// Convert a 32-bit label into a 64-bit label by adding the Z coordinate into high 32 bits.
// Also drops the high byte (alpha channel) since Raveler labels only use 24-bits.
func (d *Data) addLabelZ(geom dvid.Geometry, data32 []uint8, stride int32) ([]byte, error) {
	if len(data32)%4 != 0 {
		return nil, fmt.Errorf("expected 4 byte/voxel alignment but have %d bytes!", len(data32))
	}
	coord := geom.StartPoint()
	if coord.NumDims() < 3 {
		return nil, fmt.Errorf("expected n-d (n >= 3) offset for image.  Got %d dimensions.",
			coord.NumDims())
	}
	superpixelBytes := make([]byte, 8, 8)
	binary.BigEndian.PutUint32(superpixelBytes[0:4], uint32(coord.Value(2)))

	nx := int(geom.Size().Value(0))
	ny := int(geom.Size().Value(1))
	numBytes := nx * ny * 8
	data64 := make([]byte, numBytes, numBytes)
	dstI := 0
	for y := 0; y < ny; y++ {
		srcI := y * int(stride)
		for x := 0; x < nx; x++ {
			if data32[srcI] == 0 && data32[srcI+1] == 0 && data32[srcI+2] == 0 {
				copy(data64[dstI:dstI+8], ZeroBytes())
			} else {
				superpixelBytes[5] = data32[srcI+2]
				superpixelBytes[6] = data32[srcI+1]
				superpixelBytes[7] = data32[srcI]
				copy(data64[dstI:dstI+8], superpixelBytes)
			}
			// NOTE: we skip the 4th byte (alpha) at srcI+3
			//a := uint32(data32[srcI+3])
			//b := uint32(data32[srcI+2])
			//g := uint32(data32[srcI+1])
			//r := uint32(data32[srcI+0])
			//spid := (b << 16) | (g << 8) | r
			srcI += 4
			dstI += 8
		}
	}
	return data64, nil
}

// NewLabels returns labelblk Labels, a representation of externally usable subvolume
// or slice data, given some geometry and optional image data.
// If img is passed in, the function will initialize Voxels with data from the image.
// Otherwise, it will allocate a zero buffer of appropriate size.
//
// TODO : Unlike the standard imageblk.NewVoxels, the labelblk version can modify the
// labels based on the z-coordinate of the given geometry for Raveler labeling.
// This will be removed when Raveler-specific labels are moved outside DVID.
func (d *Data) NewLabels(geom dvid.Geometry, img interface{}) (*Labels, error) {
	bytesPerVoxel := d.Properties.Values.BytesPerElement()
	stride := geom.Size().Value(0) * bytesPerVoxel
	var data []byte

	if img == nil {
		numVoxels := geom.NumVoxels()
		if numVoxels <= 0 {
			return nil, fmt.Errorf("Illegal geometry requested: %s", geom)
		}
		requestSize := int64(bytesPerVoxel) * numVoxels
		if requestSize > server.MaxDataRequest {
			return nil, fmt.Errorf("Requested payload (%d bytes) exceeds this DVID server's set limit (%d)",
				requestSize, server.MaxDataRequest)
		}
		data = make([]byte, requestSize)
	} else {
		switch t := img.(type) {
		case image.Image:
			var inputBytesPerVoxel, actualStride int32
			var err error
			data, inputBytesPerVoxel, actualStride, err = dvid.ImageData(t)
			if err != nil {
				return nil, err
			}
			if actualStride != stride {
				// Need to do some conversion here.
				switch d.Labeling {
				case Standard64bit:
					data, err = d.convertTo64bit(geom, data, int(inputBytesPerVoxel), int(actualStride))
					if err != nil {
						return nil, err
					}
				case RavelerLabel:
					data, err = d.addLabelZ(geom, data, actualStride)
					if err != nil {
						return nil, err
					}
				default:
					return nil, fmt.Errorf("unexpected label type in labelblk: %s", d.Labeling)
				}
			}
		case []byte:
			data = t
			actualLen := int64(len(data))
			expectedLen := int64(bytesPerVoxel) * geom.NumVoxels()
			if actualLen != expectedLen {
				return nil, fmt.Errorf("labels data was %d bytes, expected %d bytes for %s",
					actualLen, expectedLen, geom)
			}
		default:
			return nil, fmt.Errorf("unexpected image type given to NewVoxels(): %T", t)
		}
	}

	labels := &Labels{
		imageblk.NewVoxels(geom, d.Properties.Values, data, stride),
	}
	return labels, nil
}

