module Main where
 
import Network.Curl
import Text.CSV
import Network.CGI (urlEncode)
import Text.XML.Light
import Data.Maybe (fromMaybe, fromJust)
import Control.Monad
import System.Environment (getArgs)
 
-- The top artists of last.fm
url u = "http://ws.audioscrobbler.com/1.0/user/" ++ u ++ "/topartists.txt"
 
-- Upcomings's country_id for The Netherlands 
country_id = "9"
upcoming_url artist =  "http://upcoming.yahooapis.com/services/rest/?api_key=" 
                    ++ apikey ++ "&method=event.search&search_text=" 
                    ++ urlEncode artist ++ "&country_id=" ++ country_id
apikey = "ee395ae6dd"
 
main = do
  [username] <- getArgs
  text <- unsafeCurlGetString (url username)
  let (Right a') = parseCSV (url username) text
      artists = getArtists a'
  mapM_ getEvents artists
 
-- The artist is always in the 3rd column of the csv-file
getArtists = map (!! 2) . filter (\x -> length x == 3)
 
getEvents artist = unsafeCurlGetString (upcoming_url artist) >>= processArtist artist
 
processArtist artist contents = do
  let eventEls = elChildren $ fromJust $ parseXMLDoc contents
  when (length eventEls > 0) $ do
    putStrLn artist
    putStrLn (replicate (length artist) '-')
    mapM_ processEvent eventEls
    putStrLn ""
 
processEvent evt = putStrLn $ title ++ " @ " ++ location ++ " [" ++ date ++ "]"
 where [title, location, date] = map fa ["name", "venue_name", "start_date"]
       fa n = fromJust $ findAttr (unqual n) evt
 
unsafeCurlGetString url = curlGetString url [] >>= return . snd