Add arg parsing, loading config from XDG_CONFIG_HOME and -c arg for loading config file

1 files changed, 59 insertions, 2 deletions

diff --git a/exe/Main.hs b/exe/Main.hs
index 3ac3375..2bfe08b 100644
--- a/exe/Main.hs
+++ b/exe/Main.hs
@@ -1,15 +1,72 @@
 module Main where
 
 import qualified Brick.Main as M
+import Control.Exception (throwIO)
 import Control.Monad (void)
 import qualified Daffm
 import Daffm.Configuration (loadConfigFile)
+import Data.Maybe (fromMaybe)
 import qualified Data.Text as Text
 import System.Directory (getCurrentDirectory)
+import System.Environment (getArgs)
+
+data Args = Args
+  { argsCwd :: Maybe Text.Text,
+    argsConfigFile :: Maybe FilePath,
+    argsHelp :: Bool
+  }
+  deriving (Show)
 
 main :: IO ()
 main = do
+  args <- getArgs >>= parseArgs
+  evaluate args
+
+evaluate :: Args -> IO ()
+evaluate (Args {argsHelp = True}) =
+  putStrLn helpMenuContents
+evaluate (Args {argsCwd, argsConfigFile}) = do
   cwd <- getCurrentDirectory
-  config <- loadConfigFile
-  initialState <- Daffm.loadDirToState (Text.pack cwd) $ Daffm.mkEmptyAppState config
+  config <- loadConfigFile argsConfigFile
+  let dir = fromMaybe (Text.pack cwd) argsCwd
+  initialState <- Daffm.loadDirToState dir $ Daffm.mkEmptyAppState config
   void $ M.defaultMain Daffm.app initialState
+
+parseArgs :: [String] -> IO Args
+parseArgs rawArgs = case parsedArgs of
+  Left e -> throwIO $ userError e
+  Right v -> pure v
+  where
+    parsedArgs = parse rawArgs (Args {argsCwd = Nothing, argsConfigFile = Nothing, argsHelp = False})
+    parse :: [String] -> Args -> Either String Args
+    parse [] args = Right args
+    parse ("-h" : _) args = Right $ args {argsHelp = True}
+    parse ("--help" : _) args = Right $ args {argsHelp = True}
+    parse ("-c" : config : rest) args = parse rest $ args {argsConfigFile = Just config}
+    parse ["-c"] _ = Left "Missing value for -c arg"
+    parse ("--config" : config : rest) args = parse rest $ args {argsConfigFile = Just config}
+    parse ["--config"] _ = Left "Missing value for --config arg"
+    parse (flag@('-' : _) : _) _ = Left $ "Invalid flag " <> flag
+    parse (dir : rest) args = parse rest $ args {argsCwd = Just $ Text.pack dir}
+
+helpMenuContents :: String
+helpMenuContents =
+  unlines
+    [ "daffm - Dumb as-fuck file manager",
+      "",
+      "Usage: daffm [options] [dir]",
+      "",
+      "Arguments:",
+      "  [dir]",
+      "      Directory to load. Defaults to current working directory",
+      "",
+      "Options:",
+      "  -c, --config <CONFIG-PATH>",
+      "      Load toml config from file",
+      "      If path is prefixed with @, will use alternate config",
+      "        Ex: -c @foo will load $XDG_CONFIG_HOME/daffm/config.foo.toml",
+      "      Default: $XDG_CONFIG_HOME/daffm/config.toml",
+      "",
+      "  -h, --help",
+      "      This help menu"
+    ]