{-# LANGUAGE PatternGuards #-}

{-
Copyright (C) 2017-2018 Jesse Rosenthal <jrosenthal@jhu.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.Writers.Powerpoint.Output
   Copyright   : Copyright (C) 2017-2018 Jesse Rosenthal
   License     : GNU GPL, version 2 or above

   Maintainer  : Jesse Rosenthal <jrosenthal@jhu.edu>
   Stability   : alpha
   Portability : portable

Conversion of Presentation datatype (defined in
Text.Pandoc.Writers.Powerpoint.Presentation) to a zip archive.
-}

module Text.Pandoc.Writers.Powerpoint.Output ( presentationToArchive
                                             ) where

import Control.Monad.Except (throwError, catchError)
import Control.Monad.Reader
import Control.Monad.State
import Codec.Archive.Zip
import Data.List (intercalate, stripPrefix, nub, union, isPrefixOf)
import Data.Default
import Text.Pandoc.Compat.Time (formatTime, defaultTimeLocale)
import Data.Time.Clock (UTCTime)
import Data.Time.Clock.POSIX (utcTimeToPOSIXSeconds, posixSecondsToUTCTime)
import System.FilePath.Posix (splitDirectories, splitExtension, takeExtension)
import Text.XML.Light
import Text.Pandoc.Definition
import qualified Text.Pandoc.UTF8 as UTF8
import Text.Pandoc.Class (PandocMonad)
import Text.Pandoc.Error (PandocError(..))
import qualified Text.Pandoc.Class as P
import Text.Pandoc.Options
import Text.Pandoc.MIME
import qualified Data.ByteString.Lazy as BL
import Text.Pandoc.Writers.OOXML
import qualified Data.Map as M
import Data.Maybe (mapMaybe, listToMaybe, fromMaybe)
import Text.Pandoc.ImageSize
import Control.Applicative ((<|>))
import System.FilePath.Glob
import Text.TeXMath
import Text.Pandoc.Writers.Math (convertMath)
import Text.Pandoc.Writers.Powerpoint.Presentation

-- This populates the global ids map with images already in the
-- template, so the ids won't be used by images introduced by the
-- user.
initialGlobalIds :: Archive -> Archive -> M.Map FilePath Int
initialGlobalIds refArchive distArchive =
  let archiveFiles = filesInArchive refArchive `union` filesInArchive distArchive
      mediaPaths = filter (isPrefixOf "ppt/media/image") archiveFiles

      go :: FilePath -> Maybe (FilePath, Int)
      go fp = do
        s <- stripPrefix "ppt/media/image" $ fst $ splitExtension fp
        (n, _) <- listToMaybe $ reads s
        return (fp, n)
  in
    M.fromList $ mapMaybe go mediaPaths

getPresentationSize :: Archive -> Archive -> Maybe (Integer, Integer)
getPresentationSize refArchive distArchive = do
  entry <- findEntryByPath "ppt/presentation.xml" refArchive  `mplus`
           findEntryByPath "ppt/presentation.xml" distArchive
  presElement <- parseXMLDoc $ UTF8.toStringLazy $ fromEntry entry
  let ns = elemToNameSpaces presElement
  sldSize <- findChild (elemName ns "p" "sldSz") presElement
  cxS <- findAttr (QName "cx" Nothing Nothing) sldSize
  cyS <- findAttr (QName "cy" Nothing Nothing) sldSize
  (cx, _) <- listToMaybe $ reads cxS :: Maybe (Integer, String)
  (cy, _) <- listToMaybe $ reads cyS :: Maybe (Integer, String)
  return (cx `div` 12700, cy `div` 12700)

data WriterEnv = WriterEnv { envRefArchive :: Archive
                           , envDistArchive :: Archive
                           , envUTCTime :: UTCTime
                           , envOpts :: WriterOptions
                           , envPresentationSize :: (Integer, Integer)
                           , envSlideHasHeader :: Bool
                           , envInList :: Bool
                           , envInNoteSlide :: Bool
                           , envCurSlideId :: Int
                           -- the difference between the number at
                           -- the end of the slide file name and
                           -- the rId number
                           , envSlideIdOffset :: Int
                           , envContentType :: ContentType
                           , envSlideIdMap :: M.Map SlideId Int
                           }
                 deriving (Show)

instance Default WriterEnv where
  def = WriterEnv { envRefArchive = emptyArchive
                  , envDistArchive = emptyArchive
                  , envUTCTime = posixSecondsToUTCTime 0
                  , envOpts = def
                  , envPresentationSize = (720, 540)
                  , envSlideHasHeader = False
                  , envInList = False
                  , envInNoteSlide = False
                  , envCurSlideId = 1
                  , envSlideIdOffset = 1
                  , envContentType = NormalContent
                  , envSlideIdMap = mempty
                  }

data ContentType = NormalContent
                 | TwoColumnLeftContent
                 | TwoColumnRightContent
                 deriving (Show, Eq)

data MediaInfo = MediaInfo { mInfoFilePath :: FilePath
                           , mInfoLocalId  :: Int
                           , mInfoGlobalId :: Int
                           , mInfoMimeType :: Maybe MimeType
                           , mInfoExt      :: Maybe String
                           , mInfoCaption  :: Bool
                           } deriving (Show, Eq)

data WriterState = WriterState { stLinkIds :: M.Map Int (M.Map Int LinkTarget)
                               -- (FP, Local ID, Global ID, Maybe Mime)
                               , stMediaIds :: M.Map Int [MediaInfo]
                               , stMediaGlobalIds :: M.Map FilePath Int
                               } deriving (Show, Eq)

instance Default WriterState where
  def = WriterState { stLinkIds = mempty
                    , stMediaIds = mempty
                    , stMediaGlobalIds = mempty
                    }

type P m = ReaderT WriterEnv (StateT WriterState m)

runP :: Monad m => WriterEnv -> WriterState -> P m a -> m a
runP env st p = evalStateT (runReaderT p env) st

--------------------------------------------------------------------

copyFileToArchive :: PandocMonad m => Archive -> FilePath -> P m Archive
copyFileToArchive arch fp = do
  refArchive <- asks envRefArchive
  distArchive <- asks envDistArchive
  case findEntryByPath fp refArchive `mplus` findEntryByPath fp distArchive of
    Nothing -> fail $ fp ++ " missing in reference file"
    Just e -> return $ addEntryToArchive e arch

inheritedPatterns :: [Pattern]
inheritedPatterns = map compile [ "docProps/app.xml"
                                , "ppt/slideLayouts/slideLayout*.xml"
                                , "ppt/slideLayouts/_rels/slideLayout*.xml.rels"
                                , "ppt/slideMasters/slideMaster1.xml"
                                , "ppt/slideMasters/_rels/slideMaster1.xml.rels"
                                , "ppt/theme/theme1.xml"
                                , "ppt/theme/_rels/theme1.xml.rels"
                                , "ppt/presProps.xml"
                                , "ppt/viewProps.xml"
                                , "ppt/tableStyles.xml"
                                , "ppt/media/image*"
                                ]

patternToFilePaths :: PandocMonad m => Pattern -> P m [FilePath]
patternToFilePaths pat = do
  refArchive <- asks envRefArchive
  distArchive <- asks envDistArchive

  let archiveFiles = filesInArchive refArchive `union` filesInArchive distArchive
  return $ filter (match pat) archiveFiles

patternsToFilePaths :: PandocMonad m => [Pattern] -> P m [FilePath]
patternsToFilePaths pats = concat <$> mapM patternToFilePaths pats

-- Here are the files we'll require to make a Powerpoint document. If
-- any of these are missing, we should error out of our build.
requiredFiles :: [FilePath]
requiredFiles = [ "docProps/app.xml"
                , "ppt/presProps.xml"
                , "ppt/slideLayouts/slideLayout1.xml"
                , "ppt/slideLayouts/_rels/slideLayout1.xml.rels"
                , "ppt/slideLayouts/slideLayout2.xml"
                , "ppt/slideLayouts/_rels/slideLayout2.xml.rels"
                , "ppt/slideLayouts/slideLayout3.xml"
                , "ppt/slideLayouts/_rels/slideLayout3.xml.rels"
                , "ppt/slideLayouts/slideLayout4.xml"
                , "ppt/slideLayouts/_rels/slideLayout4.xml.rels"
                , "ppt/slideMasters/slideMaster1.xml"
                , "ppt/slideMasters/_rels/slideMaster1.xml.rels"
                , "ppt/theme/theme1.xml"
                , "ppt/viewProps.xml"
                , "ppt/tableStyles.xml"
                ]


presentationToArchiveP :: PandocMonad m => Presentation -> P m Archive
presentationToArchiveP p@(Presentation docProps slides) = do
  filePaths <- patternsToFilePaths inheritedPatterns

