{-# OPTIONS_GHC -Wall #-}

-- An example of representing a connection

-- Types
data ConnInfo = ConnInfo
    { connState :: ConnState
    , server    :: String
    } deriving (Show)

data ConnState
    = C1 Connecting
    | C2 Connected
    | C3 Disconnected
    deriving (Show)

data Connecting = Connecting
    { whenInitiated :: Int
    } deriving (Show)

data Connected = Connected
    { sessionId :: String
    , lastPing  :: Maybe Int
    } deriving (Show)

data Disconnected = Disconnected
    { whenDisconnected :: Int
    } deriving (Show)

-- Code
getSessionId :: ConnInfo -> String
getSessionId ci = getSid $ connState ci where
    getSid (C1 _) = "Connecting..."
    getSid (C2 c) = sessionId c
    getSid (C3 _) = "Disconnected"

connected :: ConnInfo
connected = ConnInfo
    (C2 (Connected "session_id_1234" Nothing))
    "api.foo.app"

main :: IO ()
main = print $ getSessionId connected -- "session_id_1234"