{-# LANGUAGE FlexibleContexts     #-}
{-# LANGUAGE LambdaCase           #-}
{-# LANGUAGE OverloadedStrings    #-}
{-# LANGUAGE ScopedTypeVariables  #-}
{-# LANGUAGE TypeApplications     #-}
{-# LANGUAGE TupleSections        #-}
{- |

Marshal values of types that make up 'Inline' elements.
-}
module Text.Pandoc.Lua.Marshal.Inline
  ( -- * Single Inline elements
    peekInline
  , peekInlineFuzzy
  , pushInline
    -- * List of Inlines
  , peekInlines
  , peekInlinesFuzzy
  , pushInlines
    -- * Constructors
  , inlineConstructors
  , mkInlines
    -- * Walking
  , walkInlineSplicing
  , walkInlinesStraight
  ) where

import Control.Applicative ((<|>), optional)
import Control.Monad.Catch (throwM)
import Control.Monad ((<$!>))
import Data.Data (showConstr, toConstr)
import Data.Maybe (fromMaybe)
import Data.Text (Text)
import HsLua
import Text.Pandoc.Definition (Inline (..), nullAttr)
import Text.Pandoc.Lua.Marshal.Attr (peekAttr, pushAttr)
import {-# SOURCE #-} Text.Pandoc.Lua.Marshal.Block (peekBlocksFuzzy)
import Text.Pandoc.Lua.Marshal.Citation (peekCitation, pushCitation)
import Text.Pandoc.Lua.Marshal.Content
  ( Content (..), contentTypeDescription, peekContent, pushContent )
import Text.Pandoc.Lua.Marshal.Filter (Filter, peekFilter)
import Text.Pandoc.Lua.Marshal.Format (peekFormat, pushFormat)
import Text.Pandoc.Lua.Marshal.List (pushPandocList, newListMetatable)
import Text.Pandoc.Lua.Marshal.MathType (peekMathType, pushMathType)
import Text.Pandoc.Lua.Marshal.QuoteType (peekQuoteType, pushQuoteType)
import Text.Pandoc.Lua.Marshal.Shared (walkBlocksAndInlines)
import Text.Pandoc.Lua.Walk (SpliceList, Walkable, walkSplicing, walkStraight)
import qualified Text.Pandoc.Builder as B

-- | Pushes an Inline value as userdata object.
pushInline :: LuaError e => Pusher e Inline
pushInline = pushUD typeInline
{-# INLINE pushInline #-}

-- | Retrieves an Inline value.
peekInline :: LuaError e => Peeker e Inline
peekInline = peekUD typeInline
{-# INLINE peekInline #-}

-- | Retrieves a list of Inline values.
peekInlines :: LuaError e
            => Peeker e [Inline]
peekInlines = peekList peekInline
{-# INLINABLE peekInlines #-}

-- | Pushes a list of Inline values.
pushInlines :: LuaError e
            => Pusher e [Inline]
pushInlines xs = do
  pushList pushInline xs
  newListMetatable "Inlines" $ do
    pushName "walk"
    pushDocumentedFunction $ lambda
      ### flip walkBlocksAndInlines
      <#> parameter peekInlinesFuzzy "Blocks" "self" ""
      <#> parameter peekFilter "Filter" "lua_filter" "table of filter functions"
      =#> functionResult pushInlines "Blocks" "modified list"
    rawset (nth 3)
  setmetatable (nth 2)
{-# INLINABLE pushInlines #-}

-- | Try extra hard to retrieve an Inline value from the stack. Treats
-- bare strings as @Str@ values.
peekInlineFuzzy :: LuaError e => Peeker e Inline
peekInlineFuzzy idx = retrieving "Inline" $ liftLua (ltype idx) >>= \case
  TypeString   -> Str <$!> peekText idx
  _            -> peekInline idx
{-# INLINABLE peekInlineFuzzy #-}

-- | Try extra-hard to return the value at the given index as a list of
-- inlines.
peekInlinesFuzzy :: LuaError e
                 => Peeker e [Inline]
peekInlinesFuzzy idx = liftLua (ltype idx) >>= \case
  TypeString -> B.toList . B.text <$> peekText idx
  _ ->  peekList peekInlineFuzzy idx
    <|> (pure <$> peekInlineFuzzy idx)
    <|> (failPeek =<<
         typeMismatchMessage "Inline, list of Inlines, or string" idx)
{-# INLINABLE peekInlinesFuzzy #-}

