import Development.Shake
import Development.Shake.Command
import Development.Shake.FilePath
import Development.Shake.Util
import Data.Char (toUpper)

capitalise (x:xs) = toUpper x : xs

ghcflags =
  [ "-no-hs-main"
  , "-optl-mexec-model=reactor"
  , "-optl-Wl,--export=hello,--export=hs_init"
  ]

main = shakeArgs shakeOptions $ do
  want ["call-hello.wasm","hello.wasm"]
  "call-hello.wasm" %> \out -> do
    need ["call-hello.wat"]
    cmd_ "wasm-tools parse call-hello.wat" "-o" [out]
  "hello.wasm" %> \out -> do
      need ["Hello.hs"]
      cmd_
        "wasm32-wasi-ghc"
        "Hello.hs" ghcflags
        "-o" [out]
  phony "run" $ do
    need ["call-hello.wasm","hello.wasm"]
    cmd_ "wasmtime run"
      "--preload" "env=hello.wasm"
      "--invoke" "call-hello"
      "call-hello.wasm"
  phony "clean" $ do
    removeFilesAfter ".shake" ["//*"]
    liftIO $ removeFiles "."
      [ "*.wasm"
      , "*.o"
      , "*_stub.h"
      , "*.hi"
      ]