Phoenix.Channel

module Phoenix.Channel exposing (Channel, State(..), init, withPayload, onError, onClose, onJoin, onJoinError, setState)

{-|

@docs Channel, State, init, withPayload, onError, onClose, onJoin, onJoinError, setState

-}

import Phoenix.Helpers exposing (emptyPayload)
import Json.Encode as JE


{-| Represents a phoenix channel
-}
type alias Channel msg =
  { name : String
  , payload : JE.Value
  , state : State
  , onClose : Maybe (JE.Value -> msg)
  , onError : Maybe (JE.Value -> msg)
  , onJoin : Maybe (JE.Value -> msg)
  , onJoinError : Maybe (JE.Value -> msg)
  , joinRef : Int
  , leaveRef : Int
  }


{-| All possible states a channel can be in
-}
type State
  = Closed
  | Errored
  | Joined
  | Joining
  | Leaving


{-| Initializes a channel

    init "rooms:lobby"

-}
init : String -> Channel msg
init name =
  { name = name
  , payload = emptyPayload
  , state = Closed
  , onClose = Nothing
  , onError = Nothing
  , onJoin = Nothing
  , onJoinError = Nothing
  , joinRef = -1
  , leaveRef = -1
  }


{-| Attaches a payload that's used for authentication

    payload = JE.object [ ("user_id", JE.string "123") ]
    init "rooms:lobby"
      |> withPayload payload

-}
withPayload : JE.Value -> Channel msg -> Channel msg
withPayload payload channel =
  { channel | payload = payload }


{-| -}
onError : (JE.Value -> msg) -> Channel msg -> Channel msg
onError valueToMsg channel =
  { channel | onError = Just valueToMsg }


{-| -}
onClose : (JE.Value -> msg) -> Channel msg -> Channel msg
onClose valueToMsg channel =
  { channel | onClose = Just valueToMsg }


{-| -}
onJoin : (JE.Value -> msg) -> Channel msg -> Channel msg
onJoin valueToMsg channel =
  { channel | onJoin = Just valueToMsg }


{-| -}
onJoinError : (JE.Value -> msg) -> Channel msg -> Channel msg
onJoinError valueToMsg channel =
  { channel | onJoinError = Just valueToMsg }


{-| Sets the state of a channel. Internal use only.
-}
setState : State -> Channel msg -> Channel msg
setState state channel =
  { channel | state = state }