{-# LANGUAGE FlexibleContexts      #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE TemplateHaskell       #-}
module Language.Dockerfile.EDSL
  where

-- import           Control.Exception
-- import           Data.List                      (isInfixOf)
import           Control.Monad.Free
import           Control.Monad.Free.TH
import           Control.Monad.Writer
import           Data.ByteString                (ByteString)

import qualified Language.Dockerfile.PrettyPrint as PrettyPrint
import qualified Language.Dockerfile.Syntax      as Syntax

import           Language.Dockerfile.EDSL.Types

type EInstructionM = Free EInstruction

makeFree ''EInstruction

runDockerWriter
    :: (MonadWriter [Syntax.Instruction] m)
    => EInstructionM a -> m a
runDockerWriter = iterM runD
  where
    runDef f a n = tell [ f a ] >> n
    runDef2 f a b n = tell [ f a b ] >> n
    runD (From bi n) = case bi of
        EUntaggedImage bi' -> runDef Syntax.From (Syntax.UntaggedImage bi') n
        ETaggedImage bi' tg -> runDef Syntax.From (Syntax.TaggedImage bi' tg) n
        EDigestedImage bi' d -> runDef Syntax.From (Syntax.DigestedImage bi' d) n
    runD (CmdArgs as n) = runDef Syntax.Cmd as n
    runD (Add s d n) = runDef2 Syntax.Add s d n
    runD (User u n) = runDef Syntax.User u n
    runD (Label ps n) = runDef Syntax.Label ps n
    runD (StopSignal s n) = runDef Syntax.Stopsignal s n
    runD (Copy s d n) = runDef2 Syntax.Copy s d n
    runD (RunArgs as n) = runDef Syntax.Run as n
    runD (Workdir d n) = runDef Syntax.Workdir d n
    runD (Expose ps n) = runDef Syntax.Expose ps n
    runD (Volume v n) = runDef Syntax.Volume v n
    runD (EntrypointArgs e n) = runDef Syntax.Entrypoint e n
    runD (Maintainer m n) = runDef Syntax.Maintainer m n
    runD (Env ps n) = runDef Syntax.Env ps n
    runD (Arg s n) = runDef Syntax.Arg s n
    runD (Comment c n) = runDef Syntax.Comment c n
    runD (OnBuildRaw i n) = runDef Syntax.OnBuild i n
    runD (Embed is n) = do
        tell (map Syntax.instruction is)
        n

instructionPos :: Syntax.Instruction -> Syntax.InstructionPos
instructionPos i = Syntax.InstructionPos i "" 0

-- | Runs the Dockerfile EDSL and returns a 'Dockerfile' you can pretty print
-- or manipulate
toDockerfile :: EInstructionM a -> Syntax.Dockerfile
toDockerfile e =
    let (_, w) = runWriter (runDockerWriter e)
    in map instructionPos w

-- | Runs the Dockerfile EDSL and returns a 'String' using
-- 'Language.Dockerfile.PrettyPrint'
--
-- @
-- import           Language.Dockerfile
--
-- main :: IO ()
-- main = writeFile "something.dockerfile" $ toDockerfileStr $ do
--     from (tagged "fpco/stack-build" "lts-6.9")
--     add "." "/app/language-dockerfile"
--     workdir "/app/language-dockerfile"
--     run (words "stack build --test --only-dependencies")
--     cmd (words "stack test")
-- @
toDockerfileStr :: EInstructionM a -> String
toDockerfileStr = PrettyPrint.prettyPrint . toDockerfile

untagged :: String -> EBaseImage
untagged = EUntaggedImage

tagged :: String -> String -> EBaseImage
tagged = ETaggedImage

digested :: String -> ByteString -> EBaseImage
digested = EDigestedImage

run :: MonadFree EInstruction m => String -> m ()
run = runArgs . words

entrypoint :: MonadFree EInstruction m => String -> m ()
entrypoint = entrypointArgs . words

cmd :: MonadFree EInstruction m => String -> m ()
cmd = cmdArgs . words

-- | ONBUILD Dockerfile instruction
--
-- Each nested instruction gets emitted as a separate @ONBUILD@ block
--
-- @
-- 'toDockerfile' $ do
--     from "node"
--     run "apt-get update"
--     onBuild $ do
--         run "echo more-stuff"
--         run "echo here"
-- @
onBuild
  :: MonadFree EInstruction m
  => EInstructionM a
  -> m ()
onBuild b = mapM_ (onBuildRaw . Syntax.instruction) (toDockerfile b)

-- dockerIgnore :: String -> IO ()
-- dockerIgnore str = do
--     let str' = str ++ "\n"
--     -- TODO - Use projectroot
--     di <- readFile "./.dockerignore" `catch` (\(SomeException _) -> return "")
--     unless (str' `isInfixOf` di) $
--         appendFile "./.dockerignore" str'
-- dockerBuild :: FilePath -> IO ()
-- dockerBuild _dir = undefined