Main.hs

import Control.Monad
import Data.Maybe
import Text.Printf
import qualified Data.DateTime as DT

data Interval = Interval { start :: DT.DateTime
                         , end   :: DT.DateTime }
                deriving (Show)

-- TODO: this shouldn't exist
dayToInt :: DT.DateTime -> Int
dayToInt day = d where (y, m, d, _, _, _) = DT.toGregorian day

days :: Interval -> [DT.DateTime]
days inv = map (DT.fromGregorian' sy sm) range
           where (sy, sm, sd, _, _, _) = DT.toGregorian (start inv)
                 ed = dayToInt (end inv)
                 range = [sd..ed]

intakeBase = "/Users/andrew/code/hsandbox/events"

buildFilename :: Int -> String
buildFilename d = printf (intakeBase ++ "/%d.json") d

filesForInterval :: Interval -> [String]
filesForInterval inv = map buildFilename dayNums
                       where dayNums = map dayToInt (days inv)


-- Main.hs:33:28:
--     Couldn't match type ‘IO’ with ‘Maybe’
--     Expected type: Maybe String
--       Actual type: IO String
--     In a stmt of a 'do' block: content <- readFile f
--     In the expression:
--       do { content <- readFile f;
--            return $ Just (lines content) }
--
-- Main.hs:34:17:
--     Couldn't match type ‘Maybe [String]’ with ‘[String]’
--     Expected type: Maybe [String]
--       Actual type: Maybe (Maybe [String])
--     In a stmt of a 'do' block: return $ Just (lines content)
--     In the expression:
--       do { content <- readFile f;
--            return $ Just (lines content) }
--     In an equation for ‘parseFile’:
--         parseFile f
--           = do { content <- readFile f;
--                  return $ Just (lines content) }
-- Failed, modules loaded: none.
parseFile :: String -> Maybe [String]
parseFile f = do
                content <- readFile f
                return $ Just (lines content)

main :: IO ()
main = do
         let start = DT.fromGregorian' 2014 12 16
             end = DT.fromGregorian' 2014 12 20
         print $ filesForInterval $ Interval start end