"""Build a shared center on the original Cutout mesh."""


from .nodes import evaluate_field, group_input, sample_field


def vector(group, operation, first, second=None):
    node = group.nodes.new("ShaderNodeVectorMath")
    node.operation = operation
    for value, socket in ((first, node.inputs[0]), (second, node.inputs[3 if operation == "SCALE" else 1])):
        if value is None:
            continue
        if hasattr(value, "node"):
            group.links.new(value, socket)
        else:
            socket.default_value = value
    return node.outputs[0]


def axes(group, value):
    node = group.nodes.new("ShaderNodeSeparateXYZ")
    group.links.new(value, node.inputs[0])
    return node.outputs


def combine(group, x, y, z=0):
    node = group.nodes.new("ShaderNodeCombineXYZ")
    for value, socket in zip((x, y, z), node.inputs):
        if hasattr(value, "node"):
            group.links.new(value, socket)
        else:
            socket.default_value = value
    return node.outputs[0]


def set_position(group, geometry, position):
    node = group.nodes.new("GeometryNodeSetPosition")
    group.links.new(geometry, node.inputs["Geometry"])
    group.links.new(position, node.inputs["Position"])
    return node.outputs[0]


def sample_surface(group, geometry, value, data_type, domain_position, query):
    """Keep point indices on points before the face interpolation adapts domains."""
    field = evaluate_field(group, sample_field(group, geometry, value, data_type), data_type, "POINT")
    flat = set_position(group, geometry, domain_position)
    sample = group.nodes.new("GeometryNodeSampleNearestSurface")
    sample.data_type = data_type
    group.links.new(flat, sample.inputs["Mesh"])
    group.links.new(field, sample.inputs["Value"])
    group.links.new(query, sample.inputs["Sample Position"])
    return sample.outputs[0]


def build_center_surface(group, unsplit):
    """Smooth the unsplit displaced surface without moving its XY coordinates."""
    nodes, links = group.nodes, group.links
    controls = group_input(nodes, {"Center Smooth"})
    position = nodes.new("GeometryNodeInputPosition").outputs[0]
    components = axes(group, position)
    uv = nodes.new("GeometryNodeInputNamedAttribute")
    uv.data_type = "FLOAT_VECTOR"
    uv.inputs["Name"].default_value = "UVMap"
    coordinates = uv.outputs["Attribute"]
    blur = nodes.new("GeometryNodeBlurAttribute")
    blur.data_type = "FLOAT"
    links.new(components["Z"], blur.inputs["Value"])
    links.new(controls.outputs["Center Smooth"], blur.inputs["Iterations"])
    support = set_position(group, unsplit, combine(group, components["X"], components["Y"], blur.outputs[0]))
    height = sample_surface(group, support, components["Z"], "FLOAT", coordinates, coordinates)
    normal = nodes.new("GeometryNodeInputNormal").outputs[0]
    normal_blur = nodes.new("GeometryNodeBlurAttribute")
    normal_blur.data_type = "FLOAT_VECTOR"
    links.new(evaluate_field(group, normal, "FLOAT_VECTOR", "POINT"), normal_blur.inputs["Value"])
    links.new(controls.outputs["Center Smooth"], normal_blur.inputs["Iterations"])
    normal = normal_blur.outputs[0]
    normal = vector(group, "NORMALIZE", sample_surface(group, support, normal, "FLOAT_VECTOR", coordinates, coordinates))
    return {"geometry": support, "preview": support, "height": height, "normal": normal}