# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:

# Copyright 2014-2018 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
# Copyright 2015-2018 Antoni Boucher (antoyo) <bouanto@zoho.com>
#
# This file is part of qutebrowser.
#
# qutebrowser is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# qutebrowser is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.
#
# pylint complains when using .render() on jinja templates, so we make it shut
# up for this whole module.

"""Handler functions for file:... pages."""

import os

from qutebrowser.browser.webkit.network import networkreply
from qutebrowser.utils import jinja


def get_file_list(basedir, all_files, filterfunc):
    """Get a list of files filtered by a filter function and sorted by name.

    Args:
        basedir: The parent directory of all files.
        all_files: The list of files to filter and sort.
        filterfunc: The filter function.

    Return:
        A list of dicts. Each dict contains the name and absname keys.
    """
    items = []
    for filename in all_files:
        absname = os.path.join(basedir, filename)
        if filterfunc(absname):
            items.append({'name': filename, 'absname': absname})
    return sorted(items, key=lambda v: v['name'].lower())


def is_root(directory):
    """Check if the directory is the root directory.

    Args:
        directory: The directory to check.

    Return:
        Whether the directory is a root directory or not.
    """
    # If you're curious as why this works:
    # dirname('/') = '/'
    # dirname('/home') = '/'
    # dirname('/home/') = '/home'
    # dirname('/home/foo') = '/home'
    # basically, for files (no trailing slash) it removes the file part, and
    # for directories, it removes the trailing slash, so the only way for this
    # to be equal is if the directory is the root directory.
    return os.path.dirname(directory) == directory


def parent_dir(directory):
    """Return the parent directory for the given directory.

    Args:
        directory: The path to the directory.

    Return:
        The path to the parent directory.
    """
    return os.path.normpath(os.path.join(directory, os.pardir))


def dirbrowser_html(path):
    """Get the directory browser web page.

    Args:
        path: The directory path.

    Return:
        The HTML of the web page.
    """
    title = "Browse directory: {}".format(path)

    if is_root(path):
        parent = None
    else:
        parent = parent_dir(path)

    try:
        all_files = os.listdir(path)
    except OSError as e:
        html = jinja.render('error.html',
                            title="Error while reading directory",
                            url='file:///{}'.format(path), error=str(e))
        return html.encode('UTF-8', errors='xmlcharrefreplace')

    files = get_file_list(path, all_files, os.path.isfile)
    directories = get_file_list(path, all_files, os.path.isdir)
    html = jinja.render('dirbrowser.html', title=title, url=path,
                        parent=parent, files=files, directories=directories)
    return html.encode('UTF-8', errors='xmlcharrefreplace')


def handler(request, _operation, _current_url):
    """Handler for a file:// URL.

    Args:
        request: QNetworkRequest to answer to.
        _operation: The HTTP operation being done.
        _current_url: The page we're on currently.

    Return:
        A QNetworkReply for directories, None for files.
    """
    path = request.url().toLocalFile()
    try:
        if os.path.isdir(path):
            data = dirbrowser_html(path)
            return networkreply.FixedDataNetworkReply(
                request, data, 'text/html')
        return None
    except UnicodeEncodeError:
        return None
