42, Event 42  -- 3.0 s
  , Event 42, Event 42, Event 42, NoEvent   -- 4.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 5.0 s
  , Event 42
  ]

evsrc_t7 :: [Event Int]
evsrc_t7 = testSF1 (repeatedly 0.24 42)

evsrc_t7r :: [Event Int]
evsrc_t7r =
  [ NoEvent,  Event 42, Event 42, Event 42  -- 0.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 1.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 2.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 3.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 4.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 5.0 s
  , Event 42
  ]

evsrc_t8 :: [Event Int]
evsrc_t8 = testSF1 (afterEach [ (0.00, 1), (0.00, 2), (0.01, 3), (0.23, 4)
                              , (0.02, 5), (0.75, 6), (0.10, 7), (0.10, 8)
                              , (0.10, 9), (2.00, 10)
                              ]
                   )

evsrc_t8r :: [Event Int]
evsrc_t8r =
  [ Event 1,  Event 3,  Event 5,  NoEvent  -- 0.0 s
  , NoEvent,  Event 6,  Event 9,  NoEvent  -- 1.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 2.0 s
  , NoEvent,  NoEvent,  Event 10, NoEvent  -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 4.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t9 :: [Event Int]
evsrc_t9 = testSF1 (afterEach [ (2.03, 0)
                              , (0.00, 1), (0.00, 2), (0.01, 3), (0.23, 4)
                              , (0.02, 5), (0.75, 6), (0.10, 7), (0.10, 8)
                              , (0.10, 9), (2.00, 10), (0.00, 11), (0.00, 12)
                              ]
                   )

evsrc_t9r :: [Event Int]
evsrc_t9r =
  [ NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 0.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 1.0 s
  , NoEvent,  Event 0,  Event 4,  NoEvent  -- 2.0 s
  , NoEvent,  Event 6,  Event 9,  NoEvent  -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 4.0 s
  , NoEvent,  NoEvent,  Event 10, NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t10 :: [Event [Int]]
evsrc_t10 = testSF1 (afterEachCat [ (0.00, 1), (0.00, 2), (0.01, 3), (0.23, 4)
                                  , (0.02, 5), (0.75, 6), (0.10, 7), (0.10, 8)
                                  , (0.10, 9), (2.00, 10)
                                  ]
                    )

evsrc_t10r :: [Event [Int]]
evsrc_t10r =
  [ Event [1,2],  Event [3,4],    Event [5],  NoEvent  -- 0.0 s
  , NoEvent,      Event [6,7,8],  Event [9],  NoEvent  -- 1.0 s
  , NoEvent,      NoEvent,        NoEvent,    NoEvent  -- 2.0 s
  , NoEvent,      NoEvent,        Event [10], NoEvent  -- 3.0 s
  , NoEvent,      NoEvent,        NoEvent,    NoEvent  -- 4.0 s
  , NoEvent,      NoEvent,        NoEvent,    NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t11 :: [Event [Int]]
evsrc_t11 = testSF1 (afterEachCat [ (2.03, 0)
                                  , (0.00, 1), (0.00, 2), (0.01, 3), (0.23, 4)
                                  , (0.02, 5), (0.75, 6), (0.10, 7), (0.10, 8)
                                  , (0.10, 9), (2.00, 10)
                                  ]
                    )

evsrc_t11r :: [Event [Int]]
evsrc_t11r =
  [ NoEvent,  NoEvent,         NoEvent,     NoEvent  -- 0.0 s
  , NoEvent,  NoEvent,         NoEvent,     NoEvent  -- 1.0 s
  , NoEvent,  Event [0,1,2,3], Event [4,5], NoEvent  -- 2.0 s
  , NoEvent,  Event [6,7,8],   Event [9],   NoEvent  -- 3.0 s
  , NoEvent,  NoEvent,         NoEvent,     NoEvent  -- 4.0 s
  , NoEvent,  NoEvent,         Event [10],  NoEvent  -- 5.0 s
  , NoEvent
  ]

propDelayEvent :: Property
propDelayEvent =
    forAll delayFactorG $ \delayFactor ->
    forAll myStream $ evalT $
      Always $ SP $ (==) <$> originalSF delayFactor
                         <*> sfModelDelayEvent delayFactor
  where
    -- SF under test
    originalSF :: Int -> SF () (Event ())
    originalSF factor =
      time
        >>> arr cos
        >>> arr (< 0)
        >>> edge
        >>> delayEvent (fromIntegral factor * delay)

