import pathlib
import sys

import bpy


SCENES = (
    ("M11 Constant", (0.125, 0.25, 0.5, 0.75), ()),
    ("M11 Exposure", (0.125, 0.25, 0.5, 0.75), (("EXPOSURE", 1.0),)),
    ("M11 Invert", (0.125, 0.25, 0.5, 0.75), (("INVERT", None),)),
    ("M11 Chain", (0.125, 0.25, 0.5, 0.75), (("EXPOSURE", 1.0), ("INVERT", None))),
)


def add_graph(scene, color_value, operations):
    tree = bpy.data.node_groups.new(f"{scene.name} Tree", "CompositorNodeTree")
    scene.compositing_node_group = tree
    tree.interface.new_socket(name="Image", in_out="OUTPUT", socket_type="NodeSocketColor")
    color = tree.nodes.new("CompositorNodeRGB")
    color.name = f"{scene.name} Constant"
    color.outputs["Color"].default_value = color_value
    previous = color.outputs["Color"]
    for index, (operation, parameter) in enumerate(operations):
        if operation == "EXPOSURE":
            node = tree.nodes.new("CompositorNodeExposure")
            node.inputs["Exposure"].default_value = parameter
        else:
            node = tree.nodes.new("CompositorNodeInvert")
        node.name = f"{scene.name} {operation.title()} {index}"
        tree.links.new(previous, node.inputs["Image" if operation == "EXPOSURE" else "Color"])
        previous = node.outputs["Image" if operation == "EXPOSURE" else "Color"]
    output = tree.nodes.new("NodeGroupOutput")
    output.name = f"{scene.name} Composite"
    tree.links.new(previous, output.inputs["Image"])


def main(output_path):
    bpy.ops.wm.read_factory_settings(use_empty=True)
    first = bpy.context.scene
    for index, (name, color, operations) in enumerate(SCENES):
        scene = first if index == 0 else bpy.data.scenes.new(name)
        scene.name = name
        add_graph(scene, color, operations)
    output = pathlib.Path(output_path).resolve()
    output.parent.mkdir(parents=True, exist_ok=True)
    bpy.ops.wm.save_as_mainfile(filepath=str(output), compress=True)
    print(f"m11-compositor-allowlist fixture={output} scenes={len(SCENES)}")


if __name__ == "__main__":
    arguments = sys.argv[sys.argv.index("--") + 1:]
    if len(arguments) != 1:
        raise SystemExit("usage: blender -b --python generate-m11-compositor-allowlist.py -- OUTPUT")
    main(arguments[0])