"""Request helper methods."""

import re

from flask import request

from abacus_contract.constants.constants import DEFAULT_PAGE_LIMIT, DEFAULT_PAGE_OFFSET
from abacus_contract.constants.error import ERROR_INVALID_LIMIT_OFFSET

_LIKE_WILDCARD_RE = re.compile(r'([\\%_])')


def escape_like_pattern(search_term: str) -> str:
    r"""Escape MySQL LIKE wildcards (``\``, ``%``, ``_``) in user-supplied search input.

    Without this, ``search_term=%`` matches every row and ``search_term=foo_bar``
    matches ``foo<anychar>bar``. Mirrors ``abacus_account.models.Account``'s
    private helper at module scope so other endpoints can reuse it.
    """
    return _LIKE_WILDCARD_RE.sub(r'\\\1', str(search_term))


def get_optional_numeric_list_from_params(optional: bool = False):
    """Get contract_ids from request params and validate them."""
    optional_params = request.json
    if not optional_params:
        if optional:
            return
        raise ValueError()
    return [int(param) for param in optional_params]


def validate_pagination_params(
    limit: int = DEFAULT_PAGE_LIMIT, offset: int = DEFAULT_PAGE_OFFSET
) -> dict:
    """Format and validate pagination parameters."""
    try:
        limit = int(limit)
        offset = int(offset)
    except ValueError:
        raise Exception(ERROR_INVALID_LIMIT_OFFSET)

    pagination_params = {
        'limit': max(limit, 1),
        'offset': max(offset, DEFAULT_PAGE_OFFSET),
    }

    return pagination_params