import os
import shutil
import beets.plugins

class ExtrasPlugin(beets.plugins.BeetsPlugin):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.register_listener('item_moved', self.on_item_moved)
        self.register_listener('item_copied', self.on_item_copied)

    def on_item_moved(self, item, source, destination):
        for (sourcepath, destpath) in self.gather(source, destination):
            os.rename(sourcepath, destpath)

    def on_item_copied(self, item, source, destination):
        for (sourcepath, destpath) in self.gather(source, destination):
            if os.path.isdir(sourcepath):
                shutil.copytree(sourcepath, destpath)
            else:
                shutil.copy(sourcepath, destpath)

    def gather(self, source, destination):
        candidates = []
        sourcedir = os.path.dirname(source)
        destdir = os.path.dirname(destination)

        if sourcedir == destdir:
            return []

        paths = [beets.util.bytestring_path(p) for p in self.config['paths'].get()]

        for path in paths:
            sourcepath = os.path.join(sourcedir, path)
            if not os.path.exists(sourcepath):
                continue

            destpath = os.path.join(destdir, path)
            if os.path.exists(destpath):
                continue

            candidates.append((sourcepath, destpath))

        return candidates