"""Face separation and connected thickness for Depth Surface assets."""

from .nodes import evaluate_field, store_float_attribute, store_boolean_attribute, remove_attribute_pattern, sample_field


CUT_ATTRIBUTE = "_o_anyimage_depth_cut"


def _math(group, operation, a, b=None):
    node = group.nodes.new("ShaderNodeMath")
    node.operation = operation
    for index, value in enumerate((a, b)):
        if value is None:
            continue
        if isinstance(value, (int, float)):
            node.inputs[index].default_value = value
        else:
            group.links.new(value, node.inputs[index])
    return node.outputs[0]


def _remove_strip_faces(group, geometry, *, triangles=False):
    """Delete boundary strips from one unchanged topology snapshot."""
    if triangles:
        return _remove_triangle_strip_faces(group, geometry)
    return _remove_quad_strip_faces(group, geometry)


def _remove_quad_strip_faces(group, geometry):
    """Delete boundary quad strips while preserving open boundary edges."""
    nodes, links = group.nodes, group.links

    def equals(value, count):
        compare = nodes.new("FunctionNodeCompare")
        compare.data_type, compare.operation = "INT", "EQUAL"
        links.new(value, compare.inputs[2])
        if isinstance(count, int):
            compare.inputs[3].default_value = count
        else:
            links.new(count, compare.inputs[3])
        return compare.outputs["Result"]

    def combine(operation, a, b):
        node = nodes.new("FunctionNodeIntegerMath")
        node.operation = operation
        links.new(a, node.inputs[0])
        links.new(b, node.inputs[1])
        return node.outputs[0]

    boundaries = []
    for offset in range(4):
        index = nodes.new("GeometryNodeInputIndex")
        corners = nodes.new("GeometryNodeCornersOfFace")
        links.new(index.outputs[0], corners.inputs["Face Index"])
        corner = nodes.new("GeometryNodeOffsetCornerInFace")
        corner.inputs["Offset"].default_value = offset
        links.new(corners.outputs["Corner Index"], corner.inputs["Corner Index"])
        edge = nodes.new("GeometryNodeEdgesOfCorner")
        links.new(corner.outputs["Corner Index"], edge.inputs["Corner Index"])
        sample = nodes.new("GeometryNodeFieldAtIndex")
        sample.data_type, sample.domain = "INT", "EDGE"
        links.new(edge.outputs["Next Edge Index"], sample.inputs["Index"])
        neighbors = nodes.new("GeometryNodeInputMeshEdgeNeighbors")
        links.new(neighbors.outputs["Face Count"], sample.inputs["Value"])
        boundaries.append(equals(sample.outputs["Value"], 1))
    opposite = combine(
        "MAXIMUM",
        combine("MULTIPLY", boundaries[0], boundaries[2]),
        combine("MULTIPLY", boundaries[1], boundaries[3]),
    )
    face = nodes.new("GeometryNodeInputMeshFaceNeighbors")
    selected = combine("MULTIPLY", equals(face.outputs["Vertex Count"], 4), opposite)
    delete = nodes.new("GeometryNodeDeleteGeometry")
    delete.domain, delete.mode = "FACE", "ALL"
    links.new(geometry, delete.inputs["Geometry"])
    links.new(selected, delete.inputs["Selection"])
    return delete.outputs["Geometry"]


def _remove_triangle_strip_faces(group, geometry):
    """Delete symmetric triangle strip pairs and all-boundary ears."""
    nodes, links = group.nodes, group.links

    def equals(value, count):
        compare = nodes.new("FunctionNodeCompare")
        compare.data_type, compare.operation = "INT", "EQUAL"
        links.new(value, compare.inputs[2])
        if isinstance(count, int):
            compare.inputs[3].default_value = count
        else:
            links.new(count, compare.inputs[3])
        return compare.outputs["Result"]

    def combine(operation, a, b):
        node = nodes.new("FunctionNodeIntegerMath")
        node.operation = operation
        links.new(a, node.inputs[0])
        links.new(b, node.inputs[1])
        return node.outputs[0]

