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

module Worldcup.Teams (Teams, Team(..), parseTeams, lookupTeam) where

import           Data.Aeson
import           Data.Aeson.Types    as AET
import           Data.HashMap.Strict as HM
import           Data.Maybe          as M
import           Data.Scientific     as S
import           Prelude             as P

type Teams = HashMap Int Team

data Team = Team {
    teamId        :: Int,
    teamCountryId :: Int } deriving (Show)

instance ToJSON Team where
    toJSON Team{..} = Number $ scientific (P.toInteger teamCountryId) 0

instance FromJSON Team where
    parseJSON = withObject "team" $ \o -> do
        teamId <- o .: "id"
        teamCountryId <- o .: "country_id"
        return Team{..}

parseTeams :: Either String [Value] -> Teams
parseTeams (Left x)   = error x
parseTeams (Right xs) = P.foldl reduce HM.empty xs where
    reduce acc x = case (parseEither parseJSON x :: Either String Team) of
        (Left s)  -> error s
        (Right v) -> HM.insert (teamId v) v acc

lookupTeam :: Int -> Teams -> Team
lookupTeam _id hm = M.fromMaybe (Team 999 999) (HM.lookup _id hm)