    {-
    Copyright (C) 2015 Martin Linnemann <theCodingMarlin@googlemail.com>

    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.Readers.Odt.Generic.Namespaces
       Copyright   : Copyright (C) 2015 Martin Linnemann
       License     : GNU GPL, version 2 or above

       Maintainer  : Martin Linnemann <theCodingMarlin@googlemail.com>
       Stability   : alpha
       Portability : portable

    A class containing a set of namespace identifiers. Used to convert between
    typesafe Haskell namespace identifiers and unsafe "real world" namespaces.
    -}

    module Text.Pandoc.Readers.Odt.Generic.Namespaces where

    import qualified Data.Map as M

    --
    type NameSpaceIRI          = String

    --
    type NameSpaceIRIs     nsID = M.Map nsID NameSpaceIRI

    --
    class (Eq nsID, Ord nsID) => NameSpaceID nsID where

      -- | Given a IRI, possibly update the map and return the id of the namespace.
      -- May fail if the namespace is unknown and the application does not
      -- allow unknown namespaces.
      getNamespaceID   :: NameSpaceIRI
                          -> NameSpaceIRIs nsID
                          -> Maybe (NameSpaceIRIs nsID, nsID)
      -- | Given a namespace id, lookup its IRI. May be overriden for performance.
      getIRI           :: nsID
                          -> NameSpaceIRIs nsID
                          -> Maybe NameSpaceIRI
      -- | The root element of an XML document has a namespace, too, and the
      -- "XML.Light-parser" is eager to remove the corresponding namespace
      -- attribute.
      -- As a result, at least this root namespace must be provided.
      getInitialIRImap :: NameSpaceIRIs nsID

      getIRI           = M.lookup
      getInitialIRImap = M.empty