#!/usr/bin/python
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/. */

"""
mac_desktop_image.py

Mac-specific utility to get/set the desktop background image or check that
the current background image path matches a provided path.

Depends on Objective-C python binding imports which are in the python import
paths by default when using macOS's /usr/bin/python.

Includes generous amount of logging to aid debugging for use in automated tests.
"""

import argparse
import logging
import os
import sys

#
# These Objective-C bindings imports are included in the import path by default
# for the Mac-bundled python installed in /usr/bin/python. They're needed to
# call the Objective-C API's to set and retrieve the current desktop background
# image.
#
from AppKit import NSScreen, NSWorkspace
from Cocoa import NSURL


def main():
    parser = argparse.ArgumentParser(
        description="Utility to print, set, or "
        + "check the path to image being used as "
        + "the desktop background image. By "
        + "default, prints the path to the "
        + "current desktop background image."
    )
    parser.add_argument(
        "-v",
        "--verbose",
        action="store_true",
        help="print verbose debugging information",
        default=False,
    )
    group = parser.add_mutually_exclusive_group()
    group.add_argument(
        "-s",
        "--set-background-image",
        dest="newBackgroundImagePath",
        required=False,
        help="path to the new background image to set. A zero "
        + "exit code indicates no errors occurred.",
        default=None,
    )
    group.add_argument(
        "-c",
        "--check-background-image",
        dest="checkBackgroundImagePath",
        required=False,
        help="check if the provided background image path "
        + "matches the provided path. A zero exit code "
        + "indicates the paths match.",
        default=None,
    )
    args = parser.parse_args()

    # Using logging for verbose output
    if args.verbose:
        logging.basicConfig(level=logging.DEBUG)
    else:
        logging.basicConfig(level=logging.CRITICAL)
    logger = logging.getLogger("desktopImage")

    # Print what we're going to do
    if args.checkBackgroundImagePath is not None:
        logger.debug(
            "checking provided desktop image %s matches current "
            "image" % args.checkBackgroundImagePath
        )
    elif args.newBackgroundImagePath is not None:
        logger.debug("setting image to %s " % args.newBackgroundImagePath)
    else:
        logger.debug("retrieving desktop image path")

    focussedScreen = NSScreen.mainScreen()
    if not focussedScreen:
        raise RuntimeError("mainScreen error")

    ws = NSWorkspace.sharedWorkspace()
    if not ws:
        raise RuntimeError("sharedWorkspace error")

    # If we're just checking the image path, check it and then return.
    # A successful exit code (0) indicates the paths match.
    if args.checkBackgroundImagePath is not None:
        # Get existing desktop image path and resolve it
        existingImageURL = getCurrentDesktopImageURL(focussedScreen, ws, logger)
        existingImagePath = existingImageURL.path()
        existingImagePathReal = os.path.realpath(existingImagePath)
        logger.debug("existing desktop image: %s" % existingImagePath)
        logger.debug("existing desktop image realpath: %s" % existingImagePath)

        # Resolve the path we're going to check
        checkImagePathReal = os.path.realpath(args.checkBackgroundImagePath)
        logger.debug("check desktop image: %s" % args.checkBackgroundImagePath)
        logger.debug("check desktop image realpath: %s" % checkImagePathReal)

        if existingImagePathReal == checkImagePathReal:
            print("desktop image path matches provided path")
            return True

        print("desktop image path does NOT match provided path")
        return False

    # Log the current desktop image
    if args.verbose:
        existingImageURL = getCurrentDesktopImageURL(focussedScreen, ws, logger)
        logger.debug("existing desktop image: %s" % existingImageURL.path())

    # Set the desktop image
    if args.newBackgroundImagePath is not None:
        newImagePath = args.newBackgroundImagePath
        if not os.path.exists(newImagePath):
            logger.critical("%s does not exist" % newImagePath)
            return False
        if not os.access(newImagePath, os.R_OK):
            logger.critical("%s is not readable" % newImagePath)
            return False

        logger.debug("new desktop image to set: %s" % newImagePath)
        newImageURL = NSURL.fileURLWithPath_(newImagePath)
        logger.debug("new desktop image URL to set: %s" % newImageURL)

        status = False
        (status, error) = ws.setDesktopImageURL_forScreen_options_error_(
            newImageURL, focussedScreen, None, None
        )
        if not status:
            raise RuntimeError("setDesktopImageURL error")

    # Print the current desktop image
    imageURL = getCurrentDesktopImageURL(focussedScreen, ws, logger)
    imagePath = imageURL.path()
    imagePathReal = os.path.realpath(imagePath)
    logger.debug("updated desktop image URL: %s" % imageURL)
    logger.debug("updated desktop image path: %s" % imagePath)
    logger.debug("updated desktop image path (resolved): %s" % imagePathReal)
    print(imagePathReal)
    return True


def getCurrentDesktopImageURL(focussedScreen, workspace, logger):
    imageURL = workspace.desktopImageURLForScreen_(focussedScreen)
    if not imageURL:
        raise RuntimeError("desktopImageURLForScreen returned invalid URL")
    if not imageURL.isFileURL():
        logger.warning("desktop image URL is not a file URL")
    return imageURL


if __name__ == "__main__":
    if not main():
        sys.exit(1)
    else:
        sys.exit(0)