-- Copyright 2024 United States Government as represented by the Administrator
-- of the National Aeronautics and Space Administration. All Rights Reserved.
--
-- Disclaimers
--
-- Licensed under the Apache License, Version 2.0 (the "License"); you may
-- not use this file except in compliance with the License. You may obtain a
-- copy of the License at
--
-- https://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-- WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-- License for the specific language governing permissions and limitations
-- under the License.
--
-- | Parser for Ogma specs stored in JSON files.
module Language.JSONSpec.Parser where
-- External imports
import Control.Monad.Except (ExceptT (..), runExceptT)
import Data.Aeson (FromJSON (..), Value (..), decode, (.:))
import Data.Aeson.Key (toString)
import qualified Data.Aeson.KeyMap as M
import Data.Aeson.Types (prependFailure, typeMismatch)
import Data.Bifunctor (first)
import Data.ByteString.Lazy (fromStrict)
import Data.JSONPath.Execute (executeJSONPath)
import Data.JSONPath.Parser (jsonPath)
import Data.JSONPath.Types (JSONPathElement(..))
import Data.Text (pack, unpack)
import qualified Data.Text as T
import qualified Data.Text.Encoding as T
import qualified Data.Text.IO as T
import System.FilePath (takeBaseName, takeFileName)
import Text.Megaparsec (eof, errorBundlePretty, parse)
-- External imports: ogma-spec
import Data.OgmaSpec (ExternalVariableDef (..), InternalVariableDef (..),
Requirement (..), Spec (..))
data JSONFormat = JSONFormat
{ specInternalVars :: Maybe String
, specInternalVarId :: String
, specInternalVarExpr :: String
, specInternalVarType :: Maybe String
, specExternalVars :: Maybe String
, specExternalVarId :: String
, specExternalVarType :: Maybe String
, specRequirements :: String
, specRequirementId :: FieldSource
, specRequirementDesc :: Maybe String
, specRequirementExpr :: String
, specRequirementResultType :: Maybe String
, specRequirementResultExpr :: Maybe String
}
deriving (Read)
-- | Source used to populate the value of a field in a spec.
data FieldSource
= JSONPath String -- ^ JSON path
| FileName -- ^ Filename with extension
| BaseName -- ^ Filename without extension
deriving (Show)
-- | Custom instance to read a 'FieldSource' that allows JSON paths to be
-- written down as plain strings.
instance Read FieldSource where
readsPrec prec str =
case lex str of
[("JSONPath", rest)] -> first JSONPath <$> readsPrec prec rest
[("FileName", rest)] -> [(FileName, rest)]
[("BaseName", rest)] -> [(BaseName, rest)]
-- If it doesn't match a constructor, we attempt to read a string and
-- treat it as a JSONPath.
_ -> first JSONPath <$> readsPrec prec str
data JSONFormatInternal = JSONFormatInternal
{ jfiInternalVars :: Maybe [JSONPathElement]
, jfiInternalVarId :: [JSONPathElement]
, jfiInternalVarExpr :: [JSONPathElement]
, jfiInternalVarType :: Maybe [JSONPathElement]
, jfiExternalVars :: Maybe [JSONPathElement]
, jfiExternalVarId :: [JSONPathElement]
, jfiExternalVarType :: Maybe [JSONPathElement]
, jfiRequirements :: [JSONPathElement]
, jfiRequirementId :: FieldSourceInternal
, jfiRequirementDesc :: Maybe [JSONPathElement]
, jfiRequirementExpr :: [JSONPathElement]
, jfiRequirementResultType :: Maybe [JSONPathElement]
, jfiRequirementResultExpr :: Maybe [JSONPathElement]
}
-- | Internal representation of the source used to populate the value of a
-- field in a spec.
