module Main where

import Compiler
import Eval                   (evalTricu, result)
import Library                (library)
import Parser                 (parseTricu)
import REPL
import Research

import Text.Megaparsec        (runParser)
import System.Console.CmdArgs

import qualified Data.Map as Map

data TricuArgs
  = Repl
  | Compile { file :: FilePath, output :: Maybe FilePath, form :: CompiledForm }
  | Decode { input :: Maybe FilePath }
  deriving (Show, Data, Typeable)

replMode :: TricuArgs
replMode = Repl
  &= help "Start interactive REPL"
  &= auto
  &= name "repl"

compileMode :: TricuArgs
compileMode = Compile 
  { file = def &= typ "FILE" 
      &= help "Relative or absolute path to file input for compilation" &= name "f"
  , output = def &= typ "OUTPUT" 
      &= help "Optional output file path for resulting output" &= name "o"
  , form = FSL &= typ "FORM" 
      &= help "Output form: (fsl|tree|ast|ternary|ascii)" 
      &= name "t"
  }
  &= help "Compile a file and return the result of the expression in the final line"
  &= explicit
  &= name "compile"

decodeMode :: TricuArgs
decodeMode = Decode
  { input = def &= typ "FILE"
            &= help "Optional file path containing a Tree Calculus value. Defaults to stdin." &= name "f"
  }
  &= help "Decode a Tree Calculus value into a string representation"
  &= explicit
  &= name "decode"

main :: IO ()
main = do
  args <- cmdArgs $ modes [replMode, compileMode, decodeMode]
    &= help "tricu: Exploring Tree Calculus"
    &= program "tricu"
    &= summary "tricu - compiler and repl"

  case args of
    Repl -> do
      putStrLn "Welcome to the tricu REPL"
      putStrLn "You can exit with `CTRL+D` or the `:_exit` command.`"
      repl library
    Compile { file = filePath, output = maybeOutputPath, form = form } -> do
      result <- evaluateFile filePath
      let fRes = formatResult form result
      case maybeOutputPath of
        Just outputPath -> do
          writeFile outputPath fRes
          putStrLn $ "Output to: " ++ outputPath
        Nothing -> putStr fRes
    Decode { input = maybeInputPath } -> do
      value <- case maybeInputPath of
        Just inputPath -> readFile inputPath
        Nothing -> getContents
      putStrLn $ decodeResult $ result $ evalTricu library $ parseTricu value