    def sample(value, index, domain):
        node = nodes.new("GeometryNodeFieldAtIndex")
        node.data_type, node.domain = "INT", domain
        links.new(value, node.inputs["Value"])
        links.new(index, node.inputs["Index"])
        return node.outputs["Value"]

    def offset_corner(corner, offset):
        node = nodes.new("GeometryNodeOffsetCornerInFace")
        links.new(corner, node.inputs["Corner Index"])
        node.inputs["Offset"].default_value = offset
        return node.outputs["Corner Index"]

    def vertex(corner):
        node = nodes.new("GeometryNodeVertexOfCorner")
        links.new(corner, node.inputs["Corner Index"])
        return node.outputs["Vertex Index"]

    def boundary(corner):
        edge = nodes.new("GeometryNodeEdgesOfCorner")
        links.new(corner, edge.inputs["Corner Index"])
        count = nodes.new("GeometryNodeInputMeshEdgeNeighbors")
        return equals(sample(count.outputs["Face Count"], edge.outputs["Next Edge Index"], "EDGE"), 1)

    edge_index = nodes.new("GeometryNodeInputIndex")
    sides = []
    for side in (0, 1):
        corners = nodes.new("GeometryNodeCornersOfEdge")
        links.new(edge_index.outputs[0], corners.inputs["Edge Index"])
        corners.inputs["Sort Index"].default_value = side
        corner = corners.outputs["Corner Index"]
        face_index = nodes.new("GeometryNodeFaceOfCorner")
        links.new(corner, face_index.inputs["Corner Index"])
        face_size = nodes.new("GeometryNodeInputMeshFaceNeighbors")
        triangle = equals(sample(face_size.outputs["Vertex Count"], face_index.outputs["Face Index"], "FACE"), 3)
        end, tip = offset_corner(corner, 1), offset_corner(corner, 2)
        sides.append((triangle, vertex(corner), vertex(tip), boundary(end), boundary(tip)))
    a, b = sides
    same_direction = equals(a[1], b[1])
    same_order = combine("MAXIMUM", combine("MULTIPLY", a[3], b[3]), combine("MULTIPLY", a[4], b[4]))
    reverse_order = combine("MAXIMUM", combine("MULTIPLY", a[3], b[4]), combine("MULTIPLY", a[4], b[3]))
    pair = combine(
        "MAXIMUM",
        combine("MULTIPLY", same_direction, reverse_order),
        combine("MULTIPLY", equals(same_direction, 0), same_order),
    )
    neighbors = nodes.new("GeometryNodeInputMeshEdgeNeighbors")
    for condition in (equals(neighbors.outputs["Face Count"], 2), a[0], b[0], equals(equals(a[2], b[2]), 0)):
        pair = combine("MULTIPLY", pair, condition)

    face_index = nodes.new("GeometryNodeInputIndex")
    corners = nodes.new("GeometryNodeCornersOfFace")
    links.new(face_index.outputs[0], corners.inputs["Face Index"])
    boundary_count, paired = None, None
    for offset in range(3):
        corner = offset_corner(corners.outputs["Corner Index"], offset)
        edge = nodes.new("GeometryNodeEdgesOfCorner")
        links.new(corner, edge.inputs["Corner Index"])
        match = sample(pair, edge.outputs["Next Edge Index"], "EDGE")
        paired = match if paired is None else combine("MAXIMUM", paired, match)
        rim = boundary(corner)
        boundary_count = rim if boundary_count is None else combine("ADD", boundary_count, rim)
    selected = combine(
        "MULTIPLY",
        equals(corners.outputs["Total"], 3),
        combine("MAXIMUM", paired, equals(boundary_count, 3)),
    )
    delete = nodes.new("GeometryNodeDeleteGeometry")
    delete.domain, delete.mode = "FACE", "ALL"
    links.new(geometry, delete.inputs["Geometry"])
    links.new(selected, delete.inputs["Selection"])
    return delete.outputs["Geometry"]


