"""Gradio chat with code formatting and no image inputs."""
from functools import lru_cache
import os
import threading

from .runtime import CONFIG, answer, gpu_available, load_engine
import gradio as gr

LOCK = threading.Lock()
PREVIEW = os.environ.get("POCKETCHAT_PREVIEW") == "1" or not gpu_available()
ADAPTER = os.environ.get("POCKETCHAT_ADAPTER")


@lru_cache(maxsize=1)
def engine():
    return load_engine(ADAPTER)


def respond(message, history):
    if not message or not message.strip():
        raise gr.Error("Enter a message first.")
    if PREVIEW:
        raise gr.Error("The cloud model is not connected yet.")
    try:
        with LOCK:
            tokenizer, model = engine()
            reply = answer(tokenizer, model, message, history)
    except (ValueError, RuntimeError) as error:
        raise gr.Error(str(error)) from error
    return "", (history or []) + [
        {"role": "user", "content": message}, {"role": "assistant", "content": reply}]


with gr.Blocks(title=CONFIG["name"]) as demo:
    gr.Markdown("# PocketVision · Chat & Code\nA place to talk, learn, write code, and work through bugs.")
    if PREVIEW:
        gr.Markdown("**Interface preview** · The cloud model is not connected yet.")
    elif ADAPTER:
        gr.Markdown("Custom chat and programming model · Review generated code before using it.")
    else:
        gr.Markdown("Pretrained model · Custom chat and programming training is pending.")
    chatbot = gr.Chatbot(type="messages", label="Conversation", height=460, allow_tags=False)
    message = gr.Textbox(label="Your message", lines=3, max_lines=14,
                         placeholder="Ask a question, paste code, or describe a bug…", interactive=not PREVIEW)
    with gr.Row():
        send = gr.Button("Send", variant="primary", interactive=not PREVIEW)
        clear = gr.Button("New chat")
    gr.Examples([
        "Write a Python function that removes duplicates while preserving their order.",
        "Explain JavaScript async and await with a small example.",
        "Help me debug my code. I’ll paste it in the next message.",
    ], inputs=message)
    for event in [send.click, message.submit]:
        event(respond, [message, chatbot], [message, chatbot])
    clear.click(lambda: ("", []), outputs=[message, chatbot])


def launch():
    demo.queue(default_concurrency_limit=1).launch(
        server_name="0.0.0.0" if os.environ.get("SPACE_ID") else "127.0.0.1",
        server_port=int(os.environ.get("PORT", "7860")), share=False)


if __name__ == "__main__":
    launch()