// NewVoxels returns Voxels with given geometry and optional image data.
// If img is passed in, the function will initialize the Voxels with data from the image.
// Otherwise, it will allocate a zero buffer of appropriate size.
func (d *Data) NewVoxels(geom dvid.Geometry, img interface{}) (*Voxels, error) {
	bytesPerVoxel := d.Properties.Values.BytesPerElement()
	stride := geom.Size().Value(0) * bytesPerVoxel

	voxels := &Voxels{
		Geometry: geom,
		values:   d.Properties.Values,
		stride:   stride,
	}

	if img == nil {
		numVoxels := geom.NumVoxels()
		if numVoxels <= 0 {
			return nil, fmt.Errorf("Illegal geometry requested: %s", geom)
		}
		requestSize := int64(bytesPerVoxel) * numVoxels
		if requestSize > server.MaxDataRequest {
			return nil, fmt.Errorf("Requested payload (%d bytes) exceeds this DVID server's set limit (%d)",
				requestSize, server.MaxDataRequest)
		}
		voxels.data = make([]uint8, requestSize)
	} else {
		switch t := img.(type) {
		case image.Image:
			var actualStride int32
			var err error
			voxels.data, _, actualStride, err = dvid.ImageData(t)
			if err != nil {
				return nil, err
			}
			if actualStride < stride {
				return nil, fmt.Errorf("Too little data in input image (expected stride %d)", stride)
			}
			voxels.stride = actualStride
		case []byte:
			voxels.data = t
			actualLen := int64(len(voxels.data))
			expectedLen := int64(bytesPerVoxel) * geom.NumVoxels()
			if actualLen != expectedLen {
				return nil, fmt.Errorf("voxels data was %d bytes, expected %d bytes for %s",
					actualLen, expectedLen, geom)
			}
		default:
			return nil, fmt.Errorf("Unexpected image type given to NewVoxels(): %T", t)
		}
	}
	return voxels, nil
}

// GetImage returns an image given a 2d orthogonal image description.  Since imagetile tiles
// have precomputed XY, XZ, and YZ orientations, reconstruction of the desired image should
// be much faster than computing the image from voxel blocks.
func (d *Data) GetImage(ctx storage.Context, src *imageblk.Data, geom dvid.Geometry, isotropic bool) (*dvid.Image, error) {
	// Iterate through tiles that intersect our geometry.
	if d.Levels == nil || len(d.Levels) == 0 {
		return nil, fmt.Errorf("%s has no specification for tiles at highest resolution",
			d.DataName())
	}
	levelSpec := d.Levels[0]
	minSlice, err := dvid.Isotropy2D(src.VoxelSize, geom, isotropic)
	if err != nil {
		return nil, err
	}

	// Create an image of appropriate size and type using source's ExtData creation.
	dstW := minSlice.Size().Value(0)
	dstH := minSlice.Size().Value(1)
	dst, err := src.BlankImage(dstW, dstH)
	if err != nil {
		return nil, err
	}

