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

from todo.model.task import Task, ValidTaskForm
from todo.model.tag import Tag
import todo.gui.icon
import todo.gui.tasks.form.state
import todo.gui.tags.list
from todo.util.gui.date_input import DateInput

class TextEditSignal(QtCore.QObject):
    _signal = QtCore.pyqtSignal(str, name = "textEdit")

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

    def emit(self, text: str):
        self._signal.emit(text)

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

def widget(
        parent: QtWidgets.QWidget,
        action_title: str,
        task: Task,
        tags: List[int],
        on_validated,
        on_cancel):

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

    init_name = task.name if task is not None else ""
    name_input = name_edit(widget, layout, "Nom", init_name)

    init_due_date = (task.due_date.strftime("%d/%m/%Y") if task.due_date else None) if task else None
    (due_date_input, due_date_signal) = date_edit(widget, "Échéance", init_due_date)
    layout.addWidget(due_date_input)

    (tags_list_widget, tags_signal) = tags_selection(widget, tags)
    layout.addWidget(tags_list_widget)

    init_description = task.description if task is not None else ""
    (description_input, description_signal) = text_edit(widget, "Description", init_description)
    layout.addWidget(description_input)

    task_form_edition = todo.gui.tasks.form.state.TaskFormEdition(
            init_name,
            name_input.textChanged,
            init_due_date,
            due_date_signal,
            tags,
            tags_signal,
            init_description,
            description_signal)

    def on_validate():
        form = task_form_edition.get()
        if form:
            on_validated(form)

    layout.addWidget(buttons(
            parent = widget,
            action_title = action_title,
            task_form_signal = task_form_edition.signal(),
            on_validate = on_validate,
            on_cancel = on_cancel))

    return widget

def name_edit(
        parent,
        layout: QtWidgets.QVBoxLayout,
        label: str,
        default_value: str) -> QtWidgets.QLineEdit:

    widget = QtWidgets.QWidget(parent)
    inner_layout = QtWidgets.QVBoxLayout(widget)
    widget.setLayout(inner_layout)

    label = QtWidgets.QLabel(label, parent)
    inner_layout.addWidget(label)

    edit = QtWidgets.QLineEdit(parent)
    if default_value != None:
        edit.setText(default_value)
    inner_layout.addWidget(edit)

    layout.addWidget(widget)

    return edit

def combo_box(
        parent,
        layout: QtWidgets.QGridLayout,
        n: int,
        label: str,
        values: List[str],
        default_value: int) -> QtWidgets.QComboBox:

    label = QtWidgets.QLabel(label, parent)
    layout.addWidget(label, n, 0)

    box = QtWidgets.QComboBox(parent)
    for value in values:
        box.addItem(value)
    if default_value != None:
        box.setCurrentIndex(default_value)
    layout.addWidget(box, n, 1)

    return box

def tags_selection(parent, init_tags: List[int]) -> QtWidgets.QWidget:
    return todo.gui.tags.list.widget(parent, init_tags)

def text_edit(
        parent,
        label: str,
        default_value: str
    ) -> Tuple[QtWidgets.QWidget, TextEditSignal]:

    widget = QtWidgets.QWidget(parent)
    layout = QtWidgets.QVBoxLayout(widget)

    signal = TextEditSignal()

    label = QtWidgets.QLabel(label, parent)
    layout.addWidget(label)

    edit = QtWidgets.QTextEdit(parent)
    if default_value != None:
        edit.insertPlainText(default_value)
    layout.addWidget(edit)

    edit.textChanged.connect(lambda: signal.emit(edit.toPlainText()))

    return (widget, signal)

def date_edit(
        parent,
        label: str,
        init_date: str
    ) -> QtWidgets.QLineEdit:

    widget = QtWidgets.QWidget(parent)
    layout = QtWidgets.QVBoxLayout(widget)

    label = QtWidgets.QLabel(label, parent)
    layout.addWidget(label)

    date_input = DateInput(init_date, parent)
    layout.addWidget(date_input)

    return (widget, date_input.textChanged)

def buttons(parent, action_title, task_form_signal, on_validate, on_cancel):
    widget = QtWidgets.QWidget(parent)
    layout = QtWidgets.QHBoxLayout(widget)

    validate = QtWidgets.QPushButton(action_title, widget)
    validate.setDisabled(True)
    validate.setIcon(todo.gui.icon.dialog_ok(validate.style()))
    validate.clicked.connect(on_validate);
    layout.addWidget(validate)

    def on_task_form_signal(form: Optional[ValidTaskForm]):
        if form:
            validate.setEnabled(True)
        else:
            validate.setDisabled(True)

    task_form_signal.connect(on_task_form_signal)

    cancel = QtWidgets.QPushButton("Annuler", widget)
    cancel.setIcon(todo.gui.icon.dialog_cancel(cancel.style()))
    cancel.clicked.connect(on_cancel)
    layout.addWidget(cancel)

    return widget