  -- make sure all required files are available:
  let missingFiles = filter (\fp -> not (fp `elem` filePaths)) requiredFiles
  unless (null missingFiles)
    (throwError $
      PandocSomeError $
      "The following required files are missing:\n" ++
      (unlines $ map ("  " ++) missingFiles)
    )

  newArch' <- foldM copyFileToArchive emptyArchive filePaths
  -- we make a docProps/core.xml entry out of the presentation docprops
  docPropsEntry <- docPropsToEntry docProps
  -- we make this ourself in case there's something unexpected in the
  -- one in the reference doc.
  relsEntry <- topLevelRelsEntry
  -- presentation entry and rels. We have to do the rels first to make
  -- sure we know the correct offset for the rIds.
  presEntry <- presentationToPresEntry p
  presRelsEntry <- presentationToRelsEntry p
  slideEntries <- mapM slideToEntry slides
  slideRelEntries <- mapM slideToSlideRelEntry slides
  -- These have to come after everything, because they need the info
  -- built up in the state.
  mediaEntries <- makeMediaEntries
  contentTypesEntry <- presentationToContentTypes p >>= contentTypesToEntry
  -- fold everything into our inherited archive and return it.
  return $ foldr addEntryToArchive newArch' $
    slideEntries ++
    slideRelEntries ++
    mediaEntries ++
    [contentTypesEntry, docPropsEntry, relsEntry, presEntry, presRelsEntry]

makeSlideIdMap :: Presentation -> M.Map SlideId Int
makeSlideIdMap (Presentation _ slides) =
  M.fromList $ (map slideId slides) `zip` [1..]

presentationToArchive :: PandocMonad m => WriterOptions -> Presentation -> m Archive
presentationToArchive opts pres = do
  distArchive <- (toArchive . BL.fromStrict) <$>
                      P.readDefaultDataFile "reference.pptx"
  refArchive <- case writerReferenceDoc opts of
                     Just f  -> toArchive <$> P.readFileLazy f
                     Nothing -> (toArchive . BL.fromStrict) <$>
                        P.readDataFile "reference.pptx"

  utctime <- P.getCurrentTime

  presSize <- case getPresentationSize refArchive distArchive of
                Just sz -> return sz
                Nothing -> throwError $
                           PandocSomeError $
                           "Could not determine presentation size"

  let env = def { envRefArchive = refArchive
                , envDistArchive = distArchive
                , envUTCTime = utctime
                , envOpts = opts
                , envPresentationSize = presSize
                , envSlideIdMap = makeSlideIdMap pres
                }

  let st = def { stMediaGlobalIds = initialGlobalIds refArchive distArchive
               }

  runP env st $ presentationToArchiveP pres



--------------------------------------------------

--------------------------------------------------

getLayout :: PandocMonad m => Layout -> P m Element
getLayout layout = do
  let layoutpath = case layout of
        (MetadataSlide _ _ _ _) -> "ppt/slideLayouts/slideLayout1.xml"
        (TitleSlide _)          -> "ppt/slideLayouts/slideLayout3.xml"
        (ContentSlide _ _)      -> "ppt/slideLayouts/slideLayout2.xml"
        (TwoColumnSlide _ _ _)    -> "ppt/slideLayouts/slideLayout4.xml"
  distArchive <- asks envDistArchive
  root <- case findEntryByPath layoutpath distArchive of
        Just e -> case parseXMLDoc $ UTF8.toStringLazy $ fromEntry e of
                    Just element -> return $ element
                    Nothing      -> throwError $
                                    PandocSomeError $
                                    layoutpath ++ " corrupt in reference file"
        Nothing -> throwError $
                   PandocSomeError $
                   layoutpath ++ " missing in reference file"
  return root

shapeHasName :: NameSpaces -> String -> Element -> Bool
shapeHasName ns name element
  | Just nvSpPr <- findChild (elemName ns "p" "nvSpPr") element
  , Just cNvPr <- findChild (elemName ns "p" "cNvPr") nvSpPr
  , Just nm <- findAttr (QName "name" Nothing Nothing) cNvPr =
      nm == name
  | otherwise = False

shapeHasId :: NameSpaces -> String -> Element -> Bool
shapeHasId ns ident element
  | Just nvSpPr <- findChild (elemName ns "p" "nvSpPr") element
  , Just cNvPr <- findChild (elemName ns "p" "cNvPr") nvSpPr
  , Just nm <- findAttr (QName "id" Nothing Nothing) cNvPr =
      nm == ident
  | otherwise = False

-- The content shape in slideLayout2 (Title/Content) has id=3 In
-- slideLayout4 (two column) the left column is id=3, and the right
-- column is id=4.
getContentShape :: PandocMonad m => NameSpaces -> Element -> P m Element
getContentShape ns spTreeElem
  | isElem ns "p" "spTree" spTreeElem = do
      contentType <- asks envContentType
      let ident = case contentType of
            NormalContent -> "3"
            TwoColumnLeftContent -> "3"
            TwoColumnRightContent -> "4"
      case filterChild
           (\e -> (isElem ns "p" "sp" e) && (shapeHasId ns ident e))
           spTreeElem
        of
        Just e -> return e
        Nothing -> throwError $
                   PandocSomeError $
                   "Could not find shape for Powerpoint content"
getContentShape _ _ = throwError $
                      PandocSomeError $
                      "Attempted to find content on non shapeTree"

getShapeDimensions :: NameSpaces
                   -> Element
                   -> Maybe ((Integer, Integer), (Integer, Integer))
getShapeDimensions ns element
  | isElem ns "p" "sp" element = do
      spPr <- findChild (elemName ns "p" "spPr") element
      xfrm <- findChild (elemName ns "a" "xfrm") spPr
      off <- findChild (elemName ns "a" "off") xfrm
      xS <- findAttr (QName "x" Nothing Nothing) off
      yS <- findAttr (QName "y" Nothing Nothing) off
      ext <- findChild (elemName ns "a" "ext") xfrm
      cxS <- findAttr (QName "cx" Nothing Nothing) ext
      cyS <- findAttr (QName "cy" Nothing Nothing) ext
      (x, _) <- listToMaybe $ reads xS
      (y, _) <- listToMaybe $ reads yS
      (cx, _) <- listToMaybe $ reads cxS
      (cy, _) <- listToMaybe $ reads cyS
      return $ ((x `div` 12700, y `div` 12700), (cx `div` 12700, cy `div` 12700))
  | otherwise = Nothing


getMasterShapeDimensionsById :: String
                             -> Element
                             -> Maybe ((Integer, Integer), (Integer, Integer))
getMasterShapeDimensionsById ident master = do
  let ns = elemToNameSpaces master
  cSld <- findChild (elemName ns "p" "cSld") master
  spTree <- findChild (elemName ns "p" "spTree") cSld
  sp <- filterChild (\e -> (isElem ns "p" "sp" e) && (shapeHasId ns ident e)) spTree
  getShapeDimensions ns sp

getContentShapeSize :: PandocMonad m
                    => NameSpaces
                    -> Element
                    -> Element
                    -> P m ((Integer, Integer), (Integer, Integer))
getContentShapeSize ns layout master
  | isElem ns "p" "sldLayout" layout
  , Just cSld <- findChild (elemName ns "p" "cSld") layout
  , Just spTree <- findChild (elemName ns "p" "spTree") cSld = do
      sp  <- getContentShape ns spTree
      case getShapeDimensions ns sp of
        Just sz -> return sz
        Nothing -> do let mbSz =
                            findChild (elemName ns "p" "nvSpPr") sp >>=
                            findChild (elemName ns "p" "cNvPr") >>=
                            findAttr (QName "id" Nothing Nothing) >>=
                            flip getMasterShapeDimensionsById master
                      case mbSz of
                        Just sz' -> return sz'
                        Nothing -> throwError $
                                   PandocSomeError $
                                   "Couldn't find necessary content shape size"
getContentShapeSize _ _ _ = throwError $
                            PandocSomeError $
                            "Attempted to find content shape size in non-layout"

replaceNamedChildren :: NameSpaces
                   -> String
                   -> String
                   -> [Element]
                   -> Element
                   -> Element
replaceNamedChildren ns prefix name newKids element =
  element { elContent = concat $ fun True $ elContent element }
  where
    fun :: Bool -> [Content] -> [[Content]]
    fun _ [] = []
    fun switch ((Elem e) : conts) | isElem ns prefix name e =
                                      if switch
                                      then (map Elem $ newKids) : fun False conts
                                      else fun False conts
    fun switch (cont : conts) = [cont] : fun switch conts

