"""Flask app error handlers"""

from pathlib import Path

from flask import Flask
from flask import render_template

# Add other HTTP error codes here
CODES = [404, 500]


def add_routes(app: Flask) -> None:
    """Add all error handlers

    Args:
        app (Flask): Flask application
    """

    tmpl_dir = app.template_folder
    if tmpl_dir is None:
        return

    tmpl = Path(__file__).parent / tmpl_dir

    for code in CODES:
        add_handler(app, tmpl, code)


def add_handler(
        app: Flask,
        tmpl: Path,
        code: int) -> None:
    """Add Flask app error handler.
    Only for internal use

    Args:
        app (Flask): Flask application
        file (str): Template filename
        code (int): Error code
    """

    file = f'{code}.html'

    if (tmpl / file).exists():

        @app.errorhandler(code)
        def handler(_e):
            return render_template(file), code