{-# LANGUAGE DeriveDataTypeable, DeriveGeneric, FlexibleContexts, CPP #-}

{-
Copyright (C) 2006-2013 John MacFarlane <jgm@berkeley.edu>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-}

{- |
   Module      : Text.Pandoc.Definition
   Copyright   : Copyright (C) 2006-2010 John MacFarlane
   License     : GNU GPL, version 2 or above

   Maintainer  : John MacFarlane <jgm@berkeley.edu>
   Stability   : alpha
   Portability : portable

Definition of 'Pandoc' data structure for format-neutral representation
of documents.
-}
module Text.Pandoc.Definition ( Pandoc(..)
                              , Meta(..)
                              , MetaValue(..)
                              , nullMeta
                              , isNullMeta
                              , lookupMeta
                              , docTitle
                              , docAuthors
                              , docDate
                              , Block(..)
                              , Inline(..)
                              , Alignment(..)
                              , ListAttributes
                              , ListNumberStyle(..)
                              , ListNumberDelim(..)
                              , Format(..)
                              , Attr
                              , nullAttr
                              , TableCell
                              , QuoteType(..)
                              , Target
                              , MathType(..)
                              , Citation(..)
                              , CitationMode(..)
                              ) where

import Data.Generics (Data, Typeable)
import Data.Ord (comparing)
import Data.Aeson (FromJSON(..), ToJSON(..))
import qualified Data.Aeson.Types as Aeson
import Control.Monad (guard)
import qualified Data.Map as M
import GHC.Generics (Generic, Rep (..))
import Data.String
import Data.Char (toLower)
import Data.Monoid

data Pandoc = Pandoc Meta [Block]
              deriving (Eq, Ord, Read, Show, Typeable, Data, Generic)

instance Monoid Pandoc where
  mempty = Pandoc mempty mempty
  (Pandoc m1 bs1) `mappend` (Pandoc m2 bs2) =
    Pandoc (m1 `mappend` m2) (bs1 `mappend` bs2)

-- | Metadata for the document:  title, authors, date.
newtype Meta = Meta { unMeta :: M.Map String MetaValue }
               deriving (Eq, Ord, Show, Read, Typeable, Data, Generic)

instance Monoid Meta where
  mempty = Meta (M.empty)
  (Meta m1) `mappend` (Meta m2) = Meta (M.union m1 m2)
  -- note: M.union is left-biased, so if there are fields in both m1
  -- and m2, m1 wins.

data MetaValue = MetaMap (M.Map String MetaValue)
               | MetaList [MetaValue]
               | MetaBool Bool
               | MetaString String
               | MetaInlines [Inline]
               | MetaBlocks [Block]
               deriving (Eq, Ord, Show, Read, Typeable, Data, Generic)

nullMeta :: Meta
nullMeta = Meta M.empty

isNullMeta :: Meta -> Bool
isNullMeta (Meta m) = M.null m

-- Helper functions to extract metadata

-- | Retrieve the metadata value for a given @key@.
lookupMeta :: String -> Meta -> Maybe MetaValue
lookupMeta key (Meta m) = M.lookup key m

-- | Extract document title from metadata; works just like the old @docTitle@.
docTitle :: Meta -> [Inline]
docTitle meta =
  case lookupMeta "title" meta of
         Just (MetaString s)           -> [Str s]
         Just (MetaInlines ils)        -> ils
         Just (MetaBlocks [Plain ils]) -> ils
         Just (MetaBlocks [Para ils])  -> ils
         _                             -> []

-- | Extract document authors from metadata; works just like the old
-- @docAuthors@.
docAuthors :: Meta -> [[Inline]]
docAuthors meta =
  case lookupMeta "author" meta of
        Just (MetaString s)    -> [[Str s]]
        Just (MetaInlines ils) -> [ils]
        Just (MetaList   ms)   -> [ils | MetaInlines ils <- ms] ++
                                  [ils | MetaBlocks [Plain ils] <- ms] ++
                                  [ils | MetaBlocks [Para ils]  <- ms] ++
                                  [[Str x] | MetaString x <- ms]
        _                      -> []

-- | Extract date from metadata; works just like the old @docDate@.
docDate :: Meta -> [Inline]
docDate meta =
  case lookupMeta "date" meta of
         Just (MetaString s)           -> [Str s]
         Just (MetaInlines ils)        -> ils
         Just (MetaBlocks [Plain ils]) -> ils
         Just (MetaBlocks [Para ils])  -> ils
         _                             -> []

