"""Atomic artifacts and content-addressed provenance."""

import hashlib
import json
import os
from datetime import UTC, datetime
from pathlib import Path


def now():
    return datetime.now(UTC).isoformat()


def canonical(value):
    return json.dumps(value, ensure_ascii=False, sort_keys=True, allow_nan=False)


def fingerprint(value):
    return hashlib.sha256(canonical(value).encode()).hexdigest()


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


def load(path):
    return json.loads(Path(path).read_text())


def write(path, value):
    path = Path(path)
    path.parent.mkdir(parents=True, exist_ok=True)
    tmp = path.with_name(f".{path.name}.{os.getpid()}.tmp")
    tmp.write_text(canonical(value) + "\n")
    tmp.replace(path)


def append(path, value):
    path = Path(path)
    path.parent.mkdir(parents=True, exist_ok=True)
    with path.open("a") as f:
        f.write(canonical(value) + "\n")
        f.flush()
        os.fsync(f.fileno())


def rows(path):
    with Path(path).open() as f:
        return [json.loads(line) for line in f if line.strip()]