"""Proxy camera platform that enables image processing of camera data."""
import asyncio
from datetime import timedelta
import io
import logging

from PIL import Image
import voluptuous as vol

from homeassistant.components.camera import (
    PLATFORM_SCHEMA,
    Camera,
    async_get_image,
    async_get_mjpeg_stream,
    async_get_still_stream,
)
from homeassistant.const import CONF_ENTITY_ID, CONF_MODE, CONF_NAME
from homeassistant.exceptions import HomeAssistantError
from homeassistant.helpers import config_validation as cv
import homeassistant.util.dt as dt_util

_LOGGER = logging.getLogger(__name__)

CONF_CACHE_IMAGES = "cache_images"
CONF_FORCE_RESIZE = "force_resize"
CONF_IMAGE_QUALITY = "image_quality"
CONF_IMAGE_REFRESH_RATE = "image_refresh_rate"
CONF_MAX_IMAGE_WIDTH = "max_image_width"
CONF_MAX_IMAGE_HEIGHT = "max_image_height"
CONF_MAX_STREAM_WIDTH = "max_stream_width"
CONF_MAX_STREAM_HEIGHT = "max_stream_height"
CONF_IMAGE_TOP = "image_top"
CONF_IMAGE_LEFT = "image_left"
CONF_STREAM_QUALITY = "stream_quality"

MODE_RESIZE = "resize"
MODE_CROP = "crop"

DEFAULT_BASENAME = "Camera Proxy"
DEFAULT_QUALITY = 75

PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
    {
        vol.Required(CONF_ENTITY_ID): cv.entity_id,
        vol.Optional(CONF_NAME): cv.string,
        vol.Optional(CONF_CACHE_IMAGES, False): cv.boolean,
        vol.Optional(CONF_FORCE_RESIZE, False): cv.boolean,
        vol.Optional(CONF_MODE, default=MODE_RESIZE): vol.In([MODE_RESIZE, MODE_CROP]),
        vol.Optional(CONF_IMAGE_QUALITY): int,
        vol.Optional(CONF_IMAGE_REFRESH_RATE): float,
        vol.Optional(CONF_MAX_IMAGE_WIDTH): int,
        vol.Optional(CONF_MAX_IMAGE_HEIGHT): int,
        vol.Optional(CONF_MAX_STREAM_WIDTH): int,
        vol.Optional(CONF_MAX_STREAM_HEIGHT): int,
        vol.Optional(CONF_IMAGE_LEFT): int,
        vol.Optional(CONF_IMAGE_TOP): int,
        vol.Optional(CONF_STREAM_QUALITY): int,
    }
)


async def async_setup_platform(hass, config, async_add_entities, discovery_info=None):
    """Set up the Proxy camera platform."""
    async_add_entities([ProxyCamera(hass, config)])


def _precheck_image(image, opts):
    """Perform some pre-checks on the given image."""
    if not opts:
        raise ValueError()
    try:
        img = Image.open(io.BytesIO(image))
    except OSError:
        _LOGGER.warning("Failed to open image")
        raise ValueError()
    imgfmt = str(img.format)
    if imgfmt not in ("PNG", "JPEG"):
        _LOGGER.warning("Image is of unsupported type: %s", imgfmt)
        raise ValueError()
    return img


def _resize_image(image, opts):
    """Resize image."""
    try:
        img = _precheck_image(image, opts)
    except ValueError:
        return image

    quality = opts.quality or DEFAULT_QUALITY
    new_width = opts.max_width
    (old_width, old_height) = img.size
    old_size = len(image)
    if old_width <= new_width:
        if opts.quality is None:
            _LOGGER.debug("Image is smaller-than/equal-to requested width")
            return image
        new_width = old_width

    scale = new_width / float(old_width)
    new_height = int((float(old_height) * float(scale)))

    img = img.resize((new_width, new_height), Image.ANTIALIAS)
    imgbuf = io.BytesIO()
    img.save(imgbuf, "JPEG", optimize=True, quality=quality)
    newimage = imgbuf.getvalue()
    if not opts.force_resize and len(newimage) >= old_size:
        _LOGGER.debug(
            "Using original image (%d bytes) "
            "because resized image (%d bytes) is not smaller",
            old_size,
            len(newimage),
        )
        return image