data FieldSourceInternal
= FSIJSONPath [JSONPathElement] -- ^ JSON path
| FSIFileName -- ^ Filename with extension
| FSIBaseName -- ^ Filename without extension
deriving (Show)
parseJSONFormat :: JSONFormat -> Either String JSONFormatInternal
parseJSONFormat jsonFormat = do
jfi2 <- showErrorsM $
fmap (parseJSONPath . pack) $ specInternalVars jsonFormat
jfi3 <- showErrors $
parseJSONPath $ pack $ specInternalVarId jsonFormat
jfi4 <- showErrors $
parseJSONPath $ pack $ specInternalVarExpr jsonFormat
jfi5 <- showErrorsM $
fmap (parseJSONPath . pack) $ specInternalVarType jsonFormat
jfi6 <- showErrorsM $
fmap (parseJSONPath . pack) $ specExternalVars jsonFormat
jfi7 <- showErrors $
parseJSONPath $ pack $ specExternalVarId jsonFormat
jfi8 <- showErrorsM $
fmap (parseJSONPath . pack) $ specExternalVarType jsonFormat
jfi9 <- showErrors $
parseJSONPath $ pack $ specRequirements jsonFormat
-- Handle the case where the requirement ID is the file name, with or without
-- extension.
jfi10 <- case specRequirementId jsonFormat of
FileName -> return FSIFileName
BaseName -> return FSIBaseName
JSONPath p -> showErrors $ fmap FSIJSONPath $ parseJSONPath $ pack p
jfi11 <- showErrorsM $
fmap (parseJSONPath . pack) $ specRequirementDesc jsonFormat
jfi12 <- showErrors $
parseJSONPath $ pack $ specRequirementExpr jsonFormat
jfi13 <- showErrorsM $
fmap (parseJSONPath . pack) $ specRequirementResultType jsonFormat
jfi14 <- showErrorsM $
fmap (parseJSONPath . pack) $ specRequirementResultExpr jsonFormat
return $ JSONFormatInternal
{ jfiInternalVars = jfi2
, jfiInternalVarId = jfi3
, jfiInternalVarExpr = jfi4
, jfiInternalVarType = jfi5
, jfiExternalVars = jfi6
, jfiExternalVarId = jfi7
, jfiExternalVarType = jfi8
, jfiRequirements = jfi9
, jfiRequirementId = jfi10
, jfiRequirementDesc = jfi11
, jfiRequirementExpr = jfi12
, jfiRequirementResultType = jfi13
, jfiRequirementResultExpr = jfi14
}
parseJSONSpec :: (String -> IO (Either String a))
-> JSONFormat
-> FilePath
-> Value
-> IO (Either String (Spec a))
parseJSONSpec parseExpr jsonFormat filepath value = runExceptT $ do
jsonFormatInternal <- except $ parseJSONFormat jsonFormat
let values :: [Value]
values =
maybe [] (`executeJSONPath` value) (jfiInternalVars jsonFormatInternal)
internalVarDef :: Value -> Either String InternalVariableDef
internalVarDef value = do
let msg = "internal variable name"
varId <- valueToString msg =<<
listToEither
msg
( executeJSONPath
(jfiInternalVarId jsonFormatInternal)
value
)
let msg = "internal variable type"
varType <- maybe
(Right "")
(\e -> valueToString msg =<<
listToEither msg (executeJSONPath e value)
)
(jfiInternalVarType jsonFormatInternal)
let msg = "internal variable expr"
varExpr <- valueToString msg =<<
listToEither
msg
( executeJSONPath
(jfiInternalVarExpr jsonFormatInternal)
value
)
return $ InternalVariableDef
{ internalVariableName = varId
, internalVariableType = varType
, internalVariableExpr = varExpr
}
internalVariableDefs <- except $ mapM internalVarDef values
let values :: [Value]
values =
maybe [] (`executeJSONPath` value) (jfiExternalVars jsonFormatInternal)
externalVarDef :: Value -> Either String ExternalVariableDef
externalVarDef value = do
let msg = "external variable name"
varId <- valueToString msg =<<
listToEither
msg
( executeJSONPath
(jfiExternalVarId jsonFormatInternal)
value
)
let msg = "external variable type"
varType <-
maybe
(Right "")
(\e -> valueToString msg =<<
listToEither msg (executeJSONPath e value)
)
(jfiExternalVarType jsonFormatInternal)
return $ ExternalVariableDef
{ externalVariableName = varId
, externalVariableType = varType
}
externalVariableDefs <- except $ mapM externalVarDef values
let values :: [Value]
values = executeJSONPath (jfiRequirements jsonFormatInternal) value
-- requirementDef :: Value -> Either String (Requirement a)
requirementDef value = do
let msg = "Requirement name"
-- Handle the case where the requirement ID is the file name, with or
-- without extension.
