"""Build shared boundary fields and iterative smoothing."""
from .nodes import group_input, sample_field


def edge_boundary_field(nodes, links):
    vertex_neighbors = nodes.new("GeometryNodeInputMeshVertexNeighbors")
    loose_vertex = nodes.new("FunctionNodeCompare")
    loose_vertex.data_type = "INT"
    loose_vertex.operation = "EQUAL"
    loose_vertex_a = next(
        socket for socket in loose_vertex.inputs if socket.identifier == "A_INT"
    )
    loose_vertex_b = next(
        socket for socket in loose_vertex.inputs if socket.identifier == "B_INT"
    )
    loose_vertex_b.default_value = 1
    links.new(vertex_neighbors.outputs["Vertex Count"], loose_vertex_a)

    edge_neighbors = nodes.new("GeometryNodeInputMeshEdgeNeighbors")
    boundary_edge = nodes.new("FunctionNodeCompare")
    boundary_edge.data_type = "INT"
    boundary_edge.operation = "EQUAL"
    boundary_edge_a = next(
        socket for socket in boundary_edge.inputs if socket.identifier == "A_INT"
    )
    boundary_edge_b = next(
        socket for socket in boundary_edge.inputs if socket.identifier == "B_INT"
    )
    boundary_edge_b.default_value = 1
    links.new(edge_neighbors.outputs["Face Count"], boundary_edge_a)
    edge_domain = nodes.new("GeometryNodeFieldOnDomain")
    edge_domain.data_type = "BOOLEAN"
    edge_domain.domain = "EDGE"
    links.new(boundary_edge.outputs["Result"], edge_domain.inputs["Value"])

    is_boundary = nodes.new("FunctionNodeBooleanMath")
    is_boundary.operation = "OR"
    links.new(edge_domain.outputs["Value"], is_boundary.inputs[0])
    links.new(loose_vertex.outputs["Result"], is_boundary.inputs[1])
    return is_boundary.outputs["Boolean"]


def expand_smooth(
    group, geometry, iterations_name, weight_name, *,
    influence=None, pin_sharp=True,
):
    nodes = group.nodes
    links = group.links
    iteration_controls = group_input(nodes, {iterations_name})
    weight_controls = group_input(nodes, {weight_name})
    repeat_output = nodes.new("GeometryNodeRepeatOutput")
    repeat_input = nodes.new("GeometryNodeRepeatInput")
    repeat_input.pair_with_output(repeat_output)
    links.new(
        iteration_controls.outputs[iterations_name],
        repeat_input.inputs["Iterations"],
    )

    boundary_field = edge_boundary_field(nodes, links)
    boundary_points = nodes.new("GeometryNodeFieldOnDomain")
    boundary_points.data_type = "BOOLEAN"
    boundary_points.domain = "POINT"
    links.new(boundary_field, boundary_points.inputs["Value"])

    boundary_geometry = nodes.new("GeometryNodeSeparateGeometry")
    boundary_geometry.domain = "POINT"
    links.new(repeat_input.outputs["Geometry"], boundary_geometry.inputs["Geometry"])
    links.new(boundary_points.outputs["Value"], boundary_geometry.inputs["Selection"])
    links.new(geometry, repeat_input.inputs["Geometry"])
    nearest_boundary = nodes.new("GeometryNodeSampleNearest")
    nearest_boundary.domain = "POINT"
    if influence is not None:
        # Both boundary meshes keep the same compact index order: only positions change.
        source_boundary = nodes.new("GeometryNodeSeparateGeometry")
        source_boundary.domain = "POINT"
        links.new(geometry, source_boundary.inputs["Geometry"])
        links.new(boundary_points.outputs["Value"], source_boundary.inputs["Selection"])
        links.new(source_boundary.outputs["Selection"], nearest_boundary.inputs["Geometry"])
        source_position = nodes.new("GeometryNodeInputPosition").outputs["Position"]
        fixed_position = sample_field(group, geometry, source_position, "FLOAT_VECTOR")
        links.new(fixed_position, nearest_boundary.inputs["Sample Position"])
    else:
        links.new(boundary_geometry.outputs["Selection"], nearest_boundary.inputs["Geometry"])

