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

import bpy


def rounded(value):
    return round(float(value), 6)


def socket_value(node, name, fallback):
    socket = node.inputs.get(name)
    if socket is None:
        return fallback
    value = socket.default_value
    if hasattr(value, "__len__"):
        return [rounded(item) for item in value]
    return rounded(value)


def material_report():
    material = bpy.data.materials.get("WebGapMaterial")
    if material is None or not material.use_nodes:
        raise RuntimeError("WebGapMaterial node tree is missing")
    nodes = material.node_tree.nodes
    principled = nodes.get("Principled BSDF")
    if principled is None:
        raise RuntimeError("WebGapMaterial Principled node is missing")
    return {
        "id": "material:WebGapMaterial",
        "name": material.name,
        "baseColor": socket_value(principled, "Base Color", [0.8, 0.8, 0.8, 1.0]),
        "roughness": socket_value(principled, "Roughness", 0.4),
        "metallic": socket_value(principled, "Metallic", 0.0),
        "emissionColor": socket_value(principled, "Emission Color", [0.0, 0.0, 0.0, 1.0]),
        "alpha": socket_value(principled, "Alpha", 1.0),
        "ior": socket_value(principled, "IOR", 1.45),
        "specularIORLevel": socket_value(principled, "Specular IOR Level", 0.5),
        "transmissionWeight": socket_value(principled, "Transmission Weight", 0.0),
        "coatWeight": socket_value(principled, "Coat Weight", 0.0),
        "coatRoughness": socket_value(principled, "Coat Roughness", 0.03),
        "emissionStrength": socket_value(principled, "Emission Strength", 1.0),
        "nodeTypes": sorted(node.bl_idname for node in nodes),
        "linkCount": len(material.node_tree.links),
    }


def main() -> None:
    arguments = sys.argv[sys.argv.index("--") + 1 :]
    if len(arguments) != 2:
        raise SystemExit("usage: blender -b --python check-material-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 = material_report()
    descriptor, temporary = tempfile.mkstemp(prefix="m16-material-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 = material_report()
    finally:
        pathlib.Path(temporary).unlink(missing_ok=True)
    if before != after:
        raise RuntimeError(f"material save/reopen drift: {before} != {after}")
    report = {
        "schemaVersion": 1,
        "task": "M16-GAP-00013",
        "operation": "MATERIAL_DATABLOCK_DESKTOP",
        "fixture": str(fixture),
        "fixtureSha256": hashlib.sha256(fixture.read_bytes()).hexdigest(),
        "material": 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"material-desktop-ok id={after['id']} nodes={len(after['nodeTypes'])} links={after['linkCount']} saveReopen=exact")


if __name__ == "__main__":
    main()