--------------------------------------------------------------------
-- |
-- Module    : Text.Atom.Feed
-- Copyright : (c) Galois, Inc. 2008
-- License   : BSD3
--
-- Maintainer: Sigbjorn Finne <sof@galois.com>
-- Stability : provisional
-- Portability:
--
--------------------------------------------------------------------

module Text.Atom.Feed where

import qualified Text.XML.Light as XML

-- *Core types

-- NOTE: In the future we may want to have more structured
-- types for these.
type URI        = String
type NCName     = String
type Date       = String
type MediaType  = String

data Feed
 = Feed
      { feedId           :: String
      , feedTitle        :: TextContent
      , feedUpdated      :: Date
      , feedAuthors      :: [Person]
      , feedCategories   :: [Category]
      , feedContributors :: [Person]
      , feedGenerator    :: Maybe Generator
      , feedIcon         :: Maybe URI
      , feedLinks        :: [Link]
      , feedLogo         :: Maybe URI
      , feedRights       :: Maybe TextContent
      , feedSubtitle     :: Maybe TextContent
      , feedEntries      :: [Entry]
      , feedAttrs        :: [XML.Attr]
      , feedOther        :: [XML.Element]
      }
     deriving (Show)

data Entry
 = Entry
      { entryId           :: String
      , entryTitle        :: TextContent
      , entryUpdated      :: Date
      , entryAuthors      :: [Person]
      , entryCategories   :: [Category]
      , entryContent      :: Maybe EntryContent
      , entryContributor  :: [Person]
      , entryLinks        :: [Link]
      , entryPublished    :: Maybe Date
      , entryRights       :: Maybe TextContent
      , entrySource       :: Maybe Source
      , entrySummary      :: Maybe TextContent
      , entryInReplyTo    :: Maybe InReplyTo
      , entryInReplyTotal :: Maybe InReplyTotal
      , entryAttrs        :: [XML.Attr]
      , entryOther        :: [XML.Element]
      }
     deriving (Show)

data EntryContent
 = TextContent   String
 | HTMLContent   String
 | XHTMLContent  XML.Element
 | MixedContent  (Maybe String) [XML.Content]
 | ExternalContent (Maybe MediaType) URI
     deriving (Show)

data Category
 = Category
       { catTerm   :: String         -- ^ the tag\/term of the category.
       , catScheme :: Maybe URI      -- ^ optional URL for identifying the categorization scheme.
       , catLabel  :: Maybe String   -- ^ human-readable label of the category
       , catOther  :: [XML.Element]  -- ^ unknown elements, for extensibility.
       }
     deriving (Show)


data Generator
 = Generator
       { genURI     :: Maybe URI
       , genVersion :: Maybe String
       , genText    :: String
       }
     deriving (Eq, Show)

data Link
 = Link
      { linkHref     :: URI
         -- ToDo: make the switch over to using the Atom.Feed.Link relation type.
      , linkRel      :: Maybe (Either NCName URI)
      , linkType     :: Maybe MediaType
      , linkHrefLang :: Maybe String
      , linkTitle    :: Maybe String
      , linkLength   :: Maybe String
      , linkAttrs    :: [XML.Attr]
      , linkOther    :: [XML.Element]
      }
     deriving (Show)

data TextContent
 = TextString  String
 | HTMLString  String
 | XHTMLString XML.Element
     deriving (Show)

txtToString :: TextContent -> String
txtToString (TextString s) = s
txtToString (HTMLString s) = s
txtToString (XHTMLString x) = show x

data Source
 = Source
      { sourceAuthors     :: [Person]
      , sourceCategories  :: [Category]
      , sourceGenerator   :: Maybe Generator
      , sourceIcon        :: Maybe URI
      , sourceId          :: Maybe String
      , sourceLinks       :: [Link]
      , sourceLogo        :: Maybe URI
      , sourceRights      :: Maybe TextContent
      , sourceSubtitle    :: Maybe TextContent
      , sourceTitle       :: Maybe TextContent
      , sourceUpdated     :: Maybe Date
      , sourceOther       :: [XML.Element]
      }
     deriving (Show)


data Person
 = Person
     { personName  :: String
     , personURI   :: Maybe URI
     , personEmail :: Maybe String
     , personOther :: [XML.Element]
     }
     deriving (Show)

data InReplyTo
 = InReplyTo
     { replyToRef     :: URI
     , replyToHRef    :: Maybe URI
     , replyToType    :: Maybe MediaType
     , replyToSource  :: Maybe URI
     , replyToOther   :: [XML.Attr]
     , replyToContent :: [XML.Content]
     }
     deriving (Show)

data InReplyTotal
 = InReplyTotal
     { replyToTotal      :: Integer -- non-negative :)
     , replyToTotalOther :: [XML.Attr]
     }
     deriving (Show)

-- *Smart Constructors

newCategory :: String -- ^catTerm
            -> Category
newCategory t = Category
  { catTerm   = t
  , catScheme = Nothing
  , catLabel  = Just t
  , catOther  = []
  }

nullFeed :: String  -- ^feedId
         -> TextContent -- ^feedTitle
         -> Date -- ^feedUpdated
         -> Feed
nullFeed i t u = Feed
      { feedId           = i
      , feedTitle        = t
      , feedUpdated      = u
      , feedAuthors      = []
      , feedCategories   = []
      , feedContributors = []
      , feedGenerator    = Nothing
      , feedIcon         = Nothing
      , feedLinks        = []
      , feedLogo         = Nothing
      , feedRights       = Nothing
      , feedSubtitle     = Nothing
      , feedEntries      = []
      , feedAttrs        = []
      , feedOther        = []
      }

nullEntry :: String -- ^entryId
          -> TextContent -- ^entryTitle
          -> Date -- ^entryUpdated
          -> Entry
nullEntry i t u = Entry
      { entryId           = i
      , entryTitle        = t
      , entryUpdated      = u
      , entryAuthors      = []
      , entryCategories   = []
      , entryContent      = Nothing
      , entryContributor  = []
      , entryLinks        = []
      , entryPublished    = Nothing
      , entryRights       = Nothing
      , entrySource       = Nothing
      , entrySummary      = Nothing
      , entryInReplyTo    = Nothing
      , entryInReplyTotal = Nothing
      , entryAttrs        = []
      , entryOther        = []
      }


nullGenerator :: String -- ^genText
              -> Generator
nullGenerator t = Generator
  { genURI     = Nothing
  , genVersion = Nothing
  , genText    = t
  }

nullLink :: URI -- ^linkHref
         -> Link
nullLink uri = Link
  { linkHref      = uri
  , linkRel       = Nothing
  , linkType      = Nothing
  , linkHrefLang  = Nothing
  , linkTitle     = Nothing
  , linkLength    = Nothing
  , linkAttrs     = []
  , linkOther     = []
  }

nullSource :: Source
nullSource = Source
      { sourceAuthors     = []
      , sourceCategories  = []
      , sourceGenerator   = Nothing
      , sourceIcon        = Nothing
      , sourceId          = Nothing
      , sourceLinks       = []
      , sourceLogo        = Nothing
      , sourceRights      = Nothing
      , sourceSubtitle    = Nothing
      , sourceTitle       = Nothing
      , sourceUpdated     = Nothing
      , sourceOther       = []
      }
  
nullPerson :: Person
nullPerson = Person
  { personName  = ""
  , personURI   = Nothing
  , personEmail = Nothing
  , personOther = []
  }