#!/usr/bin/env python3
import hashlib
import json
import os
import pathlib
import shutil
import sys
import tempfile

import bpy


ARMATURE_NAME = "WebGapArmatureParentClearArmature"
OBJECT_NAME = "WebGapArmatureParentClearObject"
PARENT_BONE = "WebGapArmatureParentClearParent"
CHILD_BONE = "WebGapArmatureParentClearChild"
OTHER_BONE = "WebGapArmatureParentClearOther"


def ensure_edit_mode():
    obj = bpy.data.objects.get(OBJECT_NAME)
    armature = bpy.data.armatures.get(ARMATURE_NAME)
    if armature is None or obj is None or obj.type != "ARMATURE" or obj.data != armature:
        raise RuntimeError("armature.parent_clear fixture is missing")
    bpy.context.view_layer.objects.active = obj
    obj.select_set(True)
    if obj.mode != "EDIT":
        bpy.ops.object.mode_set(mode="EDIT")
    return armature


def bone_report(bone):
    return {
        "name": bone.name,
        "selected": bool(bone.select),
        "hidden": bool(bone.hide),
        "selectHead": bool(bone.select_head),
        "selectTail": bool(bone.select_tail),
        "parent": bone.parent.name if bone.parent else None,
        "connected": bool(bone.use_connect),
        "head": [round(value, 6) for value in bone.head],
        "tail": [round(value, 6) for value in bone.tail],
    }


def state_report():
    armature = ensure_edit_mode()
    return {
        "object": OBJECT_NAME,
        "armature": ARMATURE_NAME,
        "activeBone": armature.edit_bones.active.name if armature.edit_bones.active else None,
        "bones": [bone_report(bone) for bone in armature.edit_bones],
    }


def stable_state(state):
    return {
        "object": state["object"],
        "armature": state["armature"],
        "activeBone": state["activeBone"],
        "bones": sorted(
            [
                {key: bone[key] for key in ("name", "selected", "hidden", "parent", "connected", "head", "tail")}
                for bone in state["bones"]
            ],
            key=lambda bone: bone["name"],
        ),
    }


def validate_input(before):
    by_name = {bone["name"]: bone for bone in before["bones"]}
    if set(by_name) != {PARENT_BONE, CHILD_BONE, OTHER_BONE}:
        raise RuntimeError(f"unexpected armature.parent_clear bones: {before}")
    parent, child, other = by_name[PARENT_BONE], by_name[CHILD_BONE], by_name[OTHER_BONE]
    if child["parent"] == PARENT_BONE and child["connected"] and child["selected"] and not parent["selected"] and not other["selected"]:
        return False
    if child["parent"] is None and not child["connected"] and child["selected"] and other["parent"] is None:
        return True
    raise RuntimeError(f"unexpected armature.parent_clear state: {before}")


def run_operator(already_cleared):
    ensure_edit_mode()
    poll = bool(bpy.ops.armature.parent_clear.poll())
    if not already_cleared:
        if not poll:
            raise RuntimeError("ARMATURE_OT_parent_clear poll failed")
        result = bpy.ops.armature.parent_clear(type="CLEAR")
        if result != {"FINISHED"}:
            raise RuntimeError(f"ARMATURE_OT_parent_clear returned {result}")
    return poll, not already_cleared


def validate_after(after):
    by_name = {bone["name"]: bone for bone in after["bones"]}
    parent, child, other = by_name[PARENT_BONE], by_name[CHILD_BONE], by_name[OTHER_BONE]
    if child["parent"] is not None or child["connected"] or not child["selected"]:
        raise RuntimeError(f"armature.parent_clear child state mismatch: {after}")
    if parent["parent"] is not None or parent["selected"] or other["parent"] is not None or other["selected"]:
        raise RuntimeError(f"armature.parent_clear changed independent bones: {after}")
    if child["head"] != [0.0, 1.0, 0.0] or child["tail"] != [0.0, 2.0, 0.0]:
        raise RuntimeError(f"armature.parent_clear changed child geometry: {after}")
    if parent["head"] != [0.0, 0.0, 0.0] or parent["tail"] != [0.0, 1.0, 0.0]:
        raise RuntimeError(f"armature.parent_clear changed parent geometry: {after}")
    if other["head"] != [2.0, 0.0, 0.0] or other["tail"] != [2.0, 1.0, 0.0]:
        raise RuntimeError(f"armature.parent_clear changed independent geometry: {after}")


def main():
    arguments = sys.argv[sys.argv.index("--") + 1 :]
    if len(arguments) != 2:
        raise SystemExit(
            "usage: blender -b --factory-startup --python check-action-armature-parent-clear-desktop.py -- FIXTURE REPORT"
        )
    fixture, output = (pathlib.Path(value).resolve() for value in arguments)
    bpy.ops.wm.open_mainfile(filepath=str(fixture), load_ui=False)
    before = state_report()
    already_cleared = validate_input(before)
    poll, changed = run_operator(already_cleared)
    after = state_report()
    validate_after(after)

    bpy.ops.object.mode_set(mode="OBJECT")
    descriptor, temporary = tempfile.mkstemp(prefix="m16-armature-parent-clear-reopen-", suffix=".blend")
    os.close(descriptor)
    temporary_path = pathlib.Path(temporary)
    try:
        bpy.ops.wm.save_as_mainfile(filepath=str(temporary_path), check_existing=False, compress=True)
        bpy.ops.wm.open_mainfile(filepath=str(temporary_path), load_ui=False)
        reopened = state_report()
        if stable_state(reopened) != stable_state(after):
            raise RuntimeError(f"armature.parent_clear save/reopen drift: {after} != {reopened}")
        shutil.copyfile(temporary_path, fixture)
        report = {
            "schemaVersion": 1,
            "task": "M16-GAP-00246",
            "operation": "ARMATURE_PARENT_CLEAR_DESKTOP",
            "fixture": str(fixture),
            "fixtureSha256": hashlib.sha256(fixture.read_bytes()).hexdigest(),
            "before": before,
            "after": reopened,
            "parentBone": PARENT_BONE,
            "childBone": CHILD_BONE,
            "clearType": "CLEAR",
            "poll": poll,
            "operatorStatus": "FINISHED" if changed else "SKIPPED_ALREADY_APPLIED",
            "mainMutation": "SELECTED_CHILD_PARENT_CLEARED" if changed else "SELECTED_CHILD_PARENT_ALREADY_CLEARED",
            "saveReopen": "EXACT",
            "blenderVersion": bpy.app.version_string,
        }
        output.parent.mkdir(parents=True, exist_ok=True)
        output.write_text(json.dumps(report, indent=2, sort_keys=True) + "\n", encoding="utf-8")
        print(f"armature-parent-clear-desktop-ok child={CHILD_BONE} parentCleared=true saveReopen=exact")
    finally:
        temporary_path.unlink(missing_ok=True)


if __name__ == "__main__":
    try:
        main()
    except Exception as error:
        print(f"armature-parent-clear-desktop-failed: {error}")
        raise SystemExit(1)