--------------------------------------------------------------------
-- |
-- Module    : Text.Atom.Feed
-- Copyright : (c) Galois, Inc. 2008,
--             (c) Sigbjorn Finne 2009-
-- License   : BSD3
--
-- Maintainer: Sigbjorn Finne <sof@forkIO.com>
-- Stability : provisional
-- Portability: portable
--
--------------------------------------------------------------------
module Text.Atom.Feed
  ( URI
  , NCName
  , Date
  , MediaType
  , Attr
  , Feed(..)
  , Entry(..)
  , EntryContent(..)
  , Category(..)
  , Generator(..)
  , Link(..)
  , TextContent(..)
  , txtToString
  , Source(..)
  , Person(..)
  , InReplyTo(..)
  , InReplyTotal(..)
  , newCategory
  , nullFeed
  , nullEntry
  , nullGenerator
  , nullLink
  , nullSource
  , nullPerson
  ) where

import Prelude.Compat

import Data.Text (Text, unpack)
import Data.XML.Compat
import Data.XML.Types as XML

-- *Core types
-- NOTE: In the future we may want to have more structured
-- types for these.
type URI = Text

type NCName = Text

type Date = Text

type MediaType = Text

data Feed = Feed
  { feedId :: URI
  , 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 :: [Attr]
  , feedOther :: [XML.Element]
  } deriving (Show)

data Entry = Entry
  { entryId :: URI
  , 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 :: [Attr]
  , entryOther :: [XML.Element]
  } deriving (Show)

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

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

data Generator = Generator
  { genURI :: Maybe URI
  , genVersion :: Maybe Text
  , genText :: Text
  } 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 Text
  , linkTitle :: Maybe Text
  , linkLength :: Maybe Text
  , linkAttrs :: [Attr]
  , linkOther :: [XML.Element]
  } deriving (Show)

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

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

data Source = Source
  { sourceAuthors :: [Person]
  , sourceCategories :: [Category]
  , sourceGenerator :: Maybe Generator
  , sourceIcon :: Maybe URI
  , sourceId :: Maybe URI
  , 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 :: Text
  , personURI :: Maybe URI
  , personEmail :: Maybe Text
  , personOther :: [XML.Element]
  } deriving (Show)

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

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

-- *Smart Constructors
newCategory ::
     Text -- ^catTerm
  -> Category
newCategory t = Category {catTerm = t, catScheme = Nothing, catLabel = Just t, catOther = []}

nullFeed ::
     URI -- ^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 ::
     URI -- ^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 ::
     Text -- ^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 = []}