import sys

import bpy


def mesh_object(name: str):
    mesh = bpy.data.meshes.new(f"{name}Mesh")
    mesh.from_pydata(
        [(-1.0, -1.0, 0.0), (1.0, -1.0, 0.0), (0.0, 1.0, 0.0)],
        [],
        [(0, 1, 2)],
    )
    mesh.update()
    obj = bpy.data.objects.new(name, mesh)
    bpy.context.collection.objects.link(obj)
    return obj


def location_action(name: str, axis: int):
    action = bpy.data.actions.new(name)
    slot = action.slots.new("OBJECT", "M10NlaTimeMapping")
    layer = action.layers.new("M10 NLA Keys")
    keyframe_strip = layer.strips.new(type="KEYFRAME")
    channelbag = keyframe_strip.channelbags.new(slot)
    curve = channelbag.fcurves.new(data_path="location", index=axis)
    curve.keyframe_points.add(2)
    curve.keyframe_points[0].co = (1.0, 0.0)
    curve.keyframe_points[1].co = (11.0, 10.0)
    for keyframe in curve.keyframe_points:
        keyframe.interpolation = "LINEAR"
    action.frame_start = 1.0
    action.frame_end = 11.0
    return action, slot


def configure_strip(strip, slot, *, frame_start, frame_end, scale, repeat, reverse):
    strip.action_slot = slot
    strip.action_frame_start = 1.0
    strip.action_frame_end = 11.0
    strip.frame_start = frame_start
    strip.frame_end = frame_end
    strip.scale = scale
    strip.repeat = repeat
    strip.blend_type = "REPLACE"
    strip.extrapolation = "NOTHING"
    strip.use_reverse = reverse
    strip.influence = 1.0
    strip.blend_in = 0.0
    strip.blend_out = 0.0


def main(output_path: str) -> None:
    bpy.ops.wm.read_factory_settings(use_empty=True)
    scene = bpy.context.scene
    scene.frame_start = 1
    scene.frame_end = 70

    obj = mesh_object("M10_NLA_TimeMapping")
    animation_data = obj.animation_data_create()
    track = animation_data.nla_tracks.new()
    track.name = "M10 Time Mapping"

    scaled_action, scaled_slot = location_action("M10_NLA_Scaled_X", 0)
    scaled_strip = track.strips.new("M10 Scaled Clip", 20, scaled_action)
    configure_strip(
        scaled_strip,
        scaled_slot,
        frame_start=20.0,
        frame_end=40.0,
        scale=2.0,
        repeat=1.0,
        reverse=False,
    )

    reverse_repeat_action, reverse_repeat_slot = location_action("M10_NLA_ReverseRepeat_Y", 1)
    reverse_repeat_strip = track.strips.new("M10 Reverse Repeat Clip", 45, reverse_repeat_action)
    configure_strip(
        reverse_repeat_strip,
        reverse_repeat_slot,
        frame_start=45.0,
        frame_end=65.0,
        scale=1.0,
        repeat=2.0,
        reverse=True,
    )

    scene.frame_set(1)
    bpy.ops.wm.save_as_mainfile(filepath=output_path, compress=True)


if __name__ == "__main__":
    if "--" not in sys.argv or len(sys.argv) <= sys.argv.index("--") + 1:
        raise SystemExit("usage: blender -b --python generate-nla-evaluation-fixture.py -- output.blend")
    main(sys.argv[sys.argv.index("--") + 1])