def sample_face_camera(group, image):
    """Sample camera XYZ at each planar face's UV center."""
    nodes, links = group.nodes, group.links
    uv = nodes.new("GeometryNodeInputNamedAttribute")
    uv.data_type = "FLOAT_VECTOR"
    uv.inputs["Name"].default_value = "UVMap"
    face_uv = nodes.new("GeometryNodeFieldOnDomain")
    face_uv.data_type = "FLOAT_VECTOR"
    face_uv.domain = "FACE"
    links.new(uv.outputs["Attribute"], face_uv.inputs["Value"])
    texture = nodes.new("GeometryNodeImageTexture")
    texture.interpolation = "Linear"
    texture.extension = "EXTEND"
    links.new(image, texture.inputs["Image"])
    links.new(face_uv.outputs["Value"], texture.inputs["Vector"])
    return texture.outputs["Color"]


def ray_distance(group, camera):
    """Measure the distance from the camera origin to a camera-space point."""
    length = group.nodes.new("ShaderNodeVectorMath")
    length.operation = "LENGTH"
    group.links.new(camera, length.inputs[0])
    return length.outputs["Value"]


def split_depth_surface(group, geometry, face_camera, strength, reference_depth, *,
                        face_distance=None, face_center=None, triangles=False):
    """Split relative ray-distance jumps over the base face-center spacing."""
    nodes, links = group.nodes, group.links
    if face_center is None:
        face_center = nodes.new("GeometryNodeInputPosition").outputs[0]
    face_camera = evaluate_field(group, face_camera, "FLOAT_VECTOR", "FACE")
    if face_distance is None:
        face_distance = ray_distance(group, face_camera)
    centers, depths = [], []
    for side in (0, 1):
        corner = nodes.new("GeometryNodeCornersOfEdge")
        corner.inputs["Sort Index"].default_value = side
        face = nodes.new("GeometryNodeFaceOfCorner")
        links.new(corner.outputs["Corner Index"], face.inputs["Corner Index"])
        for data_type, field, results in (
            ("FLOAT_VECTOR", face_center, centers),
            ("FLOAT", face_distance, depths),
        ):
            sample = nodes.new("GeometryNodeFieldAtIndex")
            sample.data_type = data_type
            sample.domain = "FACE"
            links.new(face.outputs["Face Index"], sample.inputs["Index"])
            links.new(field, sample.inputs["Value"])
            results.append(sample.outputs["Value"])
    distance = nodes.new("ShaderNodeVectorMath")
    distance.operation = "DISTANCE"
    for index, center in enumerate(centers):
        links.new(center, distance.inputs[index])
    delta = _math(group, "ABSOLUTE", _math(group, "SUBTRACT", *depths))
    local_distance = _math(group, "MAXIMUM", _math(group, "MULTIPLY", _math(group, "ADD", *depths), 0.5), 1e-8)
    reference = _math(group, "MAXIMUM", reference_depth, 1e-8)
    # Uniform Scale cancels between the distance jump and local spacing correction.
    # Cross multiplication also avoids dividing by the local distance.
    selected = _math(
        group,
        "GREATER_THAN",
        _math(group, "MULTIPLY", _math(group, "MULTIPLY", delta, reference), strength),
        _math(group, "MULTIPLY", _math(group, "MULTIPLY", distance.outputs["Value"], local_distance), 2.5),
    )
    selected = _math(
        group,
        "MULTIPLY",
        selected,
        _math(group, "GREATER_THAN", distance.outputs["Value"], 0.0),
    )
    neighbors = nodes.new("GeometryNodeInputMeshEdgeNeighbors")
    selected = _math(
        group,
        "MULTIPLY",
        selected,
        _math(group, "COMPARE", neighbors.outputs["Face Count"], 2.0),
    )
    cut_edges = nodes.new("GeometryNodeFieldOnDomain")
    cut_edges.data_type = "FLOAT"
    cut_edges.domain = "EDGE"
    links.new(selected, cut_edges.inputs["Value"])
    cut_vertices = nodes.new("GeometryNodeFieldOnDomain")
    cut_vertices.data_type = "FLOAT"
    cut_vertices.domain = "POINT"
    links.new(cut_edges.outputs["Value"], cut_vertices.inputs["Value"])
    corners, cut = store_boolean_attribute(
        group, geometry, CUT_ATTRIBUTE,
        _math(group, "GREATER_THAN", cut_vertices.outputs["Value"], 0.0), domain="CORNER",
    )
    split = nodes.new("GeometryNodeSplitEdges")
    links.new(corners, split.inputs["Mesh"])
    links.new(selected, split.inputs["Selection"])
    enabled = _math(group, "GREATER_THAN", strength, 0.0)
    choose = nodes.new("GeometryNodeSwitch")
    choose.input_type = "GEOMETRY"
    links.new(enabled, choose.inputs["Switch"])
    links.new(geometry, choose.inputs["False"])
    links.new(_remove_strip_faces(group, split.outputs["Mesh"], triangles=triangles), choose.inputs["True"])
    return choose.outputs["Output"], face_camera, cut


