"""
Exports sensor values via RSS feed.

For more details about this platform, please refer to the documentation at
https://home-assistant.io/components/rss_feed_template/
"""

import asyncio
from html import escape
from aiohttp import web

import voluptuous as vol

from homeassistant.components.http import HomeAssistantView
import homeassistant.helpers.config_validation as cv

CONTENT_TYPE_XML = 'text/xml'
DEPENDENCIES = ['http']

DOMAIN = 'rss_feed_template'

CONFIG_SCHEMA = vol.Schema({
    DOMAIN: vol.Schema({
        cv.match_all: vol.Schema({
            vol.Optional('requires_api_password', default=True): cv.boolean,
            vol.Optional('title'): cv.template,
            vol.Required('items'): vol.All(
                cv.ensure_list,
                [{
                    vol.Optional('title'): cv.template,
                    vol.Optional('description'): cv.template,
                }]
                )
            })
        })
    }, extra=vol.ALLOW_EXTRA)


def setup(hass, config):
    """Set up the RSS feed template component."""
    for (feeduri, feedconfig) in config[DOMAIN].items():
        url = '/api/rss_template/%s' % feeduri

        requires_auth = feedconfig.get('requires_api_password')

        title = feedconfig.get('title')
        if title is not None:
            title.hass = hass

        items = feedconfig.get('items')
        for item in items:
            if 'title' in item:
                item['title'].hass = hass
            if 'description' in item:
                item['description'].hass = hass

        rss_view = RssView(url, requires_auth, title, items)
        hass.http.register_view(rss_view)

    return True


class RssView(HomeAssistantView):
    """Export states and other values as RSS."""

    requires_auth = True
    url = None
    name = 'rss_template'
    _title = None
    _items = None

    def __init__(self, url, requires_auth, title, items):
        """Initialize the rss view."""
        self.url = url
        self.requires_auth = requires_auth
        self._title = title
        self._items = items

    @asyncio.coroutine
    def get(self, request, entity_id=None):
        """Generate the RSS view XML."""
        response = '<?xml version="1.0" encoding="utf-8"?>\n\n'

        response += '<rss>\n'
        if self._title is not None:
            response += ('  <title>%s</title>\n' %
                         escape(self._title.async_render()))

        for item in self._items:
            response += '  <item>\n'
            if 'title' in item:
                response += '    <title>'
                response += escape(item['title'].async_render())
                response += '</title>\n'
            if 'description' in item:
                response += '    <description>'
                response += escape(item['description'].async_render())
                response += '</description>\n'
            response += '  </item>\n'

        response += '</rss>\n'

        return web.Response(
            body=response, content_type=CONTENT_TYPE_XML, status=200)