----------------------------------------------------------------

registerLink :: PandocMonad m => LinkTarget -> P m Int
registerLink link = do
  curSlideId <- asks envCurSlideId
  linkReg <- gets stLinkIds
  mediaReg <- gets stMediaIds
  let maxLinkId = case M.lookup curSlideId linkReg of
        Just mp -> case M.keys mp of
          [] -> 1
          ks -> maximum ks
        Nothing -> 1
      maxMediaId = case M.lookup curSlideId mediaReg of
        Just [] -> 1
        Just mInfos -> maximum $ map mInfoLocalId mInfos
        Nothing -> 1
      maxId = max maxLinkId maxMediaId
      slideLinks = case M.lookup curSlideId linkReg of
        Just mp -> M.insert (maxId + 1) link mp
        Nothing -> M.singleton (maxId + 1) link
  modify $ \st -> st{ stLinkIds = M.insert curSlideId slideLinks linkReg}
  return $ maxId + 1

registerMedia :: PandocMonad m => FilePath -> [ParaElem] -> P m MediaInfo
registerMedia fp caption = do
  curSlideId <- asks envCurSlideId
  linkReg <- gets stLinkIds
  mediaReg <- gets stMediaIds
  globalIds <- gets stMediaGlobalIds
  let maxLinkId = case M.lookup curSlideId linkReg of
        Just mp -> case M.keys mp of
          [] -> 1
          ks -> maximum ks
        Nothing -> 1
      maxMediaId = case M.lookup curSlideId mediaReg of
        Just [] -> 1
        Just mInfos -> maximum $ map mInfoLocalId mInfos
        Nothing -> 1
      maxLocalId = max maxLinkId maxMediaId

      maxGlobalId = case M.elems globalIds of
        [] -> 0
        ids -> maximum ids

  (imgBytes, mbMt) <- P.fetchItem fp
  let imgExt = (mbMt >>= extensionFromMimeType >>= (\x -> return $ '.':x))
               <|>
               case imageType imgBytes of
                 Just Png  -> Just ".png"
                 Just Jpeg -> Just ".jpeg"
                 Just Gif  -> Just ".gif"
                 Just Pdf  -> Just ".pdf"
                 Just Eps  -> Just ".eps"
                 Just Svg  -> Just ".svg"
                 Nothing   -> Nothing

  let newGlobalId = case M.lookup fp globalIds of
        Just ident -> ident
        Nothing    -> maxGlobalId + 1

  let newGlobalIds = M.insert fp newGlobalId globalIds

  let mediaInfo = MediaInfo { mInfoFilePath = fp
                            , mInfoLocalId = maxLocalId + 1
                            , mInfoGlobalId = newGlobalId
                            , mInfoMimeType = mbMt
                            , mInfoExt = imgExt
                            , mInfoCaption = (not . null) caption
                            }

  let slideMediaInfos = case M.lookup curSlideId mediaReg of
        Just minfos -> mediaInfo : minfos
        Nothing     -> [mediaInfo]


  modify $ \st -> st{ stMediaIds = M.insert curSlideId slideMediaInfos mediaReg
                    , stMediaGlobalIds = newGlobalIds
                    }
  return mediaInfo

makeMediaEntry :: PandocMonad m => MediaInfo -> P m Entry
makeMediaEntry mInfo = do
  epochtime <- (floor . utcTimeToPOSIXSeconds) <$> asks envUTCTime
  (imgBytes, _) <- P.fetchItem (mInfoFilePath mInfo)
  let ext = case mInfoExt mInfo of
              Just e -> e
              Nothing -> ""
  let fp = "ppt/media/image" ++ (show $ mInfoGlobalId mInfo) ++ ext
  return $ toEntry fp epochtime $ BL.fromStrict imgBytes

makeMediaEntries :: PandocMonad m => P m [Entry]
makeMediaEntries = do
  mediaInfos <- gets stMediaIds
  let allInfos = mconcat $ M.elems mediaInfos
  mapM makeMediaEntry allInfos

-- -- | Scales the image to fit the page
-- -- sizes are passed in emu
-- fitToPage' :: (Double, Double)  -- image size in emu
--            -> Integer           -- pageWidth
--            -> Integer           -- pageHeight
--            -> (Integer, Integer) -- imagesize
-- fitToPage' (x, y) pageWidth pageHeight
--   -- Fixes width to the page width and scales the height
--   | x <= fromIntegral pageWidth && y <= fromIntegral pageHeight =
--       (floor x, floor y)
--   | x / fromIntegral pageWidth > y / fromIntegral pageWidth =
--       (pageWidth, floor $ ((fromIntegral pageWidth) / x) * y)
--   | otherwise =
--       (floor $ ((fromIntegral pageHeight) / y) * x, pageHeight)

-- positionImage :: (Double, Double) -> Integer -> Integer -> (Integer, Integer)
-- positionImage (x, y) pageWidth pageHeight =
--   let (x', y') = fitToPage' (x, y) pageWidth pageHeight
--   in
--     ((pageWidth - x') `div` 2, (pageHeight - y') `div`  2)

getMaster :: PandocMonad m => P m Element
getMaster = do
  refArchive <- asks envRefArchive
  distArchive <- asks envDistArchive
  parseXml refArchive distArchive "ppt/slideMasters/slideMaster1.xml"

-- We want to get the header dimensions, so we can make sure that the
-- image goes underneath it. We only use this in a content slide if it
-- has a header.

-- getHeaderSize :: PandocMonad m => P m ((Integer, Integer), (Integer, Integer))
-- getHeaderSize = do
--   master <- getMaster
--   let ns = elemToNameSpaces master
--       sps = [master] >>=
--             findChildren (elemName ns "p" "cSld") >>=
--             findChildren (elemName ns "p" "spTree") >>=
--             findChildren (elemName ns "p" "sp")
--       mbXfrm =
--         listToMaybe (filter (shapeHasName ns "Title Placeholder 1") sps) >>=
--         findChild (elemName ns "p" "spPr") >>=
--         findChild (elemName ns "a" "xfrm")
--       xoff = mbXfrm >>=
--              findChild (elemName ns "a" "off") >>=
--              findAttr (QName "x" Nothing Nothing) >>=
--              (listToMaybe . (\s -> reads s :: [(Integer, String)]))
--       yoff = mbXfrm >>=
--              findChild (elemName ns "a" "off") >>=
--              findAttr (QName "y" Nothing Nothing) >>=
--              (listToMaybe . (\s -> reads s :: [(Integer, String)]))
--       xext = mbXfrm >>=
--              findChild (elemName ns "a" "ext") >>=
--              findAttr (QName "cx" Nothing Nothing) >>=
--              (listToMaybe . (\s -> reads s :: [(Integer, String)]))
--       yext = mbXfrm >>=
--              findChild (elemName ns "a" "ext") >>=
--              findAttr (QName "cy" Nothing Nothing) >>=
--              (listToMaybe . (\s -> reads s :: [(Integer, String)]))
--       off = case xoff of
--               Just (xoff', _) | Just (yoff',_) <- yoff -> (xoff', yoff')
--               _                               -> (1043490, 1027664)
--       ext = case xext of
--               Just (xext', _) | Just (yext',_) <- yext -> (xext', yext')
--               _                               -> (7024744, 1143000)
--   return $ (off, ext)

