from django.http import Http404
from django.shortcuts import render
from django.template import Template
from django.utils._os import safe_join
from . import settings
import os

def get_page_or_404(name):
    """Return page content as a Django template or raise 404 err."""
    try:
        file_path  = safe_join(settings.SITE_PAGES_DIR, name)
    except ValueError:
        raise Http404('Page not found[1].')
    else:
        if not os.path.exists(file_path):
            raise Http404('Page not found[2].')
    with open(file_path,'r') as f:
        page = Template(f.read())
    return page

def page(request, slug='index'):
    """render the requested page if found."""
    file_name = slug + '.html'
    page = get_page_or_404(file_name)
    context = {
        'slug' : slug,
        'page' : page,
    }
    return render(request,'page.html', context)