module Grocery.Data.Grocery  where

type Category = String

data Recurrence = Low | Medium | High deriving (Show, Eq, Ord, Read)

data Grocery = Grocery {name::String, inStock::Bool, recurrence::Recurrence, categories::[Category]} deriving (Eq, Ord, Show, Read)

-- default Grocery data
grocery = Grocery {name="", inStock=False, recurrence=High, categories=[]}

-- Create a default Grocery item with the specified name
createGrocery :: String -> Grocery
createGrocery s = grocery {name=s}

-- Creates a default initialized list of Grocery items from a list of names
createList :: [String] -> [Grocery]
createList = map createGrocery 

-- Saves list of Grocery items to a file
saveGroceryList :: FilePath -> [Grocery] -> IO ()
saveGroceryList f groceries = do
   let output = map show groceries
   writeFile f $ unlines output

-- Loads list of Grocery items from a file
loadGroceryList :: FilePath -> IO [Grocery]
loadGroceryList f = do
   contents <- readFile f
   let items = lines contents
   return $ map read items 

-- Returns list of Groceries "in stock"
getInStock :: [Grocery] -> [Grocery]
getInStock = filter inStock

-- Returns a list of Groceries "not in stock"
getNotInStock :: [Grocery] -> [Grocery]
getNotInStock = filter (not . inStock)

-- Converts string to Recurrence 
stringToRecurrence :: String -> Recurrence
stringToRecurrence "high" = High
stringToRecurrence "med" = Medium
stringToRecurrence "low" = Low