"""
Fragments for rendering programs.
"""


import json

from django.http import Http404
from django.template.loader import render_to_string
from django.urls import reverse
from django.utils.translation import ugettext_lazy as _  # lint-amnesty, pylint: disable=unused-import
from web_fragments.fragment import Fragment

from lms.djangoapps.commerce.utils import EcommerceService
from lms.djangoapps.learner_dashboard.utils import FAKE_COURSE_KEY, strip_course_id
from openedx.core.djangoapps.catalog.constants import PathwayType
from openedx.core.djangoapps.catalog.utils import get_pathways
from openedx.core.djangoapps.credentials.utils import get_credentials_records_url
from openedx.core.djangoapps.plugin_api.views import EdxFragmentView
from openedx.core.djangoapps.programs.models import ProgramsApiConfig
from openedx.core.djangoapps.programs.utils import (
    ProgramDataExtender,
    ProgramProgressMeter,
    get_certificates,
    get_program_marketing_url
)
from openedx.core.djangoapps.user_api.preferences.api import get_user_preferences


class ProgramsFragmentView(EdxFragmentView):
    """
    A fragment to program listing.
    """

    def render_to_fragment(self, request, **kwargs):
        """
        Render the program listing fragment.
        """
        user = request.user
        try:
            mobile_only = json.loads(request.GET.get('mobile_only', 'false'))
        except ValueError:
            mobile_only = False

        programs_config = kwargs.get('programs_config') or ProgramsApiConfig.current()
        if not programs_config.enabled or not user.is_authenticated:
            raise Http404

        meter = ProgramProgressMeter(request.site, user, mobile_only=mobile_only)

        context = {
            'marketing_url': get_program_marketing_url(programs_config, mobile_only),
            'programs': meter.engaged_programs,
            'progress': meter.progress()
        }
        html = render_to_string('learner_dashboard/programs_fragment.html', context)
        programs_fragment = Fragment(html)
        self.add_fragment_resource_urls(programs_fragment)

        return programs_fragment

    def standalone_page_title(self, request, fragment, **kwargs):
        """
        Return page title for the standalone page.
        """
        return _('Programs')


class ProgramDetailsFragmentView(EdxFragmentView):
    """
    Render the program details fragment.
    """

    def render_to_fragment(self, request, program_uuid, **kwargs):  # lint-amnesty, pylint: disable=arguments-differ
        """View details about a specific program."""
        programs_config = kwargs.get('programs_config') or ProgramsApiConfig.current()
        if not programs_config.enabled or not request.user.is_authenticated:
            raise Http404

        meter = ProgramProgressMeter(request.site, request.user, uuid=program_uuid)
        program_data = meter.programs[0]

        if not program_data:
            raise Http404

        try:
            mobile_only = json.loads(request.GET.get('mobile_only', 'false'))
        except ValueError:
            mobile_only = False

        program_data = ProgramDataExtender(program_data, request.user, mobile_only=mobile_only).extend()
        course_data = meter.progress(programs=[program_data], count_only=False)[0]
        certificate_data = get_certificates(request.user, program_data)

        program_data.pop('courses')
        skus = program_data.get('skus')
        ecommerce_service = EcommerceService()

        # TODO: Don't have business logic of course-certificate==record-available here in LMS.
        # Eventually, the UI should ask Credentials if there is a record available and get a URL from it.
        # But this is here for now so that we can gate this URL behind both this business logic and
        # a waffle flag. This feature is in active developoment.
        program_record_url = get_credentials_records_url(program_uuid=program_uuid)
        if not certificate_data:
            program_record_url = None

        industry_pathways = []
        credit_pathways = []
        try:
            for pathway_id in program_data['pathway_ids']:
                pathway = get_pathways(request.site, pathway_id)
                if pathway and pathway['email']:
                    if pathway['pathway_type'] == PathwayType.CREDIT.value:
                        credit_pathways.append(pathway)
                    elif pathway['pathway_type'] == PathwayType.INDUSTRY.value:
                        industry_pathways.append(pathway)
        # if pathway caching did not complete fully (no pathway_ids)
        except KeyError:
            pass

        urls = {
            'program_listing_url': reverse('program_listing_view'),
            'track_selection_url': strip_course_id(
                reverse('course_modes_choose', kwargs={'course_id': FAKE_COURSE_KEY})
            ),
            'commerce_api_url': reverse('commerce_api:v0:baskets:create'),
            'buy_button_url': ecommerce_service.get_checkout_page_url(*skus),
            'program_record_url': program_record_url,
        }

        context = {
            'urls': urls,
            'user_preferences': get_user_preferences(request.user),
            'program_data': program_data,
            'course_data': course_data,
            'certificate_data': certificate_data,
            'industry_pathways': industry_pathways,
            'credit_pathways': credit_pathways,
        }

        html = render_to_string('learner_dashboard/program_details_fragment.html', context)
        program_details_fragment = Fragment(html)
        self.add_fragment_resource_urls(program_details_fragment)
        return program_details_fragment

    def standalone_page_title(self, request, fragment, **kwargs):
        """
        Return page title for the standalone page.
        """
        return _('Program Details')