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

import bpy


def graph_report():
    material = bpy.data.materials.get("WebGapNodeTreeMaterial")
    if material is None or not material.use_nodes:
        raise RuntimeError("WebGapNodeTreeMaterial is missing")
    tree = material.node_tree
    return {
        "id": "nodetree:WebGapNodeTreeMaterial",
        "name": tree.name,
        "nodeTypes": sorted(node.bl_idname for node in tree.nodes),
        "nodeNames": sorted(node.name for node in tree.nodes),
        "linkCount": len(tree.links),
        "links": sorted([[link.from_node.bl_idname, link.from_socket.name, link.to_node.bl_idname, link.to_socket.name] for link in tree.links]),
    }


def main():
    arguments = sys.argv[sys.argv.index("--") + 1 :]
    if len(arguments) != 2:
        raise SystemExit("usage: blender -b --python check-nodetree-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 = graph_report()
    descriptor, temporary = tempfile.mkstemp(prefix="m16-nodetree-reopen-", suffix=".blend", dir=fixture.parent)
    os.close(descriptor)
    try:
        bpy.ops.wm.save_as_mainfile(filepath=temporary, check_existing=False, compress=True)
        bpy.ops.wm.open_mainfile(filepath=temporary, load_ui=False)
        after = graph_report()
    finally:
        pathlib.Path(temporary).unlink(missing_ok=True)
    if before != after:
        raise RuntimeError(f"node tree save/reopen drift: {before} != {after}")
    report = {"schemaVersion": 1, "task": "M16-GAP-00016", "operation": "NODETREE_DATABLOCK_DESKTOP", "fixture": str(fixture), "fixtureSha256": hashlib.sha256(fixture.read_bytes()).hexdigest(), "nodeTree": after, "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"nodetree-desktop-ok id={after['id']} nodes={len(after['nodeTypes'])} links={after['linkCount']} saveReopen=exact")


if __name__ == "__main__":
    main()