-- | Inline object type.
typeInline :: forall e. LuaError e => DocumentedType e Inline
typeInline = deftype "Inline"
  [ operation Tostring $ lambda
    ### liftPure (show @Inline)
    <#> parameter peekInline "inline" "Inline" "Object"
    =#> functionResult pushString "string" "stringified Inline"
  , operation Eq $ defun "__eq"
      ### liftPure2 (\a b -> fromMaybe False ((==) <$> a <*> b))
      <#> parameter (optional . peekInline) "a" "Inline" ""
      <#> parameter (optional . peekInline) "b" "Inline" ""
      =#> functionResult pushBool "boolean" "whether the two are equal"
  ]
  [ possibleProperty "attr" "element attributes"
      (pushAttr, \case
          Code attr _    -> Actual attr
          Image attr _ _ -> Actual attr
          Link attr _ _  -> Actual attr
          Span attr _    -> Actual attr
          _              -> Absent)
      (peekAttr, \case
          Code _ cs       -> Actual . (`Code` cs)
          Image _ cpt tgt -> Actual . \attr -> Image attr cpt tgt
          Link _ cpt tgt  -> Actual . \attr -> Link attr cpt tgt
          Span _ inlns    -> Actual . (`Span` inlns)
          _               -> const Absent)

  , possibleProperty "caption" "image caption"
      (pushInlines, \case
          Image _ capt _ -> Actual capt
          _              -> Absent)
      (peekInlinesFuzzy, \case
          Image attr _ target -> Actual . (\capt -> Image attr capt target)
          _                   -> const Absent)

  , possibleProperty "citations" "list of citations"
      (pushPandocList pushCitation, \case
          Cite cs _    -> Actual cs
          _            -> Absent)
      (peekList peekCitation, \case
          Cite _ inlns -> Actual . (`Cite` inlns)
          _            -> const Absent)

  , possibleProperty "content" "element contents"
      (pushContent, \case
          Cite _ inlns      -> Actual $ ContentInlines inlns
          Emph inlns        -> Actual $ ContentInlines inlns
          Link _ inlns _    -> Actual $ ContentInlines inlns
          Quoted _ inlns    -> Actual $ ContentInlines inlns
          SmallCaps inlns   -> Actual $ ContentInlines inlns
          Span _ inlns      -> Actual $ ContentInlines inlns
          Strikeout inlns   -> Actual $ ContentInlines inlns
          Strong inlns      -> Actual $ ContentInlines inlns
          Subscript inlns   -> Actual $ ContentInlines inlns
          Superscript inlns -> Actual $ ContentInlines inlns
          Underline inlns   -> Actual $ ContentInlines inlns
          Note blks         -> Actual $ ContentBlocks blks
          _                 -> Absent)
      (peekContent,
        let inlineContent = \case
              ContentInlines inlns -> inlns
              c -> throwM . luaException @e $
                   "expected Inlines, got " <> contentTypeDescription c
            blockContent = \case
              ContentBlocks blks -> blks
              ContentInlines []  -> []
              c -> throwM . luaException @e $
                   "expected Blocks, got " <> contentTypeDescription c
        in \case
          -- inline content
          Cite cs _     -> Actual . Cite cs . inlineContent
          Emph _        -> Actual . Emph . inlineContent
          Link a _ tgt  -> Actual . (\inlns -> Link a inlns tgt) . inlineContent
          Quoted qt _   -> Actual . Quoted qt . inlineContent
          SmallCaps _   -> Actual . SmallCaps . inlineContent
          Span attr _   -> Actual . Span attr . inlineContent
          Strikeout _   -> Actual . Strikeout . inlineContent
          Strong _      -> Actual . Strong . inlineContent
          Subscript _   -> Actual . Subscript . inlineContent
          Superscript _ -> Actual . Superscript . inlineContent
          Underline _   -> Actual . Underline . inlineContent
          -- block content
          Note _        -> Actual . Note . blockContent
          _             -> const Absent
      )

