import gradio as gr
from transformers import DonutProcessor, VisionEncoderDecoderModel
import requests
from PIL import Image
import torch, os, re

torch.hub.download_url_to_file('https://raw.githubusercontent.com/vis-nlp/ChartQA/main/ChartQA%20Dataset/test/png/multi_col_40777.png', 'chart_example_1.png')
torch.hub.download_url_to_file('https://raw.githubusercontent.com/vis-nlp/ChartQA/main/ChartQA%20Dataset/test/png/OECD_SECONDARY_GRADUATION_RATE_ESP_ITA_MEX_000019.png', 'chart_example_2.png')


model_name = "ahmed-masry/unichart-chartqa-960"
model = VisionEncoderDecoderModel.from_pretrained(model_name)
processor = DonutProcessor.from_pretrained(model_name)
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
model.to(device)


def predict(image, input_prompt):
    input_prompt = "<chartqa> " + input_prompt + " <s_answer>"
    decoder_input_ids = processor.tokenizer(input_prompt, add_special_tokens=False, return_tensors="pt").input_ids
    pixel_values = processor(image, return_tensors="pt").pixel_values
    
    outputs = model.generate(
        pixel_values.to(device),
        decoder_input_ids=decoder_input_ids.to(device),
        max_length=model.decoder.config.max_position_embeddings,
        early_stopping=True,
        pad_token_id=processor.tokenizer.pad_token_id,
        eos_token_id=processor.tokenizer.eos_token_id,
        use_cache=True,
        num_beams=4,
        bad_words_ids=[[processor.tokenizer.unk_token_id]],
        return_dict_in_generate=True,
    )
    sequence = processor.batch_decode(outputs.sequences)[0]
    sequence = sequence.replace(processor.tokenizer.eos_token, "").replace(processor.tokenizer.pad_token, "")
    sequence = sequence.split("<s_answer>")[1].strip()
    return sequence

   
image = gr.inputs.Image(type="pil", label="Chart Image")
input_prompt = gr.inputs.Textbox(label="Question")
model_output = gr.outputs.Textbox(label="Model Output")
examples = [["chart_example_1.png", "What is the lowest value in blue bar?"],
            ["chart_example_2.png", "Which country has highest secondary graduation rate in 2018?"]]

title = "Interactive Gradio Demo for UniChart-ChartQA model"
interface = gr.Interface(fn=predict, 
                         inputs=[image, input_prompt], 
                         outputs=model_output, 
                         examples=examples, 
                         title=title,
                         theme='gradio/soft',
                         enable_queue=True)

interface.launch()