    -- Model SF that applies the delay internally
    sfModelDelayEvent :: Int -> SF () (Event ())
    sfModelDelayEvent factor =
      time
        >>> arr (\x -> x - (fromIntegral factor * delay))
        >>> arr cos
        >>> arr (< 0)
        >>> edge

    -- Generator: Factor by which the signal is delayed
    delayFactorG :: Gen Int
    delayFactorG = getPositive <$> arbitrary

    -- Generator: Random input stream. Delays and values are fixed but the
    -- length is not.
    myStream :: Gen (SignalSampleStream ())
    myStream = fixedDelayStream delay

    -- Constant: Max delay
    delay :: DTime
    delay = 0.01

evsrc_t28 :: [(Event Int, Event Int)]
evsrc_t28 = embed (repeatedly 0.5 ()
                   >>> accumBy (\n _ -> n + 1) 0
                   >>> identity &&& delayEvent 2.0)
                  (deltaEncode 0.125 (replicate 50 ()))

evsrc_t28r =
  [ (NoEvent,NoEvent),  (NoEvent,NoEvent)  -- 0.0 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 1,NoEvent),  (NoEvent,NoEvent)  -- 0.5 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 2,NoEvent),  (NoEvent,NoEvent)  -- 1.0 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 3,NoEvent),  (NoEvent,NoEvent)  -- 1.5 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 4,NoEvent),  (NoEvent,NoEvent)  -- 2.0 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 5,Event 1),  (NoEvent,NoEvent)  -- 2.5 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 6,Event 2),  (NoEvent,NoEvent)  -- 3.0 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 7,Event 3),  (NoEvent,NoEvent)  -- 3.5 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 8,Event 4),  (NoEvent,NoEvent)  -- 4.0 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 9,Event 5),  (NoEvent,NoEvent)  -- 4.5 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 10,Event 6), (NoEvent,NoEvent)  -- 5.0 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 11,Event 7), (NoEvent,NoEvent)  -- 5.5 s
  , (NoEvent,NoEvent),  (NoEvent,NoEvent)
  , (Event 12,Event 8), (NoEvent,NoEvent)  -- 6.0 s
  ]

-- "delayEvent" in a feedback loop. Should work like "repeatedly".
evsrc_t30 :: [(Event ())]
evsrc_t30 = embed (now ()
                   >>> (loop $
                          arr (uncurry lMerge)
                          >>> delayEvent 1.0
                          >>> arr dup))
                  (deltaEncode 0.125 (replicate 50 ()))

evsrc_t30r :: [(Event ())]
evsrc_t30r =
  [ NoEvent,  NoEvent, NoEvent, NoEvent  -- 0.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 0.5 s
  , Event (), NoEvent, NoEvent, NoEvent  -- 1.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 1.5 s
  , Event (), NoEvent, NoEvent, NoEvent  -- 2.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 2.5 s
  , Event (), NoEvent, NoEvent, NoEvent  -- 3.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 3.5 s
  , Event (), NoEvent, NoEvent, NoEvent  -- 4.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 4.5 s
  , Event (), NoEvent, NoEvent, NoEvent  -- 5.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 5.5 s
  , Event (), NoEvent                    -- 6.0 s
  ]

evsrc_t29 :: [Event [Double]]
evsrc_t29 = embed (time &&& repeatedly 0.5001 ()
                   >>> arr (\(t,e) -> e `tag` t)
                   >>> delayEventCat 3.0)
                  input
  where
    dts   = replicate 40 0.1 ++ [2.0] ++ replicate 40 0.1
    input = ((), [(dt, Just ()) | dt <- dts])

