"""
Demo camera platform that has a fake camera.

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

import homeassistant.util.dt as dt_util
from homeassistant.components.camera import Camera


def setup_platform(hass, config, add_devices, discovery_info=None):
    """Setup the Demo camera platform."""
    add_devices([
        DemoCamera('Demo camera')
    ])


class DemoCamera(Camera):
    """A Demo camera."""

    def __init__(self, name):
        super().__init__()
        self._name = name

    def camera_image(self):
        """Return a faked still image response."""
        now = dt_util.utcnow()

        image_path = os.path.join(os.path.dirname(__file__),
                                  'demo_{}.jpg'.format(now.second % 4))
        with open(image_path, 'rb') as file:
            return file.read()

    @property
    def name(self):
        """Return the name of this camera."""
        return self._name
