# Copyright (C) 2017-2020  The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU Affero General Public License version 3, or any later version
# See top-level LICENSE file for more information

import os

from django.http import HttpResponse
from django.shortcuts import render, redirect
from django.template.defaultfilters import filesizeformat
import sentry_sdk

from swh.web.common import service
from swh.web.common.utils import (
    reverse, gen_path_info
)
from swh.web.common.exc import handle_view_exception, NotFoundExc
from swh.web.browse.utils import (
    get_directory_entries, get_snapshot_context,
    get_readme_to_display, get_swh_persistent_ids,
    gen_link
)

from swh.web.browse.browseurls import browse_route


@browse_route(r'directory/(?P<sha1_git>[0-9a-f]+)/',
              r'directory/(?P<sha1_git>[0-9a-f]+)/(?P<path>.+)/',
              view_name='browse-directory',
              checksum_args=['sha1_git'])
def directory_browse(request, sha1_git, path=None):
    """Django view for browsing the content of a directory identified
    by its sha1_git value.

    The url that points to it is
    :http:get:`/browse/directory/(sha1_git)/[(path)/]`
    """
    root_sha1_git = sha1_git
    try:
        if path:
            dir_info = service.lookup_directory_with_path(sha1_git, path)
            sha1_git = dir_info['target']

        dirs, files = get_directory_entries(sha1_git)
        origin_url = request.GET.get('origin_url', None)
        if not origin_url:
            origin_url = request.GET.get('origin', None)
        snapshot_context = None
        if origin_url:
            try:
                snapshot_context = get_snapshot_context(origin_url=origin_url)
            except NotFoundExc:
                raw_dir_url = reverse('browse-directory',
                                      url_args={'sha1_git': sha1_git})
                error_message = \
                    ('The Software Heritage archive has a directory '
                     'with the hash you provided but the origin '
                     'mentioned in your request appears broken: %s. '
                     'Please check the URL and try again.\n\n'
                     'Nevertheless, you can still browse the directory '
                     'without origin information: %s'
                        % (gen_link(origin_url), gen_link(raw_dir_url)))

                raise NotFoundExc(error_message)
        if snapshot_context:
            snapshot_context['visit_info'] = None
    except Exception as exc:
        return handle_view_exception(request, exc)

    path_info = gen_path_info(path)

    query_params = {'origin': origin_url}

    breadcrumbs = []
    breadcrumbs.append({'name': root_sha1_git[:7],
                        'url': reverse('browse-directory',
                                       url_args={'sha1_git': root_sha1_git},
                                       query_params=query_params)})
    for pi in path_info:
        breadcrumbs.append({'name': pi['name'],
                            'url': reverse('browse-directory',
                                           url_args={'sha1_git': root_sha1_git,
                                                     'path': pi['path']},
                                           query_params=query_params)})

    path = '' if path is None else (path + '/')

    for d in dirs:
        if d['type'] == 'rev':
            d['url'] = reverse('browse-revision',
                               url_args={'sha1_git': d['target']},
                               query_params=query_params)
        else:
            d['url'] = reverse('browse-directory',
                               url_args={'sha1_git': root_sha1_git,
                                         'path': path + d['name']},
                               query_params=query_params)

    sum_file_sizes = 0

    readmes = {}

    for f in files:
        query_string = 'sha1_git:' + f['target']
        f['url'] = reverse('browse-content',
                           url_args={'query_string': query_string},
                           query_params={'path': root_sha1_git + '/' +
                                         path + f['name'],
                                         'origin': origin_url})
        if f['length'] is not None:
            sum_file_sizes += f['length']
            f['length'] = filesizeformat(f['length'])
        if f['name'].lower().startswith('readme'):
            readmes[f['name']] = f['checksums']['sha1']

    readme_name, readme_url, readme_html = get_readme_to_display(readmes)

    sum_file_sizes = filesizeformat(sum_file_sizes)

    dir_metadata = {"directory": sha1_git,
                    "number of regular files": len(files),
                    "number of subdirectories": len(dirs),
                    "sum of regular file sizes": sum_file_sizes}

    vault_cooking = {
        'directory_context': True,
        'directory_id': sha1_git,
        'revision_context': False,
        'revision_id': None
    }

    swh_objects = [{'type': 'directory', 'id': sha1_git}]

    swh_ids = get_swh_persistent_ids(
        swh_objects=swh_objects, snapshot_context=snapshot_context)

    heading = 'Directory - %s' % sha1_git
    if breadcrumbs:
        dir_path = '/'.join([bc['name'] for bc in breadcrumbs]) + '/'
        heading += ' - %s' % dir_path

    return render(request, 'browse/directory.html',
                  {'heading': heading,
                   'swh_object_id': swh_ids[0]['swh_id'],
                   'swh_object_name': 'Directory',
                   'swh_object_metadata': dir_metadata,
                   'dirs': dirs,
                   'files': files,
                   'breadcrumbs': breadcrumbs,
                   'top_right_link': None,
                   'readme_name': readme_name,
                   'readme_url': readme_url,
                   'readme_html': readme_html,
                   'snapshot_context': snapshot_context,
                   'vault_cooking': vault_cooking,
                   'show_actions_menu': True,
                   'swh_ids': swh_ids})


@browse_route(r'directory/resolve/content-path/(?P<sha1_git>[0-9a-f]+)/(?P<path>.+)/',  # noqa
              view_name='browse-directory-resolve-content-path',
              checksum_args=['sha1_git'])
def _directory_resolve_content_path(request, sha1_git, path):
    """
    Internal endpoint redirecting to data url for a specific file path
    relative to a root directory.
    """
    try:
        path = os.path.normpath(path)
        if not path.startswith('../'):
            dir_info = service.lookup_directory_with_path(sha1_git, path)
            if dir_info['type'] == 'file':
                sha1 = dir_info['checksums']['sha1']
                data_url = reverse('browse-content-raw',
                                   url_args={'query_string': sha1})
                return redirect(data_url)
    except Exception as exc:
        sentry_sdk.capture_exception(exc)
    return HttpResponse(status=404)