reqId <- case jfiRequirementId jsonFormatInternal of
FSIFileName -> return $ takeFileName filepath
FSIBaseName -> return $ takeBaseName filepath
FSIJSONPath p -> except $
valueToString msg =<< listToEither msg (executeJSONPath p value)
let msg = "Requirement expression"
reqExpr <- except $ valueToString msg =<<
listToEither
msg
( executeJSONPath
(jfiRequirementExpr jsonFormatInternal)
value
)
reqExpr' <- ExceptT $ parseExpr reqExpr
let msg = "Requirement description"
reqDesc <- except $ maybe
(Right "")
(\e -> valueToString msg =<<
listToEither msg (executeJSONPath e value)
)
(jfiRequirementDesc jsonFormatInternal)
let msg = "Requirement result type"
ty :: Maybe (Either String String)
ty = (\e -> valueToString msg =<<
listToEither msg (executeJSONPath e value)
)
<$> jfiRequirementResultType jsonFormatInternal
reqResType <- except $ maybeEither ty
let msg = "Requirement result expression"
resultExpr :: Maybe (Either String String)
resultExpr = (\e -> valueToString msg =<<
listToEither msg (executeJSONPath e value)
)
<$> jfiRequirementResultExpr jsonFormatInternal
reqResExpr <- except $ maybeEither resultExpr
reqResExpr' <- ExceptT $ case reqResExpr of
Nothing -> return $ Right Nothing
Just x -> fmap Just <$> parseExpr x
return $ Requirement
{ requirementName = reqId
, requirementExpr = reqExpr'
, requirementDescription = reqDesc
, requirementResultType = reqResType
, requirementResultExpr = reqResExpr'
}
requirements <- mapM requirementDef values
return $ Spec internalVariableDefs externalVariableDefs requirements
valueToString :: String -> Value -> Either String String
valueToString msg (String x) = Right $ unpack x
valueToString msg _ = Left $
"The JSON value provided for " ++ msg ++ " does not contain a string"
listToEither :: String -> [a] -> Either String a
listToEither _ [x] = Right x
listToEither msg [] = Left $ "Failed to find a value for " ++ msg
listToEither msg _ = Left $ "Unexpectedly found multiple values for " ++ msg
-- | Parse a JSONPath expression, returning its element components.
parseJSONPath :: T.Text -> Either String [JSONPathElement]
parseJSONPath = first errorBundlePretty . parse (jsonPath eof) ""
showErrors :: Show a => Either a b -> Either String b
showErrors (Left s) = Left (show s)
showErrors (Right x) = Right x
showErrorsM :: Show a => Maybe (Either a b) -> Either String (Maybe b)
showErrorsM Nothing = Right Nothing
showErrorsM (Just (Left s)) = Left (show s)
showErrorsM (Just (Right x)) = Right (Just x)
-- | Wrap an 'Either' value in an @ExceptT m@ monad.
except :: Monad m => Either e a -> ExceptT e m a
except = ExceptT . return
-- | Swap the order in a Maybe and an Either monad.
maybeEither :: Maybe (Either a b) -> Either a (Maybe b)
maybeEither Nothing = Right Nothing
maybeEither (Just e) = fmap Just e