    position = nodes.new("GeometryNodeInputPosition")
    smooth_all = nodes.new("GeometryNodeBlurAttribute")
    smooth_all.data_type = "FLOAT_VECTOR"
    smooth_all.inputs["Iterations"].default_value = 1
    smooth_all.inputs["Weight"].default_value = 1.0
    links.new(position.outputs["Position"], smooth_all.inputs["Value"])

    boundary_position = nodes.new("GeometryNodeInputPosition")
    smooth_boundary = nodes.new("GeometryNodeBlurAttribute")
    smooth_boundary.data_type = "FLOAT_VECTOR"
    smooth_boundary.inputs["Iterations"].default_value = 1
    smooth_boundary.inputs["Weight"].default_value = 0.5
    links.new(boundary_position.outputs["Position"], smooth_boundary.inputs["Value"])
    sample_boundary = nodes.new("GeometryNodeSampleIndex")
    sample_boundary.data_type = "FLOAT_VECTOR"
    sample_boundary.domain = "POINT"
    sample_boundary.clamp = False
    links.new(boundary_geometry.outputs["Selection"], sample_boundary.inputs["Geometry"])
    links.new(smooth_boundary.outputs["Value"], sample_boundary.inputs["Value"])
    links.new(nearest_boundary.outputs["Index"], sample_boundary.inputs["Index"])

    choose_boundary = nodes.new("GeometryNodeSwitch")
    choose_boundary.input_type = "VECTOR"
    links.new(boundary_points.outputs["Value"], choose_boundary.inputs["Switch"])
    links.new(smooth_all.outputs["Value"], choose_boundary.inputs["False"])
    links.new(sample_boundary.outputs["Value"], choose_boundary.inputs["True"])

    weight = weight_controls.outputs[weight_name]
    if pin_sharp:
        normal = nodes.new("GeometryNodeInputNormal")
        smooth_normal = nodes.new("GeometryNodeBlurAttribute")
        smooth_normal.data_type = "FLOAT_VECTOR"
        smooth_normal.inputs["Iterations"].default_value = 10
        smooth_normal.inputs["Weight"].default_value = 1.0
        links.new(normal.outputs["Normal"], smooth_normal.inputs["Value"])
        normal_coherence = nodes.new("ShaderNodeVectorMath")
        normal_coherence.operation = "LENGTH"
        links.new(smooth_normal.outputs["Value"], normal_coherence.inputs[0])
        smooth_weight = nodes.new("ShaderNodeMath")
        smooth_weight.operation = "MULTIPLY"
        links.new(weight_controls.outputs[weight_name], smooth_weight.inputs[0])
        links.new(normal_coherence.outputs["Value"], smooth_weight.inputs[1])
        weight = smooth_weight.outputs[0]
    if influence is not None:
        masked_weight = nodes.new("ShaderNodeMath")
        masked_weight.operation = "MULTIPLY"
        links.new(weight, masked_weight.inputs[0])
        links.new(influence, masked_weight.inputs[1])
        weight = masked_weight.outputs[0]

    current_position = nodes.new("GeometryNodeInputPosition")
    mix_position = nodes.new("ShaderNodeMix")
    mix_position.data_type = "VECTOR"
    links.new(weight, mix_position.inputs[0])
    links.new(current_position.outputs["Position"], mix_position.inputs[4])
    links.new(choose_boundary.outputs["Output"], mix_position.inputs[5])
    set_position = nodes.new("GeometryNodeSetPosition")
    links.new(repeat_input.outputs["Geometry"], set_position.inputs["Geometry"])
    links.new(mix_position.outputs["Result"], set_position.inputs["Position"])
    links.new(set_position.outputs["Geometry"], repeat_output.inputs["Geometry"])
    if influence is not None:
        enabled = nodes.new("GeometryNodeSwitch")
        enabled.input_type = "GEOMETRY"
        links.new(iteration_controls.outputs[iterations_name], enabled.inputs["Switch"])
        links.new(geometry, enabled.inputs["False"])
        links.new(repeat_output.outputs["Geometry"], enabled.inputs["True"])
        return enabled.outputs["Output"]
    return repeat_output.outputs["Geometry"]