main :: IO()
main = do
    print $ sunkK 0 database == [("Germany",0),("Gt.Britain",0)]
    print $ sunkK 2 database == [("Germany",0),("Japan",2),("Gt.Britain",0)]
    print $ sunkK 9 database == [("Germany",0),("USA",4),("Japan",2),("Gt.Britain",0)]
    print $ sunkK 20 database == [("Germany",0),("USA",4),("Japan",2),("Gt.Britain",0)]

-- algebraic data types

type Name = String
type Date = String
type Class = String
type Type = String
type Result = String
type Launched = Int

type Battle = (Name, Date)
type Ship = (Name, Class, Launched)
type Outcome = (Name, Name, Result)
type ShipClass = (Name, Type, Name)

type Database = ([Outcome], [Battle], [Ship], [ShipClass])

outcomes :: [Outcome]
outcomes = [ ("Bismarck", "North Atlantic", "sunk"),
("California", "Surigao Strait", "ok"), ("Duke of York",
"North Cape", "ok"), ("Fuso", "Surigao Strait", "sunk"),
("Hood", "North Atlantic", "sunk"), ("King George V", "North
Atlantic", "ok"), ("Kirishima", "Guadalcanal", "sunk"),
("Prince of Wales", "North Atlantic", "damaged"), ("Rodney",
"North Atlantic", "ok"), ("Schamhorst", "North Cape",
"sunk"), ("South Dakota", "Guadalcanal", "damaged"),
("Tennessee", "Surigao Strait", "ok"), ("Washington",
"Guadalcanal", "ok"), ("Prince of Wales", "Guadalcanal",
"ok"), ("West Virginia", "Surigao Strait", "ok"),
("Yamashiro", "Surigao Strait", "sunk"), ("California",
"Guadalcanal", "damaged") ]

battles :: [Battle]
battles = [ ("Guadalcanal", "1942-11-15"), ("North Atlantic",
"1941-05-25"), ("North Cape", "1943-12-26"), ("Surigao
Strait", "1944-10-25") ]

ships :: [Ship]
ships = [ ("California", "Tennessee", 1921), ("Haruna",
"Kongo", 1916), ("Hiei", "Kongo", 1914), ("Iowa", "Iowa",
1943), ("Kirishima", "Kongo", 1915), ("Kongo", "Kongo", 1913),
("Missouri", "Iowa", 1944), ("Musashi", "Yamato", 1942), ("New
Jersey", "Iowa", 1943), ("North Carolina", "North Carolina",
1941), ("Ramillies", "Revenge", 1917), ("Renown", "Renown",
1916), ("Repulse", "Renown", 1916), ("Resolution", "Renown",
1916), ("Revenge", "Revenge", 1916), ("Royal Oak", "Revenge",
1916), ("Royal Sovereign", "Revenge", 1916), ("Tennessee",
"Tennessee", 1920), ("Washington", "North Carolina", 1941),
("Wisconsin", "Iowa", 1944), ("Yamato", "Yamato", 1941),
("Yamashiro", "Yamato", 1947), ("South Dakota", "North
Carolina", 1941), ("Bismarck", "North Carolina", 1911), ("Duke
of York", "Renown", 1916), ("Fuso", "Iowa", 1940), ("Hood",
"Iowa", 1942), ("Rodney", "Yamato", 1915), ("Yanashiro",
"Yamato", 1918), ("Schamhorst", "North Carolina", 1917),
("Prince of Wales", "North Carolina", 1937), ("King George V",
"Iowa", 1942), ("West Virginia", "Iowa", 1942) ]

classes :: [ShipClass]
classes = [("Bismarck", "bb", "Germany"), ("Iowa", "bb",
"USA"), ("Kongo", "bc", "Japan"), ("North Carolina", "bb",
"USA"), ("Renown", "bc", "Gt.Britain"), ("Revenge", "bb",
"Gt.Britain"), ("Tennessee", "bb", "USA"), ("Yamato", "bb",
"Japan")]


database :: Database
database = (outcomes, battles, ships, classes)

-- bs - battles, ss - ships, os - outcomes, sc - shipClass

sunkK :: Int -> Database -> [(Name, Int)]
sunkK n (os, bs, ss, sc) = [(name, countOfSunkShips n) | name <- allCountriesName]
    where
        allCountries :: [Name]
        allCountries = [name | (_, _, name) <- sc]

        countOfSunkShips :: Name -> [Name]
        countOfSunkShips bName = length [ ship | (shipName, bN , result) <- os, bN == bName, result == "sunk"]