-- Hard-coded for now
-- captionPosition :: ((Integer, Integer), (Integer, Integer))
-- captionPosition = ((457200, 6061972), (8229600, 527087))

captionHeight :: Integer
captionHeight = 40

createCaption :: PandocMonad m
              => ((Integer, Integer), (Integer, Integer))
              -> [ParaElem]
              -> P m Element
createCaption contentShapeDimensions paraElements = do
  let para = Paragraph def{pPropAlign = Just AlgnCenter} paraElements
  elements <- mapM paragraphToElement [para]
  let ((x, y), (cx, cy)) = contentShapeDimensions
  let txBody = mknode "p:txBody" [] $
               [mknode "a:bodyPr" [] (), mknode "a:lstStyle" [] ()] ++ elements
  return $
    mknode "p:sp" [] [ mknode "p:nvSpPr" []
                       [ mknode "p:cNvPr" [("id","1"), ("name","TextBox 3")] ()
                       , mknode "p:cNvSpPr" [("txBox", "1")] ()
                       , mknode "p:nvPr" [] ()
                       ]
                     , mknode "p:spPr" []
                       [ mknode "a:xfrm" []
                         [ mknode "a:off" [("x", show $ 12700 * x),
                                           ("y", show $ 12700 * (y + cy - captionHeight))] ()
                         , mknode "a:ext" [("cx", show $ 12700 * cx),
                                           ("cy", show $ 12700 * captionHeight)] ()
                         ]
                       , mknode "a:prstGeom" [("prst", "rect")]
                         [ mknode "a:avLst" [] ()
                         ]
                       , mknode "a:noFill" [] ()
                       ]
                     , txBody
                     ]

makePicElements :: PandocMonad m
                => Element
                -> PicProps
                -> MediaInfo
                -> [ParaElem]
                -> P m [Element]
makePicElements layout picProps mInfo alt = do
  opts <- asks envOpts
  (pageWidth, pageHeight) <- asks envPresentationSize
  -- hasHeader <- asks envSlideHasHeader
  let hasCaption = mInfoCaption mInfo
  (imgBytes, _) <- P.fetchItem (mInfoFilePath mInfo)
  let (pxX, pxY) = case imageSize opts imgBytes of
        Right sz -> sizeInPixels $ sz
        Left _   -> sizeInPixels $ def
  master <- getMaster
  let ns = elemToNameSpaces layout
  ((x, y), (cx, cytmp)) <- getContentShapeSize ns layout master
                           `catchError`
                           (\_ -> return ((0, 0), (pageWidth, pageHeight)))

  let cy = if hasCaption then cytmp - captionHeight else cytmp

  let imgRatio = fromIntegral pxX / fromIntegral pxY :: Double
      boxRatio = fromIntegral cx / fromIntegral cy :: Double
      (dimX, dimY) = if imgRatio > boxRatio
                     then (fromIntegral cx, fromIntegral cx / imgRatio)
                     else (fromIntegral cy * imgRatio, fromIntegral cy)

      (dimX', dimY') = (round dimX * 12700, round dimY * 12700) :: (Integer, Integer)
      (xoff, yoff) = (fromIntegral x + (fromIntegral cx - dimX) / 2,
                      fromIntegral y + (fromIntegral cy - dimY) / 2)
      (xoff', yoff') = (round xoff * 12700, round yoff * 12700) :: (Integer, Integer)

  let cNvPicPr = mknode "p:cNvPicPr" [] $
                 mknode "a:picLocks" [("noGrp","1")
                                     ,("noChangeAspect","1")] ()
  -- cNvPr will contain the link information so we do that separately,
  -- and register the link if necessary.
  let cNvPrAttr = [("descr", mInfoFilePath mInfo), ("id","0"),("name","Picture 1")]
  cNvPr <- case picPropLink picProps of
    Just link -> do idNum <- registerLink link
                    return $ mknode "p:cNvPr" cNvPrAttr $
                      mknode "a:hlinkClick" [("r:id", "rId" ++ show idNum)] ()
    Nothing   -> return $ mknode "p:cNvPr" cNvPrAttr ()
  let nvPicPr  = mknode "p:nvPicPr" []
                 [ cNvPr
                 , cNvPicPr
                 , mknode "p:nvPr" [] ()]
  let blipFill = mknode "p:blipFill" []
                 [ mknode "a:blip" [("r:embed", "rId" ++ (show $ mInfoLocalId mInfo))] ()
                 , mknode "a:stretch" [] $
                   mknode "a:fillRect" [] () ]
  let xfrm =    mknode "a:xfrm" []
                [ mknode "a:off" [("x",show xoff'), ("y",show yoff')] ()
                , mknode "a:ext" [("cx",show dimX')
                                 ,("cy",show dimY')] () ]
  let prstGeom = mknode "a:prstGeom" [("prst","rect")] $
                 mknode "a:avLst" [] ()
  let ln =      mknode "a:ln" [("w","9525")]
                [ mknode "a:noFill" [] ()
                , mknode "a:headEnd" [] ()
                , mknode "a:tailEnd" [] () ]
  let spPr =    mknode "p:spPr" [("bwMode","auto")]
                [xfrm, prstGeom, mknode "a:noFill" [] (), ln]

  let picShape = mknode "p:pic" []
                 [ nvPicPr
                 , blipFill
                 , spPr ]

  -- And now, maybe create the caption:
  if hasCaption
    then do cap <- createCaption ((x, y), (cx, cytmp)) alt
            return [picShape, cap]
    else return [picShape]


paraElemToElement :: PandocMonad m => ParaElem -> P m Element
paraElemToElement Break = return $ mknode "a:br" [] ()
paraElemToElement (Run rpr s) = do
  let sizeAttrs = case rPropForceSize rpr of
                    Just n -> [("sz", (show $ n * 100))]
                    Nothing -> []
      attrs = sizeAttrs ++
        if rPropCode rpr
        then []
        else (if rPropBold rpr then [("b", "1")] else []) ++
             (if rPropItalics rpr then [("i", "1")] else []) ++
             (case rStrikethrough rpr of
                Just NoStrike     -> [("strike", "noStrike")]
                Just SingleStrike -> [("strike", "sngStrike")]
                Just DoubleStrike -> [("strike", "dblStrike")]
                Nothing -> []) ++
             (case rBaseline rpr of
                Just n -> [("baseline", show n)]
                Nothing -> []) ++
             (case rCap rpr of
                Just NoCapitals -> [("cap", "none")]
                Just SmallCapitals -> [("cap", "small")]
                Just AllCapitals -> [("cap", "all")]
                Nothing -> []) ++
             []
  linkProps <- case rLink rpr of
                 Just link -> do
                   idNum <- registerLink link
                   -- first we have to make sure that if it's an
                   -- anchor, it's in the anchor map. If not, there's
                   -- no link.
                   return $ case link of
                     InternalTarget _ ->
                       let linkAttrs =
                             [ ("r:id", "rId" ++ show idNum)
                             , ("action", "ppaction://hlinksldjump")
                             ]
                       in [mknode "a:hlinkClick" linkAttrs ()]
                     -- external
                     ExternalTarget _ ->
                       let linkAttrs =
                             [ ("r:id", "rId" ++ show idNum)
                             ]
                       in [mknode "a:hlinkClick" linkAttrs ()]
                 Nothing -> return []
  let propContents = if rPropCode rpr
                     then [mknode "a:latin" [("typeface", "Courier")] ()]
                     else linkProps
  return $ mknode "a:r" [] [ mknode "a:rPr" attrs propContents
                           , mknode "a:t" [] s
                           ]
paraElemToElement (MathElem mathType texStr) = do
  res <- convertMath writeOMML mathType (unTeXString texStr)
  case res of
    Right r -> return $ mknode "a14:m" [] $ addMathInfo r
    Left (Str s) -> paraElemToElement (Run def s)
    Left _       -> throwError $ PandocShouldNeverHappenError "non-string math fallback"

-- This is a bit of a kludge -- really requires adding an option to
-- TeXMath, but since that's a different package, we'll do this one
-- step at a time.
addMathInfo :: Element -> Element
addMathInfo element =
  let mathspace = Attr { attrKey = (QName "m" Nothing (Just "xmlns"))
                       , attrVal = "http://schemas.openxmlformats.org/officeDocument/2006/math"
                       }
  in add_attr mathspace element

