{-# LANGUAGE Safe #-}

module Data.Time.Calendar.Private where

import Data.Fixed

data PadOption
    = Pad Int
          Char
    | NoPad

showPadded :: PadOption -> String -> String
showPadded :: PadOption -> String -> String
showPadded PadOption
NoPad String
s = String
s
showPadded (Pad Int
i Char
c) String
s = Int -> Char -> String
forall a. Int -> a -> [a]
replicate (Int
i Int -> Int -> Int
forall a. Num a => a -> a -> a
- String -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length String
s) Char
c String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
s

class (Num t, Ord t, Show t) => ShowPadded t where
    showPaddedNum :: PadOption -> t -> String

instance ShowPadded Integer where
    showPaddedNum :: PadOption -> Integer -> String
showPaddedNum PadOption
NoPad Integer
i = Integer -> String
forall a. Show a => a -> String
show Integer
i
    showPaddedNum PadOption
pad Integer
i
        | Integer
i Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
< Integer
0 = Char
'-' Char -> String -> String
forall a. a -> [a] -> [a]
: (PadOption -> Integer -> String
forall t. ShowPadded t => PadOption -> t -> String
showPaddedNum PadOption
pad (Integer -> Integer
forall a. Num a => a -> a
negate Integer
i))
    showPaddedNum PadOption
pad Integer
i = PadOption -> String -> String
showPadded PadOption
pad (String -> String) -> String -> String
forall a b. (a -> b) -> a -> b
$ Integer -> String
forall a. Show a => a -> String
show Integer
i

instance ShowPadded Int where
    showPaddedNum :: PadOption -> Int -> String
showPaddedNum PadOption
NoPad Int
i = Int -> String
forall a. Show a => a -> String
show Int
i
    showPaddedNum PadOption
_pad Int
i
        | Int
i Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
forall a. Bounded a => a
minBound = Int -> String
forall a. Show a => a -> String
show Int
i
    showPaddedNum PadOption
pad Int
i
        | Int
i Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
< Int
0 = Char
'-' Char -> String -> String
forall a. a -> [a] -> [a]
: (PadOption -> Int -> String
forall t. ShowPadded t => PadOption -> t -> String
showPaddedNum PadOption
pad (Int -> Int
forall a. Num a => a -> a
negate Int
i))
    showPaddedNum PadOption
pad Int
i = PadOption -> String -> String
showPadded PadOption
pad (String -> String) -> String -> String
forall a b. (a -> b) -> a -> b
$ Int -> String
forall a. Show a => a -> String
show Int
i

show2Fixed :: Pico -> String
show2Fixed :: Pico -> String
show2Fixed Pico
x
    | Pico
x Pico -> Pico -> Bool
forall a. Ord a => a -> a -> Bool
< Pico
10 = Char
'0' Char -> String -> String
forall a. a -> [a] -> [a]
: (Bool -> Pico -> String
forall k (a :: k). HasResolution a => Bool -> Fixed a -> String
showFixed Bool
True Pico
x)
show2Fixed Pico
x = Bool -> Pico -> String
forall k (a :: k). HasResolution a => Bool -> Fixed a -> String
showFixed Bool
True Pico
x

show2 :: (ShowPadded t) => t -> String
show2 :: t -> String
show2 = PadOption -> t -> String
forall t. ShowPadded t => PadOption -> t -> String
showPaddedNum (PadOption -> t -> String) -> PadOption -> t -> String
forall a b. (a -> b) -> a -> b
$ Int -> Char -> PadOption
Pad Int
2 Char
'0'

show3 :: (ShowPadded t) => t -> String
show3 :: t -> String
show3 = PadOption -> t -> String
forall t. ShowPadded t => PadOption -> t -> String
showPaddedNum (PadOption -> t -> String) -> PadOption -> t -> String
forall a b. (a -> b) -> a -> b
$ Int -> Char -> PadOption
Pad Int
3 Char
'0'

show4 :: (ShowPadded t) => t -> String
show4 :: t -> String
show4 = PadOption -> t -> String
forall t. ShowPadded t => PadOption -> t -> String
showPaddedNum (PadOption -> t -> String) -> PadOption -> t -> String
forall a b. (a -> b) -> a -> b
$ Int -> Char -> PadOption
Pad Int
4 Char
'0'

mod100 :: (Integral i) => i -> i
mod100 :: i -> i
mod100 i
x = i -> i -> i
forall a. Integral a => a -> a -> a
mod i
x i
100

div100 :: (Integral i) => i -> i
div100 :: i -> i
div100 i
x = i -> i -> i
forall a. Integral a => a -> a -> a
div i
x i
100

clip :: (Ord t) => t -> t -> t -> t
clip :: t -> t -> t -> t
clip t
a t
_ t
x
    | t
x t -> t -> Bool
forall a. Ord a => a -> a -> Bool
< t
a = t
a
clip t
_ t
b t
x
    | t
x t -> t -> Bool
forall a. Ord a => a -> a -> Bool
> t
b = t
b
clip t
_ t
_ t
x = t
x

clipValid :: (Ord t) => t -> t -> t -> Maybe t
clipValid :: t -> t -> t -> Maybe t
clipValid t
a t
_ t
x
    | t
x t -> t -> Bool
forall a. Ord a => a -> a -> Bool
< t
a = Maybe t
forall a. Maybe a
Nothing
clipValid t
_ t
b t
x
    | t
x t -> t -> Bool
forall a. Ord a => a -> a -> Bool
> t
b = Maybe t
forall a. Maybe a
Nothing
clipValid t
_ t
_ t
x = t -> Maybe t
forall a. a -> Maybe a
Just t
x

quotBy :: (Real a, Integral b) => a -> a -> b
quotBy :: a -> a -> b
quotBy a
d a
n = Rational -> b
forall a b. (RealFrac a, Integral b) => a -> b
truncate ((a -> Rational
forall a. Real a => a -> Rational
toRational a
n) Rational -> Rational -> Rational
forall a. Fractional a => a -> a -> a
/ (a -> Rational
forall a. Real a => a -> Rational
toRational a
d))

remBy :: Real a => a -> a -> a
remBy :: a -> a -> a
remBy a
d a
n = a
n a -> a -> a
forall a. Num a => a -> a -> a
- (Integer -> a
forall a. Num a => Integer -> a
fromInteger Integer
f) a -> a -> a
forall a. Num a => a -> a -> a
* a
d
  where
    f :: Integer
f = a -> a -> Integer
forall a b. (Real a, Integral b) => a -> a -> b
quotBy a
d a
n

quotRemBy :: (Real a, Integral b) => a -> a -> (b, a)
quotRemBy :: a -> a -> (b, a)
quotRemBy a
d a
n = let
    f :: b
f = a -> a -> b
forall a b. (Real a, Integral b) => a -> a -> b
quotBy a
d a
n
    in (b
f, a
n a -> a -> a
forall a. Num a => a -> a -> a
- (b -> a
forall a b. (Integral a, Num b) => a -> b
fromIntegral b
f) a -> a -> a
forall a. Num a => a -> a -> a
* a
d)