app.py

import torch
import numpy as np
import json
import gradio as gr
from transformers import AutoTokenizer
from captum.attr import IntegratedGradients
from torch_geometric.data import Data
from empath import Empath
import spacy

# -----------------------
# Devices
# -----------------------
DEVICE = torch.device("cuda" if torch.cuda.is_available() else "cpu")

# -----------------------
# Load NLP
# -----------------------
try:
    nlp = spacy.load("en_core_web_sm")
except:
    import os
    os.system("python -m spacy download en_core_web_sm")
    nlp = spacy.load("en_core_web_sm")

empath = Empath()

# -----------------------
# Load Artifacts
# -----------------------
tokenizer = AutoTokenizer.from_pretrained("UFNLP/gatortron-base-2k")

with open("artifacts/union_trigrams.json") as f:
    TRIGRAM_LIST = json.load(f)

with open("artifacts/empath_cats.json") as f:
    EMPATH_CATS = json.load(f)

with open("artifacts/ip_op_trigram_sets.json") as f:
    sets = json.load(f)
    IP_SET = set(sets["ip"])
    OP_SET = set(sets["op"])

# -----------------------
# Model Definitions (same as training)
# -----------------------
from gatortron_gnn_captum import GatorTronEncoder, MetaGNN, GNNWrapper

ckpt = torch.load("artifacts/best_model.pt", map_location=DEVICE)

gatortron = GatorTronEncoder("UFNLP/gatortron-base-2k").to(DEVICE)
gatortron.load_state_dict(ckpt["gatortron"])
gatortron.eval()

gnn = MetaGNN(
    in_dim=ckpt["params"]["in_dim"],
    hidden_dim=ckpt["params"]["hidden_dim"],
    out_dim=2
).to(DEVICE)
gnn.load_state_dict(ckpt["gnn"])
gnn.eval()

# -----------------------
# Helpers
# -----------------------
def extract_trigrams(text):
    doc = nlp(text.lower())
    toks = [t.lemma_ for t in doc if t.is_alpha and not t.is_stop]
    return [" ".join(toks[i:i+3]) for i in range(len(toks)-2)]

def build_feature_vector(text):
    inp = tokenizer(
        text,
        truncation=True,
        padding="max_length",
        max_length=2000,
        return_tensors="pt"
    ).to(DEVICE)

    with torch.no_grad():
        gt = gatortron(inp["input_ids"], inp["attention_mask"]).cpu().numpy()[0]

    emp = empath.analyze(text, normalize=True)
    emp_vec = np.array([emp.get(c, 0.0) for c in EMPATH_CATS])

    trigs = extract_trigrams(text)
    tri_vec = np.array([trigs.count(t) for t in TRIGRAM_LIST])

    rsn = np.zeros(384)  # reasoning placeholder

    return np.concatenate([gt, emp_vec, tri_vec, rsn])

def explain(x_tensor):
    dummy_edge = torch.tensor([[0], [0]]).to(DEVICE)
    wrapper = GNNWrapper(gnn, dummy_edge)
    ig = IntegratedGradients(wrapper)

    attr = ig.attribute(
        x_tensor,
        baselines=torch.zeros_like(x_tensor),
        target=0,
        internal_batch_size=16
    )

    return attr.abs().cpu().numpy()[0]

# -----------------------
# Inference Function
# -----------------------
def predict(note):
    x = build_feature_vector(note)
    x_tensor = torch.tensor(x, dtype=torch.float32).unsqueeze(0).to(DEVICE)

    dummy_edge = torch.tensor([[0], [0]]).to(DEVICE)
    data = Data(x=x_tensor, edge_index=dummy_edge)

    with torch.no_grad():
        out = gnn(data)
        probs = torch.exp(out)[0].cpu().numpy()

    pred = "IP" if probs[0] > probs[1] else "OP"

    attr = explain(x_tensor)

    # ---- Empath ----
    emp_start = len(x) - (len(EMPATH_CATS) + len(TRIGRAM_LIST) + 384)
    emp_attr = attr[emp_start:emp_start+len(EMPATH_CATS)]

    top_empath = sorted(
        zip(EMPATH_CATS, emp_attr),
        key=lambda x: x[1],
        reverse=True
    )[:5]

    # ---- Trigrams ----
    tri_start = emp_start + len(EMPATH_CATS)
    tri_attr = attr[tri_start:tri_start+len(TRIGRAM_LIST)]

    top_trigrams = sorted(
        zip(TRIGRAM_LIST, tri_attr),
        key=lambda x: x[1],
        reverse=True
    )[:10]

    return (
        pred,
        float(probs[0]),
        float(probs[1]),
        top_empath,
        top_trigrams
    )

# -----------------------
# Gradio UI
# -----------------------
demo = gr.Interface(
    fn=predict,
    inputs=gr.Textbox(lines=12, label="Clinical Note"),
    outputs=[
        gr.Label(label="Prediction (IP / OP)"),
        gr.Number(label="IP Probability"),
        gr.Number(label="OP Probability"),
        gr.JSON(label="Top 5 Empath Categories"),
        gr.JSON(label="Top 10 Trigrams"),
    ],
    title="Clinical IP / OP Classifier with Explainability",
    description="GatorTron + GNN + Captum interpretability"
)

demo.launch()