# Copyright 2021 (c) Anna Schumaker.
from . import publisher
import threading
from gi.repository import GLib

Start = publisher.Publisher()
RETRY = GLib.SOURCE_CONTINUE

class Bus:
    def __init__(self, milliseconds):
        self.timeout = milliseconds
        self.timeout_id = None
        self.passengers = [ ]
        self.lock = threading.Lock()

    def __do_board(self, func, *args):
        with self.lock:
            if (func, args) not in self.passengers:
                self.passengers.append( (func, args) )
            if self.timeout_id == None:
                self.timeout_id = GLib.timeout_add(self.timeout, self.run)
                return True
        return False

    def board(self, func, *args):
        if self.__do_board(func, *args):
            Start.publish(self)

    def clear(self):
        with self.lock:
            if self.timeout_id:
                GLib.source_remove(self.timeout_id)
                self.timeout_id = None
            self.passengers.clear()

    def complete(self):
        with self.lock:
            for (func, args) in self.passengers:
                func(*args)

            GLib.source_remove(self.timeout_id)
            self.timeout_id = None
            self.passengers.clear()

    def running(self):
        with self.lock:
            return self.timeout_id != None

    def run(self):
        with self.lock:
            (func, args) = self.passengers[0]
            if func(*args) == RETRY:
                return GLib.SOURCE_CONTINUE

            self.passengers.pop(0)
            if len(self.passengers) == 0:
                self.timeout_id = None
                return GLib.SOURCE_REMOVE
            return GLib.SOURCE_CONTINUE