module FactorizationUI (run) where

import System.Exit (exitSuccess)
import Utils (askChoice, askNumber)
import Factorization
    ( fermatFactorization, pollardPminus1, dixon
    , gnfsWith, GNFSParams(..), defaultParams
    )

run :: IO ()
run = do
    putStrLn "Factorization"
    putStrLn "1) Fermat factorization"
    putStrLn "2) Pollard p-1"
    putStrLn "3) Dixon"
    putStrLn "4) General Number Field Sieve (GNFS)"

    choice <- askChoice 4

    case choice of
        1 -> fermatUI
        2 -> pollardUI
        3 -> dixonUI
        4 -> gnfsUI
        _ -> error "Impossible"

fermatUI :: IO ()
fermatUI = do
    n <- askNumber "Enter an integer n > 1:"
    let (p, q) = fermatFactorization n
    putStrLn ("n = " ++ show n)
    putStrLn ("p = " ++ show p)
    putStrLn ("q = " ++ show q)

pollardUI :: IO ()
pollardUI = do
    n <- askNumber "Enter an integer n > 1:"
    b <- askNumber "Enter the bound B:"
    case pollardPminus1 n b of
        Just factor -> do
            putStrLn ("Found factor: " ++ show factor)
            putStrLn ("Other factor: " ++ show (n `div` factor))
        Nothing ->
            putStrLn "Failed to find a factor (try a different B or method)."

dixonUI :: IO ()
dixonUI = do
    n <- askNumber "Enter an integer n > 1:"
    b <- askNumber "Enter the bound B:"
    x <- askNumber "Enter the max random integer x:"

    case dixon n b x of
        Left err -> do
            putStrLn ("Error: " ++ err)
        Right (p, q) -> do
            putStrLn ("n = " ++ show n)
            putStrLn ("p = " ++ show p)
            putStrLn ("q = " ++ show q)

gnfsUI :: IO ()
gnfsUI = do
    putStrLn "General Number Field Sieve"
    putStrLn "Factors a composite n (not a prime or a prime power) into two non-trivial factors."
    putStrLn "Practical for n up to roughly 30 digits; the running time grows quickly beyond that."
    n <- askNumber "Enter an integer n > 1:"

    putStrLn "Parameters:"
    putStrLn "1) Automatic (recommended)"
    putStrLn "2) Custom"
    mode <- askChoice 2

    let auto = defaultParams n
    params <- case mode of
        1 -> return auto
        _ -> do
            putStrLn ("Automatic values for this n: degree = " ++ show (paramDegree auto)
                      ++ ", bound B = " ++ show (paramRatBound auto)
                      ++ ", sieve half-width = " ++ show (paramHalfWidth auto))
            d <- askNumber "Enter the polynomial degree d (odd, 3 or 5):"
            if d /= 3 && d /= 5
                then do
                    putStrLn "The degree must be 3 or 5."
                    exitSuccess
                else return ()
            b <- askNumber "Enter the factor base bound B (used for both bases):"
            w <- askNumber "Enter the sieve half-width (a ranges over [-w, w]):"
            return auto { paramDegree    = fromInteger d
                        , paramRatBound  = b
                        , paramAlgBound  = b
                        , paramHalfWidth = fromInteger w
                        }

    putStrLn "Running GNFS (this may take a while)..."
    case gnfsWith params n of
        Left err ->
            putStrLn ("Error: " ++ err)
        Right (p, q) -> do
            putStrLn ("n = " ++ show n)
            putStrLn ("p = " ++ show p)
            putStrLn ("q = " ++ show q)