app.py

import gradio as gr
import os
import json
import uuid
import torch
import datetime
import torch.nn as nn
from transformers import AutoTokenizer, AutoModel, AutoConfig
from huggingface_hub import HfApi, create_repo, hf_hub_download
from torchcrf import CRF

# Constants
HF_DATASET_REPO = "M2ai/mgtd-logs"
HF_TOKEN = os.getenv("Mgtd")
DATASET_CREATED = False

# Model identifiers
code = "ENG"
pntr = 2
model_name_or_path = "microsoft/mdeberta-v3-base"
hf_token = os.environ.get("Mgtd")  # Set this before running

# Download model checkpoint
file_path = hf_hub_download(
    repo_id="1024m/MGTD-Long-New",
    filename=f"{code}/mdeberta-epoch-{pntr}.pt",
    token=hf_token,
    local_dir="./checkpoints"
)

# Define CRF model
class AutoModelCRF(nn.Module):
    def __init__(self, model_name_or_path, dropout=0.075):
        super().__init__()
        self.config = AutoConfig.from_pretrained(model_name_or_path)
        self.num_labels = 2
        self.encoder = AutoModel.from_pretrained(model_name_or_path, trust_remote_code=True, config=self.config)
        self.dropout = nn.Dropout(dropout)
        self.linear = nn.Linear(self.config.hidden_size, self.num_labels)
        self.crf = CRF(self.num_labels, batch_first=True)

    def forward(self, input_ids, attention_mask):
        outputs = self.encoder(input_ids=input_ids, attention_mask=attention_mask)
        seq_output = self.dropout(outputs[0])
        emissions = self.linear(seq_output)
        tags = self.crf.decode(emissions, attention_mask.byte())
        return tags, emissions

# Load model
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
tokenizer = AutoTokenizer.from_pretrained(model_name_or_path)
model = AutoModelCRF(model_name_or_path)
checkpoint = torch.load(file_path, map_location="cpu")
model.load_state_dict(checkpoint.get("model_state_dict", checkpoint), strict=False)
model = model.to(device)
model.eval()

# Inference function

def get_word_probabilities(text):
    try:
        text = " ".join(text.split(" ")[:2048])
    except Exception as e:
        print("Error during text preprocessing:", e)
        return []

    try:
        inputs = tokenizer(text, return_tensors="pt", truncation=True, padding=True)
        inputs = {k: v.to(device) for k, v in inputs.items()}
    except Exception as e:
        print("Error during tokenization or moving inputs to device:", e)
        return []

    try:
        tokens = tokenizer.convert_ids_to_tokens(inputs["input_ids"][0])
    except Exception as e:
        print("Error during token conversion:", e)
        return []

    try:
        with torch.no_grad():
            tags, emission = model(input_ids=inputs["input_ids"], attention_mask=inputs["attention_mask"])
    except Exception as e:
        print("Error during model inference:", e)
        return []

    try:
        probs = torch.softmax(emission, dim=-1)[0, :, 1].cpu().numpy()
    except Exception as e:
        print("Error during softmax or extracting class probabilities:", e)
        return []

    word_probs = []
    current_word = ""
    current_probs = []

    try:
        for token, prob in zip(tokens, probs):
            if token in ["<s>", "</s>"]:
                continue
            if token.startswith("▁"):
                if current_word and current_probs:
                    word_probs.append(sum(current_probs) / len(current_probs))
                current_word = token[1:] if token != "▁" else ""
                current_probs = [prob]
            else:
                current_word += token
                current_probs.append(prob)
        if current_word and current_probs:
            word_probs.append(sum(current_probs) / len(current_probs))
    except Exception as e:
        print("Error during word aggregation:", e)
        return []
    word_probs = [float(p) for p in word_probs]

    return word_probs


    

# def get_word_classifications(text):
#     text = " ".join(text.split(" ")[:2048])
#     inputs = tokenizer(text, return_tensors="pt", truncation=True, padding=True)
#     inputs = {k: v.to(device) for k, v in inputs.items()}
#     tokens = tokenizer.convert_ids_to_tokens(inputs["input_ids"][0])
    
#     with torch.no_grad():
#         tags, emissions = model(input_ids=inputs["input_ids"], attention_mask=inputs["attention_mask"])

#     word_tags = []
#     color_output = []
#     current_word = ""
#     current_prob = 0.0

#     for token, prob in zip(tokens, tags[0]):
#         if token in ["<s>", "</s>"]:
#             continue
#         if token.startswith("▁"):
#             if current_word:
#                 word_tags.append(round(current_prob, 3))
#                 color = (
#                     "green" if current_prob < 0.25 else
#                     "yellow" if current_prob < 0.5 else
#                     "orange" if current_prob < 0.75 else
#                     "red"
#                 )
#                 color_output.append(f'<span style="color:{color}">{current_word}</span>')
#             current_word = token[1:] if token != "▁" else ""
#             current_prob = prob
#         else:
#             current_word += token
#             current_prob = max(current_prob, prob)

#     if current_word:
#         word_tags.append(round(current_prob, 3))
#         color = (
#             "green" if current_prob < 0.25 else
#             "yellow" if current_prob < 0.5 else
#             "orange" if current_prob < 0.75 else
#             "red"
#         )
#         color_output.append(f'<span style="color:{color}">{current_word}</span>')

#     output = " ".join(color_output)
#     return output, word_tags


# HF logging setup
def setup_hf_dataset():
    global DATASET_CREATED
    if not DATASET_CREATED and HF_TOKEN:
        try:
            create_repo(HF_DATASET_REPO, repo_type="dataset", token=HF_TOKEN, exist_ok=True)
            DATASET_CREATED = True
            print(f"Dataset {HF_DATASET_REPO} is ready.")
        except Exception as e:
            print(f"Error setting up dataset: {e}")

# Main inference + logging function
def infer_and_log(text_input):
    word_tags = get_word_probabilities(text_input)
    timestamp = datetime.datetime.now().isoformat()
    submission_id = str(uuid.uuid4())

    log_data = {
        "id": submission_id,
        "timestamp": timestamp,
        "input": text_input,
        "output_tags": word_tags
    }

    os.makedirs("logs", exist_ok=True)
    log_file = f"logs/{timestamp.replace(':', '_')}.json"
    with open(log_file, "w") as f:
        json.dump(log_data, f, indent=2)

    if HF_TOKEN and DATASET_CREATED:
        try:
            HfApi().upload_file(
                path_or_fileobj=log_file,
                path_in_repo=f"logs/{os.path.basename(log_file)}",
                repo_id=HF_DATASET_REPO,
                repo_type="dataset",
                token=HF_TOKEN
            )
            print(f"Uploaded log {submission_id}")
        except Exception as e:
            print(f"Error uploading log: {e}")

    return json.dumps(word_tags, indent=2)


def clear_fields():
    return "", ""

# Prepare dataset once
setup_hf_dataset()

# Gradio UI
with gr.Blocks() as app:
    gr.Markdown("Machine Generated Text Detector")

    with gr.Row():
        input_box = gr.Textbox(label="Input Text", lines=10)
        output_box = gr.Textbox(label="Output Text", lines=10, interactive=False)

    with gr.Row():
        submit_btn = gr.Button("Submit")
        clear_btn = gr.Button("Clear")
        
    
    submit_btn.click(fn=infer_and_log, inputs=input_box, outputs=output_box)
    clear_btn.click(fn=clear_fields, outputs=[input_box, output_box])

if __name__ == "__main__":
    app.launch()