-- We look through the element to see if it contains an a14:m
-- element. If so, we surround it. This is a bit ugly, but it seems
-- more dependable than looking through shapes for math. Plus this is
-- an xml implementation detail, so it seems to make sense to do it at
-- the xml level.
surroundWithMathAlternate :: Element -> Element
surroundWithMathAlternate element =
  case findElement (QName "m" Nothing (Just "a14")) element of
    Just _ ->
      mknode "mc:AlternateContent"
         [("xmlns:mc", "http://schemas.openxmlformats.org/markup-compatibility/2006")
         ] [ mknode "mc:Choice"
             [ ("xmlns:a14", "http://schemas.microsoft.com/office/drawing/2010/main")
             , ("Requires", "a14")] [ element ]
           ]
    Nothing -> element

paragraphToElement :: PandocMonad m => Paragraph -> P m Element
paragraphToElement par = do
  let
    attrs = [("lvl", show $ pPropLevel $ paraProps par)] ++
            (case pPropMarginLeft (paraProps par) of
               Just px -> [("marL", show $ 12700 * px), ("indent", "0")]
               Nothing -> []
            ) ++
            (case pPropAlign (paraProps par) of
               Just AlgnLeft -> [("algn", "l")]
               Just AlgnRight -> [("algn", "r")]
               Just AlgnCenter -> [("algn", "ctr")]
               Nothing -> []
            )
    props = [] ++
            (case pPropSpaceBefore $ paraProps par of
               Just px -> [mknode "a:spcBef" [] [
                              mknode "a:spcPts" [("val", show $ 100 * px)] ()
                              ]
                          ]
               Nothing -> []
            ) ++
            (case pPropBullet $ paraProps par of
               Just Bullet -> []
               Just (AutoNumbering attrs') ->
                 [mknode "a:buAutoNum" [("type", autoNumberingToType attrs')] ()]
               Nothing -> [mknode "a:buNone" [] ()]
            )
  paras <- mapM paraElemToElement (paraElems par)
  return $ mknode "a:p" [] $ [mknode "a:pPr" attrs props] ++ paras

shapeToElement :: PandocMonad m => Element -> Shape -> P m Element
shapeToElement layout (TextBox paras)
  | ns <- elemToNameSpaces layout
  , Just cSld <- findChild (elemName ns "p" "cSld") layout
  , Just spTree <- findChild (elemName ns "p" "spTree") cSld = do
      sp <- getContentShape ns spTree
      elements <- mapM paragraphToElement paras
      let txBody = mknode "p:txBody" [] $
                   [mknode "a:bodyPr" [] (), mknode "a:lstStyle" [] ()] ++ elements
          emptySpPr = mknode "p:spPr" [] ()
      return $
        surroundWithMathAlternate $
        replaceNamedChildren ns "p" "txBody" [txBody] $
        replaceNamedChildren ns "p" "spPr" [emptySpPr] $
        sp
-- GraphicFrame and Pic should never reach this.
shapeToElement _ _ = return $ mknode "p:sp" [] ()

shapeToElements :: PandocMonad m => Element -> Shape -> P m [Element]
shapeToElements layout (Pic picProps fp alt) = do
  mInfo <- registerMedia fp alt
  case mInfoExt mInfo of
    Just _ -> do
      makePicElements layout picProps mInfo alt
    Nothing -> shapeToElements layout $ TextBox [Paragraph def alt]
shapeToElements layout (GraphicFrame tbls cptn) =
  graphicFrameToElements layout tbls cptn
shapeToElements layout shp = do
  element <- shapeToElement layout shp
  return [element]

shapesToElements :: PandocMonad m => Element -> [Shape] -> P m [Element]
shapesToElements layout shps = do
 concat <$> mapM (shapeToElements layout) shps

graphicFrameToElements :: PandocMonad m => Element -> [Graphic] -> [ParaElem] -> P m [Element]
graphicFrameToElements layout tbls caption = do
  -- get the sizing
  master <- getMaster
  (pageWidth, pageHeight) <- asks envPresentationSize
  let ns = elemToNameSpaces layout
  ((x, y), (cx, cytmp)) <- getContentShapeSize ns layout master
                           `catchError`
                           (\_ -> return ((0, 0), (pageWidth, pageHeight)))

  let cy = if (not $ null caption) then cytmp - captionHeight else cytmp

  elements <- mapM (graphicToElement cx) tbls
  let graphicFrameElts =
        mknode "p:graphicFrame" [] $
        [ mknode "p:nvGraphicFramePr" [] $
          [ mknode "p:cNvPr" [("id", "6"), ("name", "Content Placeholder 5")] ()
          , mknode "p:cNvGraphicFramePr" [] $
            [mknode "a:graphicFrameLocks" [("noGrp", "1")] ()]
          , mknode "p:nvPr" [] $
            [mknode "p:ph" [("idx", "1")] ()]
          ]
        , mknode "p:xfrm" [] $
          [ mknode "a:off" [("x", show $ 12700 * x), ("y", show $ 12700 * y)] ()
          , mknode "a:ext" [("cx", show $ 12700 * cx), ("cy", show $ 12700 * cy)] ()
          ]
        ] ++ elements

  if (not $ null caption)
    then do capElt <- createCaption ((x, y), (cx, cytmp)) caption
            return [graphicFrameElts, capElt]
    else return [graphicFrameElts]

graphicToElement :: PandocMonad m => Integer -> Graphic -> P m Element
graphicToElement tableWidth (Tbl tblPr hdrCells rows) = do
  let colWidths = if null hdrCells
                  then case rows of
                         r : _ | not (null r) -> replicate (length r) $
                                                (tableWidth `div` (toInteger $ length r))
                         -- satisfy the compiler. This is the same as
                         -- saying that rows is empty, but the compiler
                         -- won't understand that `[]` exhausts the
                         -- alternatives.
                         _ -> []
                  else replicate (length hdrCells) $
                       (tableWidth `div` (toInteger $ length hdrCells))

  let cellToOpenXML paras =
        do elements <- mapM paragraphToElement paras
           let elements' = if null elements
                           then [mknode "a:p" [] [mknode "a:endParaRPr" [] ()]]
                           else elements
           return $
             [mknode "a:txBody" [] $
               ([ mknode "a:bodyPr" [] ()
                , mknode "a:lstStyle" [] ()]
                 ++ elements')]
  headers' <- mapM cellToOpenXML hdrCells
  rows' <- mapM (mapM cellToOpenXML) rows
  let borderProps = mknode "a:tcPr" [] ()
  let emptyCell = [mknode "a:p" [] [mknode "a:pPr" [] ()]]
  let mkcell border contents = mknode "a:tc" []
                            $ (if null contents
                               then emptyCell
                               else contents) ++ [ borderProps | border ]
  let mkrow border cells = mknode "a:tr" [("h", "0")] $ map (mkcell border) cells

  let mkgridcol w = mknode "a:gridCol"
                       [("w", show ((12700 * w) :: Integer))] ()
  let hasHeader = not (all null hdrCells)
  return $ mknode "a:graphic" [] $
    [mknode "a:graphicData" [("uri", "http://schemas.openxmlformats.org/drawingml/2006/table")] $
     [mknode "a:tbl" [] $
      [ mknode "a:tblPr" [ ("firstRow", if tblPrFirstRow tblPr then "1" else "0")
                         , ("bandRow", if tblPrBandRow tblPr then "1" else "0")
                         ] ()
      , mknode "a:tblGrid" [] (if all (==0) colWidths
                               then []
                               else map mkgridcol colWidths)
      ]
      ++ [ mkrow True headers' | hasHeader ] ++ map (mkrow False) rows'
     ]
    ]

getShapeByName :: NameSpaces -> Element -> String -> Maybe Element
getShapeByName ns spTreeElem name
  | isElem ns "p" "spTree" spTreeElem =
  filterChild (\e -> (isElem ns "p" "sp" e) && (shapeHasName ns name e)) spTreeElem
  | otherwise = Nothing

