from flask import Blueprint, session, request, redirect, url_for
from urllib.parse import urlparse

language_bp = Blueprint('language', __name__)

@language_bp.route('/set_language/<lang>')
def set_language(lang):
    session['lang'] = lang

    referrer = request.referrer
    if referrer:
        ref_url = urlparse(referrer)
        if ref_url.netloc == request.host:
            return redirect(referrer)

    return redirect(url_for('main.index'))