import streamlit as st
import numpy as np
import pandas as pd
import plotly.express as px
import plotly.graph_objects as go
from sklearn.linear_model import LinearRegression, LogisticRegression
from sklearn.cluster import KMeans
from sklearn.preprocessing import StandardScaler
from sklearn.datasets import make_blobs

def generate_regression_data(n_samples=100, noise=10):
    """Generate data for linear regression visualization."""
    np.random.seed(42)
    X = np.linspace(0, 10, n_samples)
    y = 2 * X + 1 + np.random.normal(0, noise, n_samples)
    return X.reshape(-1, 1), y

def generate_classification_data(n_samples=100):
    """Generate data for logistic regression visualization."""
    np.random.seed(42)
    X = np.random.randn(n_samples, 2)
    y = (X[:, 0] + X[:, 1] > 0).astype(int)
    return X, y

def generate_clustering_data(n_samples=300):
    """Generate data for clustering visualization."""
    np.random.seed(42)
    X, _ = make_blobs(n_samples=n_samples, centers=3, cluster_std=1.5)
    return X

def show():
    """Display the interactive machine learning visualizations."""
    st.title("Interactive Machine Learning Visualizations")

    # Introduction
    st.info("""
        This module provides interactive visualizations of three fundamental machine learning concepts:
        - 📈 Linear Regression: Predict continuous values
        - 🎯 Logistic Regression: Classify binary outcomes
        - 🔍 K-Means Clustering: Group similar data points
    """)

    # Create tabs for different ML concepts
    tab1, tab2, tab3 = st.tabs(["📈 Linear Regression", "🎯 Logistic Regression", "🔍 Clustering"])

    with tab1:
        st.subheader("Linear Regression")
        
        # Interactive controls
        col1, col2 = st.columns(2)
        with col1:
            n_samples = st.slider("Number of samples", 50, 200, 100)
        with col2:
            noise = st.slider("Noise level", 1, 20, 10)
        
        # Generate and plot data
        X, y = generate_regression_data(n_samples, noise)
        
        # Create scatter plot with dark theme
        fig = px.scatter(x=X.flatten(), y=y, 
                        title="Linear Regression Visualization",
                        labels={'x': 'Feature (X)', 'y': 'Target (y)'},
                        template="plotly_dark")
        
        # Add regression line
        model = LinearRegression()
        model.fit(X, y)
        y_pred = model.predict(X)
        
        fig.add_trace(go.Scatter(x=X.flatten(), y=y_pred, 
                                mode='lines', 
                                name='Regression Line',
                                line=dict(color='red')))
        
        fig.update_layout(
            plot_bgcolor='#1E1E1E',
            paper_bgcolor='#1E1E1E',
            font=dict(color='white')
        )
        
        st.plotly_chart(fig, use_container_width=True)
        
        # Display model information
        st.success(f"""
            **Model Information**
            - Slope (Coefficient): {model.coef_[0]:.2f}
            - Intercept: {model.intercept_:.2f}
            - R² Score: {model.score(X, y):.2f}
        """)

    with tab2:
        st.subheader("Logistic Regression")
        
        # Generate data
        X, y = generate_classification_data()
        
        # Create scatter plot with dark theme
        fig = px.scatter(x=X[:, 0], y=X[:, 1], 
                        color=y.astype(str),
                        title="Logistic Regression Visualization",
                        labels={'x': 'Feature 1', 'y': 'Feature 2'},
                        template="plotly_dark")
        
        # Add decision boundary
        model = LogisticRegression()
        model.fit(X, y)
        
        # Create mesh grid for decision boundary
        x_min, x_max = X[:, 0].min() - 1, X[:, 0].max() + 1
        y_min, y_max = X[:, 1].min() - 1, X[:, 1].max() + 1
        xx, yy = np.meshgrid(np.arange(x_min, x_max, 0.1),
                            np.arange(y_min, y_max, 0.1))
        
        Z = model.predict(np.c_[xx.ravel(), yy.ravel()])
        Z = Z.reshape(xx.shape)
        
        fig.add_trace(go.Contour(x=xx[0], y=yy[:, 0], z=Z,
                                showscale=False,
                                opacity=0.3,
                                colorscale='RdBu'))
        
        fig.update_layout(
            plot_bgcolor='#1E1E1E',
            paper_bgcolor='#1E1E1E',
            font=dict(color='white')
        )
        
        st.plotly_chart(fig, use_container_width=True)
        
        # Display model information
        st.success(f"""
            **Model Information**
            - Accuracy: {model.score(X, y):.2f}
            - Coefficients: [{model.coef_[0][0]:.2f}, {model.coef_[0][1]:.2f}]
            - Intercept: {model.intercept_[0]:.2f}
        """)

    with tab3:
        st.subheader("K-Means Clustering")
        
        # Interactive controls
        n_clusters = st.slider("Number of clusters", 2, 6, 3)
        
        # Generate data
        X = generate_clustering_data()
        
        # Perform clustering
        kmeans = KMeans(n_clusters=n_clusters, random_state=42)
        clusters = kmeans.fit_predict(X)
        
        # Create scatter plot with dark theme
        fig = px.scatter(x=X[:, 0], y=X[:, 1], 
                        color=clusters.astype(str),
                        title="K-Means Clustering Visualization",
                        labels={'x': 'Feature 1', 'y': 'Feature 2'},
                        template="plotly_dark")
        
        # Add cluster centers
        fig.add_trace(go.Scatter(x=kmeans.cluster_centers_[:, 0],
                                y=kmeans.cluster_centers_[:, 1],
                                mode='markers',
                                marker=dict(size=12, symbol='star', color='white'),
                                name='Cluster Centers'))
        
        fig.update_layout(
            plot_bgcolor='#1E1E1E',
            paper_bgcolor='#1E1E1E',
            font=dict(color='white')
        )
        
        st.plotly_chart(fig, use_container_width=True)
        
        # Display clustering information
        st.success(f"""
            **Clustering Information**
            - Number of Clusters: {n_clusters}
            - Inertia (Sum of Squared Distances): {kmeans.inertia_:.2f}
        """)

    # Footer
    st.info("""
        **Key Takeaways**
        - Linear Regression: Fits a line to predict continuous values
        - Logistic Regression: Creates a decision boundary for classification
        - K-Means Clustering: Groups similar data points into clusters
    """)