# Copyright (C) 2019  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

from base64 import b64encode
from typing import cast, Optional

from django.conf.urls import url
from django.contrib.staticfiles import finders
from django.http import HttpResponse, HttpRequest

from pybadges import badge

from swh.model.exceptions import ValidationError
from swh.model.identifiers import (
    persistent_identifier, parse_persistent_identifier,
    CONTENT, DIRECTORY, ORIGIN, RELEASE, REVISION, SNAPSHOT
)
from swh.web.common import service
from swh.web.common.exc import BadInputExc, NotFoundExc
from swh.web.common.identifiers import resolve_swh_persistent_id
from swh.web.common.utils import reverse


_orange = '#f36a24'
_blue = '#0172b2'
_red = '#cd5741'

_swh_logo_data = None

_badge_config = {
    CONTENT: {
        'color': _blue,
        'title': 'Archived source file',
    },
    DIRECTORY: {
        'color': _blue,
        'title': 'Archived source tree',
    },
    ORIGIN: {
        'color': _orange,
        'title': 'Archived software repository',
    },
    RELEASE: {
        'color': _blue,
        'title': 'Archived software release',
    },
    REVISION: {
        'color': _blue,
        'title': 'Archived commit',
    },
    SNAPSHOT: {
        'color': _blue,
        'title': 'Archived software repository snapshot',
    },
    'error': {
        'color': _red,
        'title': 'An error occurred when generating the badge'
    }
}


def _get_logo_data() -> str:
    """
    Get data-URI for Software Heritage SVG logo to embed it in
    the generated badges.
    """
    global _swh_logo_data
    if _swh_logo_data is None:
        swh_logo_path = cast(str, finders.find('img/swh-logo-white.svg'))
        with open(swh_logo_path, 'rb') as swh_logo_file:
            _swh_logo_data = ('data:image/svg+xml;base64,%s' %
                              b64encode(swh_logo_file.read()).decode('ascii'))
    return _swh_logo_data


def _swh_badge(request: HttpRequest, object_type: str, object_id: str,
               object_pid: Optional[str] = '') -> HttpResponse:
    """
    Generate a Software Heritage badge for a given object type and id.

    Args:
        request: input http request
        object_type: The type of swh object to generate a badge for,
            either *content*, *directory*, *revision*, *release*, *origin*
            or *snapshot*
        object_id: The id of the swh object, either an url for origin
            type or a *sha1* for other object types
        object_pid: If provided, the object persistent
            identifier will not be recomputed

    Returns:
        HTTP response with content type *image/svg+xml* containing the SVG
        badge data. If the provided parameters are invalid, HTTP 400 status
        code will be returned. If the object can not be found in the archive,
        HTTP 404 status code will be returned.

    """
    left_text = 'error'
    whole_link = ''

    try:
        if object_type == ORIGIN:
            service.lookup_origin({'url': object_id})
            right_text = 'repository'
            whole_link = reverse('browse-origin',
                                 url_args={'origin_url': object_id})
        else:
            # when pid is provided, object type and id will be parsed
            # from it
            if object_pid:
                parsed_pid = parse_persistent_identifier(object_pid)
                object_type = parsed_pid.object_type
                object_id = parsed_pid.object_id
            swh_object = service.lookup_object(object_type, object_id)
            if object_pid:
                right_text = object_pid
            else:
                right_text = persistent_identifier(object_type, object_id)

            whole_link = resolve_swh_persistent_id(right_text)['browse_url']
            # remove pid metadata if any for badge text
            if object_pid:
                right_text = right_text.split(';')[0]
            # use release name for badge text
            if object_type == RELEASE:
                right_text = 'release %s' % swh_object['name']
        left_text = 'archived'
    except (BadInputExc, ValidationError):
        right_text = f'invalid {object_type if object_type else "object"} id'
        object_type = 'error'
    except NotFoundExc:
        right_text = f'{object_type if object_type else "object"} not found'
        object_type = 'error'

    badge_data = badge(left_text=left_text,
                       right_text=right_text,
                       right_color=_badge_config[object_type]['color'],
                       whole_link=request.build_absolute_uri(whole_link),
                       whole_title=_badge_config[object_type]['title'],
                       logo=_get_logo_data(),
                       embed_logo=True)

    return HttpResponse(badge_data, content_type='image/svg+xml')


def _swh_badge_pid(request: HttpRequest, object_pid: str) -> HttpResponse:
    """
    Generate a Software Heritage badge for a given object persistent
    identifier.

    Args:
        request (django.http.HttpRequest): input http request
        object_pid (str): A swh object persistent identifier

    Returns:
        django.http.HttpResponse: An http response with content type
            *image/svg+xml* containing the SVG badge data. If any error
            occurs, a status code of 400 will be returned.
    """
    return _swh_badge(request, '', '', object_pid)


urlpatterns = [
    url(r'^badge/(?P<object_type>[a-z]+)/(?P<object_id>.+)/$', _swh_badge,
        name='swh-badge'),
    url(r'^badge/(?P<object_pid>swh:[0-9]+:[a-z]+:[0-9a-f]+.*)/$',
        _swh_badge_pid, name='swh-badge-pid'),
]