import json
import secrets
import string
from contextlib import contextmanager
from pathlib import Path

PROJECT_ROOT = Path(__file__).resolve().parent.parent.parent
CONTEXT_PATH = PROJECT_ROOT / '.context.json'


def set_context(contex: dict):
    CONTEXT_PATH.write_text(json.dumps(contex, indent=2))


def load_context():
    if not CONTEXT_PATH.exists():
        return {}
    return json.loads(CONTEXT_PATH.read_text())


def clean_context():
    CONTEXT_PATH.unlink(missing_ok=True)


@contextmanager
def add_context(contex: dict):
    existing_context = load_context()
    set_context(dict(existing_context, **contex))

    yield

    set_context(existing_context)


def get_feed_name(report):
    """Return feed name for filling feed status table in DynamoDB."""
    return f'tadas_{report}'


def get_context_id(model_version, report):
    parts = ['tadas', model_version]
    if report:
        parts.append(report)

    rand_id = _gen_rand_id(length=4)

    return '_'.join(parts) + ' ' + rand_id


def _gen_rand_id(length):
    """Generate uniq id with length chars using a simple random function."""
    choices = string.ascii_letters + string.digits
    return ''.join(secrets.choice(choices) for _ in range(length))