GeometryCollection.hs

module Data.Internal.Wkt.GeometryCollection
  ( geometryCollection
  , emptyGeometryCollection
  ) where

import           Control.Applicative       ((<|>))
import qualified Data.Geospatial           as Geospatial
import qualified Data.Vector               as Vector
import qualified Text.Trifecta             as Trifecta

import qualified Data.Internal.Wkt.Common  as Wkt
import qualified Data.Internal.Wkt.Line    as Line
import qualified Data.Internal.Wkt.Point   as Point
import qualified Data.Internal.Wkt.Polygon as Polygon

geometryCollection :: Trifecta.Parser (Vector.Vector Geospatial.GeospatialGeometry)
geometryCollection = do
  _ <- Trifecta.string "geometrycollection"
  _ <- Trifecta.spaces
  Wkt.emptySet <|> bracketedAll

bracketedAll :: Trifecta.Parser (Vector.Vector Geospatial.GeospatialGeometry)
bracketedAll = do
  _ <- Trifecta.char '(' >> Trifecta.spaces
  x <- parseAll
  _ <- Trifecta.spaces >> Trifecta.char ')'
  pure x

parseAll :: Trifecta.Parser (Vector.Vector Geospatial.GeospatialGeometry)
parseAll = do
  let
    single = Geospatial.Point <$> Point.point <|> Geospatial.Line <$> Line.lineString <|> Geospatial.Polygon <$> Polygon.polygon
    multi = Geospatial.MultiPoint <$> Point.multiPoint <|> Geospatial.MultiLine <$> Line.multiLineString <|> Geospatial.MultiPolygon <$> Polygon.multiPolygon
  x <- single <|> multi
  xs <- Trifecta.many (Trifecta.char ',' >> Trifecta.spaces >> (single <|> multi))
  pure $ Vector.cons x (Vector.fromList xs)

emptyGeometryCollection :: Vector.Vector Geospatial.GeospatialGeometry
emptyGeometryCollection = Vector.empty