app.py

import streamlit as st
import matplotlib.pyplot as plt
import networkx as nx
import bz2

# Sidebar for selecting an option
sidebar_option = st.sidebar.radio("Select an option", 
                                 ["Select an option", "Basic: Properties", 
                                  "Basic: Read and write graphs", "Basic: Simple graph", 
                                  "Basic: Simple graph Directed", "Drawing: Custom Node Position", 
                                  "Drawing: Chess Masters"])

# Helper function to draw and display graph
def draw_graph(G, pos=None, title="Graph Visualization", edgewidth=None, nodesize=None):
    if edgewidth is None:
        edgewidth = [1] * len(G.edges())  # Default edge width if not provided

    if nodesize is None:
        nodesize = [300] * len(G.nodes())  # Default node size if not provided

    plt.figure(figsize=(12, 12))
    nx.draw_networkx_edges(G, pos, alpha=0.3, width=edgewidth, edge_color="m")
    nx.draw_networkx_nodes(G, pos, node_size=nodesize, node_color="#210070", alpha=0.9)
    label_options = {"ec": "k", "fc": "white", "alpha": 0.7}
    nx.draw_networkx_labels(G, pos, font_size=14, bbox=label_options)

    # Title/legend
    font = {"fontname": "Helvetica", "color": "k", "fontweight": "bold", "fontsize": 14}
    ax = plt.gca()
    ax.set_title(title, font)
    ax.text(
        0.80,
        0.10,
        "edge width = # games played",
        horizontalalignment="center",
        transform=ax.transAxes,
        fontdict=font,
    )
    ax.text(
        0.80,
        0.06,
        "node size = # games won",
        horizontalalignment="center",
        transform=ax.transAxes,
        fontdict=font,
    )

    # Resize figure for label readability
    ax.margins(0.1, 0.05)
    plt.axis("off")
    st.pyplot(plt)


def chess_pgn_graph(pgn_file="chess_masters_WCC.pgn.bz2"):
    """Read chess games in pgn format in pgn_file.
    
    Filenames ending in .bz2 will be uncompressed.
    
    Return the MultiDiGraph of players connected by a chess game.
    Edges contain game data in a dict.
    """
    G = nx.MultiDiGraph()
    game = {}
    with bz2.BZ2File(pgn_file) as datafile:
        lines = [line.decode().rstrip("\r\n") for line in datafile]
    for line in lines:
        if line.startswith("["):
            tag, value = line[1:-1].split(" ", 1)
            game[str(tag)] = value.strip('"')
        else:
            if game:
                white = game.pop("White")
                black = game.pop("Black")
                G.add_edge(white, black, **game)
                game = {}
    return G


# Draw Chess Masters Graph (the main section)
def display_chess_masters_graph():
    st.title("Drawing: Chess Masters")

    option = st.radio("Choose a graph type:", ("Default Example", "Create your own"))

    if option == "Default Example":
        G = chess_pgn_graph("chess_masters_WCC.pgn.bz2")

        # identify connected components of the undirected version
        H = G.to_undirected()
        Gcc = [H.subgraph(c) for c in nx.connected_components(H)]
        if len(Gcc) > 1:
            st.write(f"Note the disconnected component consisting of:\n{Gcc[1].nodes()}")

        # find all games with B97 opening (as described in ECO)
        openings = {game_info["ECO"] for (white, black, game_info) in G.edges(data=True)}
        st.write(f"\nFrom a total of {len(openings)} different openings,")
        st.write("the following games used the Sicilian opening")
        st.write('with the Najdorff 7...Qb6 "Poisoned Pawn" variation.\n')

        for white, black, game_info in G.edges(data=True):
            if game_info["ECO"] == "B97":
                summary = f"{white} vs {black}\n"
                for k, v in game_info.items():
                    summary += f"   {k}: {v}\n"
                summary += "\n"
                st.write(summary)

        # Create undirected graph H without multi-edges
        H = nx.Graph(G)

        # Edge width is proportional to number of games played
        edgewidth = [len(G.get_edge_data(u, v)) for u, v in H.edges()]