-- getShapeById :: NameSpaces -> Element -> String -> Maybe Element
-- getShapeById ns spTreeElem ident
--   | isElem ns "p" "spTree" spTreeElem =
--   filterChild (\e -> (isElem ns "p" "sp" e) && (shapeHasId ns ident e)) spTreeElem
--   | otherwise = Nothing

nonBodyTextToElement :: PandocMonad m => Element -> String -> [ParaElem] -> P m Element
nonBodyTextToElement layout shapeName paraElements
  | ns <- elemToNameSpaces layout
  , Just cSld <- findChild (elemName ns "p" "cSld") layout
  , Just spTree <- findChild (elemName ns "p" "spTree") cSld
  , Just sp <- getShapeByName ns spTree shapeName = do
      let hdrPara = Paragraph def paraElements
      element <- paragraphToElement hdrPara
      let txBody = mknode "p:txBody" [] $
                   [mknode "a:bodyPr" [] (), mknode "a:lstStyle" [] ()] ++
                   [element]
      return $ replaceNamedChildren ns "p" "txBody" [txBody] sp
  -- XXX: TODO
  | otherwise = return $ mknode "p:sp" [] ()

contentToElement :: PandocMonad m => Element -> [ParaElem] -> [Shape] -> P m Element
contentToElement layout hdrShape shapes
  | ns <- elemToNameSpaces layout
  , Just cSld <- findChild (elemName ns "p" "cSld") layout
  , Just spTree <- findChild (elemName ns "p" "spTree") cSld = do
      element <- nonBodyTextToElement layout "Title 1" hdrShape
      let hdrShapeElements = if null hdrShape
                             then []
                             else [element]
      contentElements <- local
                         (\env -> env {envContentType = NormalContent})
                         (shapesToElements layout shapes)
      return $
        replaceNamedChildren ns "p" "sp"
        (hdrShapeElements ++ contentElements)
        spTree
contentToElement _ _ _ = return $ mknode "p:sp" [] ()

twoColumnToElement :: PandocMonad m => Element -> [ParaElem] -> [Shape] -> [Shape] -> P m Element
twoColumnToElement layout hdrShape shapesL shapesR
  | ns <- elemToNameSpaces layout
  , Just cSld <- findChild (elemName ns "p" "cSld") layout
  , Just spTree <- findChild (elemName ns "p" "spTree") cSld = do
      element <- nonBodyTextToElement layout "Title 1" hdrShape
      let hdrShapeElements = if null hdrShape
                             then []
                             else [element]
      contentElementsL <- local
                          (\env -> env {envContentType =TwoColumnLeftContent})
                          (shapesToElements layout shapesL)
      contentElementsR <- local
                          (\env -> env {envContentType =TwoColumnRightContent})
                          (shapesToElements layout shapesR)
      -- let contentElementsL' = map (setIdx ns "1") contentElementsL
      --     contentElementsR' = map (setIdx ns "2") contentElementsR
      return $
        replaceNamedChildren ns "p" "sp"
        (hdrShapeElements ++ contentElementsL ++ contentElementsR)
        spTree
twoColumnToElement _ _ _ _= return $ mknode "p:sp" [] ()


titleToElement :: PandocMonad m => Element -> [ParaElem] -> P m Element
titleToElement layout titleElems
  | ns <- elemToNameSpaces layout
  , Just cSld <- findChild (elemName ns "p" "cSld") layout
  , Just spTree <- findChild (elemName ns "p" "spTree") cSld = do
      element <- nonBodyTextToElement layout "Title 1" titleElems
      let titleShapeElements = if null titleElems
                               then []
                               else [element]
      return $ replaceNamedChildren ns "p" "sp" titleShapeElements spTree
titleToElement _ _ = return $ mknode "p:sp" [] ()

metadataToElement :: PandocMonad m => Element -> [ParaElem] -> [ParaElem] -> [[ParaElem]] -> [ParaElem] -> P m Element
metadataToElement layout titleElems subtitleElems authorsElems dateElems
  | ns <- elemToNameSpaces layout
  , Just cSld <- findChild (elemName ns "p" "cSld") layout
  , Just spTree <- findChild (elemName ns "p" "spTree") cSld = do
      titleShapeElements <- if null titleElems
                            then return []
                            else sequence [nonBodyTextToElement layout "Title 1" titleElems]
      let combinedAuthorElems = intercalate [Break] authorsElems
          subtitleAndAuthorElems = intercalate [Break, Break] [subtitleElems, combinedAuthorElems]
      subtitleShapeElements <- if null subtitleAndAuthorElems
                               then return []
                               else sequence [nonBodyTextToElement layout "Subtitle 2" subtitleAndAuthorElems]
      dateShapeElements <- if null dateElems
                           then return []
                           else sequence [nonBodyTextToElement layout "Date Placeholder 3" dateElems]
      return $ replaceNamedChildren ns "p" "sp"
        (titleShapeElements ++ subtitleShapeElements ++ dateShapeElements)
        spTree
metadataToElement _ _ _ _ _ = return $ mknode "p:sp" [] ()

slideToElement :: PandocMonad m => Slide -> P m Element
slideToElement (Slide _ l@(ContentSlide hdrElems shapes) _ )= do
  layout <- getLayout l
  spTree <- local (\env -> if null hdrElems
                           then env
                           else env{envSlideHasHeader=True}) $
            contentToElement layout hdrElems shapes
  return $ mknode "p:sld"
    [ ("xmlns:a", "http://schemas.openxmlformats.org/drawingml/2006/main"),
      ("xmlns:r", "http://schemas.openxmlformats.org/officeDocument/2006/relationships"),
      ("xmlns:p", "http://schemas.openxmlformats.org/presentationml/2006/main")
    ] [mknode "p:cSld" [] [spTree]]
slideToElement (Slide _ l@(TwoColumnSlide hdrElems shapesL shapesR) _) = do
  layout <- getLayout l
  spTree <- local (\env -> if null hdrElems
                           then env
                           else env{envSlideHasHeader=True}) $
            twoColumnToElement layout hdrElems shapesL shapesR
  return $ mknode "p:sld"
    [ ("xmlns:a", "http://schemas.openxmlformats.org/drawingml/2006/main"),
      ("xmlns:r", "http://schemas.openxmlformats.org/officeDocument/2006/relationships"),
      ("xmlns:p", "http://schemas.openxmlformats.org/presentationml/2006/main")
    ] [mknode "p:cSld" [] [spTree]]
slideToElement (Slide _ l@(TitleSlide hdrElems) _) = do
  layout <- getLayout l
  spTree <- titleToElement layout hdrElems
  return $ mknode "p:sld"
    [ ("xmlns:a", "http://schemas.openxmlformats.org/drawingml/2006/main"),
      ("xmlns:r", "http://schemas.openxmlformats.org/officeDocument/2006/relationships"),
      ("xmlns:p", "http://schemas.openxmlformats.org/presentationml/2006/main")
    ] [mknode "p:cSld" [] [spTree]]
slideToElement (Slide _ l@(MetadataSlide titleElems subtitleElems authorElems dateElems) _) = do
  layout <- getLayout l
  spTree <- metadataToElement layout titleElems subtitleElems authorElems dateElems
  return $ mknode "p:sld"
    [ ("xmlns:a", "http://schemas.openxmlformats.org/drawingml/2006/main"),
      ("xmlns:r", "http://schemas.openxmlformats.org/officeDocument/2006/relationships"),
      ("xmlns:p", "http://schemas.openxmlformats.org/presentationml/2006/main")
    ] [mknode "p:cSld" [] [spTree]]

-----------------------------------------------------------------------

getSlideIdNum :: PandocMonad m => SlideId -> P m Int
getSlideIdNum sldId = do
  slideIdMap <- asks envSlideIdMap
  case  M.lookup sldId slideIdMap of
    Just n -> return n
    Nothing -> throwError $
               PandocShouldNeverHappenError $
               "Slide Id " ++ (show sldId) ++ " not found."