-- | Alignment of a table column.
data Alignment = AlignLeft
               | AlignRight
               | AlignCenter
               | AlignDefault deriving (Eq, Ord, Show, Read, Typeable, Data, Generic)

-- | List attributes.
type ListAttributes = (Int, ListNumberStyle, ListNumberDelim)

-- | Style of list numbers.
data ListNumberStyle = DefaultStyle
                     | Example
                     | Decimal
                     | LowerRoman
                     | UpperRoman
                     | LowerAlpha
                     | UpperAlpha deriving (Eq, Ord, Show, Read, Typeable, Data, Generic)

-- | Delimiter of list numbers.
data ListNumberDelim = DefaultDelim
                     | Period
                     | OneParen
                     | TwoParens deriving (Eq, Ord, Show, Read, Typeable, Data, Generic)

-- | Attributes: identifier, classes, key-value pairs
type Attr = (String, [String], [(String, String)])

nullAttr :: Attr
nullAttr = ("",[],[])

-- | Table cells are list of Blocks
type TableCell = [Block]

-- | Formats for raw blocks
newtype Format = Format String
               deriving (Read, Show, Typeable, Data, Generic)

instance IsString Format where
  fromString f = Format $ map toLower f

instance Eq Format where
  Format x == Format y = map toLower x == map toLower y

instance Ord Format where
  compare (Format x) (Format y) = compare (map toLower x) (map toLower y)

-- | Block element.
data Block
    = Plain [Inline]        -- ^ Plain text, not a paragraph
    | Para [Inline]         -- ^ Paragraph
    | CodeBlock Attr String -- ^ Code block (literal) with attributes
    | RawBlock Format String -- ^ Raw block
    | BlockQuote [Block]    -- ^ Block quote (list of blocks)
    | OrderedList ListAttributes [[Block]] -- ^ Ordered list (attributes
                            -- and a list of items, each a list of blocks)
    | BulletList [[Block]]  -- ^ Bullet list (list of items, each
                            -- a list of blocks)
    | DefinitionList [([Inline],[[Block]])]  -- ^ Definition list
                            -- Each list item is a pair consisting of a
                            -- term (a list of inlines) and one or more
                            -- definitions (each a list of blocks)
    | Header Int Attr [Inline] -- ^ Header - level (integer) and text (inlines)
    | HorizontalRule        -- ^ Horizontal rule
    | Table [Inline] [Alignment] [Double] [TableCell] [[TableCell]]  -- ^ Table,
                            -- with caption, column alignments,
                            -- relative column widths (0 = default),
                            -- column headers (each a list of blocks), and
                            -- rows (each a list of lists of blocks)
    | Div Attr [Block]      -- ^ Generic block container with attributes
    | Null                  -- ^ Nothing
    deriving (Eq, Ord, Read, Show, Typeable, Data, Generic)

-- | Type of quotation marks to use in Quoted inline.
data QuoteType = SingleQuote | DoubleQuote deriving (Show, Eq, Ord, Read, Typeable, Data, Generic)

-- | Link target (URL, title).
type Target = (String, String)

-- | Type of math element (display or inline).
data MathType = DisplayMath | InlineMath deriving (Show, Eq, Ord, Read, Typeable, Data, Generic)

-- | Inline elements.
data Inline
    = Str String            -- ^ Text (string)
    | Emph [Inline]         -- ^ Emphasized text (list of inlines)
    | Strong [Inline]       -- ^ Strongly emphasized text (list of inlines)
    | Strikeout [Inline]    -- ^ Strikeout text (list of inlines)
    | Superscript [Inline]  -- ^ Superscripted text (list of inlines)
    | Subscript [Inline]    -- ^ Subscripted text (list of inlines)
    | SmallCaps [Inline]    -- ^ Small caps text (list of inlines)
    | Quoted QuoteType [Inline] -- ^ Quoted text (list of inlines)
    | Cite [Citation]  [Inline] -- ^ Citation (list of inlines)
    | Code Attr String      -- ^ Inline code (literal)
    | Space                 -- ^ Inter-word space
    | LineBreak             -- ^ Hard line break
    | Math MathType String  -- ^ TeX math (literal)
    | RawInline Format String -- ^ Raw inline
    | Link [Inline] Target  -- ^ Hyperlink: text (list of inlines), target
    | Image [Inline] Target -- ^ Image:  alt text (list of inlines), target
    | Note [Block]          -- ^ Footnote or endnote
    | Span Attr [Inline]    -- ^ Generic inline container with attributes
    deriving (Show, Eq, Ord, Read, Typeable, Data, Generic)

