from PyQt5 import QtWidgets, QtCore
from typing import List, Tuple

from todo.model.tag import Tag
import todo.db.tags
import todo.database

class SelectionSignal(QtCore.QObject):
    _signal = QtCore.pyqtSignal(list, name = "selection")

    def __init__(self):
        QtCore.QObject.__init__(self)

    def emit(self, tag_ids):
        self._signal.emit(tag_ids)

    def connect(self, f):
        self._signal.connect(f)

def widget(parent, init_tags: List[int]) -> Tuple[QtWidgets.QWidget, SelectionSignal]:
    widget = QtWidgets.QWidget(parent)
    signal = SelectionSignal()

    layout = QtWidgets.QVBoxLayout(widget)
    widget.setLayout(layout)

    layout.addWidget(QtWidgets.QLabel("Tags"))

    list_widget = QtWidgets.QListWidget()
    list_widget.setSelectionMode(QtWidgets.QAbstractItemView.MultiSelection)
    layout.addWidget(list_widget)

    tags = sorted(todo.db.tags.get(todo.database.cursor()), key=lambda t: t.name)

    for tag in tags:
        item = QtWidgets.QListWidgetItem(tag.name)
        list_widget.addItem(item)
        if tag.id in init_tags:
            item.setSelected(True)

    def on_item_selection_changed():
        tag_texts = [item.text() for item in list_widget.selectedItems()]
        signal.emit([tag.id for tag in tags if tag.name in tag_texts])

    list_widget.itemSelectionChanged.connect(on_item_selection_changed)

    return (widget, signal)