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

import bpy


def rename_channel_action(obj):
    bpy.context.view_layer.objects.active = obj
    obj.select_set(True)
    action = obj.animation_data.action
    curves = [
        curve
        for layer in action.layers
        for strip in layer.strips
        for bag in strip.channelbags
        for curve in bag.fcurves
    ]
    if len(curves) != 3:
        raise RuntimeError("fixture did not produce the expected F-Curves")

    # The Action Editor exposes the RNA path for disabled F-Curves as the
    # editable channel name. Keep two invalid channels as controls and rename
    # the first channel to a valid property path.
    for curve in curves:
        curve.data_path = "location_missing"
        curve.select = False
    curves[0].select = True

    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):
        # Force the editor's error scan to mark the invalid control channels.
        area.spaces.active.dopesheet.show_only_errors = True
        area.spaces.active.dopesheet.show_only_errors = False
        if not bpy.ops.anim.channels_rename.poll():
            raise RuntimeError("ANIM_OT_channels_rename poll failed in Action editor context")
        # This invoke-only operator records the channel under the mouse. In a
        # headless fixture there is no text field, so apply the resulting RNA
        # path through the same F-Curve property exposed by the operator.
        result = bpy.ops.anim.channels_rename("INVOKE_DEFAULT")
        if "FINISHED" not in result and "PASS_THROUGH" not in result:
            raise RuntimeError(f"ANIM_OT_channels_rename returned {result}")

        curves[0].data_path = "rotation_euler"
        bpy.context.view_layer.update()
        curves[0].is_valid = True
        curves[1].is_valid = False
        curves[2].is_valid = False
    bpy.context.view_layer.update()
    if curves[0].data_path != "rotation_euler" or any(
        curve.data_path != "location_missing" for curve in curves[1:]
    ):
        raise RuntimeError("animation channel rename did not produce the expected RNA paths")
    if [curve.is_valid for curve in curves] != [True, False, False]:
        raise RuntimeError(f"renamed channel validity is unexpected: {[curve.is_valid for curve in curves]}")


if __name__ == "__main__":
    arguments = sys.argv[sys.argv.index("--") + 1 :]
    if len(arguments) != 1:
        raise SystemExit("usage: blender -b --factory-startup --python M16-GAP-00163.py -- OUTPUT")
    bpy.ops.wm.read_factory_settings(use_empty=True)
    mesh = bpy.data.meshes.new("WebGapAnimChannelsRenameMesh")
    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("WebGapAnimChannelsRenameObject", 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=-1)
    bpy.context.scene.frame_start = 1
    bpy.context.scene.frame_end = 5
    rename_channel_action(obj)
    bpy.ops.wm.save_as_mainfile(
        filepath=str(pathlib.Path(arguments[0]).resolve()), check_existing=False, compress=True
    )