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

import db.tasks
from model.task import Task, ValidTaskForm
from model import difficulty, priority
import gui.icons
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.MEDIUM
    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.MEDIUM
    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.icons.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.icons.dialog_cancel(cancel.style()))
    cancel.clicked.connect(on_cancel)
    layout.addWidget(cancel)

    return widget