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
from todo.model import difficulty, priority
import todo.gui.icon
import todo.gui.tasks.form.state
import todo.gui.tasks.duration
import todo.gui.tags.list

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, "Name", init_name)

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

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

    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))

    (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_duration,
            duration_input.textChanged,
            init_difficulty,
            difficulty_input.currentIndexChanged,
            init_priority,
            priority_input.currentIndexChanged,
            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 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 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 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("cancel", widget)
    cancel.setIcon(todo.gui.icon.dialog_cancel(cancel.style()))
    cancel.clicked.connect(on_cancel)
    layout.addWidget(cancel)

    return widget