def build_surface_camera(group, original, separated, cut_vertex, strength, *, always_vertex=None):
    """Change cut depth along the original ray, preserving every other vertex."""
    enabled = group.nodes.new("GeometryNodeSwitch")
    enabled.input_type = "BOOLEAN"
    group.links.new(_math(group, "GREATER_THAN", strength, 0.0), enabled.inputs["Switch"])
    enabled.inputs["False"].default_value = False
    group.links.new(cut_vertex, enabled.inputs["True"])
    if always_vertex is not None:
        combined = group.nodes.new("FunctionNodeBooleanMath")
        combined.operation = "OR"
        group.links.new(enabled.outputs["Output"], combined.inputs[0])
        group.links.new(always_vertex, combined.inputs[1])
        enabled = combined.outputs["Boolean"]
    else:
        enabled = enabled.outputs["Output"]
    original_axes = group.nodes.new("ShaderNodeSeparateXYZ")
    separated_axes = group.nodes.new("ShaderNodeSeparateXYZ")
    group.links.new(original, original_axes.inputs[0])
    group.links.new(separated, separated_axes.inputs[0])
    ratio = _math(
        group, "DIVIDE", separated_axes.outputs["Z"], original_axes.outputs["Z"]
    )
    projected = group.nodes.new("ShaderNodeVectorMath")
    projected.operation = "SCALE"
    group.links.new(original, projected.inputs[0])
    group.links.new(ratio, projected.inputs[3])
    choose = group.nodes.new("GeometryNodeSwitch")
    choose.input_type = "VECTOR"
    group.links.new(enabled, choose.inputs["Switch"])
    group.links.new(original, choose.inputs["False"])
    group.links.new(projected.outputs[0], choose.inputs["True"])
    return evaluate_field(group, choose.outputs["Output"], "FLOAT_VECTOR", "POINT")


def thicken_depth_surface(group, geometry, thickness, normal_smooth=None, *,
                          back_mask=None, weld_zero_thickness=False):
    """Connect caps with single quads by source vertex and cap identity."""
    nodes, links = group.nodes, group.links
    position = nodes.new("GeometryNodeInputPosition")
    index = nodes.new("GeometryNodeInputIndex")
    # Encode identity in the construction geometry before extrusion. The source
    # surface remains a separate sampling input; no position or ID is stored.
    identity = nodes.new("ShaderNodeCombineXYZ")
    for operation, axis in (("MODULO", "X"), ("DIVIDE", "Z")):
        part = nodes.new("FunctionNodeIntegerMath")
        part.operation = operation
        part.inputs[1].default_value = 4096
        links.new(index.outputs[0], part.inputs[0])
        links.new(part.outputs[0], identity.inputs[axis])
    sheet = nodes.new("GeometryNodeSetPosition")
    links.new(geometry, sheet.inputs["Geometry"])
    links.new(identity.outputs[0], sheet.inputs["Position"])
    saved = sheet.outputs["Geometry"]
    layer_axes = nodes.new("ShaderNodeSeparateXYZ")
    links.new(position.outputs[0], layer_axes.inputs[0])
    row = nodes.new("FunctionNodeIntegerMath")
    row.operation = "MULTIPLY"
    row.inputs[1].default_value = 4096
    links.new(layer_axes.outputs["Z"], row.inputs[0])
    vertex = nodes.new("FunctionNodeIntegerMath")
    vertex.operation = "ADD"
    links.new(layer_axes.outputs["X"], vertex.inputs[0])
    links.new(row.outputs[0], vertex.inputs[1])
    source_index = vertex.outputs[0]
    source_position = sample_field(group, geometry, position.outputs[0], "FLOAT_VECTOR", index=source_index)
    source_thickness = sample_field(group, geometry, thickness, "FLOAT", index=source_index)

