app.py

import streamlit as st
import joblib
import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.svm import SVC
from sklearn.model_selection import train_test_split
from sklearn.metrics import accuracy_score, confusion_matrix

# Set Streamlit page config
st.set_page_config(page_title="SMS Spam Detector", page_icon="📩", layout="wide")

# Custom CSS for centering and styling
st.markdown("""
    <style>
        .centered-container {
            display: flex;
            justify-content: center;
            align-items: center;
            flex-direction: column;
            text-align: center;
            width: 80%;
        }
        .padded-container {
            padding: 20px;
        }
        .big-dataset {
            font-size: 12px;
            max-width: 100%;
            margin: auto;
        }
        .stDataFrame {
            display: flex;
            justify-content: center;
            align-items: center;
        }
        img {
            max-width: 150px;
            height: 600px;
        }
    </style>
""", unsafe_allow_html=True)

# Title
st.title("📩 SMS Spam Detector")

# Load dataset
@st.cache_data
def load_data():
    dataset_path = "spam.csv"
    df = pd.read_csv(dataset_path, encoding='latin-1')[['v1', 'v2']]
    df.columns = ['label', 'message']
    df['label'] = df['label'].map({'ham': 0, 'spam': 1})
    return df

df = load_data()

# Train and save model
@st.cache_resource
def train_and_save_model():
    X_train, X_test, y_train, y_test = train_test_split(df['message'], df['label'], test_size=0.2, random_state=42)
    vectorizer = TfidfVectorizer(stop_words='english', max_features=5000)
    X_train_tfidf = vectorizer.fit_transform(X_train)
    X_test_tfidf = vectorizer.transform(X_test)
    
    svm_model = SVC(kernel='linear')
    svm_model.fit(X_train_tfidf, y_train)
    
    y_pred = svm_model.predict(X_test_tfidf)
    accuracy = accuracy_score(y_test, y_pred)
    
    joblib.dump(svm_model, "svm_sms_spam.pkl")
    joblib.dump(vectorizer, "vectorizer.pkl")
    
    return svm_model, vectorizer, accuracy

svm_model, vectorizer, accuracy = train_and_save_model()

# Create tabs
tab1, tab2, tab3 = st.tabs(["📊 Data Overview", "📈 Data Visualization", "🔍 Spam Detector"])

# Tab 1: Data Overview
with tab1:
    st.subheader("Dataset Overview")
    st.markdown('<div class="centered-container">', unsafe_allow_html=True)
    st.markdown('<div style="display: flex; justify-content: center;">', unsafe_allow_html=True)
    st.dataframe(df, height=300, width=1000)
    st.markdown('</div>', unsafe_allow_html=True)
    st.markdown('</div>', unsafe_allow_html=True)

    # Smaller class distribution title
    st.subheader("Class Distribution")
    fig, ax = plt.subplots(figsize=(2, 2))  # Smaller figure size
    sns.countplot(
        x=df['label'].map({0: 'Not Spam', 1: 'Spam'}), 
        palette='coolwarm', 
        ax=ax,
        width=0.2 
    )
    ax.set_title("Distribution of Spam vs. Not Spam Messages", fontsize=8)  # Smaller title
    ax.set_xlabel("Message Type", fontsize=5)  # Smaller x-axis label
    ax.set_ylabel("Count", fontsize=5)  # Smaller y-axis label
    ax.tick_params(axis='both', labelsize=5)  # Smaller tick labels
    st.pyplot(fig)
    
    st.markdown(f"### 📊 Model Accuracy: **{accuracy * 100:.2f}%**")

# Tab 2: Data Visualization
with tab2:
    st.subheader("Data Visualizations")
    
    # Confusion Matrix
    st.markdown("### Confusion Matrix")
    X_train, X_test, y_train, y_test = train_test_split(df['message'], df['label'], test_size=0.2, random_state=42)
    X_test_tfidf = vectorizer.transform(X_test)
    y_pred = svm_model.predict(X_test_tfidf)
    
    cm = confusion_matrix(y_test, y_pred)
    fig, ax = plt.subplots(figsize=(5, 3))
    sns.heatmap(cm, annot=True, fmt='d', cmap='Blues', xticklabels=['Not Spam', 'Spam'], yticklabels=['Not Spam', 'Spam'])
    ax.set_xlabel("Predicted")
    ax.set_ylabel("Actual")
    ax.set_title("Confusion Matrix")
    st.pyplot(fig)
    
    # Heatmap
    st.markdown("### Heatmap of Feature Correlations")
    df['message_length'] = df['message'].apply(len)
    correlation_matrix = df[['message_length', 'label']].corr()
    fig, ax = plt.subplots(figsize=(5, 3))
    sns.heatmap(correlation_matrix, annot=True, cmap='coolwarm', ax=ax)
    ax.set_title("Feature Correlation Heatmap")
    st.pyplot(fig)
    
    st.markdown('</div>', unsafe_allow_html=True)

# Tab 3: Spam Detector
with tab3:
    st.subheader("Check SMS Message")
    st.write("Enter an SMS message below to check if it's spam or not.")
    user_input = st.text_area("Enter SMS Message:")
    
    if st.button("Check Message"):
        if user_input:
            input_features = vectorizer.transform([user_input])
            prediction = svm_model.predict(input_features)
            
            if prediction[0] == 1:
                st.error("🚨 This message is Spam!")
            else:
                st.success("✅ This message is NOT Spam!")
        else:
            st.warning("Please enter a message before checking.")