ai-agent-diff-patch-0.0.1.0: app/AiAgentDiff.hs

{-# LANGUAGE OverloadedStrings #-}

-- | Boot layer: entry point for the ai-agent-diff executable.
-- Handles command-line argument parsing and error reporting only.
-- All file I/O and diff computation are delegated to U.diff (AIAgent.DiffPatch.Unified).
module Main where

import System.IO
import System.Exit
import Options.Applicative
import qualified Data.ByteString as BS
import qualified Data.Text as T
import qualified Data.Text.Encoding as TE
import qualified AIAgent.DiffPatch.Unified as U
import Paths_ai_agent_diff_patch (version)
import Data.Version (showVersion)

-- | Command-line arguments for ai-agent-diff.
data ArgData = ArgData
  { _oldFileArgData :: FilePath
  , _newFileArgData :: FilePath
  } deriving (Show)

-- | Entry point.
main :: IO ()
main = do
  hSetBinaryMode stdout True
  hSetBinaryMode stderr True
  args <- execParser parseInfo
  result <- U.diff (_oldFileArgData args) (_newFileArgData args)
  case result of
    Right () -> return ()
    Left err -> do
      BS.hPutStr stderr (TE.encodeUtf8 (T.pack ("Error: " ++ err ++ "\n")))
      exitFailure

-- | Version option: display version string and exit.
verOpt :: Parser (a -> a)
verOpt = infoOption msg $ mconcat
  [ short 'v'
  , long  "version"
  , help  "Show version"
  ]
  where
    msg = "ai-agent-diff-" ++ showVersion version

-- | Parser info with help text.
parseInfo :: ParserInfo ArgData
parseInfo = info (helper <*> verOpt <*> options) $ mconcat
  [ fullDesc
  , header   "ai-agent-diff - Generate unified diff between two files"
  , progDesc "Read OLD-FILE and NEW-FILE, output unified diff to stdout."
  ]

-- | Positional argument parser.
options :: Parser ArgData
options = ArgData
  <$> strArgument (metavar "OLD-FILE" <> help "Original file")
  <*> strArgument (metavar "NEW-FILE" <> help "Modified file")