#!/usr/bin/env python3
import pathlib
import sys

import bpy


def delete_channels_action(obj):
    bpy.context.view_layer.objects.active = obj
    obj.select_set(True)
    action = obj.animation_data.action
    for layer in action.layers:
        for strip in layer.strips:
            for bag in strip.channelbags:
                for curve in bag.fcurves:
                    curve.select = curve.array_index == 0
    window = bpy.context.window
    screen = window.screen
    area = next(
        (candidate for candidate in screen.areas
         if candidate.type == "DOPESHEET_EDITOR" and candidate.height >= 200),
        None,
    )
    if area is None:
        area = next(candidate for candidate in screen.areas if candidate.type == "VIEW_3D")
        area.type = "DOPESHEET_EDITOR"
    area.spaces.active.ui_mode = "ACTION"
    region = next(candidate for candidate in area.regions if candidate.type == "WINDOW")
    with bpy.context.temp_override(window=window, screen=screen, area=area, region=region):
        if not bpy.ops.anim.channels_delete.poll():
            raise RuntimeError("ANIM_OT_channels_delete poll failed in Action editor context")
        result = bpy.ops.anim.channels_delete()
        if "FINISHED" not in result:
            raise RuntimeError(f"ANIM_OT_channels_delete returned {result}")


if __name__ == "__main__":
    arguments = sys.argv[sys.argv.index("--") + 1 :]
    if len(arguments) != 1:
        raise SystemExit("usage: blender -b --factory-startup --python M16-GAP-00157.py -- OUTPUT")
    bpy.ops.wm.read_factory_settings(use_empty=True)
    mesh = bpy.data.meshes.new("WebGapAnimChannelsDeleteMesh")
    mesh.from_pydata(
        [(-1.0, -1.0, 0.0), (1.0, -1.0, 0.0), (1.0, 1.0, 0.0), (-1.0, 1.0, 0.0)],
        [],
        [(0, 1, 2, 3)],
    )
    obj = bpy.data.objects.new("WebGapAnimChannelsDeleteObject", mesh)
    bpy.context.scene.collection.objects.link(obj)
    for frame, location in ((1, (0.0, 0.0, 0.0)), (3, (2.0, 3.0, 4.0)), (5, (4.0, 6.0, 8.0))):
        obj.location = location
        obj.keyframe_insert(data_path="location", frame=frame, index=0)
    bpy.context.scene.frame_start = 1
    bpy.context.scene.frame_end = 5
    delete_channels_action(obj)
    if len(obj.animation_data.action.layers[0].strips[0].channelbags[0].fcurves) != 0:
        raise RuntimeError("selected animation channel was not deleted")
    bpy.ops.wm.save_as_mainfile(
        filepath=str(pathlib.Path(arguments[0]).resolve()), check_existing=False, compress=True
    )