"""General page functionality.

SPDX-FileCopyrightText: © 2020 Brian S. Stephan <bss@incorporeal.org>
SPDX-License-Identifier: AGPL-3.0-or-later
"""
import logging
import os

from markupsafe import Markup
from werkzeug.security import safe_join

from incorporealcms import env
from incorporealcms.config import Config
from incorporealcms.lib import get_meta_str, init_md, instance_resource_path_to_request_path, parse_md

logger = logging.getLogger(__name__)


def handle_markdown_file_path(path: str) -> str:
    """Given a location on disk, attempt to open it and render the markdown within."""
    try:
        content, md, page_name, page_title, mtime = parse_md(path)
    except OSError:
        logger.exception("path '%s' could not be opened!", path)
        raise
    except ValueError:
        logger.exception("error parsing/rendering markdown!")
        raise
    except TypeError:
        logger.exception("error loading/rendering markdown!")
        raise
    else:
        parent_navs = generate_parent_navs(path)
        extra_footer = get_meta_str(md, 'footer') if md.Meta.get('footer') else None
        template_name = get_meta_str(md, 'template') if md.Meta.get('template') else 'base.html'

        # check if this has a HTTP redirect
        redirect_url = get_meta_str(md, 'redirect') if md.Meta.get('redirect') else None
        if redirect_url:
            raise ValueError("redirects in markdown are unsupported!")

        template = env.get_template(template_name)
        return template.render(title=page_title,
                               config=Config,
                               description=get_meta_str(md, 'description'),
                               image=get_meta_str(md, 'image'),
                               content=content,
                               stylesheet=(Config.DEFAULT_PAGE_STYLE,
                                           Config.PAGE_STYLES.get(Config.DEFAULT_PAGE_STYLE)),
                               page_styles=Config.PAGE_STYLES,
                               base_url=Config.BASE_HOST + instance_resource_path_to_request_path(path),
                               navs=parent_navs,
                               mtime=mtime.strftime('%Y-%m-%d %H:%M:%S %Z'),
                               extra_footer=extra_footer)


def generate_parent_navs(path):
    """Create a series of paths/links to navigate up from the given resource path."""
    if path == 'index.md':
        # bail and return the domain name as a terminal case
        return [(Config.DOMAIN_NAME, '/')]
    else:
        if path.endswith('index.md'):
            # index case: one dirname for foo/bar/index.md -> foo/bar, one for foo/bar -> foo
            parent_resource_dir = os.path.dirname(os.path.dirname(path))
        else:
            # usual case: foo/buh.md -> foo
            parent_resource_dir = os.path.dirname(path)

        # generate the request path (i.e. what the link will be) for this path, and
        # also the resource path of this parent (which is always a dir, so always index.md)
        request_path = instance_resource_path_to_request_path(path)
        parent_resource_path = os.path.join(parent_resource_dir, 'index.md')

        logger.debug("resource path: '%s'; request path: '%s'; parent resource path: '%s'", path,
                     request_path, parent_resource_path)

        # for issues regarding parser reuse (see lib.init_md) we reinitialize the parser here
        md = init_md()

        # read the resource
        try:
            with open(path, 'r') as entry_file:
                entry = entry_file.read()
            _ = Markup(md.convert(entry))
            page_name = (" ".join(md.Meta.get('title')) if md.Meta.get('title')
                         else request_path_to_breadcrumb_display(request_path))
            return generate_parent_navs(parent_resource_path) + [(page_name, request_path)]
        except FileNotFoundError:
            return generate_parent_navs(parent_resource_path) + [(request_path, request_path)]


def request_path_to_breadcrumb_display(path):
    """Given a request path, e.g. "/foo/bar/baz/", turn it into breadcrumby text "baz"."""
    undired = path.rstrip('/')
    leaf = undired[undired.rfind('/'):]
    return leaf.strip('/')