slideNum :: PandocMonad m => Slide -> P m Int
slideNum slide = getSlideIdNum $ slideId slide

idNumToFilePath :: Int -> FilePath
idNumToFilePath idNum = "slide" ++ (show $ idNum) ++ ".xml"

slideToFilePath :: PandocMonad m => Slide -> P m FilePath
slideToFilePath slide = do
  idNum <- slideNum slide
  return $ "slide" ++ (show $ idNum) ++ ".xml"

slideToRelId :: PandocMonad m => Slide -> P m String
slideToRelId slide = do
  n <- slideNum slide
  offset <- asks envSlideIdOffset
  return $ "rId" ++ (show $ n + offset)


data Relationship = Relationship { relId :: Int
                                 , relType :: MimeType
                                 , relTarget :: FilePath
                                 } deriving (Show, Eq)

elementToRel :: Element -> Maybe Relationship
elementToRel element
  | elName element == QName "Relationship" (Just "http://schemas.openxmlformats.org/package/2006/relationships") Nothing =
      do rId <- findAttr (QName "Id" Nothing Nothing) element
         numStr <- stripPrefix "rId" rId
         num <- case reads numStr :: [(Int, String)] of
           (n, _) : _ -> Just n
           []         -> Nothing
         type' <- findAttr (QName "Type" Nothing Nothing) element
         target <- findAttr (QName "Target" Nothing Nothing) element
         return $ Relationship num type' target
  | otherwise = Nothing

slideToPresRel :: PandocMonad m => Slide -> P m Relationship
slideToPresRel slide = do
  idNum <- slideNum slide
  n <- asks envSlideIdOffset
  let rId = idNum + n
      fp = "slides/" ++ idNumToFilePath idNum
  return $ Relationship { relId = rId
                        , relType = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/slide"
                        , relTarget = fp
                        }

getRels :: PandocMonad m => P m [Relationship]
getRels = do
  refArchive <- asks envRefArchive
  distArchive <- asks envDistArchive
  relsElem <- parseXml refArchive distArchive "ppt/_rels/presentation.xml.rels"
  let globalNS = "http://schemas.openxmlformats.org/package/2006/relationships"
  let relElems = findChildren (QName "Relationship" (Just globalNS) Nothing) relsElem
  return $ mapMaybe elementToRel relElems

presentationToRels :: PandocMonad m => Presentation -> P m [Relationship]
presentationToRels (Presentation _ slides) = do
  mySlideRels <- mapM slideToPresRel slides
  rels <- getRels
  let relsWithoutSlides = filter (\r -> relType r /= "http://schemas.openxmlformats.org/officeDocument/2006/relationships/slide") rels
  -- We want to make room for the slides in the id space. The slides
  -- will start at Id2 (since Id1 is for the slide master). There are
  -- two slides in the data file, but that might change in the future,
  -- so we will do this:
  --
  -- 1. We look to see what the minimum relWithoutSlide id (greater than 1) is.
  -- 2. We add the difference between this and the number of slides to
  -- all relWithoutSlide rels (unless they're 1)

  let minRelNotOne = case filter (1<) $ map relId relsWithoutSlides of
        [] -> 0                 -- doesn't matter in this case, since
                                -- there will be nothing to map the
                                -- function over
        l  -> minimum l

      modifyRelNum :: Int -> Int
      modifyRelNum 1 = 1
      modifyRelNum n = n - minRelNotOne + 2 + length slides

      relsWithoutSlides' = map (\r -> r{relId = modifyRelNum $ relId r}) relsWithoutSlides

  return $ mySlideRels ++ relsWithoutSlides'

-- We make this ourselves, in case there's a thumbnail in the one from
-- the template.
topLevelRels :: [Relationship]
topLevelRels =
  [ Relationship { relId = 1
                 , relType = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument"
                 , relTarget = "ppt/presentation.xml"
                 }
  , Relationship { relId = 2
                 , relType = "http://schemas.openxmlformats.org/package/2006/relationships/metadata/core-properties"
                 , relTarget = "docProps/core.xml"
                 }
  , Relationship { relId = 3
                 , relType = "http://schemas.openxmlformats.org/package/2006/relationships/metadata/extended-properties"
                 , relTarget = "docProps/app.xml"
                 }
  ]

topLevelRelsEntry :: PandocMonad m => P m Entry
topLevelRelsEntry = elemToEntry "_rels/.rels" $ relsToElement topLevelRels

relToElement :: Relationship -> Element
relToElement rel = mknode "Relationship" [ ("Id", "rId" ++ (show $ relId rel))
                                         , ("Type", relType rel)
                                         , ("Target", relTarget rel) ] ()

relsToElement :: [Relationship] -> Element
relsToElement rels = mknode "Relationships"
                     [("xmlns", "http://schemas.openxmlformats.org/package/2006/relationships")]
                     (map relToElement rels)

presentationToRelsEntry :: PandocMonad m => Presentation -> P m Entry
presentationToRelsEntry pres = do
  rels <- presentationToRels pres
  elemToEntry "ppt/_rels/presentation.xml.rels" $ relsToElement rels

elemToEntry :: PandocMonad m => FilePath -> Element -> P m Entry
elemToEntry fp element = do
  epochtime <- (floor . utcTimeToPOSIXSeconds) <$> asks envUTCTime
  return $ toEntry fp epochtime $ renderXml element

slideToEntry :: PandocMonad m => Slide -> P m Entry
slideToEntry slide = do
  idNum <- slideNum slide
  local (\env -> env{envCurSlideId = idNum}) $ do
    element <- slideToElement slide
    elemToEntry ("ppt/slides/" ++ idNumToFilePath idNum) element

slideToSlideRelEntry :: PandocMonad m => Slide -> P m Entry
slideToSlideRelEntry slide = do
  idNum <- slideNum slide
  element <- slideToSlideRelElement slide
  elemToEntry ("ppt/slides/_rels/" ++ idNumToFilePath idNum ++ ".rels") element

linkRelElement :: PandocMonad m => Int -> LinkTarget -> P m Element
linkRelElement rIdNum (InternalTarget targetId) = do
  targetIdNum <- getSlideIdNum targetId
  return $
    mknode "Relationship" [ ("Id", "rId" ++ show rIdNum)
                          , ("Type", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/slide")
                          , ("Target", "slide" ++ show targetIdNum ++ ".xml")
                          ] ()
linkRelElement rIdNum (ExternalTarget (url, _)) = do
  return $
    mknode "Relationship" [ ("Id", "rId" ++ show rIdNum)
                          , ("Type", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink")
                          , ("Target", url)
                          , ("TargetMode", "External")
                          ] ()

linkRelElements :: PandocMonad m => M.Map Int LinkTarget -> P m [Element]
linkRelElements mp = mapM (\(n, lnk) -> linkRelElement n lnk) (M.toList mp)

mediaRelElement :: MediaInfo -> Element
mediaRelElement mInfo =
  let ext = case mInfoExt mInfo of
              Just e -> e
              Nothing -> ""
  in
    mknode "Relationship" [ ("Id", "rId" ++ (show $ mInfoLocalId mInfo))
                          , ("Type", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/image")
                          , ("Target", "../media/image" ++ (show $ mInfoGlobalId mInfo) ++ ext)
                          ] ()

slideToSlideRelElement :: PandocMonad m => Slide -> P m Element
slideToSlideRelElement slide = do
  idNum <- slideNum slide
  let target =  case slide of
        (Slide _ (MetadataSlide _ _ _ _) _) -> "../slideLayouts/slideLayout1.xml"
        (Slide _ (TitleSlide _) _)          -> "../slideLayouts/slideLayout3.xml"
        (Slide _ (ContentSlide _ _) _)      -> "../slideLayouts/slideLayout2.xml"
        (Slide _ (TwoColumnSlide _ _ _) _)  -> "../slideLayouts/slideLayout4.xml"

  linkIds <- gets stLinkIds
  mediaIds <- gets stMediaIds

  linkRels <- case M.lookup idNum linkIds of
                Just mp -> linkRelElements mp
                Nothing -> return []
  let mediaRels = case M.lookup idNum mediaIds of
                   Just mInfos -> map mediaRelElement mInfos
                   Nothing -> []

  return $
    mknode "Relationships"
    [("xmlns", "http://schemas.openxmlformats.org/package/2006/relationships")]
    ([mknode "Relationship" [ ("Id", "rId1")
                           , ("Type", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/slideLayout")
                           , ("Target", target)] ()
    ] ++ linkRels ++ mediaRels)

slideToSldIdElement :: PandocMonad m => Slide -> P m Element
slideToSldIdElement slide = do
  n <- slideNum slide
  let id' = show $ n + 255
  rId <- slideToRelId slide
  return $ mknode "p:sldId" [("id", id'), ("r:id", rId)] ()

presentationToSldIdLst :: PandocMonad m => Presentation -> P m Element
presentationToSldIdLst (Presentation _ slides) = do
  ids <- mapM slideToSldIdElement slides
  return $ mknode "p:sldIdLst" [] ids

presentationToPresentationElement :: PandocMonad m => Presentation -> P m Element
presentationToPresentationElement pres = do
  refArchive <- asks envRefArchive
  distArchive <- asks envDistArchive
  element <- parseXml refArchive distArchive "ppt/presentation.xml"
  sldIdLst <- presentationToSldIdLst pres

  let modifySldIdLst :: Content -> Content
      modifySldIdLst (Elem e) = case elName e of
        (QName "sldIdLst" _ _) -> Elem sldIdLst
        _                      -> Elem e
      modifySldIdLst ct = ct

      newContent = map modifySldIdLst $ elContent element

  return $ element{elContent = newContent}

presentationToPresEntry :: PandocMonad m => Presentation -> P m Entry
presentationToPresEntry pres = presentationToPresentationElement pres >>=
  elemToEntry "ppt/presentation.xml"