{- Resulting input to the delay for reference:
[ NoEvent,   NoEvent,   NoEvent, NoEvent, NoEvent  -- 0.0 s
, NoEvent,   Event 0.6, NoEvent, NoEvent, NoEvent  -- 0.5 s
, NoEvent,   Event 1.1, NoEvent, NoEvent, NoEvent  -- 1.0 s
, NoEvent,   Event 1.6, NoEvent, NoEvent, NoEvent  -- 1.5 s
, NoEvent,   Event 2.1, NoEvent, NoEvent, NoEvent  -- 2.0 s
, NoEvent,   Event 2.6, NoEvent, NoEvent, NoEvent  -- 2.5 s
, NoEvent,   Event 3.1, NoEvent, NoEvent, NoEvent  -- 3.0 s
, NoEvent,   Event 3.6, NoEvent, NoEvent, NoEvent  -- 3.5 s
, NoEvent                                          -- 4.0 s
, Event 6.0, Event 6.1, NoEvent, NoEvent, NoEvent  -- 6.0 s
, NoEvent,   Event 6.6, NoEvent, NoEvent, NoEvent  -- 6.5 s
, NoEvent,   Event 7.1, NoEvent, NoEvent, NoEvent  -- 7.0 s
, NoEvent,   Event 7.6, NoEvent, NoEvent, NoEvent  -- 7.5 s
, NoEvent,   Event 8.1, NoEvent, NoEvent, NoEvent  -- 8.0 s
, NoEvent,   Event 8.6, NoEvent, NoEvent, NoEvent  -- 8.5 s
, NoEvent,   Event 9.1, NoEvent, NoEvent, NoEvent  -- 9.0 s
, NoEvent,   Event 9.6, NoEvent, NoEvent, NoEvent  -- 9.5 s
, NoEvent                                          -- 10.0 s
]
-}

evsrc_t29r =
  [ NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent  -- 0.0 s
  , NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent  -- 0.5 s
  , NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent  -- 1.0 s
  , NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent  -- 1.5 s
  , NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent  -- 2.0 s
  , NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent  -- 2.5 s
  , NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent  -- 3.0 s
  , NoEvent, Event [0.6], NoEvent, NoEvent, NoEvent  -- 3.5 s
  , NoEvent                                          -- 4.0 s
  , Event [1.1, 1.6, 2.1, 2.6]                       -- 6.0 s
           , NoEvent,     Event [3.1], NoEvent, NoEvent
  , NoEvent, NoEvent,     Event [3.6], NoEvent, NoEvent  -- 6.5 s
  , NoEvent, NoEvent,     NoEvent,     NoEvent, NoEvent  -- 7.0 s
  , NoEvent, NoEvent,     NoEvent,     NoEvent, NoEvent  -- 7.5 s
  , NoEvent, NoEvent,     NoEvent,     NoEvent, NoEvent  -- 8.0 s
  , NoEvent, NoEvent,     NoEvent,     NoEvent, NoEvent  -- 8.5 s
  , NoEvent, Event [6.0], Event [6.1], NoEvent, NoEvent  -- 9.0 s
  , NoEvent, NoEvent,     Event [6.6], NoEvent, NoEvent  -- 9.5 s
  , NoEvent                                              -- 10.0 s
  ]

evsrc_t12 :: [Event ()]
evsrc_t12 = testSF1 (localTime >>> arr (>=0) >>> edge)

evsrc_t12r =
  [ NoEvent, NoEvent, NoEvent, NoEvent  -- 0.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 1.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 2.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 3.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 4.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t13 :: [Event ()]
evsrc_t13 = testSF1 (localTime >>> arr (>=4.26) >>> edge)

evsrc_t13r =
  [ NoEvent, NoEvent, NoEvent,  NoEvent  -- 0.0 s
  , NoEvent, NoEvent, NoEvent,  NoEvent  -- 1.0 s
  , NoEvent, NoEvent, NoEvent,  NoEvent  -- 2.0 s
  , NoEvent, NoEvent, NoEvent,  NoEvent  -- 3.0 s
  , NoEvent, NoEvent, Event (), NoEvent  -- 4.0 s
  , NoEvent, NoEvent, NoEvent,  NoEvent  -- 5.0 s
  , NoEvent
  ]

propIEdge :: Property
propIEdge =
    forAll initialValG $ \initialVal ->
    forAll myStream $ evalT $
      Always $ SP $ (==) <$> originalSF initialVal <*> modelSF initialVal
  where
    -- SF under test
    originalSF :: Bool -> SF Bool (Event ())
    originalSF = iEdge

    -- Model SF that behaves like edge except for the initial sample
    modelSF :: Bool -> SF Bool (Event ())
    modelSF k = proc (x) -> do
      t <- time -< ()
      e <- edge -< x

      let result | t == 0 && not k && x = Event ()
                 | t == 0 && k          = NoEvent
                 | otherwise            = e

      returnA -< result

    -- Generator: Initialization value for iEdge
    initialValG :: Gen Bool
    initialValG = arbitrary

