module Day17 where

import Debug.Trace (trace)

xmin = 111
xmax = 161
ymin = -154
ymax = -101

x_vel_to_pos :: Int -> Int
x_vel_to_pos 0 = 0
x_vel_to_pos x = x + (x_vel_to_pos (x-1))

x_vel :: Int
x_vel = head $ filter (\x -> let pos = x_vel_to_pos x in pos >= xmin && pos <= xmax) $ [0..]

max_y :: Int -> Int
max_y yv = go yv 0 where
    go vel pos = if vel <= 0 then pos else go (vel-1) (pos+vel)


x_y_reaches :: Int -> Int -> Int -> Int -> Bool
x_y_reaches xv yv x y
    | x >= xmin && x <= xmax && y >= ymin && y <= ymax = True
    | y < ymin || x > xmax = False
    | otherwise = x_y_reaches (max (xv-1) 0) (yv-1) (x+xv) (y+yv)

try_y :: [Int]
try_y = filter (\yv -> x_y_reaches x_vel yv 0 0) [0..250]

try_x_y :: Int -> [Int]
try_x_y xv = filter (\yv -> x_y_reaches xv yv 0 0) [-250..250]

main :: IO ()
main = do
    print "bye"