"""Display a game area."""

import pygame
import pymunk
import pymunk.pygame_util

from nagslang.events import ScreenChange
from nagslang.game_object import FloorSwitch
from nagslang.level import Level
from nagslang.protagonist import Protagonist
from nagslang.screens.base import Screen


class ControlKeys(object):
    def __init__(self):
        self.keys_down = set()

    def key_down(self, key):
        self.keys_down.add(key)

    def key_up(self, key):
        self.keys_down.discard(key)

    def handle_event(self, ev):
        if ev.type == pygame.locals.KEYDOWN:
            self.key_down(ev.key)
        elif ev.type == pygame.locals.KEYUP:
            self.key_up(ev.key)


class AreaScreen(Screen):

    def setup(self):
        self.keys = ControlKeys()
        self._level = Level(self.name)
        self._level.load()
        self.add_walls()
        self.add_protagonist()

    def add_walls(self):
        self.walls = []
        body = pymunk.Body()
        body.position = (0, 0)
        walls = self._level.get_walls()
        for wall in walls:
            corners = wall
            corner = corners[-1]
            for next_corner in corners:
                wall = pymunk.Segment(body, corner, next_corner, 5)
                wall.elasticity = 1.0
                self.walls.append(wall)
                corner = next_corner
        self.space.add(*self.walls)

    def add_protagonist(self):
        self.protagonist = Protagonist((400, 300))
        self.protagonist.add_to_space(self.space)
        self.toy_switch = FloorSwitch((300, 400))
        self.toy_switch.add_to_space(self.space)

    def handle_event(self, ev):
        if ev.type == pygame.locals.KEYDOWN:
            if ev.key == pygame.locals.K_ESCAPE:
                ScreenChange.post('menu')
            if ev.key == pygame.locals.K_w:
                self.protagonist.toggle_form()
        self.keys.handle_event(ev)

    def _calc_viewport(self, level_surface, display_surface):
        level_size = level_surface.get_size()
        display_size = display_surface.get_size()
        protagnist_pos = self.protagonist.physicser.render_position(
                level_surface)
        x_wide = display_size[0] // 2
        y_wide = display_size[1] // 2
        if protagnist_pos[0] < x_wide:
            x = 0
        elif protagnist_pos[0] > level_size[0] - x_wide:
            x = level_size[0] - display_size[0]
        else:
            x = protagnist_pos[0] - x_wide
        if protagnist_pos[1] < y_wide:
            y = 0
        elif protagnist_pos[1] > level_size[1] - y_wide:
            y = level_size[1] - display_size[1]
        else:
            y = protagnist_pos[1] - y_wide
        return pygame.rect.Rect(x, y, display_size[0], display_size[1])

    def render(self, surface):
        #surface.fill(pygame.color.Color(0, 0, 0))
        background = self._level.get_background()
        mysurface = background.copy()
        self.toy_switch.render(mysurface)
        self.protagonist.render(mysurface)
        render_rect = self._calc_viewport(mysurface, surface)
        surface.blit(mysurface, (0, 0), render_rect)

    def tick_protagonist(self):
        dx, dy = 0, 0
        for key, tx, ty in [
            (pygame.locals.K_UP, 0, 1), (pygame.locals.K_DOWN, 0, -1),
            (pygame.locals.K_LEFT, -1, 0), (pygame.locals.K_RIGHT, 1, 0)
        ]:
            if key in self.keys.keys_down:
                dx += tx
                dy += ty
        self.protagonist.set_direction(dx, dy)

    def tick(self, seconds):
        self.tick_protagonist()
        super(AreaScreen, self).tick(seconds)