{-|
Module      : Gargantext.Core.Viz.Graph.Utils
Description :
Copyright   : (c) CNRS, 2017-Present
License     : AGPL + CECILL v3
Maintainer  : team@gargantext.org
Stability   : experimental
Portability : POSIX

These functions are used for Vector.Matrix only.

-}

{-# LANGUAGE BangPatterns      #-}
{-# LANGUAGE Strict            #-}

module Gargantext.Core.Viz.Graph.Utils
  where

import Data.List (unzip)
import Data.Map.Strict (Map)
import Data.Matrix hiding (identity)
import Data.Maybe (catMaybes)
import Data.Set (Set)
import Data.Vector (Vector)
import Gargantext.Core.Text.Metrics.Count (occurrencesWith)
import Gargantext.Prelude
import qualified Data.List    as List
import qualified Data.Map.Strict     as Map
import qualified Data.Set     as Set
import qualified Data.Vector  as Vector

------------------------------------------------------------------------
-- | Some utils to build the matrix from cooccurrence results

-- | For tests only, to be removed
-- m1 :: Matrix Double
-- m1 = fromList 300 300 [1..]
------------------------------------------------------------------------
------------------------------------------------------------------------
data Axis = Col | Row
------------------------------------------------------------------------
-- | Matrix functions
type AxisId = Int

-- Data.Vector.Additions
dropAt :: Int -> Vector a -> Vector a
dropAt n v = debut <> (Vector.tail fin)
  where
    debut = Vector.take n v
    fin   = Vector.drop n v

total :: Num a => Matrix a -> a
total m = Vector.sum $ Vector.map (\c -> Vector.sum (getCol c m)) (Vector.enumFromTo 1 (nOf Col m))

nOf :: Axis -> Matrix a -> Int
nOf Row = nrows
nOf Col = ncols

axis :: Axis -> AxisId -> Matrix a -> Vector a
axis Col = getCol
axis Row = getRow


toListsWithIndex :: Matrix a ->  [((Int, Int), a)]
toListsWithIndex m = concat' $ zip [1..] $ List.map (\c -> zip [1..] c) $ toLists m
  where
    concat' :: [(Int, [(Int, a)])] -> [((Int, Int), a)]
    concat' xs = List.concat $ List.map (\(x, ys) -> List.map (\(y, a) -> ((x,y), a)) ys ) xs

------------------------------------------------------------------------
-- Utils to manage Graphs

edgesFilter :: (Ord a, Ord b) => Map (a,a) b -> Map (a,a) b
edgesFilter m = Map.fromList $ catMaybes results
  where
    results = [ let
                  ij = Map.lookup (i,j) m
                  ji = Map.lookup (j,i) m
                  in getMax (i,j) ij ji
              | i <- keys
              , j <- keys
              , i < j
              ]
    keys    = Set.toList $ Set.fromList (x <> y)
    (x,y)   = unzip $ Map.keys m

nodesFilter :: (Show a, Show b, Ord a, Ord b, Num b) => (b -> Bool) -> Map (a,a) b -> (Map (a,a) b, Set a)
nodesFilter f m = (m', toKeep)
  where
    m' = Map.filterWithKey (\(a,b) _ -> Set.member a toKeep && Set.member b toKeep) m
    toKeep = Set.fromList
           $ Map.keys
           $ Map.filter f
           $ occurrencesWith identity
           $ tupleConcat
           $ List.unzip
           $ Map.keys m
    tupleConcat :: ([a],[a]) -> [a]
    tupleConcat (a,b) = a <> b


getMax :: Ord b
       => (a,a)
       -> Maybe b
       -> Maybe b
       -> Maybe ((a,a), b)
getMax (i,j) (Just d) Nothing   = Just ((i,j), d)
getMax (i,j) Nothing (Just d)   = Just ((j,i), d)
getMax ij   (Just di) (Just dj) = if di >= dj then getMax ij (Just di) Nothing
                                              else getMax ij Nothing   (Just dj)
getMax _ _ _ = Nothing
