import pygame
import time
import numpy as np
from stable_baselines3 import PPO
from gymnasium import spaces
import gymnasium as gym

# -------------------------
# Side-Scrolling PixelCopter Environment (Medium/Certification Friendly)
# -------------------------
class PixelCopterCertEnv(gym.Env):
    def __init__(self, screen_width=50, screen_height=10, gap_size=6):
        super().__init__()
        self.screen_width = screen_width
        self.screen_height = screen_height
        self.copter_y = self.screen_height // 2
        self.copter_velocity = 0
        self.gravity = 0.25
        self.lift = -0.9
        self.done = False
        self.timestep = 0
        self.max_timesteps = 500
        self.gap_size = gap_size
        self.wall_gap_positions = [np.random.randint(1, self.screen_height - self.gap_size -1) 
                                   for _ in range(screen_width)]
        self.action_space = spaces.Discrete(2)
        self.observation_space = spaces.Box(
            low=0, high=self.screen_height, shape=(self.screen_width + 1,), dtype=np.float32
        )

    def reset(self, seed=None, options=None):
        self.copter_y = self.screen_height // 2
        self.copter_velocity = 0
        self.done = False
        self.timestep = 0
        self.wall_gap_positions = [np.random.randint(1, self.screen_height - self.gap_size -1) 
                                   for _ in range(self.screen_width)]
        obs = np.array([self.copter_y] + self.wall_gap_positions, dtype=np.float32)
        return obs, {}

    def step(self, action):
        if action == 1:
            self.copter_velocity += self.lift
        self.copter_velocity += self.gravity
        self.copter_y += self.copter_velocity
        self.copter_y = np.clip(self.copter_y, 0, self.screen_height)

        self.wall_gap_positions = self.wall_gap_positions[1:]
        last_gap = self.wall_gap_positions[-1]
        new_gap = last_gap + np.random.choice([-1,0,1])
        new_gap = np.clip(new_gap, 1, self.screen_height - self.gap_size -1)
        self.wall_gap_positions.append(new_gap)

        gap_top = self.wall_gap_positions[0]
        gap_bottom = gap_top + self.gap_size
        if self.copter_y <= gap_top or self.copter_y >= gap_bottom:
            self.done = True
            reward = -5
        else:
            reward = 1

        self.timestep += 1
        if self.timestep >= self.max_timesteps:
            self.done = True

        obs = np.array([self.copter_y] + self.wall_gap_positions, dtype=np.float32)
        return obs, reward, self.done, False, {}

# -------------------------
# Pygame Setup
# -------------------------
pygame.init()
WINDOW_WIDTH = 800
WINDOW_HEIGHT = 400
WIN = pygame.display.set_mode((WINDOW_WIDTH, WINDOW_HEIGHT))
pygame.display.set_caption("PixelCopter Certification Test")
WHITE = (255,255,255)
BLUE = (0,102,255)
BLACK = (0,0,0)

def draw_screen(obs, env):
    WIN.fill(WHITE)
    scale_y = WINDOW_HEIGHT / env.screen_height
    scale_x = WINDOW_WIDTH / env.screen_width
    copter_y = int(obs[0])
    wall_gaps = [int(gap) for gap in obs[1:]]

    # Draw walls
    for i, gap_top in enumerate(wall_gaps):
        gap_bottom = gap_top + env.gap_size
        pygame.draw.rect(WIN, BLACK, pygame.Rect(i*scale_x, 0, scale_x, gap_top*scale_y))
        pygame.draw.rect(WIN, BLACK, pygame.Rect(i*scale_x, gap_bottom*scale_y, scale_x, WINDOW_HEIGHT - gap_bottom*scale_y))

    # Draw copter
    pygame.draw.rect(WIN, BLUE, pygame.Rect(50, copter_y*scale_y - 10, 20, 20))
    pygame.display.update()

# -------------------------
# Load Model & Test
# -------------------------
env = PixelCopterCertEnv(screen_width=80, screen_height=10, gap_size=6)
model = PPO.load("ppo_pixelcopter_cert")

episodes = 5
for ep in range(episodes):
    obs, _ = env.reset()
    done = False
    total_reward = 0
    while not done:
        for event in pygame.event.get():
            if event.type==pygame.QUIT:
                done=True
                pygame.quit()
        action, _ = model.predict(obs)
        obs, reward, done, truncated, info = env.step(action)
        total_reward += reward
        draw_screen(obs, env)
        time.sleep(0.03)
    print(f"Episode {ep+1} reward: {total_reward}")

pygame.quit()