{-# LANGUAGE CPP #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TypeApplications #-}
{-|
Module      : HsLua.Marshalling.PushTests
Copyright   : © 2020-2021 Albert Krewinkel
License     : MIT
Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
Stability   : alpha
Portability : OverloadedStrings, TypeApplications

Test pushing Haskell values to the stack.
-}
module HsLua.Marshalling.PushTests (tests) where

import Control.Monad (forM)
import Data.ByteString (ByteString)
import Data.Maybe (fromMaybe)
import HsLua.Core (Lua, Number)
import HsLua.Marshalling.Push

import Lua.Arbitrary ()
import Test.Tasty.HsLua ((=:), pushLuaExpr)
import Test.QuickCheck.Instances ()
import Test.QuickCheck.Monadic (monadicIO, run, assert)
import Test.Tasty (TestTree, testGroup)
import Test.Tasty.HUnit (Assertion, assertFailure)
import Test.Tasty.QuickCheck (Arbitrary, testProperty)

#if !MIN_VERSION_base(4,12,0)
import Data.Semigroup (Semigroup ((<>)))
#endif

import qualified Data.Map as Map
import qualified Data.Set as Set
import qualified HsLua.Core as Lua
import qualified HsLua.Core.Utf8 as Utf8

-- | Calling Haskell functions from Lua.
tests :: TestTree
tests = testGroup "Push"
  [ testGroup "pushBool"
    [ "True" =:
      assertLuaEqual (pushBool True) "true"
    , "False" =:
      assertLuaEqual (pushBool False) "false"

    , testSingleElementProperty pushBool
    ]

  , testGroup "pushIntegral"
    [ testGroup "@Int"
      [ "0" =:
        assertLuaEqual (pushIntegral @Int 0) "0"
      , "23" =:
        assertLuaEqual (pushIntegral @Int 23) "23"
      , "-5" =:
        assertLuaEqual (pushIntegral @Int (-5)) "-5"
      , testSingleElementProperty (pushIntegral @Int)
      ]
    , testGroup "@Integer"
      [ "2^128 + 1" =:
        assertLuaEqual (pushIntegral @Integer
                         340282366920938463463374607431768211457)
                       "'340282366920938463463374607431768211457'"
      , "-2^129 + 1" =:
        assertLuaEqual (pushIntegral @Integer
                        (-680564733841876926926749214863536422911))
                       "'-680564733841876926926749214863536422911'"
      , testSingleElementProperty (pushIntegral @Integer)
      ]
    ]

  , testGroup "pushRealFloat"
    [ testGroup "@Number"
      [ "0.0" =:
        assertLuaEqual (pushRealFloat @Number 0.0) "0.0"
      , "42.0" =:
        assertLuaEqual (pushRealFloat @Number 42.0) "42.0"
      , "0.1" =:
        assertLuaEqual (pushRealFloat @Number 0.1) "0.1"
      , "-13.37" =:
        assertLuaEqual (pushRealFloat @Number (-13.37)) "-13.37"
      , testSingleElementProperty (pushRealFloat @Number)
      ]

    -- This test may fail if Lua is compiled with Float as the Number
    -- type. Usually though, numbers are doubles.
    , testGroup "@Float pushes strings"
      [ "0.0" =:
        assertLuaEqual (pushRealFloat @Float 0.0) "'0.0'"
      , "42.0" =:
        assertLuaEqual (pushRealFloat @Float 42.0) "'42.0'"
      , "-0.00071" =:
        assertLuaEqual (pushRealFloat @Float (-0.00071)) "'-7.1e-4'"
      , "-13.37" =:
        assertLuaEqual (pushRealFloat @Float (-13.37)) "'-13.37'"
      , testSingleElementProperty (pushRealFloat @Float)
      ]
    ]

  , testGroup "Strings"
    [ testGroup "pushByteString"
      [ "\"test\"" =:
        assertLuaEqual (pushByteString "test") "\"test\""
      , testSingleElementProperty pushByteString
      ]

    , testGroup "pushString"
      [ "\"test\"" =:
        assertLuaEqual (pushString "test") "\"test\""
      , "unicode" =:
        assertLuaEqual (pushString "ÄÉÏøûßð") (Utf8.fromString "'ÄÉÏøûßð'")
      , testSingleElementProperty pushString
      ]

    , testGroup "pushText"
      [ "\"test\"" =:
        assertLuaEqual (pushText "test") "\"test\""
      , "unicode" =:
        assertLuaEqual (pushText "ÄÉÏøûßð") (Utf8.fromString "'ÄÉÏøûßð'")
      , testSingleElementProperty pushText
      ]

    , testGroup "pushName"
      [ "\"test\"" =:
        assertLuaEqual (pushName "test") "\"test\""
      , "unicode" =:
        assertLuaEqual (pushName "ÄÉÏøûßð") (Utf8.fromString "'ÄÉÏøûßð'")
      , testSingleElementProperty (pushName . Lua.Name)
      ]
    ]

  , testGroup "Collections"
    [ testGroup "pushList"
      [ testProperty "creates a table" $ \x -> monadicIO $ do
          producesTable <- run $ Lua.run @Lua.Exception $ do
            pushList pushBool x
            listType <- Lua.ltype Lua.top
            return $ Lua.TypeTable == listType
          assert producesTable

