"""Driver for the Waveshare epd4in0e (4", 6-color Spectra) panel.

Thin wrapper around the vendored `waveshare_epd.epd4in0e` module -- the exact
driver already proven working under the InkyPi install on this Pi. That
driver only exposes `Clear()` and `display()`, both of which do a full
`TurnOnDisplay()` flash cycle; there is no partial-refresh path for this
panel at the hardware/SDK level, confirmed by reading the driver itself.
"""

import logging

from display import Display

logger = logging.getLogger(__name__)

RESOLUTION = (400, 600)


class EPD4in0eDisplay(Display):
    def __init__(self):
        self.resolution = RESOLUTION
        self._epd = None

    def init(self) -> None:
        from waveshare_epd import epd4in0e

        self._epd = epd4in0e.EPD()
        self._epd.init()
        logger.info("epd4in0e initialized")

    def show(self, image) -> None:
        if self._epd is None:
            self.init()

        width, height = self.resolution
        if image.size != (width, height):
            raise ValueError(
                f"Image size {image.size} does not match panel resolution {self.resolution}"
            )

        # Re-init: the panel goes to sleep after every show(), and needs a
        # fresh init() before it will accept commands again.
        self._epd.init()

        # Clear first to avoid ghosting from the previous image -- also a
        # full flash, there's no way around it on this panel.
        self._epd.Clear()

        self._epd.display(self._epd.getbuffer(image.convert("RGB")))

    def sleep(self) -> None:
        if self._epd is not None:
            self._epd.sleep()
        logger.info("epd4in0e put to sleep")