-- Refer to the WKB Wikipedia page <https://en.wikipedia.org/wiki/Well-known_text#Well-known_binary>
--
-- Allows parsing of ByteString into a Geospatial Object.
--
-------------------------------------------------------------------
module Data.Wkb
  ( parseByteString
  , parseHexByteString
  , toByteString
  ) where

import qualified Data.Binary.Get              as BinaryGet
import qualified Data.ByteString.Builder      as ByteStringBuilder
import qualified Data.ByteString.Lazy         as LazyByteString
import qualified Data.Geospatial              as Geospatial
import qualified Data.Hex                     as Hex

import qualified Data.Internal.Wkb.Endian     as Endian
import qualified Data.Internal.Wkb.Geometry   as Geometry
import qualified Data.Internal.Wkb.Geospatial as WkbGeospatial

-- |
-- Representation of WKB as Binary
parseByteString :: LazyByteString.ByteString -> Either String Geospatial.GeospatialGeometry
parseByteString :: ByteString -> Either String GeospatialGeometry
parseByteString ByteString
byteString =
  case Get GeospatialGeometry
-> ByteString
-> Either
     (ByteString, ByteOffset, String)
     (ByteString, ByteOffset, GeospatialGeometry)
forall a.
Get a
-> ByteString
-> Either
     (ByteString, ByteOffset, String) (ByteString, ByteOffset, a)
BinaryGet.runGetOrFail
        ((EndianType -> Get WkbGeometryType) -> Get GeospatialGeometry
WkbGeospatial.getGeospatialGeometry EndianType -> Get WkbGeometryType
Geometry.getWkbGeom)
        ByteString
byteString of
    Left (ByteString
_, ByteOffset
_, String
err)                 -> String -> Either String GeospatialGeometry
forall a b. a -> Either a b
Left (String -> Either String GeospatialGeometry)
-> String -> Either String GeospatialGeometry
forall a b. (a -> b) -> a -> b
$ String
"Could not parse wkb: " String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
err
    Right (ByteString
_, ByteOffset
_, GeospatialGeometry
geoSpatialGeometry) -> GeospatialGeometry -> Either String GeospatialGeometry
forall a b. b -> Either a b
Right GeospatialGeometry
geoSpatialGeometry

-- |
-- Representation of WKB as a String in Base16/Hex form i.e. "0101000000000000000000f03f0000000000000040" is POINT 1.0 2.0
parseHexByteString :: Hex.Hex -> Either String Geospatial.GeospatialGeometry
parseHexByteString :: Hex -> Either String GeospatialGeometry
parseHexByteString = (ByteString -> Either String GeospatialGeometry)
-> Hex -> Either String GeospatialGeometry
Hex.safeConvert ByteString -> Either String GeospatialGeometry
parseByteString

-- |
-- Produce the binary representation of WKB given its EndianType (Little or Big - Intel is Little).  Use EWKB when you know the SRID.
toByteString :: Endian.EndianType -> Geospatial.GeospatialGeometry -> LazyByteString.ByteString
toByteString :: EndianType -> GeospatialGeometry -> ByteString
toByteString EndianType
endianType =
  Builder -> ByteString
ByteStringBuilder.toLazyByteString (Builder -> ByteString)
-> (GeospatialGeometry -> Builder)
-> GeospatialGeometry
-> ByteString
forall b c a. (b -> c) -> (a -> b) -> a -> c
. BuilderWkbGeometryType
-> EndianType -> GeospatialGeometry -> Builder
WkbGeospatial.builderGeospatialGeometry BuilderWkbGeometryType
Geometry.builderWkbGeom EndianType
endianType