{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
module Decoder
  ( decoderTests
  ) where

import           Prelude                    (Char, Eq, Int, Show (show), String,
                                             print, (==))

import           Control.Applicative        (liftA3, (<$>))
import           Control.Category           ((.))
import           Control.Monad              (Monad, (>=>), (>>=))

import           Test.Tasty                 (TestTree, testGroup)
import           Test.Tasty.HUnit           (Assertion, assertBool, assertEqual,
                                             assertFailure, testCase, (@?=))

import           Data.Bool                  (Bool (..))
import qualified Data.ByteString            as BS
import qualified Data.Either                as Either
import           Data.Function              (const, ($))
import           Data.Maybe                 (Maybe (Just, Nothing))
import           Data.Semigroup             (Semigroup ((<>)))
import qualified Data.Sequence              as Seq
import           Data.Tagged                (untag)
import           Data.Text                  (Text)

import qualified Natural                    as N

import           Waargonaut.Generic         (mkDecoder)

import           Waargonaut.Decode.Internal (ZipperMove (BranchFail),
                                             ppCursorHistory, unCursorHistory')

import qualified Waargonaut.Decode          as D
import qualified Waargonaut.Decode.Error    as D

import           Types.Common               (imageDecodeSuccinct, parseBS,
                                             testImageDataType)

decoderTests :: TestTree
decoderTests = testGroup "Decoding"
  [ testCase "Image (test1.json)" decodeTest1Json
  , testCase "[Int]" decodeTest2Json
  , testCase "(Char,String,[Int])" decodeTest3Json
  , testCase "Fail with Bad Key" decodeTestBadObjKey
  , testCase "Fail with Missing Key" decodeTestMissingObjKey
  , testCase "Enum" decodeTestEnum
  , testCase "Enum and throwError" decodeTestEnumError
  , testCase "Using Alt" decodeAlt
  , testCase "Using Alt (Error) - Records BranchFail" decodeAltError
  , testCase "List Decoder" listDecoder
  , testCase "NonEmpty List Decoder" nonEmptyDecoder
  , testCase "Object Decoder" objectAsKeyValuesDecoder
  , testCase "Absent Key Decoder" absentKeyDecoder
  , testCase "Either decoding order - Right first" decodeEitherRightFirst
  ]

nonEmptyDecoder :: Assertion
nonEmptyDecoder = do
  let
    dec = D.runPureDecode (D.nonempty D.int) parseBS . D.mkCursor

    ok = "[1]"
    notOkay = "[]"

    badTypeObj = "{}"
    badTypeText = "\"test\""
    badTypeNum = "3"

    badElem = "[1, \"fred\"]"

  assertBool "NonEmpty Decoder - fail! non-empty list decoder BROKEN. Start panicking" (Either.isRight (dec ok))
  assertBool "NonEmpty Decoder - empty list shouldn't succeed" (Either.isLeft (dec notOkay))
  assertBool "NonEmpty Decoder - invalid element decoder accepted" (Either.isLeft (dec badElem))
  assertBool "NonEmpty Decoder - invalid type accepted - object" (Either.isLeft (dec badTypeObj))
  assertBool "NonEmpty Decoder - invalid type accepted - text" (Either.isLeft (dec badTypeText))
  assertBool "NonEmpty Decoder - invalid type accepted - num" (Either.isLeft (dec badTypeNum))

listDecoder :: Assertion
listDecoder = do
  let
    dec = D.runPureDecode (D.list D.int) parseBS . D.mkCursor

    ok = "[1,2,3]"
    okE = "[]"

    badTypeObj = "{}"
    badTypeText = "\"test\""
    badTypeNum = "3"
    badElem = "[\"fred\", \"susan\"]"

  assertBool "List Decoder - fail! List Decoder BROKEN. Start panicking." (Either.isRight (dec ok))
  assertBool "List Decoder - empty list fail" (Either.isRight (dec okE))
  assertBool "List Decoder - invalid type accepted - object" (Either.isLeft (dec badTypeObj))
  assertBool "List Decoder - invalid type accepted - text" (Either.isLeft (dec badTypeText))
  assertBool "List Decoder - invalid type accepted - num" (Either.isLeft (dec badTypeNum))
  assertBool "List Decoder - invalid element decoder accepted" (Either.isLeft (dec badElem))

objectAsKeyValuesDecoder :: Assertion
objectAsKeyValuesDecoder = do
  let
    dec = D.runPureDecode (D.objectAsKeyValues D.text D.int) parseBS . D.mkCursor

    ok = "{\"1\":1,\"2\":2,\"3\":3}"
    okE = "{}"

    badTypeArray = "[]"
    badTypeText = "\"test\""
    badTypeNum = "3"
    badKey = "{1:1}"
    badValue = "{\"1\":\"fred\", \"2\":\"susan\"}"

  assertBool "Object Decoder - fail! Object Decoder BROKEN. Start panicking." (Either.isRight (dec ok))
  assertBool "Object Decoder - empty list fail" (Either.isRight (dec okE))
  assertBool "Object Decoder - invalid type accepted - object" (Either.isLeft (dec badTypeArray))
  assertBool "Object Decoder - invalid type accepted - text" (Either.isLeft (dec badTypeText))
  assertBool "Object Decoder - invalid type accepted - num" (Either.isLeft (dec badTypeNum))
  assertBool "Object Decoder - invalid key decoder accepted" (Either.isLeft (dec badKey))
  assertBool "Object Decoder - invalid value decoder accepted" (Either.isLeft (dec badValue))

decodeTestMissingObjKey :: Assertion
decodeTestMissingObjKey = do
  let
    j = "{\"foo\":33}"

    d = D.withCursor $ D.down >=> D.fromKey "bar" D.int

  r <- D.runDecode d parseBS (D.mkCursor j)