  , possibleProperty "format" "format of raw text"
      (pushFormat, \case
          RawInline fmt _ -> Actual fmt
          _               -> Absent)
      (peekFormat, \case
          RawInline _ txt -> Actual . (`RawInline` txt)
          _               -> const Absent)

  , possibleProperty "mathtype" "math rendering method"
      (pushMathType, \case
          Math mt _  -> Actual mt
          _          -> Absent)
      (peekMathType, \case
          Math _ txt -> Actual . (`Math` txt)
          _          -> const Absent)

  , possibleProperty "quotetype" "type of quotes (single or double)"
      (pushQuoteType, \case
          Quoted qt _     -> Actual qt
          _               -> Absent)
      (peekQuoteType, \case
          Quoted _ inlns  -> Actual . (`Quoted` inlns)
          _               -> const Absent)

  , possibleProperty "src" "image source"
      (pushText, \case
          Image _ _ (src, _) -> Actual src
          _                  -> Absent)
      (peekText, \case
          Image attr capt (_, title) -> Actual . Image attr capt . (,title)
          _                          -> const Absent)

  , possibleProperty "target" "link target URL"
      (pushText, \case
          Link _ _ (tgt, _) -> Actual tgt
          _                 -> Absent)
      (peekText, \case
          Link attr capt (_, title) -> Actual . Link attr capt . (,title)
          _                         -> const Absent)
  , possibleProperty "title" "title text"
      (pushText, \case
          Image _ _ (_, tit) -> Actual tit
          Link _ _ (_, tit)  -> Actual tit
          _                  -> Absent)
      (peekText, \case
          Image attr capt (src, _) -> Actual . Image attr capt . (src,)
          Link attr capt (src, _)  -> Actual . Link attr capt . (src,)
          _                        -> const Absent)

  , possibleProperty "text" "text contents"
      (pushText, getInlineText)
      (peekText, setInlineText)

  , readonly "tag" "type of Inline"
      (pushString, showConstr . toConstr )

  , alias "t" "tag" ["tag"]
  , alias "c" "content" ["content"]
  , alias "identifier" "element identifier"       ["attr", "identifier"]
  , alias "classes"    "element classes"          ["attr", "classes"]
  , alias "attributes" "other element attributes" ["attr", "attributes"]

  , method $ defun "clone"
      ### return
      <#> parameter peekInline "inline" "Inline" "self"
      =#> functionResult pushInline "Inline" "cloned Inline"

  , method $ defun "walk"
    ### flip walkBlocksAndInlines
    <#> parameter peekInline "Inline" "self" ""
    <#> parameter peekFilter "Filter" "lua_filter" "table of filter functions"
    =#> functionResult pushInline "Inline" "modified element"
  ]

--
-- Text
--

-- | Gets the text property of an Inline, if present.
getInlineText :: Inline -> Possible Text
getInlineText = \case
  Code _ lst      -> Actual lst
  Math _ str      -> Actual str
  RawInline _ raw -> Actual raw
  Str s           -> Actual s
  _               -> Absent

-- | Sets the text property of an Inline, if present.
setInlineText :: Inline -> Text -> Possible Inline
setInlineText = \case
  Code attr _     -> Actual . Code attr
  Math mt _       -> Actual . Math mt
  RawInline f _   -> Actual . RawInline f
  Str _           -> Actual . Str
  _               -> const Absent

