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

from model.task import Task, ValidTaskForm
from model import difficulty, priority
import gui.icon
import gui.tasks.form.state
import gui.tasks.duration

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,
        on_validated,
        on_cancel):

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

    grid = QtWidgets.QWidget(widget)
    layout.addWidget(grid)
    grid_layout = QtWidgets.QGridLayout(grid)
    grid.setLayout(grid_layout)

    init_name = task.name if task is not None else ''
    name_input = line_edit(grid, grid_layout, 0, 'Name', init_name)

    init_duration = gui.tasks.duration.format(task.duration) if task is not None else ''
    duration_input = line_edit(grid, grid_layout, 1, 'Duration', init_duration)

    init_tag = task.tag if task is not None else ''
    tag_input = line_edit(grid, grid_layout, 2, 'Tag', init_tag)

    init_difficulty = task.difficulty if task is not None else difficulty.Difficulty.NORMAL
    difficulty_input = combo_box(
            grid,
            grid_layout,
            3,
            'Difficulty',
            [difficulty.format(d) for d in difficulty.values],
            int(init_difficulty))

    init_priority = task.priority if task is not None else priority.Priority.MIDDLE
    priority_input = combo_box(
            grid,
            grid_layout,
            4,
            'Priority',
            [priority.format(d) for d in priority.values],
            int(init_priority))

    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 = gui.tasks.form.state.TaskFormEdition(
            init_name,
            name_input.textChanged,
            init_duration,
            duration_input.textChanged,
            init_tag,
            tag_input.textChanged,
            init_difficulty,
            difficulty_input.currentIndexChanged,
            init_priority,
            priority_input.currentIndexChanged,
            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 line_edit(
        parent,
        layout: QtWidgets.QGridLayout,
        n: int,
        label: str,
        default_value: str) -> QtWidgets.QLineEdit:

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

    edit = QtWidgets.QLineEdit(parent)
    if default_value != None:
        edit.setText(default_value)
    layout.addWidget(edit, n, 1)

    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 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 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(gui.icon.dialog_apply(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('cancel', widget)
    cancel.setIcon(gui.icon.dialog_cancel(cancel.style()))
    cancel.clicked.connect(on_cancel)
    layout.addWidget(cancel)

    return widget