module Glyph.Key.Edge where

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import qualified Data.List                 as List

import           Glyph.Class.Stringable    ( Stringable (..) )

import           Graphics.Vty.Input.Events ( Key (..) )

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data CaptureType
  = CaptureChar
  | CaptureNum
  | CaptureUntil Key
  deriving (Eq, Ord, Show)

instance Stringable CaptureType where
  toString CaptureChar        = "{char}"
  toString CaptureNum         = "{number}"
  toString (CaptureUntil key) = "{until " <> toString key <> "}"

  fromString "{char}" = Just CaptureChar
  fromString "{number}" = Just CaptureNum
  fromString str = case str of
    _
      | (List.take 7 str == "{until ")
          `and` ((List.reverse str |> List.take 1) == "}") ->
          List.drop 7 str
            |> List.reverse
            |> List.drop 1
            |> List.reverse
            |> fromString @Key
            |> (<$>) CaptureUntil
      | otherwise -> Nothing

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data Edge a
  = Literal a
  | Capture CaptureType
  deriving (Eq, Ord, Show)

instance forall a. (Stringable a) => Stringable (Edge a) where
  toString (Literal a)   = toString a
  toString (Capture cap) = toString cap

  fromString str = case str of
    -- Required, to separate "{" from Captures
    "{"     -> fromString @a "{" <&> Literal
    '{' : _ -> fromString @CaptureType str <&> Capture
    _       -> fromString @a str <&> Literal