CommandMatcher.hs

module Hob.Context.CommandMatcher (
    createMatcherForPrefix,
    createMatcherForCommand,
    createMatcherForKeyBinding,
) where

import Hob.Context.Types


createMatcherForPrefix :: String -> (String -> CommandHandler) -> CommandMatcher
createMatcherForPrefix prefix handler = CommandMatcher (const Nothing) (matchHandler prefix)
    where
        matchHandler :: String -> String -> Maybe CommandHandler
        matchHandler (p:xs) (t:xt) = if p == t then matchHandler xs xt else Nothing
        matchHandler "" params = Just $ handler params
        matchHandler _ "" = Nothing

createMatcherForCommand :: String -> CommandHandler -> CommandMatcher
createMatcherForCommand command handler = CommandMatcher (const Nothing) (matchHandler command)
    where
        matchHandler :: String -> String -> Maybe CommandHandler
        matchHandler (p:xs) (t:xt) = if p == t then matchHandler xs xt else Nothing
        matchHandler "" "" = Just handler
        matchHandler _ "" = Nothing
        matchHandler "" _ = Nothing

createMatcherForKeyBinding :: KeyboardBinding -> CommandHandler -> CommandMatcher
createMatcherForKeyBinding keyBinding handler = CommandMatcher (matchHandler keyBinding) (const Nothing)
    where
        matchHandler :: KeyboardBinding -> KeyboardBinding -> Maybe CommandHandler
        matchHandler boundKey matchedKey = if boundKey == matchedKey then Just handler else Nothing