{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
{-|
Module      : Text.Pandoc.Lua.Module.JSON
Copyright   : © 2022-2024 Albert Krewinkel
License     : MIT
Maintainer  : Albert Krewinkel <albert+pandoc@tarleb.com>

Lua module to work with JSON.
-}
module Text.Pandoc.Lua.Module.JSON (
  -- * Module
    documentedModule

  -- ** Functions
  , decode
  , encode
  )
where

import Prelude hiding (null)
import Data.Maybe (fromMaybe)
import Data.Monoid (Alt (..))
import Data.Version (makeVersion)
import HsLua.Aeson
import HsLua.Core
import HsLua.Marshalling
import HsLua.Packaging
import Text.Pandoc.Error (PandocError)
import Text.Pandoc.Lua.PandocLua ()
import Text.Pandoc.Lua.Marshal.AST

import qualified Data.Aeson as Aeson
import qualified Data.Text as T

-- | The @aeson@ module specification.
documentedModule :: Module PandocError
documentedModule :: Module PandocError
documentedModule = Module
  { moduleName :: Name
moduleName = Name
"pandoc.json"
  , moduleDescription :: Text
moduleDescription = Text
"JSON module to work with JSON; " Text -> Text -> Text
forall a. Semigroup a => a -> a -> a
<>
                        Text
"based on the Aeson Haskell package."
  , moduleFields :: [Field PandocError]
moduleFields = [Field PandocError]
forall e. LuaError e => [Field e]
fields
  , moduleFunctions :: [DocumentedFunction PandocError]
moduleFunctions = [DocumentedFunction PandocError]
functions
  , moduleOperations :: [(Operation, DocumentedFunction PandocError)]
moduleOperations = []
  , moduleTypeInitializers :: [LuaE PandocError Name]
moduleTypeInitializers = []
  }

--
-- Fields
--

-- | Exported fields.
fields :: LuaError e => [Field e]
fields :: forall e. LuaError e => [Field e]
fields =
  [ Field e
forall e. LuaError e => Field e
null
  ]

-- | The value used to represent the JSON @null@.
null :: LuaError e => Field e
null :: forall e. LuaError e => Field e
null = Field
  { fieldName :: Text
fieldName = Text
"null"
  , fieldType :: TypeSpec
fieldType = TypeSpec
"light userdata"
  , fieldDescription :: Text
fieldDescription = Text
"Value used to represent the `null` JSON value."
  , fieldPushValue :: LuaE e ()
fieldPushValue = Pusher e Value
forall e. LuaError e => Pusher e Value
pushValue Value
Aeson.Null
  }

--
-- Functions
--

functions :: [DocumentedFunction PandocError]
functions :: [DocumentedFunction PandocError]
functions =
  [ DocumentedFunction PandocError
decode DocumentedFunction PandocError
-> Version -> DocumentedFunction PandocError
forall e. DocumentedFunction e -> Version -> DocumentedFunction e
`since` [Int] -> Version
makeVersion [Int
3, Int
1, Int
1]
  , DocumentedFunction PandocError
forall e. LuaError e => DocumentedFunction e
encode DocumentedFunction PandocError
-> Version -> DocumentedFunction PandocError
forall e. DocumentedFunction e -> Version -> DocumentedFunction e
`since` [Int] -> Version
makeVersion [Int
3, Int
1, Int
1]
  ]