    -- Generator: Random input stream.
    myStream :: Gen (SignalSampleStream Bool)
    myStream = uniDistStream

propEdgeTag :: Property
propEdgeTag =
    forAll paramValG $ \paramVal ->
    forAll myStream $ evalT $
      Always $ SP $ (==) <$> originalSF paramVal <*> modelSF paramVal
  where
    -- SF under test
    originalSF :: Int -> SF Bool (Event Int)
    originalSF = edgeTag

    -- Model SF that tags the value in the event, after applying edge
    modelSF :: Int -> SF Bool (Event Int)
    modelSF k = edge >>^ arr (tagWith k)

    -- Generator: Tagging value
    paramValG :: Gen Int
    paramValG = arbitrary

    -- Generator: Random input stream.
    myStream :: Gen (SignalSampleStream Bool)
    myStream = uniDistStream

propEdgeJust :: Property
propEdgeJust =
    forAll myStream $ evalT $
      Always $ SP $ (==) <$> originalSF <*> modelSF
  where
    -- SF under test
    originalSF :: SF (Maybe Int) (Event Int)
    originalSF = edgeJust

    -- Model SF
    modelSF :: SF (Maybe Int) (Event Int)
    modelSF = loopPre (Just 0) $ arr $ \v@(n, _) ->
      case v of
        (Just x, Nothing) -> (Event x, n)
        _                 -> (NoEvent, n)

    -- Generator: Random input stream.
    myStream :: Gen (SignalSampleStream (Maybe Int))
    myStream = uniDistStream

-- Raising edge detector.
evsrc_isEdge False False = Nothing
evsrc_isEdge False True  = Just ()
evsrc_isEdge True  True  = Nothing
evsrc_isEdge True  False = Nothing

evsrc_t14 :: [Event ()]
evsrc_t14 = testSF1 (localTime >>> arr (>=0) >>> edgeBy evsrc_isEdge False)

evsrc_t14r =
  [ Event (), NoEvent, NoEvent, NoEvent  -- 0.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 1.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 2.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 3.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 4.0 s
  , NoEvent,  NoEvent, NoEvent, NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t15 :: [Event ()]
evsrc_t15 = testSF1 (localTime >>> arr (>=4.26) >>> edgeBy evsrc_isEdge False)

evsrc_t15r =
  [ NoEvent, NoEvent, NoEvent,  NoEvent  -- 0.0 s
  , NoEvent, NoEvent, NoEvent,  NoEvent  -- 1.0 s
  , NoEvent, NoEvent, NoEvent,  NoEvent  -- 2.0 s
  , NoEvent, NoEvent, NoEvent,  NoEvent  -- 3.0 s
  , NoEvent, NoEvent, Event (), NoEvent  -- 4.0 s
  , NoEvent, NoEvent, NoEvent,  NoEvent  -- 5.0 s
  , NoEvent
  ]

-- Raising and falling edge detector.
evsrc_isEdge2 False False = Nothing
evsrc_isEdge2 False True  = Just True
evsrc_isEdge2 True  True  = Nothing
evsrc_isEdge2 True  False = Just False

evsrc_t16 :: [Event Bool]
evsrc_t16 = testSF1 (localTime
                    >>> arr (\t -> t >=2.01 && t <= 4.51)
                    >>> edgeBy evsrc_isEdge2 True)

evsrc_t16r =
  [ Event False, NoEvent,    NoEvent, NoEvent      -- 0.0 s
  , NoEvent,     NoEvent,    NoEvent, NoEvent      -- 1.0 s
  , NoEvent,     Event True, NoEvent, NoEvent      -- 2.0 s
  , NoEvent,     NoEvent,    NoEvent, NoEvent      -- 3.0 s
  , NoEvent,     NoEvent,    NoEvent, Event False  -- 4.0 s
  , NoEvent,     NoEvent,    NoEvent, NoEvent      -- 5.0 s
  , NoEvent
  ]

-- * Stateful event suppression

propNotYet :: Property
propNotYet =
    forAll myStream $ evalT $
      Always $ SP $ (==) <$> originalSF
                         <*> modelSF
  where
    -- SF under test
    originalSF :: SF (Event Int) (Event Int)
    originalSF = notYet

    -- Model SF that sets the initial value of an Event signal to noEvent
    modelSF :: SF (Event Int) (Event Int)
    modelSF = const noEvent -=> identity

