{-# LANGUAGE StrictData #-}
{-# LANGUAGE TemplateHaskell #-}

module Dodge.Data.MetaTree where

import Control.Lens
import Data.Tree

data MetaTree a b = MTree
    {_mtLabel :: b, _mtTree :: MetaNode a b, _mtBranches :: [MetaBranch a b]}

data MetaNode a b
    = NodeTree {_nodeTree :: Tree a}
    | NodeMTree {_nodeMetaTree :: MetaTree a b}

data MetaBranch a b = MBranch {_mbAttach :: a -> Maybe a, _mbTree :: MetaTree a b}

newtype SelfTree a = ST {_unST :: Tree (a, Either (Tree a) (SelfTree a))}

makeLenses ''MetaTree
makeLenses ''MetaBranch
makeLenses ''MetaNode

instance Functor (MetaTree a) where
    fmap f (MTree b mn bs) = MTree (f b) (mn & nodeMetaTree %~ fmap f) (map (mbTree %~ fmap f) bs)