    extrude = nodes.new("GeometryNodeExtrudeMesh")
    extrude.mode = "FACES"
    extrude.inputs["Individual"].default_value = False
    extrusion_offset = nodes.new("ShaderNodeCombineXYZ")
    extrusion_offset.inputs["Y"].default_value = -1.0
    links.new(extrusion_offset.outputs[0], extrude.inputs["Offset"])
    links.new(saved, extrude.inputs["Mesh"])
    sides = nodes.new("GeometryNodeSeparateGeometry")
    sides.domain = "FACE"
    links.new(extrude.outputs["Mesh"], sides.inputs["Geometry"])
    links.new(extrude.outputs["Side"], sides.inputs["Selection"])
    offset = nodes.new("ShaderNodeCombineXYZ")
    offset.inputs["Y"].default_value = -1.0
    back = nodes.new("GeometryNodeSetPosition")
    links.new(saved, back.inputs["Geometry"])
    links.new(offset.outputs[0], back.inputs["Offset"])
    flip_back = nodes.new("GeometryNodeFlipFaces")
    links.new(back.outputs["Geometry"], flip_back.inputs["Mesh"])
    flip_sides = nodes.new("GeometryNodeFlipFaces")
    links.new(sides.outputs["Selection"], flip_sides.inputs["Mesh"])
    join = nodes.new("GeometryNodeJoinGeometry")
    rear = flip_back.outputs["Mesh"]
    rim = flip_sides.outputs["Mesh"]
    back_parts = nodes.new("GeometryNodeJoinGeometry")
    links.new(rear, back_parts.inputs["Geometry"])
    links.new(rim, back_parts.inputs["Geometry"])
    rear = back_parts.outputs["Geometry"]
    if back_mask is not None:
        rear = store_float_attribute(group, rear, back_mask, 1.0)
    for value in (
        saved,
        rear,
    ):
        links.new(value, join.inputs["Geometry"])
    construction = join.outputs["Geometry"]
    if weld_zero_thickness:
        positive = _math(group, "GREATER_THAN", source_thickness, 1e-12)
        flattened = nodes.new("ShaderNodeCombineXYZ")
        for axis in ("X", "Z"):
            links.new(layer_axes.outputs[axis], flattened.inputs[axis])
        links.new(_math(group, "MULTIPLY", positive, layer_axes.outputs["Y"]), flattened.inputs["Y"])
        collapse = nodes.new("GeometryNodeSetPosition")
        links.new(construction, collapse.inputs["Geometry"])
        links.new(flattened.outputs[0], collapse.inputs["Position"])
        construction = collapse.outputs["Geometry"]
    merge = nodes.new("GeometryNodeMergeByDistance")
    merge.mode = "ALL"
    merge.inputs["Distance"].default_value = 0.1
    links.new(construction, merge.inputs["Geometry"])
    displacement = nodes.new("ShaderNodeCombineXYZ")
    distance = _math(group, "MULTIPLY", layer_axes.outputs["Y"], source_thickness)
    links.new(distance, displacement.inputs["Y"])
    restored = nodes.new("ShaderNodeVectorMath")
    restored.operation = "ADD"
    links.new(source_position, restored.inputs[0])
    links.new(displacement.outputs[0], restored.inputs[1])
    result = nodes.new("GeometryNodeSetPosition")
    links.new(merge.outputs["Geometry"], result.inputs["Geometry"])
    links.new(restored.outputs[0], result.inputs["Position"])
    if normal_smooth is not None:
        normal = nodes.new("GeometryNodeInputNormal")
        blur = nodes.new("GeometryNodeBlurAttribute")
        blur.data_type = "FLOAT_VECTOR"
        blur.inputs["Iterations"].default_value = normal_smooth
        links.new(normal.outputs[0], blur.inputs["Value"])
        normalize = nodes.new("ShaderNodeVectorMath")
        normalize.operation = "NORMALIZE"
        links.new(blur.outputs[0], normalize.inputs[0])
        source_normal = sample_field(group, geometry, normalize.outputs[0], "FLOAT_VECTOR", index=source_index)
        normal_offset = nodes.new("ShaderNodeVectorMath")
        normal_offset.operation = "SCALE"
        links.new(source_normal, normal_offset.inputs[0])
        links.new(distance, normal_offset.inputs[3])
        links.new(normal_offset.outputs[0], restored.inputs[1])
        nodes.remove(displacement)
    return {
        "geometry": result.outputs["Geometry"],
        "front": source_position,
        "source_index": source_index,
        "position": restored.outputs[0],
        "position_input": result.inputs["Position"],
    }


