#!/usr/bin/env cabal
{- cabal:
  build-depends:
    base == 4.*
    , turtle == 1.5.*
    , regex-tdfa == 1.3.*
    , text == 1.2.*
-}

{-# LANGUAGE OverloadedStrings #-}

import           Control.Monad      (when)
import qualified Data.Text          as T
import qualified Data.Text.IO       as T.IO
import           System.Environment (getArgs)
import           System.Exit        (ExitCode (..))
import qualified Text.Regex.TDFA    as TR
import           Turtle             (empty, shell, shellStrict)

main = do
    args <- getArgs
    case args of
        [version] -> makeNewRelease version
        _         -> putStrLn "Usage: new-release <version>"

makeNewRelease :: String -> IO ()
makeNewRelease newVersion = do
    (ExitSuccess, branchName) <- shellStrict "git rev-parse --abbrev-ref HEAD" empty
    when (T.strip branchName /= "release") $ error "You must run this script from the release branch!"

    let cabalFileName = "waspc.cabal"
    oldCabalFileContents <- T.unpack <$> T.IO.readFile cabalFileName

    (newCabalFileContents, oldVersion) <- updateCabalFile oldCabalFileContents newVersion
    let tag = "v" ++ newVersion

    when (newVersion == oldVersion) $ error "Version you provided is the current version!"

    putStrLn $ unlines
        [ "This will update wasp version from " ++ oldVersion ++ " to " ++ newVersion
        , cabalFileName ++ " will be updated, and this change will be commited and pushed."
        , "Also, tag " ++ tag ++ " will be created and pushed, triggering CI to"
          ++ " create new release on Github."
        , "Are you sure you want to proceed (y/n)?"
        ]
    confirmation <- getLine
    when (confirmation /= "y") $ error "Aborting"

    T.IO.writeFile cabalFileName $ T.pack newCabalFileContents

    -- TODO: Print what I am doing for each step.

    putStrLn $ "\nCreating new commit with updated " ++ cabalFileName ++ " and pushing it.\n"
    ExitSuccess <- shell (T.pack $ "git add " ++ cabalFileName) empty
    ExitSuccess <- shell (T.pack $ "git commit -m \"Updated wasp version to " ++ newVersion ++ ".\"") empty
    gitPushExitCode <- shell "git push" empty
    case gitPushExitCode of
        ExitSuccess -> return ()
        ExitFailure _ -> do
            ExitSuccess <- shell "git reset --hard HEAD~1" empty
            error "Failed to do `git push`, reverted changes."

    putStrLn $ "\nCreating tag " ++ tag ++ " and pushing it.\n"
    ExitSuccess <- shell (T.pack $ "git tag " ++ tag) empty
    ExitSuccess <- shell (T.pack $ "git push origin " ++ tag) empty

    return ()

updateCabalFile :: String -> String -> IO (String, String) -- Returns (updated cabal file contents, old version)
updateCabalFile cabalFileContents newVersion = do
    let (beforeMatch, match, afterMatch, submatches) =
            cabalFileContents TR.=~ ("^(version: *)([0-9]+\\.[0-9]+\\.[0-9]+\\.[0-9]+)" :: String) :: (String, String, String, [String])
    when (null match) $ error "Couldn't locate version in cabal file!?"
    let [matchBeforeVersion, oldVersion] = submatches
    let newContents = beforeMatch ++ matchBeforeVersion ++ newVersion ++ afterMatch
    return (newContents, oldVersion)