      , testProperty "numeric indices start at 1" $ \list -> monadicIO $ do
          retrievedList <- run $ Lua.run @Lua.Exception $ do
            pushList (pushIntegral @Lua.Integer) list
            listIdx <- Lua.absindex Lua.top
            forM [1..(fromIntegral $ length list)] $ \n ->
              Lua.rawgeti listIdx n
              *> (fromMaybe 0 <$> Lua.tointeger Lua.top)
              <* Lua.pop 1
          assert $ retrievedList == list

      , testProperty "table size equals list length" $ \list -> monadicIO $ do
          tableSize <- run $ Lua.run @Lua.Exception $ do
            pushList pushString list
            Lua.rawlen Lua.top
          assert $ tableSize == length list

      , testSingleElementProperty (pushList pushText)
      ]

    , testGroup "pushKeyValuePairs"
      [ testProperty "creates a table" $ \x -> monadicIO $ do
          producesTable <- run $ Lua.run @Lua.Exception $ do
            pushKeyValuePairs pushText (pushIntegral @Int) x
            listType <- Lua.ltype Lua.top
            return $ Lua.TypeTable == listType
          assert producesTable

      , testSingleElementProperty $
        pushKeyValuePairs (pushIntegral @Int) pushText
      ]

    , testGroup "pushSet"
      [ testProperty "creates a table" $ \x -> monadicIO $ do
          producesTable <- run $ Lua.run @Lua.Exception $ do
            pushSet pushString x
            listType <- Lua.ltype Lua.top
            return $ Lua.TypeTable == listType
          assert producesTable

      , testProperty "set values become table keys" $ \set -> monadicIO $
          case Set.lookupMin set of
            Nothing -> return ()
            Just el -> do
              hasKey <- run $ Lua.run @Lua.Exception $ do
                pushSet (pushIntegral @Lua.Integer) set
                pushIntegral el
                Lua.gettable (Lua.nth 2)
                Lua.toboolean Lua.top
              assert hasKey

      , testSingleElementProperty (pushSet pushText)
      ]

    , testGroup "pushMap"
      [ testProperty "creates a table" $ \m -> monadicIO $ do
          producesTable <- run $ Lua.run @Lua.Exception $ do
            pushMap pushString pushString m
            listType <- Lua.ltype Lua.top
            return $ Lua.TypeTable == listType
          assert producesTable

      , testProperty "pairs are in table" $ \m -> monadicIO $
          case Map.lookupMax m of
            Nothing -> return ()
            Just (k, v) -> do
              tabVal <- run $ Lua.run @Lua.Exception $ do
                pushMap pushText (pushRealFloat @Lua.Number) m
                pushText k
                Lua.gettable (Lua.nth 2)
                fromMaybe (error "key not found") <$>
                  Lua.tonumber Lua.top
              assert (tabVal == v)

      , testSingleElementProperty (pushMap pushText (pushRealFloat @Double))
      ]
    ]
  , testGroup "Combinators"
    [ testProperty "pushPair" $ \(a, b) -> monadicIO $ do
        mpair <- run $ Lua.run @Lua.Exception $ do
          pushPair pushIntegral pushByteString (a, b)
          ma <- Lua.rawgeti Lua.top 1 *> Lua.tointeger Lua.top <* Lua.pop 1
          mb <- Lua.rawgeti Lua.top 2 *> Lua.tostring Lua.top  <* Lua.pop 1
          return $ (,) <$> ma <*> mb
        assert (mpair == Just (a, b))

    , testProperty "pushTriple" $ \(a, b, c) -> monadicIO $ do
        mpair <- run $ Lua.run @Lua.Exception $ do
          pushTriple pushIntegral pushByteString Lua.pushnumber (a, b, c)
          ma <- Lua.rawgeti Lua.top 1 *> Lua.tointeger Lua.top <* Lua.pop 1
          mb <- Lua.rawgeti Lua.top 2 *> Lua.tostring Lua.top  <* Lua.pop 1
          mc <- Lua.rawgeti Lua.top 3 *> Lua.tonumber Lua.top  <* Lua.pop 1
          return $ (,,) <$> ma <*> mb <*> mc
        assert (mpair == Just (a, b, c))
    ]
  ]

-- | Executes a Lua action and checks whether a the value at the top of the
-- stack equals the value represented by the string.
assertLuaEqual :: Lua () -> ByteString -> Assertion
assertLuaEqual action lit =
  let comparison = Lua.run $ do
        action
        pushLuaExpr lit
        isSame <- Lua.rawequal (Lua.nth 1) (Lua.nth 2)
        if isSame
          then return Nothing
          else do
            expectedType <- Lua.ltype (Lua.nth 1) >>= Lua.typename
            actualType <- Lua.ltype (Lua.nth 2) >>= Lua.typename
            actual <- Lua.tostring' (Lua.nth 2)
            return . Just . Utf8.toString $
              "Expected '" <> lit <> "' (" <> expectedType <>
              ") but got '" <> actual <> "'" <> " (" <> actualType <> ")"
  in comparison >>= \case
    Nothing -> return ()
    Just err -> assertFailure err


-- | Verifies that the operation adds exactly one element to the Lua stack.
testSingleElementProperty :: (Arbitrary a, Show a)
                          => Pusher Lua.Exception a -> TestTree
testSingleElementProperty push = testProperty "pushes single element" $ \x ->
  monadicIO $ do
    (oldSize, newSize) <- run . Lua.run $ do
      old <- Lua.gettop
      push x
      new <- Lua.gettop
      return (old, new)
    assert (newSize == succ oldSize)