"""Common utilities."""
import logging
import traceback
from typing import Callable

from flask import request, Response, make_response, render_template

logger = logging.getLogger(__name__)


def add_trace(exc: Exception, errobj: dict) -> dict:
    """Add the traceback to the error handling object."""
    return {
        **errobj,
        "error-trace": "".join(traceback.format_exception(exc))
    }

def __status_code__(exc: Exception):
    """Fetch the error code for exceptions that have them."""
    error_code_attributes = (
        "code", "error_code", "errorcode", "status_code", "status_code")
    for attr in error_code_attributes:
        if hasattr(exc, attr):
            return getattr(exc, attr)

    return 500


def build_handler(description: str) -> Callable[[Exception], Response]:
    """Generic utility to build error handlers."""
    def __handler__(exc: Exception) -> Response:
        """Handle the exception as appropriate for requests of different mimetypes."""
        error = (exc.name if hasattr(exc, "name") else exc.__class__.__name__)
        status_code = __status_code__(exc)
        content_type = request.content_type
        if bool(content_type) and content_type.lower() == "application/json":
            return make_response((
                add_trace(
                    exc,
                    {
                        "requested-uri": request.url,
                        "error": error,
                        "error_description": description
                    }),
                status_code,
                {"Content-Type": "application/json"}))

        return make_response((
            render_template(
                f"http-error-{str(status_code)[0:-2]}xx.html",
                error=exc,
                page=request.url,
                description=description,
                trace=traceback.format_exception(exc)),
            status_code,
            {"Content-Type": "text/html"}))

    return __handler__