{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards   #-}

module Worldcup.EventsTeams (EventTeam(..), parseEventsTeams) where

import           Data.Aeson
import           Data.Aeson.Types
import           Prelude          as P

data EventTeam = EventTeam {
    eventTeamId   :: Int } deriving (Show)

instance FromJSON EventTeam where
    parseJSON = withObject "team" $ \o -> do
        eventTeamId <- o .: "team_id"
        return EventTeam{..}

parseEventsTeams :: Either String [Value] -> [Int]
parseEventsTeams (Left x)   = error x
parseEventsTeams (Right xs) = P.foldl reduce [] xs where
    reduce acc x = case (parseEither parseJSON x :: Either String EventTeam) of
        (Left s)  -> error s
        (Right v) -> eventTeamId v : acc