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

import bpy


ARMATURE_NAME = "WebGapArmatureDissolveArmature"
OBJECT_NAME = "WebGapArmatureDissolveObject"
ROOT_BONE = "WebGapArmatureDissolveRoot"
MIDDLE_BONE = "WebGapArmatureDissolveMiddle"
TIP_BONE = "WebGapArmatureDissolveTip"
OTHER_BONE = "WebGapArmatureDissolveOther"
EXPECTED_AFTER = [ROOT_BONE, OTHER_BONE]


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.dissolve 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),
        "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 run_operator(already_dissolved):
    ensure_edit_mode()
    poll = bool(bpy.ops.armature.dissolve.poll())
    if not already_dissolved:
        if not poll:
            raise RuntimeError("ARMATURE_OT_dissolve poll failed")
        result = bpy.ops.armature.dissolve()
        if result != {"FINISHED"}:
            raise RuntimeError(f"ARMATURE_OT_dissolve returned {result}")
    return poll, not already_dissolved


def validate_input(before):
    names = [bone["name"] for bone in before["bones"]]
    if names == [ROOT_BONE, MIDDLE_BONE, TIP_BONE, OTHER_BONE]:
        if before["activeBone"] != MIDDLE_BONE:
            raise RuntimeError(f"unexpected armature.dissolve active bone: {before}")
        selected = [bone["name"] for bone in before["bones"] if bone["selected"]]
        if selected != [MIDDLE_BONE, TIP_BONE]:
            raise RuntimeError(f"unexpected armature.dissolve selection: {before}")
        if not all(bone["connected"] for bone in before["bones"][1:3]):
            raise RuntimeError(f"unexpected armature.dissolve connections: {before}")
        return False
    if names == EXPECTED_AFTER:
        if before["activeBone"] is not None:
            raise RuntimeError(f"unexpected armature.dissolve completed active bone: {before}")
        if any(bone["selected"] for bone in before["bones"]):
            raise RuntimeError(f"unexpected armature.dissolve completed selection: {before}")
        return True
    raise RuntimeError(f"unexpected armature.dissolve bones: {before}")


def validate_after(after):
    if [bone["name"] for bone in after["bones"]] != EXPECTED_AFTER:
        raise RuntimeError(f"armature.dissolve did not remove the selected tip: {after}")
    root, other = after["bones"]
    if after["activeBone"] is not None or any(bone["selected"] for bone in after["bones"]):
        raise RuntimeError(f"armature.dissolve left unexpected active or selection state: {after}")
    if root["parent"] is not None or other["parent"] is not None or other["connected"]:
        raise RuntimeError(f"armature.dissolve changed unexpected parent state: {after}")
    if root["head"] != [0.0, 0.0, 0.0] or root["tail"] != [0.0, 3.0, 0.0]:
        raise RuntimeError(f"armature.dissolve changed root geometry: {after}")
    if other["head"] != [2.0, 0.0, 0.0] or other["tail"] != [2.0, 1.0, 0.0]:
        raise RuntimeError(f"armature.dissolve changed the independent bone: {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-dissolve-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_dissolved = validate_input(before)
    poll, changed = run_operator(already_dissolved)
    after = state_report()
    validate_after(after)

    bpy.ops.object.mode_set(mode="OBJECT")
    descriptor, temporary = tempfile.mkstemp(prefix="m16-armature-dissolve-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 reopened != after:
            raise RuntimeError(f"armature.dissolve save/reopen drift: {after} != {reopened}")
        shutil.copyfile(temporary_path, fixture)
        report = {
            "schemaVersion": 1,
            "task": "M16-GAP-00235",
            "operation": "ARMATURE_DISSOLVE_DESKTOP",
            "fixture": str(fixture),
            "fixtureSha256": hashlib.sha256(fixture.read_bytes()).hexdigest(),
            "before": before,
            "after": reopened,
            "dissolvedBone": TIP_BONE,
            "poll": poll,
            "operatorStatus": "FINISHED" if changed else "SKIPPED_ALREADY_APPLIED",
            "mainMutation": "CONNECTED_TIP_DISSOLVED" if changed else "CONNECTED_TIP_ALREADY_DISSOLVED",
            "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-dissolve-desktop-ok dissolved={TIP_BONE} saveReopen=exact")
    finally:
        temporary_path.unlink(missing_ok=True)


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