import streamlit as st
import math
import pandas as pd
import matplotlib.pyplot as plt
import numpy as np

# --- Core Mathematical Functions (The "Engineer" part) ---
# These are the exact functions we will later move to a separate toolkit.
# They ensure our Space, dataset, and reports all agree.

def mod_30(n: int) -> int:
    """Return n modulo 30."""
    return n % 30

def coprime_to_30(n: int) -> bool:
    """Return True if n is coprime to 30 (i.e., gcd(n, 30) == 1)."""
    return math.gcd(n, 30) == 1

def residue_lane(n: int) -> str:
    """Classify n based on its residue modulo 30 into one of the four 'lanes'."""
    r = n % 30
    if r in {1, 7, 11, 13, 17, 19, 23, 29}:
        return "🔵 Coprime Lane (the eight residue classes)"
    elif r % 2 == 0:
        return "🔴 Divisible by 2"
    elif r % 3 == 0:
        return "🟠 Divisible by 3"
    elif r % 5 == 0:
        return "🟢 Divisible by 5"
    else:
        # This case should theoretically not occur (r can only be 0-29)
        return "⚪ Other"

def prime_status(n: int) -> str:
    """A simple (but inefficient) primality test for small numbers."""
    if n < 2:
        return "Neither prime nor composite"
    # Trial division up to sqrt(n)
    for i in range(2, int(math.isqrt(n)) + 1):
        if n % i == 0:
            return "Composite"
    return "Prime"

# --- Streamlit App User Interface ---

st.set_page_config(page_title="Mod-30 Laboratory", page_icon="🧪")
st.title("🧪 Mod-30 Laboratory")
st.markdown("Explore the mathematical structure of integers through the lens of modulo 30 and the eight coprime residue classes.")
st.divider()

# --- Sidebar: Context ---
with st.sidebar:
    st.header("About the Eight Residues")
    st.write(
        """
        The set **{1, 7, 11, 13, 17, 19, 23, 29}** are the integers less than 30
        that are coprime to 30 (they share no common factors with 2, 3, or 5).
        
        Any integer's residue modulo 30 tells us immediately:
        - If it's in this set, it is *not* divisible by 2, 3, or 5.
        - Otherwise, it falls into a 'divisible by' lane.
        
        *Remember: Being in the coprime lane is necessary but not sufficient for a number to be prime (e.g., 49 is composite but coprime to 30).*
        """
    )
    st.divider()
    st.caption("Data and code are reproducible. See our dataset at readingpoint/mod-30-observations.")

# --- Main App Tabs: Single Query & Range Visualizer ---
tab1, tab2 = st.tabs(["🔎 Single Number Query", "📊 Range Visualizer"])

# --- TAB 1: Single Query ---
with tab1:
    st.header("Analyze a Single Integer")
    
    # Input
    user_input = st.number_input(
        "Enter an integer:",
        value=137,
        step=1,
        format="%d"
    )
    
    if st.button("Analyze", type="primary"):
        n = int(user_input)
        r = mod_30(n)
        lane = residue_lane(n)
        prime = prime_status(n)
        
        # Display Results
        col1, col2, col3 = st.columns(3)
        with col1:
            st.metric(label="Modulo 30", value=r)
        with col2:
            st.metric(label="Classification", value=lane, help="The 'lane' the number falls into.")
        with col3:
            st.metric(label="Primality", value=prime)
        
        # Visual Wheel
        st.subheader("Residue Wheel")
        fig, ax = plt.subplots(figsize=(6, 6))
        
        # Create a circle of residues 0-29
        angles = np.linspace(0, 2 * np.pi, 30, endpoint=False)
        # Color mapping
        colors = []
        for i in range(30):
            if i in {1, 7, 11, 13, 17, 19, 23, 29}:
                colors.append('#1f77b4')  # Blue for coprime
            elif i % 2 == 0:
                colors.append('#d62728')  # Red for even
            elif i % 3 == 0:
                colors.append('#ff7f0e')  # Orange for divisible by 3
            elif i % 5 == 0:
                colors.append('#2ca02c')  # Green for divisible by 5
            else:
                colors.append('#7f7f7f')  # Grey
        
        # Highlight the selected residue
        highlight = ['gold' if i == r else colors[i] for i in range(30)]
        
        # Plot as a bar chart wrapped around a circle (polar plot)
        ax = plt.subplot(111, projection='polar')
        bars = ax.bar(angles, [1]*30, width=2*np.pi/30, color=highlight, alpha=0.7, edgecolor='black', linewidth=0.5)
        ax.set_xticks(angles)
        ax.set_xticklabels([str(i) for i in range(30)], fontsize=8)
        ax.set_yticklabels([])
        ax.set_title(f"Residue {r} Highlighted in Gold", va='bottom')
        
        st.pyplot(fig)
        
        st.info(f"**{n}** is in the '{lane}' and is **{prime}**.", icon="💡")

# --- TAB 2: Range Visualizer ---
with tab2:
    st.header("Visualize a Range of Integers")
    
    col1, col2 = st.columns(2)
    with col1:
        start_val = st.number_input("Start of range:", value=1, step=1)
    with col2:
        end_val = st.number_input("End of range:", value=100, step=1, min_value=start_val+1)
    
    if st.button("Generate Visualization", type="primary"):
        n_range = list(range(int(start_val), int(end_val)+1))
        residues = [mod_30(n) for n in n_range]
        lanes = [residue_lane(n) for n in n_range]
        primes = [prime_status(n) for n in n_range]
        
        df = pd.DataFrame({
            'Integer': n_range,
            'mod_30': residues,
            'Lane': lanes,
            'Primality': primes
        })
        
        st.subheader("Data Preview")
        st.dataframe(df.head(50), use_container_width=True)
        
        # Scatter Plot: Integer vs Residue, colored by Lane
        st.subheader("Residue Scatter Plot")
        fig2, ax2 = plt.subplots(figsize=(10, 6))
        
        # Create a color map for lanes
        lane_colors = {
            '🔵 Coprime Lane (the eight residue classes)': 'blue',
            '🔴 Divisible by 2': 'red',
            '🟠 Divisible by 3': 'orange',
            '🟢 Divisible by 5': 'green',
            '⚪ Other': 'gray'
        }
        color_list = [lane_colors.get(lane, 'black') for lane in lanes]
        
        scatter = ax2.scatter(n_range, residues, c=color_list, alpha=0.7)
        ax2.set_xlabel('Integer (n)')
        ax2.set_ylabel('n mod 30')
        ax2.set_title('Residue Distribution Across the Range')
        ax2.grid(True, linestyle='--', alpha=0.5)
        ax2.set_yticks(range(0, 30, 5))
        
        # Create a custom legend
        from matplotlib.patches import Patch
        legend_elements = [
            Patch(facecolor='blue', label='🔵 Coprime Lane'),
            Patch(facecolor='red', label='🔴 Divisible by 2'),
            Patch(facecolor='orange', label='🟠 Divisible by 3'),
            Patch(facecolor='green', label='🟢 Divisible by 5'),
        ]
        ax2.legend(handles=legend_elements, title='Lane')
        
        st.pyplot(fig2)

st.divider()
st.caption("Built with Streamlit. Explore the full dataset at [readingpoint/mod-30-observations](https://huggingface.co/datasets/readingpoint/mod-30-observations).")