# Source code for joy.vui.viewer

    # -*- coding: utf-8 -*-
    #
    #    Copyright © 2019 Simon Forman
    #
    #    This file is part of joy.py
    #
    #    joy.py is free software: you can redistribute it and/or modify
    #    it under the terms of the GNU General Public License as published by
    #    the Free Software Foundation, either version 3 of the License, or
    #    (at your option) any later version.
    #
    #    joy.py is distributed in the hope that it will be useful,
    #    but WITHOUT ANY WARRANTY; without even the implied warranty of
    #    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    #    GNU General Public License for more details.
    #
    #    You should have received a copy of the GNU General Public License
    #    along with joy.py.  If not see <http://www.gnu.org/licenses/>.
    #
    '''

    Viewer
    =================

    '''
    import pygame
    from joy.vui.core import BACKGROUND, FOREGROUND

    class Viewer(object):
        '''
        Base Viewer class
        '''

        MINIMUM_HEIGHT = 11

        def __init__(self, surface):
            self.resurface(surface)
            self.last_touch = 0, 0

        def resurface(self, surface):
            self.w, self.h = surface.get_width(), surface.get_height()
            self.surface = surface

        def split(self, y):
            '''
            Split the viewer at the y coordinate (which is relative to the
            viewer's surface and must be inside it somewhere) and return the
            remaining height.  The upper part of the viewer remains (and gets
            redrawn on a new surface) and the lower space is now available
            for e.g. a new viewer.
            '''
            assert y >= self.MINIMUM_HEIGHT
            new_viewer_h = self.h - y
            self.resurface(self.surface.subsurface((0, 0, self.w, y)))
            if y <= self.last_touch[1]: self.last_touch = 0, 0
            self.draw()
            return new_viewer_h

        def handle(self, message):
            assert self is not message.sender
            pass

        def draw(self):
            '''Draw the viewer onto its surface.'''
            self.surface.fill(BACKGROUND)
            x, y, h = self.w - 1, self.MINIMUM_HEIGHT, self.h - 1
            # Right-hand side.
            pygame.draw.line(self.surface, FOREGROUND, (x, 0), (x, h))
            # Between header and body.
            pygame.draw.line(self.surface, FOREGROUND, (0, y), (x, y))
            # Bottom.
            pygame.draw.line(self.surface, FOREGROUND, (0, h), (x, h))

        def close(self):
            '''Close the viewer and release any resources, etc...'''

        def focus(self, display):
            pass

        def unfocus(self):
            pass

        # Event handling.

        def mouse_down(self, display, x, y, button):
            self.last_touch = x, y

        def mouse_up(self, display, x, y, button):
            pass

        def mouse_motion(self, display, x, y, dx, dy, button0, button1, button2):
            pass

        def key_up(self, display, key, mod):
            if key == pygame.K_q and mod & pygame.KMOD_CTRL: # Ctrl-q
                display.close_viewer(self)
                return True
            if key == pygame.K_g and mod & pygame.KMOD_CTRL: # Ctrl-g
                display.grow_viewer(self)
                return True

        def key_down(self, display, uch, key, mod):
            pass

    class SomeViewer(MenuViewer):

        def __init__(self, surface):
            MenuViewer.__init__(self, surface)

        def resurface(self, surface):
            MenuViewer.resurface(self, surface)

        def draw_menu(self):
            MenuViewer.draw_menu(self)

        def draw_body(self):
            pass

        def body_click(self, display, x, y, button):
            pass

        def menu_click(self, display, x, y, button):
            if MenuViewer.menu_click(self, display, x, y, button):
                return True

        def mouse_up(self, display, x, y, button):
            if MenuViewer.mouse_up(self, display, x, y, button):
                return True

        def mouse_motion(self, display, x, y, rel_x, rel_y, button0, button1, button2):
            if MenuViewer.mouse_motion(self, display, x, y, rel_x, rel_y,
                                   button0, button1, button2):
                return True

        def key_down(self, display, uch, key, mod):
            try:
                print chr(key),
            except ValueError:
                pass

    # Note that Oberon book says that if you split at the exact top of a viewer
    # it should close, and I think this implies the new viewer gets the old
    # viewer's whole height.  I haven't implemented that yet, so the edge-case
    # in the code is broken by "intent" for now..

    def draw_a(surface, color=FOREGROUND, blend=False):
        w, h = surface.get_width() - 2, surface.get_height() - 2
        pygame.draw.aalines(surface, color, False, (
            (1, h), (w / 2, 1), (w, h), (1, h / 2)
            ), blend)