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39 lines
1.3 KiB
39 lines
1.3 KiB
{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE RecordWildCards #-}
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module Worldcup.Countries (Countries, Country(..), parseCountries, lookupCountry) where
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import Data.Aeson
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import Data.Aeson.Types as AET
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import Data.HashMap.Strict as HM
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import Data.Maybe as M
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import Prelude as P
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type Countries = HashMap Int Country
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data Country = Country {
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countryId :: Int,
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countryContinentId :: Int,
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countryPop :: Int,
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countryName :: Value } deriving (Show)
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instance ToJSON Country where
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toJSON Country{..} = countryName
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instance FromJSON Country where
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parseJSON = withObject "country" $ \o -> do
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countryId <- o .: "id"
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countryContinentId <- o .: "continent_id"
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countryPop <- o .: "pop"
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countryName <- o .: "name"
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return Country{..}
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lookupCountry :: Int -> Countries -> Country
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lookupCountry _id hm = M.fromMaybe (Country 999 999 999 "DNE") (HM.lookup _id hm)
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parseCountries :: Either String [Value] -> Countries
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parseCountries (Left x) = error x
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parseCountries (Right xs) = P.foldl reduce HM.empty xs where
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reduce acc x = case (parseEither parseJSON x :: Either String Country) of
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(Left s) -> error s
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(Right v) -> HM.insert (countryId v) v acc
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