""" A drag drawn line. """

from __future__ import with_statement

from enable.api import Line
from traits.api import Instance

from drawing_tool import DrawingTool


class DragLine(DrawingTool):
    """
    A drag drawn line.  This is not a straight line, but can be a free-form,
    curved path.
    """

    # Override the vertex color so as to not draw it.
    vertex_color = (0.0, 0.0, 0.0, 0.0)

    # Because this class subclasses DrawingTool and not Line, it contains
    # an instance of the Line primitive.
    line = Instance(Line, args=())

    # Override the default value of this inherited trait
    draw_mode="overlay"

    def reset(self):
        self.line.vertex_color = self.vertex_color
        self.line.points = []
        self.event_state = "normal"
        return

    #------------------------------------------------------------------------
    # "complete" state
    #------------------------------------------------------------------------

    def complete_draw(self, gc):
        """ Draw the completed line. """
        self.line.line_dash = None
        self.line._draw_mainlayer(gc)
        return

    #------------------------------------------------------------------------
    # "drawing" state
    #------------------------------------------------------------------------

    def drawing_draw(self, gc):
        self.line.line_dash = (4.0, 2.0)
        self.line._draw_mainlayer(gc)
        return

    def drawing_left_up(self, event):
        """ Handle the left mouse button coming up in the 'drawing' state. """
        self.event_state = 'complete'
        event.window.set_pointer('arrow')
        self.request_redraw()
        self.complete = True
        event.handled = True
        return

    def drawing_mouse_move(self, event):
        """ Handle the mouse moving in 'drawing' state. """
        last_point = self.line.points[-1]
        # If we have moved, we need to add a point.
        if last_point != (event.x + self.x, event.y - self.y):
            self.line.points.append((event.x + self.x, event.y - self.y))
            self.request_redraw()
        return

    #------------------------------------------------------------------------
    # "normal" state
    #------------------------------------------------------------------------

    def normal_left_down(self, event):
        """ Handle the left button down in the 'normal' state. """

        self.line.points.append((event.x + self.x, event.y - self.y))
        self.event_state = 'drawing'
        event.window.set_pointer('pencil')
        event.handled = True
        self.request_redraw()
        return
