    -- | Maintainer: Félix Sipma <felix+propellor@gueux.org>
    --
    -- Properties for the Unbound caching DNS server

    module Propellor.Property.Unbound
    	( installed
    	, restarted
    	, reloaded
    	, UnboundSection
    	, UnboundZone
    	, UnboundHost
    	, UnboundSetting
    	, UnboundValue
    	, UnboundKey
    	, ConfSection
    	, ZoneType
    	, cachingDnsServer
    	) where

    import Propellor.Base
    import Propellor.Property.File
    import qualified Propellor.Property.Apt as Apt
    import qualified Propellor.Property.Service as Service

    import Data.List (find)

    type ConfSection = String

    type UnboundSetting = (UnboundKey, UnboundValue)

    type UnboundSection = (ConfSection, [UnboundSetting])

    type UnboundZone = (BindDomain, ZoneType)

    type UnboundHost = (BindDomain, Record)

    type UnboundKey = String

    type UnboundValue = String

    type ZoneType = String

    installed :: Property DebianLike
    installed = Apt.installed ["unbound"]

    restarted :: Property DebianLike
    restarted = Service.restarted "unbound"

    reloaded :: Property DebianLike
    reloaded = Service.reloaded "unbound"

    dValue :: BindDomain -> String
    dValue (RelDomain d) = d
    dValue (AbsDomain d) = d ++ "."
    dValue (RootDomain) = "@"

    sectionHeader :: ConfSection -> String
    sectionHeader header = header ++ ":"

    config :: FilePath
    config = "/etc/unbound/unbound.conf.d/propellor.conf"

    -- | Provided a [UnboundSection], a [UnboundZone] and a [UnboundHost],
    -- cachingDnsServer ensure unbound is configured accordingly.
    --
    -- Example property:
    --
    -- > cachingDnsServer
    -- >      [ ("remote-control", [("control-enable", "no")]
    -- >      , ("server",
    -- >      	[ ("interface", "0.0.0.0")
    -- >      	, ("access-control", "192.168.1.0/24 allow")
    -- >      	, ("do-tcp", "no")
    -- >      	])
    -- >      [ (AbsDomain "example.com", "transparent")
    -- >      , (AbsDomain $ reverseIP $ IPv4 "192.168.1", "static")
    -- >      ]
    -- >      [ (AbsDomain "example.com", Address $ IPv4 "192.168.1.2")
    -- >      , (AbsDomain "myhost.example.com", Address $ IPv4 "192.168.1.2")
    -- >      , (AbsDomain "myrouter.example.com", Address $ IPv4 "192.168.1.1")
    -- >      , (AbsDomain "www.example.com", Address $ IPv4 "192.168.1.2")
    -- >      , (AbsDomain "example.com", MX 10 "mail.example.com")
    -- >      , (AbsDomain "mylaptop.example.com", Address $ IPv4 "192.168.1.2")
    -- >      -- ^ connected via ethernet
    -- >      , (AbsDomain "mywifi.example.com", Address $ IPv4 "192.168.2.1")
    -- >      , (AbsDomain "mylaptop.example.com", Address $ IPv4 "192.168.2.2")
    -- >      -- ^ connected via wifi, use round robin
    -- >      , (AbsDomain "myhost.example.com", PTR $ reverseIP $ IPv4 "192.168.1.2")
    -- >      , (AbsDomain "myrouter.example.com", PTR $ reverseIP $ IPv4 "192.168.1.1")
    -- >      , (AbsDomain "mylaptop.example.com", PTR $ reverseIP $ IPv4 "192.168.1.2")
    -- >      ]
    cachingDnsServer :: [UnboundSection] -> [UnboundZone] -> [UnboundHost] -> Property DebianLike
    cachingDnsServer sections zones hosts =
    	config `hasContent` (comment : otherSections ++ serverSection)
    	`onChange` restarted
      where
    	comment = "# deployed with propellor, do not modify"
    	serverSection = genSection (fromMaybe ("server", []) $ find ((== "server") . fst) sections)
    		++ map genZone zones
    		++ map (uncurry genRecord') hosts
    	otherSections = foldr ((++) . genSection) [] $ filter ((/= "server") . fst) sections

    genSection :: UnboundSection -> [Line]
    genSection (section, settings) = sectionHeader section : map genSetting settings

    genSetting :: UnboundSetting -> Line
    genSetting (key, value) = "    " ++ key ++ ": " ++ value

    genZone :: UnboundZone -> Line
    genZone (dom, zt) = "    local-zone: \"" ++ dValue dom ++ "\" " ++ zt

    genRecord' :: BindDomain -> Record -> Line
    genRecord' dom r = "    local-data: \"" ++ fromMaybe "" (genRecord dom r) ++ "\""

    genRecord :: BindDomain -> Record -> Maybe String
    genRecord dom (Address addr) = Just $ genAddressNoTtl dom addr
    genRecord dom (MX priority dest) = Just $ genMX dom priority dest
    genRecord dom (PTR revip) = Just $ genPTR dom revip
    genRecord _ (CNAME _) = Nothing
    genRecord _ (NS _) = Nothing
    genRecord _ (TXT _) = Nothing
    genRecord _ (SRV _ _ _ _) = Nothing
    genRecord _ (SSHFP _ _ _) = Nothing
    genRecord _ (INCLUDE _) = Nothing

    genAddressNoTtl :: BindDomain -> IPAddr -> String
    genAddressNoTtl dom = genAddress dom Nothing

    genAddress :: BindDomain -> Maybe Int -> IPAddr -> String
    genAddress dom ttl addr = case addr of
    	IPv4 _ -> genAddress' "A" dom ttl addr
    	IPv6 _ -> genAddress' "AAAA" dom ttl addr

    genAddress' :: String -> BindDomain -> Maybe Int -> IPAddr -> String
    genAddress' recordtype dom ttl addr = dValue dom ++ " " ++ maybe "" (\ttl' -> val ttl' ++ " ") ttl ++ "IN " ++ recordtype ++ " " ++ val addr

    genMX :: BindDomain -> Int -> BindDomain -> String
    genMX dom priority dest = dValue dom ++ " " ++ "MX" ++ " " ++ val priority ++ " " ++ dValue dest

    genPTR :: BindDomain -> ReverseIP -> String
    genPTR dom revip = revip ++ ". " ++ "PTR" ++ " " ++ dValue dom