    -- Generator: Random input stream.
    myStream :: Gen (SignalSampleStream (Event Int))
    myStream = uniDistStream

evsrc_t17 :: [Event Int]
evsrc_t17 = testSF1 (now 17 &&& repeatedly 0.795 42
                     >>> arr (uncurry merge)
                     >>> notYet)

evsrc_t17r :: [Event Int]
evsrc_t17r =
  [ NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 0.0 s
  , Event 42, NoEvent,  NoEvent,  Event 42  -- 1.0 s
  , NoEvent,  NoEvent,  Event 42, NoEvent   -- 2.0 s
  , NoEvent,  Event 42, NoEvent,  NoEvent   -- 3.0 s
  , Event 42, NoEvent,  NoEvent,  NoEvent   -- 4.0 s
  , Event 42, NoEvent,  NoEvent,  Event 42  -- 5.0 s
  , NoEvent
  ]

evsrc_t18 :: [Event Int]
evsrc_t18 = testSF1 (now 42 >>> once)

evsrc_t18r :: [Event Int]
evsrc_t18r =
  [ Event 42, NoEvent,  NoEvent,  NoEvent  -- 0.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 1.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 2.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 4.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t19 :: [Event Int]
evsrc_t19 = testSF1 (repeatedly 0.8 42 >>> once)

evsrc_t19r :: [Event Int]
evsrc_t19r =
  [ NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 0.0 s
  , Event 42, NoEvent,  NoEvent,  NoEvent  -- 1.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 2.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 4.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t20 :: [Event Int]
evsrc_t20 = testSF1 (now 42 >>> takeEvents 0)

evsrc_t20r :: [Event Int]
evsrc_t20r =
  [ NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 0.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 1.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 2.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 4.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t21 :: [Event Int]
evsrc_t21 = testSF1 (now 42 >>> takeEvents 1)

evsrc_t21r :: [Event Int]
evsrc_t21r =
  [ Event 42, NoEvent,  NoEvent,  NoEvent  -- 0.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 1.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 2.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 4.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t22 :: [Event Int]
evsrc_t22 = testSF1 (repeatedly 0.8 42 >>> takeEvents 4)

evsrc_t22r :: [Event Int]
evsrc_t22r =
  [ NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 0.0 s
  , Event 42, NoEvent,  NoEvent,  Event 42  -- 1.0 s
  , NoEvent,  NoEvent,  Event 42, NoEvent   -- 2.0 s
  , NoEvent,  Event 42, NoEvent,  NoEvent   -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 4.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 5.0 s
  , NoEvent
  ]

evsrc_t23 :: [Event Int]
evsrc_t23 = testSF1 (repeatedly 0.2 42 >>> takeEvents 4)

evsrc_t23r :: [Event Int]
evsrc_t23r =
  [ NoEvent,  Event 42, Event 42, Event 42  -- 0.0 s
  , Event 42, NoEvent,  NoEvent,  NoEvent   -- 1.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 2.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 4.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 5.0 s
  , NoEvent
  ]

evsrc_t24 :: [Event Int]
evsrc_t24 = testSF1 (now 42 >>> dropEvents 0)

evsrc_t24r :: [Event Int]
evsrc_t24r =
  [ Event 42, NoEvent,  NoEvent,  NoEvent  -- 0.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 1.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 2.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 4.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t25 :: [Event Int]
evsrc_t25 = testSF1 (now 42 >>> dropEvents 1)

evsrc_t25r :: [Event Int]
evsrc_t25r =
  [ NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 0.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 1.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 2.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 4.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent  -- 5.0 s
  , NoEvent
  ]

evsrc_t26 :: [Event Int]
-- Drop 5 events to get rid of the event at 4.0 s which may or may not happen
-- exactly there.
evsrc_t26 = testSF1 (repeatedly 0.8 42 >>> dropEvents 5)

evsrc_t26r :: [Event Int]
evsrc_t26r =
  [ NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 0.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 1.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 2.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 3.0 s
  , NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 4.0 s
  , Event 42, NoEvent,  NoEvent,  Event 42  -- 5.0 s
  , NoEvent
  ]

evsrc_t27 :: [Event Int]
evsrc_t27 = testSF1 (repeatedly 0.2 42 >>> dropEvents 4)

evsrc_t27r :: [Event Int]
evsrc_t27r =
  [ NoEvent,  NoEvent,  NoEvent,  NoEvent   -- 0.0 s
  , NoEvent,  Event 42, Event 42, Event 42  -- 1.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 2.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 3.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 4.0 s
  , Event 42, Event 42, Event 42, Event 42  -- 5.0 s
  , Event 42
  ]

