List available commands in help text

3 files changed, 15 insertions, 2 deletions

diff --git a/src/Command.hs b/src/Command.hs
index ae24534..0ca6710 100644
--- a/src/Command.hs
+++ b/src/Command.hs
@@ -19,6 +19,7 @@ import Config
 
 class CommandArgumentsType (CommandArguments c) => Command c where
     commandName :: proxy c -> String
+    commandDescription :: proxy c -> String
 
     type CommandOptions c :: Type
     type CommandOptions c = ()
diff --git a/src/Command/Run.hs b/src/Command/Run.hs
index 677f8f1..daba8af 100644
--- a/src/Command/Run.hs
+++ b/src/Command/Run.hs
@@ -24,6 +24,7 @@ data RunCommand = RunCommand Text
 
 instance Command RunCommand where
     commandName _ = "run"
+    commandDescription _ = "Execude jobs per minici.yaml for given commits"
 
     type CommandArguments RunCommand = Maybe Text
 
diff --git a/src/Main.hs b/src/Main.hs
index 7dcc484..cdce0f9 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -61,8 +61,19 @@ main = do
             exitFailure
 
     when (optShowHelp opts) $ do
-        let header = "Usage: minici [<option>...] <command> [<args>]"
-        putStr $ usageInfo header options
+        let header = "Usage: minici [<option>...] <command> [<args>]\n\nCommon options are:"
+            commandDesc (SC proxy) = "  " <> padCommand (commandName proxy) <> commandDescription proxy
+
+            padTo n str = str <> replicate (n - length str) ' '
+            padCommand = padTo (maxCommandNameLength + 3)
+            commandNameLength (SC proxy) = length $ commandName proxy
+            maxCommandNameLength = maximum $ map commandNameLength commands
+
+        putStr $ usageInfo header options <> unlines (
+            [ ""
+            , "Available commands:"
+            ] ++ map commandDesc commands
+          )
         exitSuccess
 
     when (optShowVersion opts) $ do