app.py

import json
import random
from pathlib import Path
import gradio as gr
import numpy as np
from transformers import AutoTokenizer, AutoModelForSequenceClassification, pipeline

# Constants
MIN_WORDS = 50
MAX_WORDS = 500
SAMPLE_JSON_PATH = Path('samples.json')

# Load models
def load_model(model_name):
    tokenizer = AutoTokenizer.from_pretrained(model_name)
    model = AutoModelForSequenceClassification.from_pretrained(model_name)
    return pipeline('text-classification', model=model, tokenizer=tokenizer, truncation=True, max_length=512, top_k=4)

classifier = load_model("ziadmostafa/MGT-Detection_deberta-base")

# Load sample essays
with open(SAMPLE_JSON_PATH, 'r') as f:
    demo_essays = json.load(f)

# Global variable to store the current essay index
current_essay_index = None

TEXT_CLASS_MAPPING = {
    'LABEL_0': 'Human-Written',
    'LABEL_2': 'Machine-Generated'
}

def process_result(text): 
    result = classifier(text)[0]

    labels = [TEXT_CLASS_MAPPING[x['label']] for x in result if x['label'] in TEXT_CLASS_MAPPING]
    scores = list(np.array([x['score'] for x in result if x['label'] in TEXT_CLASS_MAPPING]))

    final_results = dict(zip(labels, scores))

    # Return only the label with the highest score
    return max(final_results, key=final_results.get)

def update_result(name):
    if name == '':
        return "" 
    return process_result(name)
   
def active_button(input_text):
    if not (50 <= len(input_text.split()) <= 500):
        return gr.Button("Check Origin", variant="primary", interactive=False) 
    return gr.Button("Check Origin", variant="primary", interactive=True)

def clear_inputs():
    return "", gr.Button("Check Origin", variant="primary", interactive=False)

def count_words(text): 
    return f'{len(text.split())}/500 words (Minimum 50 words)'

css = """
body, .gradio-container {
    font-family: Arial, sans-serif;
}
.gr-input, .gr-textarea {
}
.class-intro {
    padding: 15px;
    margin-bottom: 20px;
    border-radius: 5px;
}
.class-intro h2 {
    margin-top: 0;
}
.class-intro p {
    margin-bottom: 5px;
}
"""

class_intro_html = """
<div class="class-intro">
    <h2>Text Classes</h2>
    <p><strong>Human-Written:</strong> Original text created by humans.</p>
    <p><strong>Machine-Generated:</strong> Text created by AI from basic prompts, without style instructions.</p>
</div>
"""

with gr.Blocks(css=css) as demo:
    gr.Markdown("""<h1><centre>Machine Generated Text Detection</center></h1>""")
    gr.HTML(class_intro_html)

    with gr.Row():
        input_text = gr.Textbox(placeholder="Paste your text here...", label="Text", lines=10, max_lines=15)

    with gr.Row(): 
        wc = gr.Markdown("0/500 words (Minimum 50 words)")
    with gr.Row():
        check_button = gr.Button("Check Origin", variant="primary", interactive=False)
        clear_button = gr.ClearButton([input_text], variant="stop")

    out = gr.Label(label='Result')
    clear_button.add(out)

    check_button.click(fn=update_result, inputs=[input_text], outputs=out)

    input_text.change(count_words, input_text, wc, show_progress=False)
    input_text.input(
        active_button,
        [input_text],
        [check_button],
    )

    clear_button.click(
        clear_inputs,
        inputs=[],
        outputs=[input_text, check_button],
    )

demo.launch(share=False)