{-# LANGUAGE FlexibleInstances #-}

{- |
Module      :  ELynx.Data.Tree.PhyloTree
Description :  Phylogenetic trees
Copyright   :  (c) Dominik Schrempf 2020
License     :  GPL-3.0-or-later

Maintainer  :  dominik.schrempf@gmail.com
Stability   :  unstable
Portability :  portable

Creation date: Thu Jan 17 16:08:54 2019.

Phylogenetic nodes labels, aka 'PhyloLabel's, have a branch length and an
arbitrary label type, e.g., of type 'Int'.

-}


module ELynx.Data.Tree.PhyloTree
  ( PhyloLabel(..)
  , removeBrInfo
  )
where

import           Data.Function
import           Data.Maybe                     ( fromMaybe )
import           Data.Tree
-- import           Test.QuickCheck         hiding ( label )

import           ELynx.Data.Tree.BranchSupportTree
import           ELynx.Data.Tree.MeasurableTree
import           ELynx.Data.Tree.NamedTree

-- | A primitive label type for phylogenetic trees with a name, possibly a
-- branch support value, and possibly a branch length.
data PhyloLabel a = PhyloLabel { label :: a
                               , brSup :: Maybe Double
                               , brLen :: Maybe Double }
                  deriving (Read, Show, Eq)

instance Ord a => Ord (PhyloLabel a) where
  compare = compare `on` label

-- | If no branch length is available, 0 is returned. This is probably not the
-- best (and final) behavior.
instance Measurable (PhyloLabel a) where
  getLen = fromMaybe 0 . brLen
  setLen l x
    | l >= 0    = x { brLen = Just l }
    | otherwise = error $ "Branch lengths cannot be negative: " <> show l

instance BranchSupported (PhyloLabel a) where
  getBranchSupport = brSup
  setBranchSupport Nothing l = l { brSup = Nothing }
  setBranchSupport (Just s) l
    | s > 0     = l { brSup = Just s }
    | otherwise = error "Branch support cannot be negative."

instance Named a => Named (PhyloLabel a) where
  getName = getName . label

-- | Remove all branch relevant information from all nodes of the tree; only
-- retain the labels.
removeBrInfo :: Tree (PhyloLabel a) -> Tree a
removeBrInfo = fmap label