  Either.either
    (\(e, _) -> assertBool "Incorrect Error - Expected KeyDecodeFailed" (e == D.KeyNotFound "bar"))
    (\_ -> assertFailure "Expected Error!")
    r

decodeTestBadObjKey :: Assertion
decodeTestBadObjKey = do
  let
    j = "{33:33}"

    d = D.withCursor $ D.down >=> D.fromKey "foo" D.int

  r <- D.runDecode d parseBS (D.mkCursor j)

  Either.either
    (\(e, _) -> assertBool "Incorrect Error - Expected KeyDecodeFailed" (e == D.KeyDecodeFailed) )
    (\_ -> assertFailure "Expected Error!")
    r

decodeTest1Json :: Assertion
decodeTest1Json = D.runPureDecode imageDecodeSuccinct parseBS . D.mkCursor
  <$> BS.readFile "test/json-data/test1.json"
  >>= Either.either failWithHistory (assertEqual "Image Decode Failed" testImageDataType)
  where
    failWithHistory (err, hist) = do
      print err
      print (ppCursorHistory hist)
      assertFailure "Decode Failed :("

decodeTest2Json :: Assertion
decodeTest2Json = assertBool "[Int] Decode Success" . Either.isRight
  $ D.runPureDecode listDecode parseBS (D.mkCursor "[23,44]")
  where
    listDecode :: Monad f => D.Decoder f [Int]
    listDecode = untag mkDecoder

decodeTest3Json :: Assertion
decodeTest3Json = assertBool "(Char,String,[Int]) Decode Success" . Either.isRight
  $ D.runPureDecode decoder parseBS (D.mkCursor "[\"a\",\"fred\",1,2,3,4]")
  where
    decoder :: Monad f => D.Decoder f (Char,String,[Int])
    decoder = D.withCursor $ D.down >=> \fstElem -> liftA3 (,,)
      (D.focus D.unboundedChar fstElem)
      (D.moveRight1 fstElem >>= D.focus D.string)
      (D.moveRightN (N.successor' (N.successor' N.zero')) fstElem >>= D.rightwardSnoc [] D.int)

data MyEnum
  = A
  | B
  | C
  deriving (Eq, Show)

decodeMyEnum :: Monad f => D.Decoder f MyEnum
decodeMyEnum = D.oneOf D.text "MyEnum"
  [ ("a", A)
  , ("b", B)
  , ("c", C)
  ]

decodeTestEnum :: Assertion
decodeTestEnum = do
  chk "\"a\"" A
  chk "\"b\"" B
  chk "\"c\"" C
  where
    chk i o =
      D.runPureDecode decodeMyEnum parseBS (D.mkCursor i) @?= (Either.Right o)

decodeTestEnumError :: Assertion
decodeTestEnumError = D.runDecode decodeMyEnum parseBS (D.mkCursor "\"WUT\"")
  >>= Either.either
    (\(e, _) -> assertBool "Incorrect Error!" (e == D.ConversionFailure "MyEnum"))
    (const (assertFailure "Should not succeed"))

decodeEitherAlt :: Monad f => D.Decoder f (Either.Either Text Int)
decodeEitherAlt = D.either D.text D.int

decodeEitherRightFirst :: Assertion
decodeEitherRightFirst = do
  let d = D.runPureDecode (D.either D.scientific D.int) parseBS . D.mkCursor

  d "44e333" @?= Either.Right (Either.Left 44e333)
  d "33" @?= Either.Right (Either.Right 33)

decodeAlt :: Assertion
decodeAlt = do
  t <- D.runDecode decodeEitherAlt parseBS (D.mkCursor "\"FRED\"")
  i <- D.runDecode decodeEitherAlt parseBS (D.mkCursor "33")

  t @?= Either.Right (Either.Left "FRED")
  i @?= Either.Right (Either.Right 33)

decodeAltError :: Assertion
decodeAltError = D.runDecode decodeEitherAlt parseBS (D.mkCursor "{\"foo\":33}")
  >>= Either.either
                 (\(_,h) -> assertBool "BranchFail error not found in history" $
                   case Seq.viewr (unCursorHistory' h) of
                     _ Seq.:> (BranchFail _, _) -> True
                     _                          -> False
                 )
                 (\_ -> assertFailure "Alt Error Test should fail")

absentKeyDecoder :: Assertion
absentKeyDecoder = do
  a <- D.runDecode (D.atKeyOptional "key" D.text) parseBS (D.mkCursor "{\"key\":\"present\"}")
  b <- D.runDecode (D.atKeyOptional "missing" D.text) parseBS (D.mkCursor "{\"key\":\"present\"}")
  c <- D.runDecode (D.atKeyOptional "key" D.int) parseBS (D.mkCursor "{\"key\":\"present\"}")

  a @?= Either.Right (Just "present")
  b @?= Either.Right Nothing
  case c of
    Either.Right _ ->
      assertFailure "atKeyOptional succeeded when it shouldn't have"
    Either.Left (e, _) ->
      assertEqual ("atKeyOptional failed incorrectly: " <> show e) e (D.ConversionFailure "integral")