Add WegaBorad bot

I'm just committing all unstaged files so they don't get lost when I
delete this repo.

WegaBorad.hs

@@ -0,0 +1,111 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Haboli.Euphoria.WegaBorad where
+
+import           Control.Monad
+import           Control.Monad.Trans.Class
+import           Control.Monad.Trans.State
+import           Data.Char
+import           Data.Foldable
+import           Data.List
+import qualified Data.Map.Strict           as Map
+import qualified Data.Text                 as T
+import           Haboli.Euphoria.Api
+import           Haboli.Euphoria.Client
+
+{- Range stuff -}
+
+data Range = Range Char Char
+  deriving (Eq)
+
+instance Show Range where
+  show (Range a b)
+    | a == b    = [a]
+    | otherwise = "[" ++ [a] ++ ".." ++ [b] ++ "]"
+
+letterRange :: Char -> Char -> Range
+letterRange a b =
+  let realA = chr $ max (ord 'a') $ min (ord 'z') $ ord a
+      realB = chr $ max (ord 'a') $ min (ord 'z') $ ord b
+  in  Range realA realB
+
+fullRange :: Range
+fullRange = Range 'a' 'z'
+
+getRangeChar :: Range -> Maybe Char
+getRangeChar (Range a b)
+  | a == b = Just a
+  | otherwise = Nothing
+
+splitRange :: Int -> Range -> [Range]
+splitRange steps (Range a b) =
+  let amount = ord b - ord a + 1
+      width = amount `div` steps
+      leftover = amount `mod` steps
+      widths = zipWith (+) (replicate steps width) (replicate leftover 1 ++ repeat 0)
+      skips = scanl (+) 0 (init widths)
+  in  nub $ zipWith (\s w -> letterRange (chr $ ord a + s) (chr $ ord a + s + w - 1)) skips widths
+
+{- Bot logic -}
+
+data Search = Search
+  { searchStartMsg :: Message
+  , searchOptions  :: Map.Map Snowflake Range
+  } deriving (Show)
+
+data MyState = MyState
+  { msSplitInto     :: Int
+  , msCurrentSearch :: Maybe Search
+  } deriving (Show)
+
+defaultState :: MyState
+defaultState = MyState 3 Nothing
+
+type MyClient a = StateT MyState (Client ()) a
+
+wegaBot :: MyClient ()
+wegaBot = forever $ do
+  event <- lift $ respondingToPing nextEvent
+  case event of
+    EventSnapshot _ -> void $ lift $ nick "WegaBot"
+    EventSend e     -> onMessage (sendMessage e)
+    _               -> pure ()
+
+runWegaBot :: MyState -> MyClient a -> Client () a
+runWegaBot start bot = fst <$> runStateT bot start
+
+onMessage :: Message -> MyClient ()
+onMessage msg
+  | msgContent msg == "!wega" = startNewWega msg
+  | otherwise = do
+      s <- get
+      for_ (msCurrentSearch s) $ \search -> do
+        let maybeRange = do
+              parent <- msgParent msg
+              searchOptions search Map.!? parent
+        for_ maybeRange $ closeInOn search msg
+
+startNewWega :: Message -> MyClient ()
+startNewWega msg = do
+  startMsg <- lift $ reply msg "New character!"
+  closeInOn (Search msg Map.empty) startMsg fullRange
+
+-- | @'closeInOn' search msg range@ closes in on the currently running @search@,
+-- where @msg@ has just selected @range@.
+closeInOn :: Search -> Message -> Range -> MyClient ()
+closeInOn search msg range =
+  case getRangeChar range of
+    Just char -> do
+      void $ lift $ reply msg $ "You've selected " <> T.pack (show char)
+      startNewWega $ searchStartMsg search
+    Nothing -> do
+      s <- get
+      let possibleRanges = splitRange (msSplitInto s) range
+      rangesWithMessageIds <- mapM (sendRange msg) possibleRanges
+      let options = Map.fromList rangesWithMessageIds
+      put s{msCurrentSearch = Just search{searchOptions = options}}
+
+sendRange :: Message -> Range -> MyClient (Snowflake, Range)
+sendRange msg range = do
+  msg' <- lift $ reply msg $ "Reply to this message to choose " <> T.pack (show range) <> "."
+  pure (msgId msg', range)