-- adapted from the Docx writer
docPropsElement :: PandocMonad m => DocProps -> P m Element
docPropsElement docProps = do
  utctime <- asks envUTCTime
  let keywords = case dcKeywords docProps of
        Just xs -> intercalate "," xs
        Nothing -> ""
  return $
    mknode "cp:coreProperties"
    [("xmlns:cp","http://schemas.openxmlformats.org/package/2006/metadata/core-properties")
    ,("xmlns:dc","http://purl.org/dc/elements/1.1/")
    ,("xmlns:dcterms","http://purl.org/dc/terms/")
    ,("xmlns:dcmitype","http://purl.org/dc/dcmitype/")
    ,("xmlns:xsi","http://www.w3.org/2001/XMLSchema-instance")]
    $ (mknode "dc:title" [] $ fromMaybe "" $ dcTitle docProps)
    : (mknode "dc:creator" [] $ fromMaybe "" $ dcCreator docProps)
    : (mknode "cp:keywords" [] keywords)
    : (\x -> [ mknode "dcterms:created" [("xsi:type","dcterms:W3CDTF")] x
             , mknode "dcterms:modified" [("xsi:type","dcterms:W3CDTF")] x
             ]) (formatTime defaultTimeLocale "%FT%XZ" utctime)

docPropsToEntry :: PandocMonad m => DocProps -> P m Entry
docPropsToEntry docProps = docPropsElement docProps >>=
                           elemToEntry "docProps/core.xml"


defaultContentTypeToElem :: DefaultContentType -> Element
defaultContentTypeToElem dct =
  mknode "Default"
  [("Extension", defContentTypesExt dct),
    ("ContentType", defContentTypesType dct)]
  ()

overrideContentTypeToElem :: OverrideContentType -> Element
overrideContentTypeToElem oct =
  mknode "Override"
  [("PartName", overrideContentTypesPart oct),
    ("ContentType", overrideContentTypesType oct)]
  ()

contentTypesToElement :: ContentTypes -> Element
contentTypesToElement ct =
  let ns = "http://schemas.openxmlformats.org/package/2006/content-types"
  in
    mknode "Types" [("xmlns", ns)] $
    (map defaultContentTypeToElem $ contentTypesDefaults ct) ++
    (map overrideContentTypeToElem $ contentTypesOverrides ct)

data DefaultContentType = DefaultContentType
                           { defContentTypesExt :: String
                           , defContentTypesType:: MimeType
                           }
                         deriving (Show, Eq)

data OverrideContentType = OverrideContentType
                           { overrideContentTypesPart :: FilePath
                           , overrideContentTypesType :: MimeType
                           }
                          deriving (Show, Eq)

data ContentTypes = ContentTypes { contentTypesDefaults :: [DefaultContentType]
                                 , contentTypesOverrides :: [OverrideContentType]
                                 }
                    deriving (Show, Eq)

contentTypesToEntry :: PandocMonad m => ContentTypes -> P m Entry
contentTypesToEntry ct = elemToEntry "[Content_Types].xml" $ contentTypesToElement ct

pathToOverride :: FilePath -> Maybe OverrideContentType
pathToOverride fp = OverrideContentType ("/" ++ fp) <$> (getContentType fp)

mediaFileContentType :: FilePath -> Maybe DefaultContentType
mediaFileContentType fp = case takeExtension fp of
  '.' : ext -> Just $
               DefaultContentType { defContentTypesExt = ext
                                  , defContentTypesType =
                                      case getMimeType fp of
                                        Just mt -> mt
                                        Nothing -> "application/octet-stream"
                                  }
  _ -> Nothing

mediaContentType :: MediaInfo -> Maybe DefaultContentType
mediaContentType mInfo
  | Just ('.' : ext) <- mInfoExt mInfo =
      Just $ DefaultContentType { defContentTypesExt = ext
                                , defContentTypesType =
                                    case mInfoMimeType mInfo of
                                      Just mt -> mt
                                      Nothing -> "application/octet-stream"
                                }
  | otherwise = Nothing

presentationToContentTypes :: PandocMonad m => Presentation -> P m ContentTypes
presentationToContentTypes (Presentation _ slides) = do
  mediaInfos <- (mconcat . M.elems) <$> gets stMediaIds
  filePaths <- patternsToFilePaths inheritedPatterns
  let mediaFps = filter (match (compile "ppt/media/image*")) filePaths
  let defaults = [ DefaultContentType "xml" "application/xml"
                 , DefaultContentType "rels" "application/vnd.openxmlformats-package.relationships+xml"
                 ]
      mediaDefaults = nub $
                      (mapMaybe mediaContentType $ mediaInfos) ++
                      (mapMaybe mediaFileContentType $ mediaFps)

      inheritedOverrides = mapMaybe pathToOverride filePaths
      docPropsOverride = mapMaybe pathToOverride ["docProps/core.xml"]
      presOverride = mapMaybe pathToOverride ["ppt/presentation.xml"]
  relativePaths <- mapM slideToFilePath slides
  let slideOverrides = mapMaybe
                       (\fp -> pathToOverride $ "ppt/slides/" ++ fp)
                       relativePaths
  return $ ContentTypes
    (defaults ++ mediaDefaults)
    (inheritedOverrides ++ docPropsOverride ++ presOverride ++ slideOverrides)

presML :: String
presML = "application/vnd.openxmlformats-officedocument.presentationml"

noPresML :: String
noPresML = "application/vnd.openxmlformats-officedocument"

getContentType :: FilePath -> Maybe MimeType
getContentType fp
  | fp == "ppt/presentation.xml" = Just $ presML ++ ".presentation.main+xml"
  | fp == "ppt/presProps.xml" = Just $ presML ++ ".presProps+xml"
  | fp == "ppt/viewProps.xml" = Just $ presML ++ ".viewProps+xml"
  | fp == "ppt/tableStyles.xml" = Just $ presML ++ ".tableStyles+xml"
  | fp == "docProps/core.xml" = Just $ "application/vnd.openxmlformats-package.core-properties+xml"
  | fp == "docProps/app.xml" = Just $ noPresML ++ ".extended-properties+xml"
  | "ppt" : "slideMasters" : f : [] <- splitDirectories fp
  , (_, ".xml") <- splitExtension f =
      Just $ presML ++ ".slideMaster+xml"
  | "ppt" : "slides" : f : [] <- splitDirectories fp
  , (_, ".xml") <- splitExtension f =
      Just $ presML ++ ".slide+xml"
  | "ppt" : "notesMasters"  : f : [] <- splitDirectories fp
  , (_, ".xml") <- splitExtension f =
      Just $ presML ++ ".notesMaster+xml"
  | "ppt" : "notesSlides"  : f : [] <- splitDirectories fp
  , (_, ".xml") <- splitExtension f =
      Just $ presML ++ ".notesSlide+xml"
  | "ppt" : "theme" : f : [] <- splitDirectories fp
  , (_, ".xml") <- splitExtension f =
      Just $ noPresML ++ ".theme+xml"
  | "ppt" : "slideLayouts" : _ : [] <- splitDirectories fp=
      Just $ presML ++ ".slideLayout+xml"
  | otherwise = Nothing

autoNumberingToType :: ListAttributes -> String
autoNumberingToType (_, numStyle, numDelim) =
  typeString ++ delimString
  where
    typeString = case numStyle of
      Decimal -> "arabic"
      UpperAlpha -> "alphaUc"
      LowerAlpha -> "alphaLc"
      UpperRoman -> "romanUc"
      LowerRoman -> "romanLc"
      _          -> "arabic"
    delimString = case numDelim of
      Period -> "Period"
      OneParen -> "ParenR"
      TwoParens -> "ParenBoth"
      _         -> "Period"