app.py

# app.py
import spaces
import ast
import torch
from PIL import Image, ImageDraw
import gradio as gr

from transformers import Qwen2_5_VLForConditionalGeneration, AutoProcessor
from qwen_vl_utils import process_vision_info  # include this file in your repo if not pip-installable

# ---- model & processor loaded on CPU ----
model = Qwen2_5_VLForConditionalGeneration.from_pretrained(
    "ByteDance-Seed/UI-TARS-1.5-7B",
    device_map="auto",
    torch_dtype=torch.float16,    # CPU‑friendly
)
processor = AutoProcessor.from_pretrained(
    "ByteDance-Seed/UI-TARS-1.5-7B",
    size={"shortest_edge": 100 * 28 * 28, "longest_edge": 16384 * 28 * 28},
    use_fast=True,
)


def draw_point(image: Image.Image, point=None, radius: int = 5):
    """Overlay a red dot on the screenshot where the model clicked."""
    img = image.copy()
    if point:
        x, y = point[0] * img.width, point[1] * img.height
        ImageDraw.Draw(img).ellipse(
            (x - radius, y - radius, x + radius, y + radius), fill="red"
        )
    return img


@spaces.GPU
def navigate(screenshot, task: str, platform: str, history):
    """Run one inference step on the GUI‑reasoning model.

    Args:
        screenshot (PIL.Image): Latest UI screenshot.
        task (str): Natural‑language task description.
        platform (str): Either "web" or "phone" for prompt conditioning.
        history (list | str | None): Previous messages list. Accepts either an
            actual Python list (via gr.JSON) or a JSON/Python‑literal string.
    """

    # ───────────────────── normalise history input ──────────────────────────
    messages=[]
  
    if isinstance(history, str):
        try:
            messages= ast.literal_eval(history)
        except Exception as exc:
            raise ValueError("`history` must be a JSON/Python list: " + str(exc))
    else:
        messages = history

    prompt_header = (
            "You are a GUI agent. You are given a task and your action history, with screenshots." 
            "You need to perform the next action to complete the task. \n\n## Output Format\n```\nThought: ...\nAction: ...\n```\n\n## Action Space\n\nclick(start_box='\u003c|box_start|\u003e(x1, y1)\u003c|box_end|\u003e')\nleft_double(start_box='\u003c|box_start|\u003e(x1, y1)\u003c|box_end|\u003e')\nright_single(start_box='\u003c|box_start|\u003e(x1, y1)\u003c|box_end|\u003e')\ndrag(start_box='\u003c|box_start|\u003e(x1, y1)\u003c|box_end|\u003e', end_box='\u003c|box_start|\u003e(x3, y3)\u003c|box_end|\u003e')\nhotkey(key='')\ntype(content='') #If you want to submit your input, use \"\\n\" at the end of `content`.\nscroll(start_box='\u003c|box_start|\u003e(x1, y1)\u003c|box_end|\u003e', direction='down or up or right or left')\nwait() #Sleep for 5s and take a screenshot to check for any changes.\nfinished(content='xxx') # Use escape characters \\', \\\", and \\n in content part to ensure we can parse the content in normal python string format.\n\n\n## Note\n- Use English in `Thought` part.\n- Write a small plan and finally summarize your next action (with its target element) in one sentence in `Thought` part.\n\n"
            f"## User Instruction\n{task}"
        )
    current = {"role":"user","content":[{"type":"text","text":prompt_header},{"type": "image_url", "image_url":screenshot}]}
    messages.append(current)

    # ─────────────────────────── model forward ─────────────────────────────
    text = processor.apply_chat_template(
        messages, tokenize=False, add_generation_prompt=True
    )
    images, videos = process_vision_info(messages)
    inputs = processor(
        text=[text],
        images=images,
        videos=videos,
        padding=True,
        return_tensors="pt",
    ).to("cuda")

    generated = model.generate(**inputs, max_new_tokens=128)
    trimmed = [
        out_ids[len(in_ids) :] for in_ids, out_ids in zip(inputs.input_ids, generated)
    ]
    raw_out = processor.batch_decode(
        trimmed, skip_special_tokens=True, clean_up_tokenization_spaces=False
    )[0]

    # ─────── draw predicted click for quick visual verification (optional) ──────
    try:
        actions = ast.literal_eval(raw_out)
        for act in actions if isinstance(actions, list) else [actions]:
            pos = act.get("position")
            if pos and isinstance(pos, list) and len(pos) == 2:
                screenshot = draw_point(screenshot, pos)
    except Exception:
        # decoding failed → just return original screenshot
        pass

    return screenshot, raw_out


# ────────────────────────── Gradio interface ───────────────────────────────

demo = gr.Interface(
    fn=navigate,
    inputs=[
        gr.Image(type="pil", label="Screenshot"),
        gr.Textbox(
            lines=1,
            placeholder="e.g. Search the weather for New York",
            label="Task",
        ),
        gr.Dropdown(choices=["web", "phone"], value="web", label="Platform"),
        gr.JSON(label="Conversation History (list)", value=[]),
    ],
    outputs=[
        gr.Image(label="With Click Point"),
        gr.Textbox(label="Raw Action JSON"),
    ],
    title="UI-Tars Navigation Demo",
)

demo.launch(
    server_name="0.0.0.0",
    server_port=7860,
    share=False,      # or True if you need a public link
    ssr_mode=False,   # turn off experimental SSR so the process blocks
)