predictors.py

import requests
import httpx
import torch
import re
from bs4 import BeautifulSoup
import numpy as np
from transformers import AutoTokenizer, AutoModelForSequenceClassification
import asyncio
from evaluate import load
from datetime import date
import nltk
from transformers import GPT2LMHeadModel, GPT2TokenizerFast
import plotly.graph_objects as go
import torch.nn.functional as F
import nltk
from unidecode import unidecode
import time
from scipy.special import softmax
import yaml
import os
from utils import *
import joblib

with open("config.yaml", "r") as file:
    params = yaml.safe_load(file)
nltk.download("punkt")
nltk.download("stopwords")
device = "cuda" if torch.cuda.is_available() else "cpu"
text_bc_model_path = params["TEXT_BC_MODEL_PATH"]
text_mc_model_path = params["TEXT_MC_MODEL_PATH"]
text_quillbot_model_path = params["TEXT_QUILLBOT_MODEL_PATH"]
text_1on1_models = params["TEXT_1ON1_MODEL"]
quillbot_labels = params["QUILLBOT_LABELS"]
mc_label_map = params["MC_OUTPUT_LABELS"]
text_1on1_label_map = params["1ON1_OUTPUT_LABELS"]
mc_token_size = int(params["MC_TOKEN_SIZE"])
bc_token_size = int(params["BC_TOKEN_SIZE"])
text_bc_tokenizer = AutoTokenizer.from_pretrained(text_bc_model_path)
text_bc_model = AutoModelForSequenceClassification.from_pretrained(
    text_bc_model_path
).to(device)
text_mc_tokenizer = AutoTokenizer.from_pretrained(text_mc_model_path)
text_mc_model = AutoModelForSequenceClassification.from_pretrained(
    text_mc_model_path
).to(device)
quillbot_tokenizer = AutoTokenizer.from_pretrained(text_quillbot_model_path)
quillbot_model = AutoModelForSequenceClassification.from_pretrained(
    text_quillbot_model_path
).to(device)
tokenizers_1on1 = {}
models_1on1 = {}
for model_name, model in zip(mc_label_map, text_1on1_models):
    tokenizers_1on1[model_name] = AutoTokenizer.from_pretrained(model)
    models_1on1[model_name] = AutoModelForSequenceClassification.from_pretrained(
        model
    ).to(device)

# proxy models for explainability
mini_bc_model_name = "polygraf-ai/bc-model-bert-mini"
bc_tokenizer_mini = AutoTokenizer.from_pretrained(mini_bc_model_name)
bc_model_mini = AutoModelForSequenceClassification.from_pretrained(
    mini_bc_model_name
).to(device)
mini_humanizer_model_name = "polygraf-ai/quillbot-detector-bert-mini-9K"
humanizer_tokenizer_mini = AutoTokenizer.from_pretrained(mini_humanizer_model_name)
humanizer_model_mini = AutoModelForSequenceClassification.from_pretrained(
    mini_humanizer_model_name
).to(device)

# model score calibration
iso_reg = joblib.load("isotonic_regression_model.joblib")


def split_text_allow_complete_sentences_nltk(
    text,
    max_length=256,
    tolerance=30,
    min_last_segment_length=100,
    type_det="bc",
):
    sentences = nltk.sent_tokenize(text)
    segments = []
    current_segment = []
    current_length = 0
    if type_det == "bc":
        tokenizer = text_bc_tokenizer
        max_length = bc_token_size
    elif type_det == "mc":
        tokenizer = text_mc_tokenizer
        max_length = mc_token_size
    for sentence in sentences:
        tokens = tokenizer.tokenize(sentence)
        sentence_length = len(tokens)

        if current_length + sentence_length <= max_length + tolerance - 2:
            current_segment.append(sentence)
            current_length += sentence_length
        else:
            if current_segment:
                encoded_segment = tokenizer.encode(
                    " ".join(current_segment),
                    add_special_tokens=True,
                    max_length=max_length + tolerance,
                    truncation=True,
                )
                segments.append((current_segment, len(encoded_segment)))
            current_segment = [sentence]
            current_length = sentence_length

    if current_segment:
        encoded_segment = tokenizer.encode(
            " ".join(current_segment),
            add_special_tokens=True,
            max_length=max_length + tolerance,
            truncation=True,
        )
        segments.append((current_segment, len(encoded_segment)))

