#!/usr/bin/env python3
"""
STEP → 每 solid 一个 STL + manifest.json（需 cadquery：pip install cadquery）
用法: python3 step_parse_mvp.py <step_path> <out_dir>
stdout 打印一行 JSON: {"ok":true} 或 {"ok":false,"error":"..."}
"""
from __future__ import annotations

import json
import os
import sys


def main() -> None:
    if len(sys.argv) < 3:
        err = {"ok": False, "error": "usage: step_parse_mvp.py <step_path> <out_dir>"}
        print(json.dumps(err), flush=True)
        sys.exit(2)

    step_path = sys.argv[1]
    out_dir = sys.argv[2]

    try:
        import cadquery as cq  # type: ignore
    except ImportError as e:
        # pip3 与 python3 可能不是同一解释器，须用「当前解释器」安装：见 sys.executable
        exe = sys.executable
        pip_cmd = (
            f'"{exe}" -m pip install --break-system-packages '
            f"-i https://pypi.tuna.tsinghua.edu.cn/simple cadquery"
        )
        detail = f"{type(e).__name__}: {e}"
        err = {
            "ok": False,
            "error": (
                f"无法 import cadquery（{detail}）。当前 Python: {exe}。"
                f"请用**同一解释器**安装（勿单独用 pip3，除非确认与 python3 一致）: {pip_cmd}"
            ),
        }
        print(json.dumps(err, ensure_ascii=False), flush=True)
        sys.exit(1)

    if not os.path.isfile(step_path):
        err = {"ok": False, "error": f"文件不存在: {step_path}"}
        print(json.dumps(err), flush=True)
        sys.exit(1)

    os.makedirs(out_dir, exist_ok=True)

    try:
        wp = cq.importers.importStep(step_path)
    except Exception as e:
        err = {"ok": False, "error": f"importStep: {e}"}
        print(json.dumps(err), flush=True)
        sys.exit(1)

    solids: list = []
    try:
        solids = list(wp.solids().vals())
    except Exception:
        try:
            solids = [wp.val()]
        except Exception as e:
            err = {"ok": False, "error": f"无法取得实体: {e}"}
            print(json.dumps(err), flush=True)
            sys.exit(1)

    if not solids:
        err = {"ok": False, "error": "STEP 中未解析出任何 Solid"}
        print(json.dumps(err), flush=True)
        sys.exit(1)

    parts: list[dict] = []
    for i, solid in enumerate(solids):
        name = f"part_{i:04d}"
        stl_name = f"{name}.stl"
        stl_path = os.path.join(out_dir, stl_name)
        cq.exporters.export(solid, stl_path)
        parts.append({"id": name, "name": name, "stlRelative": stl_name})

    manifest = {"ok": True, "parts": parts, "sourceStep": os.path.abspath(step_path)}
    man_path = os.path.join(out_dir, "manifest.json")
    with open(man_path, "w", encoding="utf-8") as f:
        json.dump(manifest, f, indent=2, ensure_ascii=False)

    result_line = json.dumps({"ok": True, "parts": parts, "manifestPath": man_path})
    # Node 端若 stdout 含 OCP 杂讯，仍可从该文件读取结果
    with open(os.path.join(out_dir, "_parse_result.json"), "w", encoding="utf-8") as f:
        f.write(result_line)
    print(result_line, flush=True)


if __name__ == "__main__":
    main()