# Copyright 2021 (c) Anna Schumaker.
from gi.repository import GLib
from gi.repository import GObject
from . import task

class TaskQueue(GObject.GObject):
    def __init__(self):
        GObject.GObject.__init__(self)
        self.tasks  = [ ]
        self.total  = 0
        self.idleid = None

    def __del__(self):
        if self.idleid != None:
            GLib.source_remove(self.idleid)

    def push(self, task):
        self.emit("task-pushed", task)

    def clear(self):
        self.emit("tasks-finished")

    def run(self):
        self.emit("run-task", self.tasks.pop(0))
        if len(self.tasks) > 0:
            return GLib.SOURCE_CONTINUE

        self.emit("tasks-finished")
        return GLib.SOURCE_REMOVE

    @GObject.Property
    def progress(self):
        if len(self.tasks) == 0:
            return 0
        return (self.total - len(self.tasks)) / self.total

    @GObject.Signal(arg_types=(task.Task,))
    def task_pushed(self, task):
        self.tasks.append(task)
        self.total += 1
        if self.idleid == None:
            self.idleid = GLib.idle_add(self.run)

    @GObject.Signal(arg_types=(task.Task,))
    def run_task(self, task):
        if tasks := task.run_task():
            self.tasks += tasks
            self.total += len(tasks)

    @GObject.Signal
    def tasks_finished(self):
        if self.idleid:
            GLib.source_remove(self.idleid)
            self.tasks.clear()
            self.total  = 0
            self.idleid = None