from PyQt5 import QtCore
from typing import Optional, List
from datetime import date, datetime

from todo.model.task import ValidTaskForm
import todo.gui.tags.list

class TaskFormEdition:
    def __init__(
            self,
            name,
            name_signal,
            due_date,
            due_date_signal,
            tags: List[int],
            tags_signal: todo.gui.tags.list.SelectionSignal,
            description,
            description_signal):

        self._name = name
        self._due_date = parse_date(due_date)
        self._tags = tags
        self._description = description
        self._signal = ValidTaskFormSignal()

        name_signal.connect(lambda n: self.on_name_signal(n))
        due_date_signal.connect(lambda d: self.on_due_date_signal(d))
        tags_signal.connect(lambda ts: self.on_tags_signal(ts))
        description_signal.connect(lambda d: self.on_description_signal(d))

    def get(self) -> Optional[ValidTaskForm]:
        name = self._name.strip()
        due_date = self._due_date
        description = self._description.strip()

        if name:
            return ValidTaskForm(
                name = name,
                due_date = due_date,
                tags = self._tags,
                description = description)
        else:
            return None

    def on_name_signal(self, name: str):
        self._name = name
        self.emit()

    def on_due_date_signal(self, due_date: str):
        self._due_date = parse_date(due_date)
        self.emit()

    def on_tags_signal(self, tags: List[int]):
        self._tags = tags
        self.emit()

    def on_description_signal(self, description: str):
        self._description = description
        self.emit()

    def emit(self):
        validForm = self.get()
        if validForm:
            self._signal.emit(validForm)

    def signal(self):
        return self._signal

class ValidTaskFormSignal(QtCore.QObject):
    _signal = QtCore.pyqtSignal(ValidTaskForm, name = "validTaskForm")

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

    def emit(self, form: Optional[ValidTaskForm]):
        self._signal.emit(form)

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

def parse_date(d: str) -> date:
    return datetime.strptime(d, "%d/%m/%Y").date() if d else None