	// Read each tile that intersects the geometry and store into final image.
	slice := minSlice.DataShape()
	tileW, tileH, err := slice.GetSize2D(levelSpec.TileSize)
	if err != nil {
		return nil, err
	}
	tileSize := dvid.Point2d{tileW, tileH}
	minPtX, minPtY, err := slice.GetSize2D(minSlice.StartPoint())
	if err != nil {
		return nil, err
	}

	wg := new(sync.WaitGroup)
	topLeftGlobal := dvid.Point2d{minPtX, minPtY}
	tilePt := topLeftGlobal.Chunk(tileSize)
	bottomRightGlobal := tilePt.MaxPoint(tileSize).(dvid.Point2d)
	y0 := int32(0)
	y1 := bottomRightGlobal[1] - minPtY + 1
	for y0 < dstH {
		x0 := int32(0)
		x1 := bottomRightGlobal[0] - minPtX + 1
		for x0 < dstW {
			wg.Add(1)
			go func(x0, y0, x1, y1 int32) {
				defer wg.Done()

				// Get this tile from datastore
				tileCoord, err := slice.PlaneToChunkPoint3d(x0, y0, minSlice.StartPoint(), levelSpec.TileSize)
				goImg, err := d.GetTile(ctx, slice, 0, dvid.IndexZYX(tileCoord))
				if err != nil || goImg == nil {
					return
				}

				// Get tile space coordinate for top left.
				curStart := dvid.Point2d{x0 + minPtX, y0 + minPtY}
				p := curStart.PointInChunk(tileSize)
				ptInTile := image.Point{int(p.Value(0)), int(p.Value(1))}

				// Paste the pertinent rectangle from this tile into our destination.
				r := image.Rect(int(x0), int(y0), int(x1), int(y1))
				draw.Draw(dst.GetDrawable(), r, goImg, ptInTile, draw.Src)
			}(x0, y0, x1, y1)
			x0 = x1
			x1 += tileW
		}
		y0 = y1
		y1 += tileH
	}
	wg.Wait()

	if isotropic {
		dstW := int(geom.Size().Value(0))
		dstH := int(geom.Size().Value(1))
		dst, err = dst.ScaleImage(dstW, dstH)
		if err != nil {
			return nil, err
		}
	}
	return dst, nil
}

// Convert raw image data into a 2d array of 64-bit labels
func (d *Data) convertTo64bit(geom dvid.Geometry, data []uint8, bytesPerVoxel, stride int) ([]byte, error) {
	nx := int(geom.Size().Value(0))
	ny := int(geom.Size().Value(1))
	numBytes := nx * ny * 8
	data64 := make([]byte, numBytes, numBytes)

	var byteOrder binary.ByteOrder
	if geom.DataShape().ShapeDimensions() == 2 {
		byteOrder = binary.BigEndian // This is the default for PNG
	} else {
		byteOrder = binary.LittleEndian
	}

	switch bytesPerVoxel {
	case 1:
		dstI := 0
		for y := 0; y < ny; y++ {
			srcI := y * stride
			for x := 0; x < nx; x++ {
				binary.LittleEndian.PutUint64(data64[dstI:dstI+8], uint64(data[srcI]))
				srcI++
				dstI += 8
			}
		}
	case 2:
		dstI := 0
		for y := 0; y < ny; y++ {
			srcI := y * stride
			for x := 0; x < nx; x++ {
				value := byteOrder.Uint16(data[srcI : srcI+2])
				binary.LittleEndian.PutUint64(data64[dstI:dstI+8], uint64(value))
				srcI += 2
				dstI += 8
			}
		}
	case 4:
		dstI := 0
		for y := 0; y < ny; y++ {
			srcI := y * stride
			for x := 0; x < nx; x++ {
				value := byteOrder.Uint32(data[srcI : srcI+4])
				binary.LittleEndian.PutUint64(data64[dstI:dstI+8], uint64(value))
				srcI += 4
				dstI += 8
			}
		}
	case 8:
		dstI := 0
		for y := 0; y < ny; y++ {
			srcI := y * stride
			for x := 0; x < nx; x++ {
				value := byteOrder.Uint64(data[srcI : srcI+8])
				binary.LittleEndian.PutUint64(data64[dstI:dstI+8], uint64(value))
				srcI += 8
				dstI += 8
			}
		}
	default:
		return nil, fmt.Errorf("could not convert to 64-bit label given %d bytes/voxel", bytesPerVoxel)
	}
	return data64, nil
}