-- ** Hybrid continuous-to-discrete SF combinators.

utils_t10 :: [Event Double]
utils_t10 = testSF1 snap

utils_t10r =
  [ Event 0.0, NoEvent, NoEvent, NoEvent  -- 0.0 s
  , NoEvent,   NoEvent, NoEvent, NoEvent  -- 1.0 s
  , NoEvent,   NoEvent, NoEvent, NoEvent  -- 2.0 s
  , NoEvent,   NoEvent, NoEvent, NoEvent  -- 3.0 s
  , NoEvent,   NoEvent, NoEvent, NoEvent  -- 4.0 s
  , NoEvent,   NoEvent, NoEvent, NoEvent  -- 5.0 s
  , NoEvent
  ]

utils_t11 :: [Event Double]
utils_t11 = testSF1 (snapAfter 2.6)

utils_t11r =
  [ NoEvent, NoEvent, NoEvent, NoEvent     -- 0.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent     -- 1.0 s
  , NoEvent, NoEvent, NoEvent, Event 11.0  -- 2.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent     -- 3.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent     -- 4.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent     -- 5.0 s
  , NoEvent
  ]

utils_t12 :: [Event Double]
utils_t12 = testSF1 (sample 0.99)

utils_t12r =
  [ NoEvent,    NoEvent, NoEvent, NoEvent  -- 0.0 s
  , Event 4.0,  NoEvent, NoEvent, NoEvent  -- 1.0 s
  , Event 8.0,  NoEvent, NoEvent, NoEvent  -- 2.0 s
  , Event 12.0, NoEvent, NoEvent, NoEvent  -- 3.0 s
  , Event 16.0, NoEvent, NoEvent, NoEvent  -- 4.0 s
  , Event 20.0, NoEvent, NoEvent, NoEvent  -- 5.0 s
  , Event 24.0
  ]

utils_t15 = take 50 (embed (time >>> sampleWindow 5 0.5)
                           (deltaEncode 0.125 (repeat ())))

utils_t15r =
  [ NoEvent,                     NoEvent, NoEvent, NoEvent  -- 0.0 s
  , Event [0.5],                 NoEvent, NoEvent, NoEvent  -- 0.5 s
  , Event [0.5,1.0],             NoEvent, NoEvent, NoEvent  -- 1.0 s
  , Event [0.5,1.0,1.5],         NoEvent, NoEvent, NoEvent  -- 1.5 s
  , Event [0.5,1.0,1.5,2.0],     NoEvent, NoEvent, NoEvent  -- 2.0 s
  , Event [0.5,1.0,1.5,2.0,2.5], NoEvent, NoEvent, NoEvent  -- 2.5 s
  , Event [1.0,1.5,2.0,2.5,3.0], NoEvent, NoEvent, NoEvent  -- 3.0 s
  , Event [1.5,2.0,2.5,3.0,3.5], NoEvent, NoEvent, NoEvent  -- 3.5 s
  , Event [2.0,2.5,3.0,3.5,4.0], NoEvent, NoEvent, NoEvent  -- 4.0 s
  , Event [2.5,3.0,3.5,4.0,4.5], NoEvent, NoEvent, NoEvent  -- 4.5 s
  , Event [3.0,3.5,4.0,4.5,5.0], NoEvent, NoEvent, NoEvent  -- 5.0 s
  , Event [3.5,4.0,4.5,5.0,5.5], NoEvent, NoEvent, NoEvent  -- 5.5 s
  , Event [4.0,4.5,5.0,5.5,6.0], NoEvent                    -- 6.0 s
  ]

{-
-- Not robust
utils_t16 = take 50 (embed (time >>> sampleWindow 5 0.5) input)
  where
    input = ((), [(dt, Just ()) | dt <- dts])

    dts = replicate 15 0.1
          ++ [1.0, 1.0]
          ++ replicate 15 0.1
          ++ [2.0]
          ++ replicate 10 0.1