    final_segments = []
    for i, (seg, length) in enumerate(segments):
        if i == len(segments) - 1:
            if length < min_last_segment_length and len(final_segments) > 0:
                prev_seg, prev_length = final_segments[-1]
                combined_encoded = tokenizer.encode(
                    " ".join(prev_seg + seg),
                    add_special_tokens=True,
                    max_length=max_length + tolerance,
                    truncation=True,
                )
                if len(combined_encoded) <= max_length + tolerance:
                    final_segments[-1] = (prev_seg + seg, len(combined_encoded))
                else:
                    final_segments.append((seg, length))
            else:
                final_segments.append((seg, length))
        else:
            final_segments.append((seg, length))

    decoded_segments = []
    encoded_segments = []
    for seg, _ in final_segments:
        encoded_segment = tokenizer.encode(
            " ".join(seg),
            add_special_tokens=True,
            max_length=max_length + tolerance,
            truncation=True,
        )
        decoded_segment = tokenizer.decode(encoded_segment)
        decoded_segments.append(decoded_segment)
    return decoded_segments


def predict_quillbot(text):
    with torch.no_grad():
        quillbot_model.eval()
        tokenized_text = quillbot_tokenizer(
            text,
            padding="max_length",
            truncation=True,
            max_length=256,
            return_tensors="pt",
        ).to(device)
        output = quillbot_model(**tokenized_text)
        output_norm = softmax(output.logits.detach().cpu().numpy(), 1)[0]
        q_score = {
            "Humanized": output_norm[1].item(),
            "Original": output_norm[0].item(),
        }
        return q_score


def predict_for_explainanility(text, model_type=None):
    if model_type == "quillbot":
        cleaning = False
        max_length = 256
        model = humanizer_model_mini
        tokenizer = humanizer_tokenizer_mini
    elif model_type == "bc":
        cleaning = True
        max_length = 512
        model = bc_model_mini
        tokenizer = bc_tokenizer_mini
    else:
        raise ValueError("Invalid model type")
    with torch.no_grad():
        if cleaning:
            text = [remove_special_characters(t) for t in text]
        tokenized_text = tokenizer(
            text,
            return_tensors="pt",
            padding="max_length",
            truncation=True,
            max_length=max_length,
        ).to(device)
        outputs = model(**tokenized_text)
        tensor_logits = outputs[0]
        probas = F.softmax(tensor_logits).detach().cpu().numpy()
    return probas


def predict_bc(model, tokenizer, text):
    with torch.no_grad():
        model.eval()
        tokens = text_bc_tokenizer(
            text,
            padding="max_length",
            truncation=True,
            max_length=bc_token_size,
            return_tensors="pt",
        ).to(device)
        output = model(**tokens)
        output_norm = softmax(output.logits.detach().cpu().numpy(), 1)[0]
        return output_norm


def predict_mc(model, tokenizer, text):
    with torch.no_grad():
        model.eval()
        tokens = text_mc_tokenizer(
            text,
            padding="max_length",
            truncation=True,
            return_tensors="pt",
            max_length=mc_token_size,
        ).to(device)
        output = model(**tokens)
        output_norm = softmax(output.logits.detach().cpu().numpy(), 1)[0]
        return output_norm

def predict_bc_scores(input):
    bc_scores = []
    samples_len_bc = len(split_text_allow_complete_sentences_nltk(input, type_det="bc"))
    segments_bc = split_text_allow_complete_sentences_nltk(input, type_det="bc")
    for i in range(samples_len_bc):
        cleaned_text_bc = remove_special_characters(segments_bc[i])
        bc_score = predict_bc(text_bc_model, text_bc_tokenizer, cleaned_text_bc)
        bc_scores.append(bc_score)
    bc_scores_array = np.array(bc_scores)
    average_bc_scores = np.mean(bc_scores_array, axis=0)
    bc_score_list = average_bc_scores.tolist()
    print(f"Original BC scores: AI: {bc_score_list[1]}, HUMAN: {bc_score_list[0]}")
    # isotonic regression calibration
    ai_score = iso_reg.predict([bc_score_list[1]])[0]
    human_score = 1 - ai_score
    bc_score = {"AI": ai_score, "HUMAN": human_score}
    print(f"Calibration BC scores: AI: {ai_score}, HUMAN: {human_score}")
    return bc_score


