app.py

import gradio as gr
import chess
import chess.svg
from collections import deque
from transformers import pipeline
import torch

DEBUG = False
device = "cuda" if torch.cuda.is_available() else "cpu"
pipe = pipeline(
    "text-generation", 
    model="jrahn/rookworld_7m_3e_gpt2_124M_hf",
    torch_dtype=torch.bfloat16,
    device=device
)
pipe.tokenizer.pad_token_id = pipe.model.config.eos_token_id
pipe.tokenizer.padding_side = "left"
sampling_args = {
    "do_sample": True,
    "temperature": 0.7,
    "top_k": 15,
    "truncation": True,
    "return_full_text": False,
    "pad_token_id": pipe.tokenizer.eos_token_id,
    "max_length": 186
}
START_POSITION = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"

def generate_action(state):
    prompt = f"P: {state} "
    if DEBUG: print(prompt)
    generation = pipe(prompt, **sampling_args)
    if DEBUG: print(generation)
    try:
        action = generation[0]['generated_text'].split("B: ")[-1].strip()
        gr.Info(f"Policy generated move: {action}", duration=3)
    except:
        gr.Info(f"Policy generation invalid: {generation}", duration=None)
        action = "0000"
    if DEBUG: print(action)
    return action

def generate_state(state, action, history):
    if DEBUG: print(state, action, history)
    history_text = " ".join(history[-10:])
    prompt = f"A: {state}+{action}+{history_text}+"
    if DEBUG: print(prompt)
    generation = pipe(prompt, **sampling_args)
    if DEBUG: print(generation)
    try:
        new_state, reward, terminated, truncated = generation[0]['generated_text'].split("+")
        #gr.Info(f"Environment generated state: {new_state}", duration=3)
    except:
        new_state, reward, terminated, truncated = START_POSITION, "0", "0", "1"
        gr.Info(f"Environment generation invalid: {generation}", duration=None)
    if DEBUG: print(new_state, reward, terminated, truncated)
    return new_state, reward, terminated, truncated

def step_episode(inputs):
    state, history = inputs
    action = generate_action(state)
    if action == "0000":
        svg_string = create_chess_board_svg()
        return svg_string, START_POSITION, "", [START_POSITION, []]
    history.append(action)
    
    new_state, reward, terminated, truncated = generate_state(state, action, history)

    if int(terminated):
        player = "White" if state.split()[1] == 'w' else "Black"
        result_message = ""
        if reward == "-1":
            result_message = f"Environment ended game: {player} lost!"
        elif reward == "1":
            result_message = f"Environment ended game: {player} won!"
        elif reward == "0.5":
            result_message = "Environment ended game: It's a draw!"
        else:
            result_message = "Environment ended game: Unexpected outcome"
        
        gr.Info(result_message, duration=None)
        svg_string = create_chess_board_svg()
        return svg_string, START_POSITION, "", [START_POSITION, []]
    
    if int(truncated):
        gr.Info(f"Environment ended game: ILLEGAL_MOVE", duration=None)
        svg_string = create_chess_board_svg()
        return svg_string, START_POSITION, "", [START_POSITION, []]

    try:
        mv = chess.Move.from_uci(action)
        svg_string = create_chess_board_svg(new_state, lastmove=mv)
    except:
        svg_string = create_chess_board_svg(new_state)
    if not svg_string:
        svg_string = create_chess_board_svg()
        return svg_string, [START_POSITION, []], START_POSITION, ""
    return svg_string, new_state, ", ".join(history), [new_state, history]

def create_chess_board_svg(fen=None, lastmove=None):
    try:
        board = chess.Board(fen) if fen else chess.Board()
        return chess.svg.board(board, lastmove=lastmove, size=400)
    except:
        gr.Info(f"Python-Chess board visualization cannot be rendered from FEN: {fen}", duration=None)
        return ""
    
board = gr.HTML("""
    <div style='height: 400px; width: 400px; background-color: white;'></div>
    """, label="Chess Board")
state_fen = gr.Textbox(label="FEN")
move_history = gr.Textbox(label="Move history")
demo = gr.Interface(
    fn=step_episode,
    inputs=gr.State(value=[START_POSITION, []]),
    outputs=[board, state_fen, move_history, gr.State()],
    title="RookWorld Self-Play Demo",
    description="Click the Generate-Button to generate a new move and environment response. On CPU this can take ",
    allow_flagging="never",
    analytics_enabled=False,
    submit_btn="Generate",
    clear_btn="Reset",
)

demo.launch()