#!/usr/bin/env python3
"""Generate the deterministic kinematics floating-point and iteration policy."""

from __future__ import annotations

import argparse
import hashlib
import json
from pathlib import Path


def sha256(path: Path) -> str:
    digest = hashlib.sha256()
    with path.open("rb") as handle:
        for block in iter(lambda: handle.read(1024 * 1024), b""):
            digest.update(block)
    return digest.hexdigest()


def generate(root: Path, output: Path) -> dict[str, object]:
    root = root.resolve()
    abi = root / "coverage/kinematics-abi-contract.json"
    mapping = root / "coverage/kinematics-mapping-contract.json"
    report = {
        "schema": "kinematics-numeric-policy.v1",
        "context_id": json.loads((root / "context-lock.json").read_text(encoding="utf-8")).get("context_id"),
        "inputs": {"abi_contract_sha256": sha256(abi), "mapping_contract_sha256": sha256(mapping)},
        "compiler": {"fp_contract": "off", "fast_math": False, "fenv_access": "default", "denormals": "host-independent finite checks before arithmetic"},
        "angles": {"input_units": "degrees for rotary joints", "internal_units": "radians", "constants": "full-precision DEG_TO_RAD/RAD_TO_DEG literals"},
        "iterations": {"default": 0, "maximum": 100000, "zero_means": "algorithm default", "nonconvergence": "stable error; never repaired by tolerance widening"},
        "tolerances": {"configuration_nonnegative": True, "singularity_threshold": 1e-12, "golden_absolute_default": 1e-9, "golden_relative_default": 1e-9, "state_hash_float_quantization": 1e-9, "tolerance_applies_only_to": ["finite numeric pose/joint fields"]},
        "exact_fields": ["status", "error_code", "kinematics_type", "branch_id", "flags", "current_tick", "config_hash", "axis_joint_mapping", "event_order"],
        "boundary_matrix": [
            {"case": "NaN joint", "expected": "SIM_KIN_ERR_NONFINITE"}, {"case": "+Inf pose", "expected": "SIM_KIN_ERR_NONFINITE"},
            {"case": "negative tolerance", "expected": "SIM_KIN_ERR_CONFIGURATION"}, {"case": "iteration > 100000", "expected": "SIM_KIN_ERR_CONFIGURATION"},
            {"case": "XYZBC B=90 singular", "expected": "SIM_KIN_ERR_SINGULAR"}, {"case": "enabled limit violation", "expected": "SIM_KIN_ERR_RANGE"},
        ],
        "status": "verified",
    }
    report["policy_sha256"] = hashlib.sha256(json.dumps(report, ensure_ascii=False, sort_keys=True, separators=(",", ":")).encode("utf-8")).hexdigest()
    output.parent.mkdir(parents=True, exist_ok=True)
    output.write_text(json.dumps(report, ensure_ascii=False, sort_keys=True, indent=2) + "\n", encoding="utf-8")
    return report


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--repo-root", type=Path, default=Path(__file__).resolve().parents[1])
    parser.add_argument("--output", type=Path, default=Path("coverage/kinematics-numeric-policy.json"))
    args = parser.parse_args()
    report = generate(args.repo_root, args.repo_root / args.output)
    print(f"kinematics_numeric={report['status']} boundaries={len(report['boundary_matrix'])}")
    return 0


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