#!/usr/bin/env python3
"""Reject L1 object specs that redeclare L0-injected system fields."""

import argparse
import json
import sys
from pathlib import Path


RESERVED_FIELD_NAMES = {
    "id",
    "ownerid",
    "createdbyid",
    "lastmodifiedbyid",
    "createddate",
    "lastmodifieddate",
    "systemmodstamp",
    "isdeleted",
}


def load_json(path: Path):
    with path.open(encoding="utf-8") as handle:
        return json.load(handle)


def object_specs_for_component(pack_root: Path, component: dict):
    if "payload" in component:
        payload = component["payload"]
        if isinstance(payload, str):
            return json.loads(payload)
        return payload

    component_path = component.get("path")
    if not component_path:
        raise ValueError(f"object_spec component {component.get('businessKey', '<unknown>')} has no path or payload")

    return load_json(pack_root / component_path)


def diagnostics_for_pack(pack_root: Path):
    manifest = load_json(pack_root / "pack.json")
    diagnostics = []

    for component in manifest.get("components", []):
        if component.get("kind") != "object_spec":
            continue

        specs = object_specs_for_component(pack_root, component)
        if not isinstance(specs, list):
            raise ValueError(f"object_spec component {component.get('businessKey', '<unknown>')} must be a JSON array")

        for spec in specs:
            object_api_name = str(spec.get("apiName", "")).strip()
            for field in spec.get("fields", []) or []:
                field_api_name = str(field.get("apiName", "")).strip()
                if field_api_name.lower() in RESERVED_FIELD_NAMES:
                    diagnostics.append(
                        "component.payload.reserved_field_name: "
                        f"{object_api_name}.{field_api_name} is an L0 system column injected automatically; "
                        "L1 packs must not redeclare it"
                    )

    return diagnostics


def main(argv=None):
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "pack_roots",
        nargs="+",
        type=Path,
        help="Pack directories containing pack.json",
    )
    args = parser.parse_args(argv)

    diagnostics = []
    try:
        for pack_root in args.pack_roots:
            diagnostics.extend(diagnostics_for_pack(pack_root))
    except (OSError, ValueError, json.JSONDecodeError) as exc:
        print(f"check_object_specs_reserved_fields: {exc}", file=sys.stderr)
        return 2

    if diagnostics:
        for diagnostic in diagnostics:
            print(diagnostic, file=sys.stderr)
        return 1

    return 0


if __name__ == "__main__":
    raise SystemExit(main())