-- | Decode a JSON string into a Lua object.
decode :: DocumentedFunction PandocError
decode :: DocumentedFunction PandocError
decode = Name
-> (ByteString -> Maybe Bool -> LuaE PandocError ())
-> HsFnPrecursor
     PandocError (ByteString -> Maybe Bool -> LuaE PandocError ())
forall a e. Name -> a -> HsFnPrecursor e a
defun Name
"decode"
  ### (\str usePandocTypes ->
         fromMaybe pushnil . getAlt . mconcat . map Alt $
         (if usePandocTypes == Just False
          then []
          else [ pushInline  <$> Aeson.decode str
               , pushBlock   <$> Aeson.decode str
               , pushPandoc  <$> Aeson.decode str
               , pushInlines <$> Aeson.decode str
               , pushBlocks  <$> Aeson.decode str
               ])
         ++ [pushValue <$> Aeson.decode str])
  HsFnPrecursor
  PandocError (ByteString -> Maybe Bool -> LuaE PandocError ())
-> Parameter PandocError ByteString
-> HsFnPrecursor PandocError (Maybe Bool -> LuaE PandocError ())
forall e a b.
HsFnPrecursor e (a -> b) -> Parameter e a -> HsFnPrecursor e b
<#> Peeker PandocError ByteString
-> TypeSpec -> Text -> Text -> Parameter PandocError ByteString
forall e a. Peeker e a -> TypeSpec -> Text -> Text -> Parameter e a
parameter Peeker PandocError ByteString
forall e. Peeker e ByteString
peekLazyByteString TypeSpec
"string" Text
"str" Text
"JSON string"
  HsFnPrecursor PandocError (Maybe Bool -> LuaE PandocError ())
-> Parameter PandocError (Maybe Bool)
-> HsFnPrecursor PandocError (LuaE PandocError ())
forall e a b.
HsFnPrecursor e (a -> b) -> Parameter e a -> HsFnPrecursor e b
<#> Parameter PandocError Bool -> Parameter PandocError (Maybe Bool)
forall e a. Parameter e a -> Parameter e (Maybe a)
opt (Peeker PandocError Bool
-> TypeSpec -> Text -> Text -> Parameter PandocError Bool
forall e a. Peeker e a -> TypeSpec -> Text -> Text -> Parameter e a
parameter Peeker PandocError Bool
forall e. Peeker e Bool
peekBool TypeSpec
"boolean" Text
"pandoc_types"
           Text
"whether to use pandoc types when possible.")
  HsFnPrecursor PandocError (LuaE PandocError ())
-> FunctionResults PandocError () -> DocumentedFunction PandocError
forall e a.
HsFnPrecursor e (LuaE e a)
-> FunctionResults e a -> DocumentedFunction e
=#> Pusher PandocError ()
-> TypeSpec -> Text -> FunctionResults PandocError ()
forall e a. Pusher e a -> TypeSpec -> Text -> FunctionResults e a
functionResult Pusher PandocError ()
forall a. a -> LuaE PandocError a
forall (f :: * -> *) a. Applicative f => a -> f a
pure TypeSpec
"any" Text
"decoded object"
  #? T.unlines
     [ "Creates a Lua object from a JSON string. If the input can be decoded"
     , "as representing an [[Inline]], [[Block]], [[Pandoc]], [[Inlines]],"
     , "or [[Blocks]] element the function will return an object of the"
     , "appropriate type. Otherwise, if the input does not represent any"
     , "of the AST types, the default decoding is applied: Objects and"
     , "arrays are represented as tables, the JSON `null` value becomes"
     , "[null](#pandoc.json.null), and JSON booleans, strings, and numbers"
     , "are converted using the Lua types of the same name."
     , ""
     , "The special handling of AST elements can be disabled by setting"
     , "`pandoc_types` to `false`."
     ]

-- | Encode a Lua object as JSON.
encode :: LuaError e => DocumentedFunction e
encode :: forall e. LuaError e => DocumentedFunction e
encode = Name
-> (Value -> LuaE e ByteString)
-> HsFnPrecursor e (Value -> LuaE e ByteString)
forall a e. Name -> a -> HsFnPrecursor e a
defun Name
"encode"
  ### liftPure Aeson.encode
  HsFnPrecursor e (Value -> LuaE e ByteString)
-> Parameter e Value -> HsFnPrecursor e (LuaE e ByteString)
forall e a b.
HsFnPrecursor e (a -> b) -> Parameter e a -> HsFnPrecursor e b
<#> Peeker e Value -> TypeSpec -> Text -> Text -> Parameter e Value
forall e a. Peeker e a -> TypeSpec -> Text -> Text -> Parameter e a
parameter Peeker e Value
forall e. LuaError e => Peeker e Value
peekValue TypeSpec
"any" Text
"object" Text
"object to convert"
  HsFnPrecursor e (LuaE e ByteString)
-> FunctionResults e ByteString -> DocumentedFunction e
forall e a.
HsFnPrecursor e (LuaE e a)
-> FunctionResults e a -> DocumentedFunction e
=#> Pusher e ByteString
-> TypeSpec -> Text -> FunctionResults e ByteString
forall e a. Pusher e a -> TypeSpec -> Text -> FunctionResults e a
functionResult Pusher e ByteString
forall e. Pusher e ByteString
pushLazyByteString TypeSpec
"string"
        Text
"JSON encoding of the given `object`"
  #? T.unlines
     ["Encodes a Lua object as JSON string."
     , ""
     , "If the object has a metamethod with name `__tojson`, then the"
     , "result is that of a call to that method with `object` passed as"
     , "the sole argument. The result of that call is expected to be a"
     , "valid JSON string, but this is not checked."
     ]