# Copyright 2021 (c) Anna Schumaker.
from lib import counter
from lib import publisher
from . import tags

class TagStack:
    def __init__(self):
        self.tags = [ ]
        self.Counter = counter.Counter(-1, 99)
        self.PushPop = publisher.Publisher()
        self.NextTrack = publisher.Publisher()

    def __do_next__(self, tag):
        if track := tag.next():
            track.add_to_playlist("Previous")
        return track

    def __getstate__(self):
        return { "tags" : self.tags }

    def __setstate__(self, state):
        self.__dict__.update(state)
        self.Counter = counter.Counter(-1, 99)
        self.PushPop = publisher.Publisher()
        self.NextTrack = publisher.Publisher()

    def current(self):
        if len(self.tags) == 0:
            return tags.User.store["Collection"]
        return self.tags[0]

    def __next_track__(self):
        if len(self.tags) == 0:
            return self.__do_next__(tags.User["Collection"])
        if track := self.__do_next__(self.tags[0]):
            return track
        self.pop()
        return self.__next_track__()

    def next(self):
        ret = self.__next_track__()
        count = self.Counter.decrement()
        self.NextTrack.publish(ret)
        return (ret, count != -1)

    def pop(self):
        prev = self.tags.pop(0)
        self.PushPop.publish(prev, self.current())

    def previous(self):
        return tags.User["Previous"].next()

    def push(self, tag):
        prev = self.current()
        if tag == tags.User["Previous"]:
            return
        if tag == tags.User["Collection"]:
            self.tags.clear()
            self.PushPop.publish(prev, tags.User["Collection"])
            return
        if tag in self.tags:
            self.tags.remove(tag)

        self.tags.insert(0, tag)
        tag.stacked()
        self.PushPop.publish(prev, tag)

    def queue(self, track):
        track.add_to_playlist("Up Next")
        self.push(tags.User["Up Next"])

    def reset(self):
        self.tags.clear()
        self.count = None
        self.PushPop.reset()