import os
from paraview.simple import *

SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
VTI_PATH = os.path.join(SCRIPT_DIR, '..', 'vti_data', 'RTI_velocity_0040.vti')
OUTPUT_IMG = os.path.join(SCRIPT_DIR, 'gt_image.png')
OUTPUT_STATE = os.path.join(SCRIPT_DIR, 'gt_state.pvsm')

reader = XMLImageDataReader(FileName=[VTI_PATH])
reader.UpdatePipeline()

gradient = GradientOfUnstructuredDataSet(Input=reader)
gradient.ScalarArray = ['POINTS', 'vector']
gradient.ComputeDivergence = 1
gradient.ComputeGradient = 0
gradient.DivergenceArrayName = 'Divergence'
gradient.UpdatePipeline()

sliceFilter = Slice(Input=gradient)
sliceFilter.SliceType = 'Plane'
sliceFilter.SliceType.Origin = [63.5, 63.5, 64.0]
sliceFilter.SliceType.Normal = [0.0, 0.0, 1.0]
sliceFilter.UpdatePipeline()

renderView = GetActiveViewOrCreate('RenderView')
renderView.ViewSize = [1024, 1024]
renderView.Background = [1.0, 1.0, 1.0]

sliceDisplay = Show(sliceFilter, renderView)
sliceDisplay.Representation = 'Surface'
ColorBy(sliceDisplay, ('POINTS', 'Divergence'))

divLUT = GetColorTransferFunction('Divergence')
divLUT.ApplyPreset('Cool to Warm', True)

sliceDisplay.SetScalarBarVisibility(renderView, True)
colorBar = GetScalarBar(divLUT, renderView)
colorBar.Title = 'Velocity Divergence'
colorBar.ComponentTitle = ''

renderView.CameraPosition = [63.5, 63.5, 250.0]
renderView.CameraFocalPoint = [63.5, 63.5, 64.0]
renderView.CameraViewUp = [0.0, 1.0, 0.0]
renderView.ResetCamera()
Render()

SaveScreenshot(OUTPUT_IMG, renderView, ImageResolution=[1024, 1024])
SaveState(OUTPUT_STATE)
print(f"Task 13 done: {OUTPUT_IMG}")