Jammin.hs

module Jammin where

import Data.List

data Fruit =
  Peach
  | Plum
  | Apple
  | Blackberry
  deriving (Eq, Show, Ord)

data JamJars =
  Jam { kind :: Fruit
      , num   :: Int }
      deriving (Eq, Show)


row1 = Jam Peach 100
row2 = Jam Plum 1
row3 = Jam Apple 3
row4 = Jam Peach 2
row5 = Jam Peach 6
row6 = Jam Plum 4
allJam = [row1, row2, row3, row4, row5, row6]


getAllJarsNum :: [JamJars] -> [Int]
getAllJarsNum =
  map num

sumAllJarsNum :: [JamJars] -> Int
sumAllJarsNum =
  foldr ((+) . num) 0

maxJars :: [JamJars] -> JamJars
maxJars =
  maximumBy comp
  where comp x y = if (num x) > (num y) then GT else LT

sortJams :: [JamJars] -> [JamJars]
sortJams =
  sortBy compareKind

compareKind :: JamJars -> JamJars -> Ordering
compareKind (Jam k _) (Jam k' _) = compare k k'


groupJams :: [JamJars] -> [[JamJars]]
groupJams =
  (groupBy groupByKind) . sortJams

groupByKind :: JamJars -> JamJars -> Bool
groupByKind (Jam k _) (Jam k' _) = k == k'