"""
Fragments for rendering programs.
"""
from __future__ import absolute_import

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 get_language_bidi
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),
            '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 css_dependencies(self):
        """
        Returns list of CSS files that this view depends on.

        The helper function that it uses to obtain the list of CSS files
        works in conjunction with the Django pipeline to ensure that in development mode
        the files are loaded individually, but in production just the single bundle is loaded.
        """
        if get_language_bidi():
            return self.get_css_dependencies('style-learner-dashboard-rtl')
        else:
            return self.get_css_dependencies('style-learner-dashboard')


class ProgramDetailsFragmentView(EdxFragmentView):
    """
    Render the program details fragment.
    """
    def render_to_fragment(self, request, program_uuid, **kwargs):
        """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 css_dependencies(self):
        """
        Returns list of CSS files that this view depends on.

        The helper function that it uses to obtain the list of CSS files
        works in conjunction with the Django pipeline to ensure that in development mode
        the files are loaded individually, but in production just the single bundle is loaded.
        """
        if get_language_bidi():
            return self.get_css_dependencies('style-learner-dashboard-rtl')
        else:
            return self.get_css_dependencies('style-learner-dashboard')