module Main where

import Control.Monad
import Control.Monad.Except
import Data.Either
import System.Environment
import System.Exit
import qualified LLVM.General as General
import qualified LLVM.General.Context as General
-- import qualified LLVM.General.Target as General

import Check
import Codegen
import Parser
import PShow


fromLeft :: Either a b -> a
fromLeft (Left a) = a
fromLeft (Right _) = error "Either is not a Left"

fromRight :: Either a b -> b
fromRight (Right b) = b
fromRight (Left _) = error "Either is not a Right"

dieShow :: (Show a) => a -> IO ()
dieShow = die . show


assert :: ExceptT String IO a -> IO a
assert ex = do
    e <- runExceptT ex
    either die return e >> (return $ (\(Right r) -> r) e)

main :: IO ()
main = do
    args <- getArgs
    when (length args /= 1) $ die "Pass NL file name as a command-line parameter"

    let fname = args !! 0
    parseResult <- (\file -> parseProgram file fname) <$> readFile fname

    when (isLeft parseResult) $ dieShow $ fromLeft parseResult
    
    let ast = fromRight parseResult
    putStrLn $ pshow ast

    checked <- either die return $ checkProgram ast
    putStrLn "After checking:"
    putStrLn $ pshow checked

    llvmMod <- either die return $ codegen checked "Module" fname
    -- putStrLn "Module:"
    -- print llvmMod

    putStrLn "Calling withContext:"
    General.withContext $ \context -> do
        putStrLn "Calling withModuleFromAST:"
        assert $ General.withModuleFromAST context llvmMod $ \genmod -> do
            putStrLn "Calling moduleLLVMAssembly:"
            llvmasm <- General.moduleLLVMAssembly genmod
            putStr llvmasm
            putStrLn ""
            -- assert $ General.withHostTargetMachine $ \machine -> do
            --     General.getTargetMachineTriple machine >>= putStrLn
            --     putStrLn ""
            --     assert (General.moduleTargetAssembly machine genmod)
            --         >>= putStr
            --     bs <- assert $ General.moduleObject machine genmod
            --     BS.writeFile "output_gen.o" bs