def _projection_math(nodes, operation):
    node = nodes.new("ShaderNodeMath")
    node.operation = operation
    return node


def project_depth_surface(
    group, geometry, camera_position, uniform_scale, reference_depth, depth_scale
):
    """Interpolate the rectangular plane into the model camera coordinates."""
    nodes, links = group.nodes, group.links
    scaled = nodes.new("ShaderNodeVectorMath")
    scaled.operation = "SCALE"
    links.new(camera_position, scaled.inputs[0])
    links.new(uniform_scale, scaled.inputs[3])
    separate = nodes.new("ShaderNodeSeparateXYZ")
    links.new(scaled.outputs["Vector"], separate.inputs["Vector"])
    relative_depth = _projection_math(nodes, "SUBTRACT")
    links.new(separate.outputs["Z"], relative_depth.inputs[0])
    links.new(reference_depth, relative_depth.inputs[1])
    front = _projection_math(nodes, "MULTIPLY")
    links.new(relative_depth.outputs[0], front.inputs[0])
    links.new(depth_scale, front.inputs[1])

    negative_z = _projection_math(nodes, "MULTIPLY")
    negative_z.inputs[1].default_value = -1.0
    links.new(separate.outputs["Y"], negative_z.inputs[0])
    projected = nodes.new("ShaderNodeCombineXYZ")
    links.new(separate.outputs["X"], projected.inputs["X"])
    links.new(front.outputs[0], projected.inputs["Y"])
    links.new(negative_z.outputs[0], projected.inputs["Z"])
    current_position = nodes.new("GeometryNodeInputPosition")
    blend = nodes.new("ShaderNodeMix")
    blend.data_type = "VECTOR"
    blend.clamp_factor = False
    links.new(depth_scale, blend.inputs[0])
    links.new(current_position.outputs["Position"], blend.inputs[4])
    links.new(projected.outputs["Vector"], blend.inputs[5])
    blended_axes = nodes.new("ShaderNodeSeparateXYZ")
    links.new(blend.outputs["Result"], blended_axes.inputs["Vector"])
    surface_position = nodes.new("ShaderNodeCombineXYZ")
    links.new(blended_axes.outputs["X"], surface_position.inputs["X"])
    links.new(front.outputs[0], surface_position.inputs["Y"])
    links.new(blended_axes.outputs["Z"], surface_position.inputs["Z"])
    project_geometry = nodes.new("GeometryNodeSetPosition")
    links.new(geometry, project_geometry.inputs["Geometry"])
    links.new(surface_position.outputs["Vector"], project_geometry.inputs["Position"])

    return remove_attribute_pattern(group, project_geometry.outputs["Geometry"], "_o_*")