    _LOGGER.debug(
        "Resized image from (%dx%d - %d bytes) to (%dx%d - %d bytes)",
        old_width,
        old_height,
        old_size,
        new_width,
        new_height,
        len(newimage),
    )
    return newimage


def _crop_image(image, opts):
    """Crop image."""
    try:
        img = _precheck_image(image, opts)
    except ValueError:
        return image

    quality = opts.quality or DEFAULT_QUALITY
    (old_width, old_height) = img.size
    old_size = len(image)
    if opts.top is None:
        opts.top = 0
    if opts.left is None:
        opts.left = 0
    if opts.max_width is None or opts.max_width > old_width - opts.left:
        opts.max_width = old_width - opts.left
    if opts.max_height is None or opts.max_height > old_height - opts.top:
        opts.max_height = old_height - opts.top

    img = img.crop(
        (opts.left, opts.top, opts.left + opts.max_width, opts.top + opts.max_height)
    )
    imgbuf = io.BytesIO()
    img.save(imgbuf, "JPEG", optimize=True, quality=quality)
    newimage = imgbuf.getvalue()

    _LOGGER.debug(
        "Cropped image from (%dx%d - %d bytes) to (%dx%d - %d bytes)",
        old_width,
        old_height,
        old_size,
        opts.max_width,
        opts.max_height,
        len(newimage),
    )
    return newimage


class ImageOpts:
    """The representation of image options."""

    def __init__(self, max_width, max_height, left, top, quality, force_resize):
        """Initialize image options."""
        self.max_width = max_width
        self.max_height = max_height
        self.left = left
        self.top = top
        self.quality = quality
        self.force_resize = force_resize

    def __bool__(self):
        """Bool evaluation rules."""
        return bool(self.max_width or self.quality)


class ProxyCamera(Camera):
    """The representation of a Proxy camera."""

    def __init__(self, hass, config):
        """Initialize a proxy camera component."""
        super().__init__()
        self.hass = hass
        self._proxied_camera = config.get(CONF_ENTITY_ID)
        self._name = config.get(CONF_NAME) or "{} - {}".format(
            DEFAULT_BASENAME, self._proxied_camera
        )
        self._image_opts = ImageOpts(
            config.get(CONF_MAX_IMAGE_WIDTH),
            config.get(CONF_MAX_IMAGE_HEIGHT),
            config.get(CONF_IMAGE_LEFT),
            config.get(CONF_IMAGE_TOP),
            config.get(CONF_IMAGE_QUALITY),
            config.get(CONF_FORCE_RESIZE),
        )

        self._stream_opts = ImageOpts(
            config.get(CONF_MAX_STREAM_WIDTH),
            config.get(CONF_MAX_STREAM_HEIGHT),
            config.get(CONF_IMAGE_LEFT),
            config.get(CONF_IMAGE_TOP),
            config.get(CONF_STREAM_QUALITY),
            True,
        )

        self._image_refresh_rate = config.get(CONF_IMAGE_REFRESH_RATE)
        self._cache_images = bool(
            config.get(CONF_IMAGE_REFRESH_RATE) or config.get(CONF_CACHE_IMAGES)
        )
        self._last_image_time = dt_util.utc_from_timestamp(0)
        self._last_image = None
        self._mode = config.get(CONF_MODE)

    def camera_image(self):
        """Return camera image."""
        return asyncio.run_coroutine_threadsafe(
            self.async_camera_image(), self.hass.loop
        ).result()

    async def async_camera_image(self):
        """Return a still image response from the camera."""
        now = dt_util.utcnow()

        if self._image_refresh_rate and now < self._last_image_time + timedelta(
            seconds=self._image_refresh_rate
        ):
            return self._last_image

        self._last_image_time = now
        image = await async_get_image(self.hass, self._proxied_camera)
        if not image:
            _LOGGER.error("Error getting original camera image")
            return self._last_image

        if self._mode == MODE_RESIZE:
            job = _resize_image
        else:
            job = _crop_image
        image = await self.hass.async_add_executor_job(
            job, image.content, self._image_opts
        )

        if self._cache_images:
            self._last_image = image
        return image

    async def handle_async_mjpeg_stream(self, request):
        """Generate an HTTP MJPEG stream from camera images."""
        if not self._stream_opts:
            return await async_get_mjpeg_stream(
                self.hass, request, self._proxied_camera
            )

        return await async_get_still_stream(
            request, self._async_stream_image, self.content_type, self.frame_interval,
        )

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

    async def _async_stream_image(self):
        """Return a still image response from the camera."""
        try:
            image = await async_get_image(self.hass, self._proxied_camera)
            if not image:
                return None
        except HomeAssistantError:
            raise asyncio.CancelledError()

        if self._mode == MODE_RESIZE:
            job = _resize_image
        else:
            job = _crop_image
        return await self.hass.async_add_executor_job(
            job, image.content, self._stream_opts
        )
