import openmc

###############################################################################
#                      Simulation Input File Parameters
###############################################################################

# OpenMC simulation parameters
batches = 20
inactive = 10
particles = 10000


###############################################################################
#                 Exporting to OpenMC materials.xml File
###############################################################################

# Instantiate some Materials and register the appropriate Nuclides
fuel = openmc.Material(material_id=1, name='fuel')
fuel.set_density('g/cc', 4.5)
fuel.add_nuclide('U235', 1.)

moderator = openmc.Material(material_id=2, name='moderator')
moderator.set_density('g/cc', 1.0)
moderator.add_element('H', 2.)
moderator.add_element('O', 1.)
moderator.add_s_alpha_beta('c_H_in_H2O')

iron = openmc.Material(material_id=3, name='iron')
iron.set_density('g/cc', 7.9)
iron.add_element('Fe', 1.)

# Instantiate a Materials collection and export to XML
materials_file = openmc.Materials([moderator, fuel, iron])
materials_file.export_to_xml()


###############################################################################
#                 Exporting to OpenMC geometry.xml file
###############################################################################

# Instantiate Surfaces
left = openmc.XPlane(surface_id=1, x0=-3, name='left')
right = openmc.XPlane(surface_id=2, x0=3, name='right')
bottom = openmc.YPlane(surface_id=3, y0=-4, name='bottom')
top = openmc.YPlane(surface_id=4, y0=4, name='top')
fuel_surf = openmc.ZCylinder(surface_id=5, x0=0, y0=0, r=0.4)

left.boundary_type = 'vacuum'
right.boundary_type = 'vacuum'
top.boundary_type = 'vacuum'
bottom.boundary_type = 'vacuum'

# Instantiate Cells
cell1 = openmc.Cell(cell_id=1, name='Cell 1')
cell2 = openmc.Cell(cell_id=101, name='cell 2')
cell3 = openmc.Cell(cell_id=102, name='cell 3')
cell4 = openmc.Cell(cell_id=500, name='cell 4')
cell5 = openmc.Cell(cell_id=600, name='cell 5')
cell6 = openmc.Cell(cell_id=601, name='cell 6')

# Use surface half-spaces to define regions
cell1.region = +left & -right & +bottom & -top
cell2.region = -fuel_surf
cell3.region = +fuel_surf
cell5.region = -fuel_surf
cell6.region = +fuel_surf

# Register Materials with Cells
cell2.fill = fuel
cell3.fill = moderator
cell4.fill = moderator
cell5.fill = iron
cell6.fill = moderator

# Instantiate Universe
univ1 = openmc.Universe(universe_id=1)
univ2 = openmc.Universe(universe_id=3)
univ3 = openmc.Universe(universe_id=4)
root = openmc.Universe(universe_id=0, name='root universe')

# Register Cells with Universe
univ1.add_cells([cell2, cell3])
univ2.add_cells([cell4])
univ3.add_cells([cell5, cell6])
root.add_cell(cell1)

# Instantiate a Lattice
lattice = openmc.HexLattice(lattice_id=5)
lattice.center = [0., 0., 0.]
lattice.pitch = [1., 2.]
lattice.universes = \
    [ [ [univ2] + [univ3]*11, [univ2] + [univ3]*5, [univ3] ],
      [ [univ2] + [univ1]*11, [univ2] + [univ1]*5, [univ1] ],
      [ [univ2] + [univ3]*11, [univ2] + [univ3]*5, [univ3] ] ]
lattice.outer = univ2

# Fill Cell with the Lattice
cell1.fill = lattice

# Instantiate a Geometry, register the root Universe, and export to XML
geometry = openmc.Geometry(root)
geometry.export_to_xml()


###############################################################################
#                   Exporting to OpenMC settings.xml file
###############################################################################

# Instantiate a Settings object, set all runtime parameters, and export to XML
settings_file = openmc.Settings()
settings_file.batches = batches
settings_file.inactive = inactive
settings_file.particles = particles

# Create an initial uniform spatial source distribution over fissionable zones
bounds = [-1, -1, -1, 1, 1, 1]
uniform_dist = openmc.stats.Box(bounds[:3], bounds[3:], only_fissionable=True)
settings_file.source = openmc.source.Source(space=uniform_dist)

settings_file.keff_trigger = {'type' : 'std_dev', 'threshold' : 5E-4}
settings_file.trigger_active = True
settings_file.trigger_max_batches = 100
settings_file.export_to_xml()


###############################################################################
#                   Exporting to OpenMC plots.xml file
###############################################################################

plot_xy = openmc.Plot(plot_id=1)
plot_xy.filename = 'plot_xy'
plot_xy.origin = [0, 0, 0]
plot_xy.width = [6, 6]
plot_xy.pixels = [400, 400]
plot_xy.color_by = 'material'

plot_yz = openmc.Plot(plot_id=2)
plot_yz.filename = 'plot_yz'
plot_yz.basis = 'yz'
plot_yz.origin = [0, 0, 0]
plot_yz.width = [8, 8]
plot_yz.pixels = [400, 400]
plot_yz.color_by = 'material'

# Instantiate a Plots collection, add plots, and export to XML
plot_file = openmc.Plots((plot_xy, plot_yz))
plot_file.export_to_xml()


###############################################################################
#                   Exporting to OpenMC tallies.xml File
###############################################################################

# Instantiate a distribcell Tally
tally = openmc.Tally(tally_id=1)
tally.filters = [openmc.DistribcellFilter(cell2)]
tally.scores = ['total']

# Instantiate a Tallies collection and export to XML
tallies_file = openmc.Tallies([tally])
tallies_file.export_to_xml()