app.py

import pickle
import pandas as pd
import shap
from shap.plots._force_matplotlib import draw_additive_plot
import gradio as gr
import numpy as np
import matplotlib.pyplot as plt
from PIL import Image

# Load model
loaded_model = pickle.load(open("default_xgb.pkl", 'rb'))

# SHAP Explainer
explainer = shap.Explainer(loaded_model)

# Load images for different profiles
img_mary = Image.open("mary_profile.png")
img_james = Image.open("james_profile.png")
img_landon = Image.open("landon_profile.png")

# Define main function
def main_func(LIMIT_BAL,
              PAY_0, PAY_2, PAY_3, PAY_4, PAY_5, PAY_6,
              b1, b2, b3, b4, b5, b6,
              profile=""):

    new_row = pd.DataFrame.from_dict({
        'LIMIT_BAL': [LIMIT_BAL],
        'PAY_0': [PAY_0],
        'PAY_2': [PAY_2],
        'PAY_3': [PAY_3],
        'PAY_4': [PAY_4],
        'PAY_5': [PAY_5],
        'PAY_6': [PAY_6],
        'b1': [b1],
        'b2': [b2],
        'b3': [b3],
        'b4': [b4],
        'b5': [b5],
        'b6': [b6]
    })

    prob = loaded_model.predict_proba(new_row)[0][1]

    shap_values = explainer(new_row)
    plt.figure(figsize=(10, 6))
    shap.plots.bar(shap_values[0], max_display=10, show=False)
    plt.tight_layout()
    local_plot = plt.gcf()
    plt.close()

    # Select image based on profile
    if profile == "Mary":
        image = img_mary
    elif profile == "James":
        image = img_james
    elif profile == "Landon":
        image = img_landon
    else:
        image = None

    return {"No Default": 1 - float(prob), "Default": float(prob)}, local_plot, image

# UI Text
title = "**Credit Card Default Risk Predictor** 📊"
description1 = """
This app uses financial data such as credit limits, repayment behavior, and bill balances to estimate the probability that a person may **default on their next credit payment**.
"""
description2 = """
To use the app, either adjust the values or click one of the examples. Then click on **Analyze** to get predictions and interpretations. 🔍
"""

# Launch Gradio app
with gr.Blocks(title=title) as demo:
    gr.Markdown(f"## {title}")
    gr.Markdown(description1)
    gr.Markdown("---")
    gr.Markdown(description2)
    gr.Markdown("---")

    with gr.Row():
        with gr.Column():
            LIMIT_BAL = gr.Slider(label="Credit Limit (LIMIT_BAL)", minimum=10000, maximum=1000000, value=150000, step=5000)
            PAY_0 = gr.Slider(label="PAY_0 (Most recent payment status)", minimum=-2, maximum=8, value=0, step=1)
            PAY_2 = gr.Slider(label="PAY_2", minimum=-2, maximum=8, value=-1, step=1)
            PAY_3 = gr.Slider(label="PAY_3", minimum=-2, maximum=8, value=-1, step=1)
            PAY_4 = gr.Slider(label="PAY_4", minimum=-2, maximum=8, value=-1, step=1)
            PAY_5 = gr.Slider(label="PAY_5", minimum=-2, maximum=8, value=-1, step=1)
            PAY_6 = gr.Slider(label="PAY_6", minimum=-2, maximum=8, value=-1, step=1)
            b1 = gr.Slider(label="Balance 1 (b1)", minimum=-100000, maximum=100000, value=5000, step=1000)
            b2 = gr.Slider(label="Balance 2 (b2)", minimum=-100000, maximum=100000, value=4500, step=1000)
            b3 = gr.Slider(label="Balance 3 (b3)", minimum=-100000, maximum=100000, value=4700, step=1000)
            b4 = gr.Slider(label="Balance 4 (b4)", minimum=-100000, maximum=100000, value=4300, step=1000)
            b5 = gr.Slider(label="Balance 5 (b5)", minimum=-100000, maximum=100000, value=4000, step=1000)
            b6 = gr.Slider(label="Balance 6 (b6)", minimum=-100000, maximum=100000, value=3900, step=1000)
            profile_input = gr.Textbox(visible=False)

            submit_btn = gr.Button("Analyze")

        with gr.Column(visible=True, scale=1, min_width=600):
            label = gr.Label(label="Predicted Default Risk")
            local_plot = gr.Plot(label="SHAP Explanation Plot")
            profile_image = gr.Image(label="Customer Profile Image", width=400, height=400)

            submit_btn.click(
                main_func,
                [LIMIT_BAL,
                 PAY_0, PAY_2, PAY_3, PAY_4, PAY_5, PAY_6,
                 b1, b2, b3, b4, b5, b6,
                 profile_input],
                [label, local_plot, profile_image],
                api_name="Default_Risk"
            )

    gr.Markdown("""### Example inputs to try: 3 credit profiles
- Mary: Did not miss payments in last 6 months, with a decreasing remaining balance and credit limit = 200,000. 
- James: Constantly missed payments in last 6 months, with an increasing remaining balance and credit limit = 80,000. 
- Landon: Missed payments in early months, with high fluctuations in remaining balance and credit limit = 300,000.
    """)
    gr.Examples(
        examples=[
            [200000, -1, -1, -1, -1, -1, -1, 7500, 10000, 12500, 15000, 17500, 20000, "Mary"],
            [80000, 2, 2, 2, 3, 2, 2, 20000, 17500, 15500, 12500, 10000, 7500, "James"],
            [300000, -1, 1, -1, 1, 2, 2, 15000, 20000, 0, 10000, 25000, 10000, "Landon"]
        ],
        inputs=[LIMIT_BAL, PAY_0, PAY_2, PAY_3, PAY_4, PAY_5, PAY_6,
                b1, b2, b3, b4, b5, b6, profile_input],
        outputs=[label, local_plot, profile_image],
        fn=main_func,
        cache_examples=True
    )

demo.launch()