data Citation = Citation { citationId      :: String
                         , citationPrefix  :: [Inline]
                         , citationSuffix  :: [Inline]
                         , citationMode    :: CitationMode
                         , citationNoteNum :: Int
                         , citationHash    :: Int
                         }
                deriving (Show, Eq, Read, Typeable, Data, Generic)

instance Ord Citation where
    compare = comparing citationHash

data CitationMode = AuthorInText | SuppressAuthor | NormalCitation
                    deriving (Show, Eq, Ord, Read, Typeable, Data, Generic)

-- derive generic instances of FromJSON, ToJSON:

#if MIN_VERSION_aeson(0,6,2)
jsonOpts :: Aeson.Options
jsonOpts = Aeson.Options{ Aeson.fieldLabelModifier = id
                        , Aeson.constructorTagModifier = id
                        , Aeson.allNullaryToStringTag = True
                        , Aeson.omitNothingFields = False
                        , Aeson.sumEncoding = Aeson.ObjectWithSingleField
                        }

toJSON' :: (Generic a, Aeson.GToJSON (Rep a))
        => a -> Aeson.Value
toJSON' = Aeson.genericToJSON jsonOpts

parseJSON' :: (Generic a, Aeson.GFromJSON (Rep a))
           => Aeson.Value -> Aeson.Parser a
parseJSON' = Aeson.genericParseJSON jsonOpts

instance FromJSON MetaValue
  where parseJSON = parseJSON'
instance ToJSON MetaValue
  where toJSON = toJSON'

instance FromJSON Meta
  where parseJSON = parseJSON'
instance ToJSON Meta
  where toJSON = toJSON'

instance FromJSON CitationMode
  where parseJSON = parseJSON'
instance ToJSON CitationMode
  where toJSON = toJSON'

instance FromJSON Citation
  where parseJSON = parseJSON'
instance ToJSON Citation
  where toJSON = toJSON'

instance FromJSON QuoteType
  where parseJSON = parseJSON'
instance ToJSON QuoteType
  where toJSON = toJSON'

instance FromJSON MathType
  where parseJSON = parseJSON'
instance ToJSON MathType
  where toJSON = toJSON'

instance FromJSON ListNumberStyle
  where parseJSON = parseJSON'
instance ToJSON ListNumberStyle
  where toJSON = toJSON'

instance FromJSON ListNumberDelim
  where parseJSON = parseJSON'
instance ToJSON ListNumberDelim
  where toJSON = toJSON'

instance FromJSON Alignment
  where parseJSON = parseJSON'
instance ToJSON Alignment
  where toJSON = toJSON'

instance FromJSON Format
  where parseJSON = parseJSON'
instance ToJSON Format
  where toJSON = toJSON'

instance FromJSON Inline
  where parseJSON = parseJSON'
instance ToJSON Inline
  where toJSON = toJSON'

instance FromJSON Block
  where parseJSON = parseJSON'
instance ToJSON Block
  where toJSON = toJSON'

instance FromJSON Pandoc
  where parseJSON = parseJSON'
instance ToJSON Pandoc
  where toJSON = toJSON'

#else
instance FromJSON MetaValue
instance ToJSON MetaValue

instance FromJSON Meta
instance ToJSON Meta

instance FromJSON CitationMode
instance ToJSON CitationMode

instance FromJSON Citation
instance ToJSON Citation

instance FromJSON QuoteType
instance ToJSON QuoteType

instance FromJSON MathType
instance ToJSON MathType

instance FromJSON ListNumberStyle
instance ToJSON ListNumberStyle

instance FromJSON ListNumberDelim
instance ToJSON ListNumberDelim

instance FromJSON Alignment
instance ToJSON Alignment

instance FromJSON Format
instance ToJSON Format

instance FromJSON Inline
instance ToJSON Inline

instance FromJSON Block
instance ToJSON Block

instance FromJSON Pandoc
instance ToJSON Pandoc
#endif