-- | Constructor functions for 'Inline' elements.
inlineConstructors :: LuaError e =>  [DocumentedFunction e]
inlineConstructors =
  [ defun "Cite"
    ### liftPure2 (flip Cite)
    <#> parameter peekInlinesFuzzy "content" "Inline" "placeholder content"
    <#> parameter (peekList peekCitation) "citations" "list of Citations" ""
    =#> functionResult pushInline "Inline" "cite element"
  , defun "Code"
    ### liftPure2 (\text mattr -> Code (fromMaybe nullAttr mattr) text)
    <#> textParam "code" "code string"
    <#> opt (parameter peekAttr "Attr" "attr" "additional attributes")
    =#> functionResult pushInline "Inline" "code element"
  , mkInlinesConstr "Emph" Emph
  , defun "Image"
    ### liftPure4 (\caption src mtitle mattr ->
                     let attr = fromMaybe nullAttr mattr
                         title = fromMaybe mempty mtitle
                     in Image attr caption (src, title))
    <#> parameter peekInlinesFuzzy "Inlines" "caption" "image caption / alt"
    <#> textParam "src" "path/URL of the image file"
    <#> opt (textParam "title" "brief image description")
    <#> opt (parameter peekAttr "Attr" "attr" "image attributes")
    =#> functionResult pushInline "Inline" "image element"
  , defun "LineBreak"
    ### return LineBreak
    =#> functionResult pushInline "Inline" "line break"
  , defun "Link"
    ### liftPure4 (\content target mtitle mattr ->
                     let attr = fromMaybe nullAttr mattr
                         title = fromMaybe mempty mtitle
                     in Link attr content (target, title))
    <#> parameter peekInlinesFuzzy "Inlines" "content" "text for this link"
    <#> textParam "target" "the link target"
    <#> opt (textParam "title" "brief link description")
    <#> opt (parameter peekAttr "Attr" "attr" "link attributes")
    =#> functionResult pushInline "Inline" "link element"
  , defun "Math"
    ### liftPure2 Math
    <#> parameter peekMathType "quotetype" "Math" "rendering method"
    <#> textParam "text" "math content"
    =#> functionResult pushInline "Inline" "math element"
  , defun "Note"
    ### liftPure Note
    <#> parameter peekBlocksFuzzy "content" "Blocks" "note content"
    =#> functionResult pushInline "Inline" "note"
  , defun "Quoted"
    ### liftPure2 Quoted
    <#> parameter peekQuoteType "quotetype" "QuoteType" "type of quotes"
    <#> parameter peekInlinesFuzzy "content" "Inlines" "inlines in quotes"
    =#> functionResult pushInline "Inline" "quoted element"
  , defun "RawInline"
    ### liftPure2 RawInline
    <#> parameter peekFormat "format" "Format" "format of content"
    <#> textParam "text" "string content"
    =#> functionResult pushInline "Inline" "raw inline element"
  , mkInlinesConstr "SmallCaps" SmallCaps
  , defun "SoftBreak"
    ### return SoftBreak
    =#> functionResult pushInline "Inline" "soft break"
  , defun "Space"
    ### return Space
    =#> functionResult pushInline "Inline" "new space"
  , defun "Span"
    ### liftPure2 (\inlns mattr -> Span (fromMaybe nullAttr mattr) inlns)
    <#> parameter peekInlinesFuzzy "content" "Inlines" "inline content"
    <#> opt (parameter peekAttr "Attr" "attr" "additional attributes")
    =#> functionResult pushInline "Inline" "span element"
  , defun "Str"
    ### liftPure Str
    <#> textParam "text" ""
    =#> functionResult pushInline "Inline" "new Str object"
  , mkInlinesConstr "Strong" Strong
  , mkInlinesConstr "Strikeout" Strikeout
  , mkInlinesConstr "Subscript" Subscript
  , mkInlinesConstr "Superscript" Superscript
  , mkInlinesConstr "Underline" Underline
  ]
 where
   mkInlinesConstr name constr = defun name
     ### liftPure (\x -> x `seq` constr x)
     <#> parameter peekInlinesFuzzy "Inlines" "content" ""
     =#> functionResult pushInline "Inline" "new object"

-- | Constructor for a list of `Inline` values.
mkInlines :: LuaError e => DocumentedFunction e
mkInlines = defun "Inlines"
  ### liftPure id
  <#> parameter peekInlinesFuzzy "Inlines" "inlines" "inline elements"
  =#> functionResult pushInlines "Inlines" "list of inline elements"

-- | Walks an element of type @a@ and applies the filter to all 'Inline'
-- elements.  The filter result is spliced back into the list.
walkInlineSplicing :: (LuaError e, Walkable (SpliceList Inline) a)
                   => Filter -> a -> LuaE e a
walkInlineSplicing = walkSplicing pushInline peekInlinesFuzzy

-- | Walks an element of type @a@ and applies the filter to all lists of
-- 'Inline' elements.
walkInlinesStraight :: (LuaError e, Walkable [Inline] a)
                    => Filter -> a -> LuaE e a
walkInlinesStraight = walkStraight "Inlines" pushInlines peekInlinesFuzzy