import os
from enum import Enum

from PyQt5.QtCore import Qt
from PyQt5.QtGui import QCursor
from PyQt5 import QtWidgets, uic

from clusterview.exceptions import handle_exceptions, InvalidModeError
from clusterview.mode import Mode
from clusterview.mode_handlers import MODE_HANDLER_MAP
from clusterview.opengl_widget import (initialize_gl, paint_gl, resize_gl,
                                       set_drawing_mode, set_drawing_context)
from clusterview_ui import Ui_MainWindow

class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
    """
    A wrapper class for handling creating a window based
    on the `clusterview_ui.py` code generated from
    `clusterview.ui`.
    """

    __mode = Mode.OFF

    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.setupUi(self)

        # We only need to set the context in our OpenGL state machine
        # wrapper once here since the window is fixed size.
        # If we allow resizing of the window, the context must be updated
        # each resize so that coordinates are converted from screen (x, y)
        # to OpenGL coordinates properly.
        set_drawing_context(self.opengl_widget)

        #-----------------------------------------------
        # OpenGL Graphics Handlers are set
        # here and defined in clusterview.opengl_widget.
        #-----------------------------------------------
        self.opengl_widget.initializeGL = initialize_gl
        self.opengl_widget.paintGL = paint_gl
        self.opengl_widget.resizeGL = resize_gl

        # -------------------------------------
        # UI Handlers
        # -------------------------------------
        self.action_add_points.triggered.connect(self.__add_points)
        self.action_edit_points.triggered.connect(self.__edit_points)
        self.action_delete_points.triggered.connect(self.__delete_points)
        self.action_move_points.triggered.connect(self.__move_points)
        self.action_solve.triggered.connect(self.__solve_launcher)

        # Override handler for mouse press so we can draw points based on
        # the OpenGL coordinate system inside of the OpenGL Widget.
        self.opengl_widget.mousePressEvent = self.__ogl_click_dispatcher

    #-----------------------------------------------------------------
    # Mode changers - these will be used to signal the action in the
    #                 OpenGL Widget.
    #-----------------------------------------------------------------
    def __add_points(self):
        self.__mode = Mode.ADD
        set_drawing_mode(self.__mode)
        self.opengl_widget.setCursor(QCursor(Qt.CursorShape.CrossCursor))

    def __edit_points(self):
        self.__mode = Mode.EDIT
        set_drawing_mode(self.__mode)
        self.opengl_widget.setCursor(QCursor(Qt.CursorShape.CrossCursor))

    def __delete_points(self):
        self.__mode = Mode.DELETE
        set_drawing_mode(self.__mode)
        self.opengl_widget.setCursor(QCursor(Qt.CursorShape.PointingHandCursor))

    def __move_points(self):
        self.__mode = Mode.MOVE
        set_drawing_mode(self.__mode)
        self.opengl_widget.setCursor(QCursor(Qt.CursorShape.SizeAllCursor))

    @handle_exceptions
    def __solve_launcher(self):
        """
        Launched the solve menu. This function will call into a subclass
        of the solve dialog widget from the UI.

        TODO: Write the subclass once you know the parameters for the
              solve window.
        """
        print("LAUNCHING SOLVE DIALOG...")


    @handle_exceptions
    def __ogl_click_dispatcher(self, event):
        """
        Mode dispatcher for click actions on the OpenGL widget.
        """
        if self.__mode is Mode.OFF:
            raise InvalidModeError(Mode.OFF)

        # Map from Mode -> function
        # where the function is a handler for the
        # OpenGL Widget.
        MODE_HANDLER_MAP[self.__mode](self.opengl_widget, event)