"""Canonical JSON serialization: sorted keys, compact separators, no NaN/Infinity,
deterministic float repr, UTF-8, ensure_ascii=False.

NOT RFC 8785 (JCS), and not claimed to be. JCS is IEEE-754 double-based with its
own number grammar; this module emits Python's `repr` for floats and passes int
through unchanged. Three measured divergences from RFC 8785 Table 1:

    -0.0    -> "-0.0"                (JCS: "0")
    1e-06   -> "1e-06"               (JCS: "0.000001")
    2**53+1 -> "9007199254740993"    (JCS max positive integer: 9007199254740992)

Key order is `sort_keys=True`, i.e. by Unicode code point; JCS sorts by UTF-16
code unit, so the two diverge above U+FFFF.
"""
from __future__ import annotations
import json
import math
from typing import Any


class CanonicalError(ValueError):
    pass


def _normalize(obj):
    if obj is None or isinstance(obj, bool) or isinstance(obj, int) or isinstance(obj, str):
        return obj
    if isinstance(obj, float):
        if not math.isfinite(obj):
            raise CanonicalError("non-finite float: %r" % obj)
        return obj
    if isinstance(obj, (list, tuple)):
        return [_normalize(x) for x in obj]
    if isinstance(obj, dict):
        out = {}
        for k, v in obj.items():
            if not isinstance(k, str):
                raise CanonicalError("non-string key: %r" % (k,))
            out[k] = _normalize(v)
        return out
    raise CanonicalError("unsupported type: %r" % (type(obj),))


def canonical(obj) -> str:
    n = _normalize(obj)
    return json.dumps(n, sort_keys=True, separators=(",", ":"), ensure_ascii=False,
                      allow_nan=False)


def canonical_bytes(obj) -> bytes:
    return canonical(obj).encode("utf-8")