{-# LANGUAGE OverloadedStrings #-}
module Network.Lastfm.Error where

import Control.Applicative ((<$>), empty)
import Control.Monad ((<=<))
import Control.Monad.Error (Error)
import Data.Aeson
import Data.ByteString.Lazy.Char8 (ByteString)
import Text.XML.Light

data LastfmError
  = NotUsed -- To avoid subtracting 1 from Lastfm reponses
  | DoesntExist
  | InvalidService
  | InvalidMethod
  | AuthenticationFailed
  | InvalidFormat
  | InvalidParameters
  | InvalidResource
  | OperationFailed
  | InvalidSessionKey
  | InvalidAPIKey
  | ServiceOffline
  | SubscribersOnly
  | InvalidMethodSignature
  | TokenHasNotAuthorized
  | NotForStreaming
  | TemporaryUnavailable
  | LoginRequired
  | TrialExpired
  | DoesntExistAgain
  | NotEnoughContent
  | NotEnoughMembers
  | NotEnoughFans
  | NotEnoughNeighbours
  | NoPeakRadio
  | RadioNotFound
  | SuspendedAPIKey
  | Deprecated
  | RateLimitExceeded
    deriving Enum

instance Show LastfmError where
  show NotUsed = "NotUsed: Internal liblastfm error for convenience"
  show DoesntExist = "DoesntExist: This error does not exist"
  show InvalidService = "InvalidService: This service does not exist"
  show InvalidMethod = "InvalidMethod: No method with that name in this package"
  show AuthenticationFailed = "AuthenticationFailed: You do not have permissions to access the service"
  show InvalidFormat = "InvalidFormat: This service doesn't exist in that format"
  show InvalidParameters = "InvalidParameters: Your request is missing a required parameter"
  show InvalidResource = "InvalidResource: Invalid resource specified"
  show OperationFailed = "OperationFailed: Something else went wrong"
  show InvalidSessionKey = "InvalidSessionKey: Please re-authenticate"
  show InvalidAPIKey = "InvalidAPIKey: You must be granted a valid key by last.fm"
  show ServiceOffline = "ServiceOffline: This service is temporarily offline. Try again later."
  show SubscribersOnly  = "SubscribersOnly : This station is only available to paid last.fm subscribers"
  show InvalidMethodSignature = "InvalidMethodSignature: Invalid method signature supplied"
  show TokenHasNotAuthorized = "TokenHasNotAuthorized: This token has not been authorized"
  show NotForStreaming = "NotForStreaming: This item is not available for streaming."
  show TemporaryUnavailable = "TemporaryUnavailable: The service is temporarily unavailable, please try again."
  show LoginRequired = "LoginRequired: Login: User requires to be logged in"
  show TrialExpired = "TrialExpired: This user has no free radio plays left. Subscription required."
  show DoesntExistAgain = "DoesntExistAgain: This error does not exist"
  show NotEnoughContent = "NotEnoughContent: There is not enough content to play this station"
  show NotEnoughMembers = "NotEnoughMembers: This group does not have enough members for radio"
  show NotEnoughFans = "NotEnoughFans: This artist does not have enough fans for for radio"
  show NotEnoughNeighbours = "NotEnoughNeighbours: There are not enough neighbours for radio"
  show NoPeakRadio = "NoPeakRadio: This user is not allowed to listen to radio during peak usage"
  show RadioNotFound = "RadioNotFound: Radio station not found"
  show SuspendedAPIKey = "SuspendedAPIKey: Access for your account has been suspended, please contact Last.fm"
  show Deprecated = "Deprecated: This type of request is no longer supported"
  show RateLimitExceeded = "RateLimitExceeded: Your IP has made too many requests in a short period"

instance Error LastfmError

xmlError ∷ ByteString → Maybe LastfmError
xmlError r = do
  xml ← parseXMLDoc r
  toEnum . read <$> (findAttr (unqual "code") <=< findChild (unqual "error")) xml

jsonError ∷ ByteString → Maybe LastfmError
jsonError = decode

instance FromJSON LastfmError where
  parseJSON (Object v) = toEnum <$> v .: "error"
  parseJSON _ = empty