from flask import request

from src.cache.constants import DEFAULT_CACHE_MODE, CacheMode
from src.cache.exceptions import UnsupportedCacheMode
from src.config.base import ALLOW_CACHE_MODES


def get_cache_mode():
    """Get cache mode based on headers value and configuration."""
    mode = request.headers.get("Cache-Mode")
    if not mode or not ALLOW_CACHE_MODES:
        return DEFAULT_CACHE_MODE
    if mode and not CacheMode.has(mode):
        raise UnsupportedCacheMode(f"Got unsupported cache mode value {mode}")
    return CacheMode(mode)