utils_t16r =
  [ NoEvent, NoEvent,          NoEvent, NoEvent, NoEvent             -- 0.0
  , NoEvent, Event [0.6],      NoEvent, NoEvent, NoEvent             -- 0.5
  , NoEvent, Event [0.6, 1.1], NoEvent, NoEvent, NoEvent             -- 1.0
  , NoEvent                                                          -- 1.5
  , Event [0.6,1.1,2.5,2.5,2.5]                                      -- 2.5
  , Event [2.5,2.5,2.5,3.5,3.5], NoEvent, NoEvent, NoEvent, NoEvent  -- 3.5
  , NoEvent, Event [2.5,2.5,3.5,3.5,4.1], NoEvent, NoEvent, NoEvent  -- 4.0
  , NoEvent, Event [2.5,3.5,3.5,4.1,4.6], NoEvent, NoEvent, NoEvent  -- 4.5
  , NoEvent                                                          -- 5.0
  , Event [7.0,7.0,7.0,7.0,7.0], NoEvent, NoEvent, NoEvent, NoEvent  -- 7.0
  , NoEvent, Event [7.0,7.0,7.0,7.0,7.6], NoEvent, NoEvent, NoEvent  -- 7.5
  , NoEvent                                                          -- 8.0
  ]
-}

utils_t16 = take 50 (embed (time >>> sampleWindow 5 0.4999) input)
  where
    input = ((), [(dt, Just ()) | dt <- dts])

    dts = replicate 15 0.1
          ++ [1.0, 1.0]
          ++ replicate 15 0.1
          ++ [2.0]
          ++ replicate 10 0.1

utils_t16r =
  [ NoEvent,          NoEvent, NoEvent, NoEvent, NoEvent        -- 0.0
  , Event [0.5],      NoEvent, NoEvent, NoEvent, NoEvent        -- 0.5
  , Event [0.5, 1.0], NoEvent, NoEvent, NoEvent, NoEvent        -- 1.0
  , Event [0.5, 1.0, 1.5]                                       -- 1.5
  , Event [0.5, 1.0, 1.5, 2.5, 2.5]                             -- 2.5
  , Event [1.5, 2.5, 2.5, 3.5, 3.5], NoEvent, NoEvent, NoEvent  -- 3.5
  ,                                                    NoEvent
  , Event [2.5, 2.5, 3.5, 3.5, 4.0], NoEvent, NoEvent, NoEvent  -- 4.0
  ,                                                    NoEvent
  , Event [2.5, 3.5, 3.5, 4.0, 4.5], NoEvent, NoEvent, NoEvent  -- 4.5
  ,                                                    NoEvent
  , Event [3.5, 3.5, 4.0, 4.5, 5.0]                             -- 5.0
  , Event [5.0, 7.0, 7.0, 7.0, 7.0], NoEvent, NoEvent, NoEvent  -- 7.0
  ,                                                    NoEvent
  , Event [7.0, 7.0, 7.0, 7.0, 7.5], NoEvent, NoEvent, NoEvent  -- 7.5
  ,                                                    NoEvent
  , Event [7.0, 7.0, 7.0, 7.5, 8.0]                             -- 8.0
  ]

-- * Repetition and switching

utils_t13 :: [Event ()]
utils_t13 = testSF1 (recur (after 0.99 ()))

utils_t13r =
  [ NoEvent,  NoEvent, NoEvent, NoEvent  -- 0.0 s
  , Event (), NoEvent, NoEvent, NoEvent  -- 1.0 s
  , Event (), NoEvent, NoEvent, NoEvent  -- 2.0 s
  , Event (), NoEvent, NoEvent, NoEvent  -- 3.0 s
  , Event (), NoEvent, NoEvent, NoEvent  -- 4.0 s
  , Event (), NoEvent, NoEvent, NoEvent  -- 5.0 s
  , Event ()
  ]

utils_t14 :: [Event Int]
utils_t14 = testSF1 (after 1.0 1 `andThen` now 2 `andThen` after 2.0 3)

utils_t14r =
  [ NoEvent, NoEvent, NoEvent, NoEvent  -- 0.0 s
  , Event 1, NoEvent, NoEvent, NoEvent  -- 1.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 2.0 s
  , Event 3, NoEvent, NoEvent, NoEvent  -- 3.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 4.0 s
  , NoEvent, NoEvent, NoEvent, NoEvent  -- 5.0 s
  , NoEvent
  ]

-- * Auxiliary

-- prop :: SF a b -> (a -> b ->
prop (a,b) = SP ((identity &&& a) >>^ uncurry b)

-- * Arbitrary value generation

instance Arbitrary a => Arbitrary (Event a) where
  arbitrary = oneof [ return NoEvent
                    , do x <- arbitrary
                         return $ Event x
                    ]