#!/usr/bin/env python3
#
# talideon-wallpaper
# by Keith Gaughan <http://talideon.com/>
#
# A pipemenu script for Openbox for selecting and setting the current
# wallpaper.
#
# Copyright (c) Keith Gaughan, 2008.
# All Rights Reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#  1. Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer.
#
#  2. Redistributions in binary form must reproduce the above copyright
#     notice, this list of conditions and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS "AS IS" AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# This license is subject to the laws and courts of the Republic of Ireland.
#

import os, sys
from os import path
from sys import argv

try:
    from xml.etree import cElementTree as et
except:
    from xml.etree import ElementTree as et

FALLBACK_SETTERS = ["hsetroot -center"]
SETTINGS = path.expanduser("~/.config/talideon.com/wallpaper")
WP_LINK = path.join(SETTINGS, "current")


def which(name):
    """
    Finds the path of some named executable available on PATH.
    """
    env_path = os.environ.get("PATH")
    if env_path:
        for dirname in env_path.split(os.pathsep):
            executable = path.join(dirname, name)
            if path.isfile(executable):
                return executable
    return None


def get_setters():
    """
    Loads the list of all wallpaper setting commands.
    """
    setters = []
    setters_path = path.join(SETTINGS, "setters")
    if path.isfile(setters_path):
        try:
            handle = open(setters_path, "r")
            for line in handle:
                line = line.strip()
                if line != "" and line[0] != "#":
                    setters.append(line)
        finally:
            handle.close()
    setters.extend(FALLBACK_SETTERS)
    return setters


def show_wallpaper():
    """
    Gets a wallpaper setter to set the backdrop on the root window.
    """
    for setter in get_setters():
        parts = setter.split(" ", 2)
        location = which(parts[0])
        if location is not None:
            parts[0] = location
            parts.append(path.realpath(WP_LINK))
            os.spawnvpe(os.P_NOWAIT, location, parts, os.environ)
            return


def set_wallpaper(wallpaper):
    """
    Records the user's wallpaper selection.
    """
    if path.isfile(wallpaper) and wallpaper != WP_LINK:
        os.unlink(WP_LINK)
        os.symlink(wallpaper, WP_LINK)


def generate_directory_menu(dirname, tree):
    """
    Generates the Openbox menuitems for a given directory.
    """
    for name in sorted(os.listdir(dirname)):
        full_path = path.join(dirname, name)
        if path.isfile(full_path):
            tree.start("item", {"label": name[: name.rfind(".")]})
            tree.start("action", {"name": "Execute"})
            tree.start("execute")
            tree.data("%s '%s'" % (argv[0], full_path))
            tree.end("execute")
            tree.end("action")
            tree.end("item")
        # Unfortunately, submenus, either as pipemenus or directly embedded
        # in a pipemenu, aren't allowed, but we'll leave this in anyway as
        # if/when it does, it'll be a nice hidden bonus feature.
        elif path.isdir(full_path):
            tree.start("menu", {"label": name})
            generate_directory_menu(full_path, tree)
            tree.end("menu")


def generate_pipemenu(dirname):
    """
    Generates a pipemenu for a given directory.
    """
    tree = et.TreeBuilder()
    tree.start("openbox_pipe_menu")
    generate_directory_menu(dirname, tree)
    return et.tostring(tree.close(), "UTF-8")


def bad_path():
    """
    Generates a pipemenu indicating that the path given was not a valid one.
    """
    tree = et.TreeBuilder()
    tree.start("openbox_pipe_menu")
    tree.start("item", {"label": "Bad path"})
    return et.tostring(tree.close(), "UTF-8")


if __name__ == "__main__":
    if not path.exists(SETTINGS):
        os.makedirs(SETTINGS)
    if len(argv) == 1:
        # With no args, the currently selected wallpaper is rendered.
        show_wallpaper()
    elif len(argv) >= 2:
        if path.isdir(argv[1]):
            # With one arg that' a directory, a pipemenu of that directory's
            # contents is generated.
            print(generate_pipemenu(argv[1]))
        elif path.isfile(argv[1]):
            # With one arg that's a file, that file is make the current
            # wallpaper.
            set_wallpaper(path.realpath(argv[1]))
            show_wallpaper()
        else:
            print(bad_path())
            print("Bad path.", file=sys.stderr)