def predict_1on1(model, tokenizer, text):
    with torch.no_grad():
        model.eval()
        tokens = tokenizer(
            text,
            padding="max_length",
            truncation=True,
            return_tensors="pt",
            max_length=mc_token_size,
        ).to(device)
        output = model(**tokens)
        output_norm = softmax(output.logits.detach().cpu().numpy(), 1)[0]
        return output_norm


def predict_1on1_combined(input):
    predictions = []
    for i, model in enumerate(text_1on1_models):
        predictions.append(
            predict_1on1(models_1on1[model], tokenizers_1on1[model], input)[1]
        )
    return predictions


def predict_1on1_single(input, model):
    predictions = predict_1on1(models_1on1[model], tokenizers_1on1[model], input)[1]
    return predictions


def predict_mc_scores(input, models):

    if len(models) == 0:
        return {}

    print(f"Models to Test: {models}")
    # BC SCORE
    bc_scores = []
    samples_len_bc = len(split_text_allow_complete_sentences_nltk(input, type_det="bc"))
    segments_bc = split_text_allow_complete_sentences_nltk(input, type_det="bc")
    for i in range(samples_len_bc):
        cleaned_text_bc = remove_special_characters(segments_bc[i])
        bc_score = predict_bc(text_bc_model, text_bc_tokenizer, cleaned_text_bc)
        bc_scores.append(bc_score)
    bc_scores_array = np.array(bc_scores)
    average_bc_scores = np.mean(bc_scores_array, axis=0)
    bc_score_list = average_bc_scores.tolist()
    print(f"Original BC scores: AI: {bc_score_list[1]}, HUMAN: {bc_score_list[0]}")
    # isotonic regression calibration
    ai_score = iso_reg.predict([bc_score_list[1]])[0]
    human_score = 1 - ai_score
    bc_score = {"AI": ai_score, "HUMAN": human_score}
    print(f"Calibration BC scores: AI: {ai_score}, HUMAN: {human_score}")
    
    # MC SCORE
    if len(models) > 1:
        print("Starting MC")
        mc_scores = []
        segments_mc = split_text_allow_complete_sentences_nltk(input, type_det="mc")
        samples_len_mc = len(
            split_text_allow_complete_sentences_nltk(input, type_det="mc")
        )
        for i in range(samples_len_mc):
            cleaned_text_mc = remove_special_characters(segments_mc[i])
            mc_score = predict_mc(text_mc_model, text_mc_tokenizer, cleaned_text_mc)
            mc_scores.append(mc_score)
        mc_scores_array = np.array(mc_scores)
        average_mc_scores = np.mean(mc_scores_array, axis=0)
        mc_score_list = average_mc_scores.tolist()
        mc_score = {}
        for score, label in zip(mc_score_list, mc_label_map):
            mc_score[label.upper()] = score

        mc_score = {
            key: mc_score[key.upper()] for key in models if key.upper() in mc_score
        }
        total = sum(mc_score.values())
        # Normalize each value by dividing it by the total
        mc_score = {key: value / total for key, value in mc_score.items()}
        sum_prob = 1 - bc_score["HUMAN"]
        for key, value in mc_score.items():
            mc_score[key] = value * sum_prob
        print('MC Score:',mc_score)
        if sum_prob < 0.01:
            mc_score = {}

    elif len(models) == 1:
        print("Starting 1on1")
        mc_scores = []
        segments_mc = split_text_allow_complete_sentences_nltk(input, type_det="mc")
        samples_len_mc = len(
            split_text_allow_complete_sentences_nltk(input, type_det="mc")
        )
        for i in range(samples_len_mc):
            cleaned_text_mc = remove_special_characters(segments_mc[i])
            mc_score = predict_1on1_single(cleaned_text_mc, models[0])
            mc_scores.append(mc_score)
        mc_scores_array = np.array(mc_scores)
        average_mc_scores = np.mean(mc_scores_array, axis=0)
        print(average_mc_scores)
        mc_score_list = average_mc_scores.tolist()
        mc_score = {}
        mc_score[models[0].upper()] = mc_score_list
        mc_score["OTHER"] = 1 - mc_score_list

        sum_prob = 1 - bc_score["HUMAN"]
        for key, value in mc_score.items():
            mc_score[key] = value * sum_prob
        if sum_prob < 0.01:
            mc_score = {}

    return mc_score