        # Node size is proportional to number of games won
        wins = dict.fromkeys(G.nodes(), 0.0)
        for u, v, d in G.edges(data=True):
            r = d["Result"].split("-")
            if r[0] == "1":
                wins[u] += 1.0
            elif r[0] == "1/2":
                wins[u] += 0.5
                wins[v] += 0.5
            else:
                wins[v] += 1.0
        nodesize = [wins[v] * 50 for v in H]

        # Generate layout for visualization
        pos = nx.kamada_kawai_layout(H)

        # Manually tweak some positions to avoid label overlap
        pos["Reshevsky, Samuel H"] += (0.05, -0.10)
        pos["Botvinnik, Mikhail M"] += (0.03, -0.06)
        pos["Smyslov, Vassily V"] += (0.05, -0.03)

        # Draw the graph
        draw_graph(H, pos, title="World Chess Championship Games: 1886 - 1985", edgewidth=edgewidth, nodesize=nodesize)

    elif option == "Create your own":
        uploaded_file = st.file_uploader("Upload your own PGN file", type="pgn")
        if uploaded_file is not None:
            G_custom = chess_pgn_graph(uploaded_file)
            # Identify connected components and draw the graph for the uploaded data
            H_custom = G_custom.to_undirected()
            edgewidth = [len(G_custom.get_edge_data(u, v)) for u, v in H_custom.edges()]
            wins = dict.fromkeys(G_custom.nodes(), 0.0)
            for u, v, d in G_custom.edges(data=True):
                r = d["Result"].split("-")
                if r[0] == "1":
                    wins[u] += 1.0
                elif r[0] == "1/2":
                    wins[u] += 0.5
                    wins[v] += 0.5
                else:
                    wins[v] += 1.0
            nodesize = [wins[v] * 50 for v in H_custom]
            pos_custom = nx.kamada_kawai_layout(H_custom)
            draw_graph(H_custom, pos_custom, title="Custom Chess Game Graph", edgewidth=edgewidth, nodesize=nodesize)

# Display other sections
def display_basic_properties():
    st.title("Basic: Properties")
    option = st.radio("Choose a graph type:", ("Default Example", "Create your own"))

    # Default example: 5x5 grid graph
    if option == "Default Example":
        G = nx.lollipop_graph(4, 6)
        display_graph_properties(G)

    elif option == "Create your own":
        num_nodes = st.number_input("Number of nodes:", min_value=2, max_value=50, value=5)
        num_edges = st.number_input("Number of edges per group (for lollipop graph):", min_value=1, max_value=10, value=3)

        if st.button("Generate"):
            if num_nodes >= 2 and num_edges >= 1:
                G_custom = nx.lollipop_graph(num_nodes, num_edges)
                display_graph_properties(G_custom)

def display_graph_properties(G):
    pathlengths = []
    st.write("### Source vertex {target:length, }")
    for v in G.nodes():
        spl = dict(nx.single_source_shortest_path_length(G, v))
        st.write(f"Vertex {v}: {spl}")
        for p in spl:
            pathlengths.append(spl[p])

    avg_path_length = sum(pathlengths) / len(pathlengths)
    st.write(f"### Average shortest path length: {avg_path_length}")

    dist = {}
    for p in pathlengths:
        if p in dist:
            dist[p] += 1
        else:
            dist[p] = 1

    st.write("### Length #paths")
    for d in sorted(dist.keys()):
        st.write(f"Length {d}: {dist[d]} paths")

    st.write("### Properties")
    st.write(f"Radius: {nx.radius(G)}")
    st.write(f"Diameter: {nx.diameter(G)}")
    st.write(f"Eccentricity: {nx.eccentricity(G)}")
    st.write(f"Center: {nx.center(G)}")
    st.write(f"Periphery: {nx.periphery(G)}")
    st.write(f"Density: {nx.density(G)}")

    st.write("### Graph Visualization")
    pos = nx.spring_layout(G, seed=3068)
    plt.figure(figsize=(8, 6))
    nx.draw(G, pos=pos, with_labels=True, node_color='lightblue', node_size=500, font_size=10, font_weight='bold')
    st.pyplot(plt)

# Display other sections
def display_read_write_graph():
    st.title("Basic: Read and write graphs")
    G = nx.karate_club_graph()

    # Write the graph
    nx.write_gml(G, "karate_club.gml")
    st.write("Graph written to 'karate_club.gml'.")

    # Read the graph back
    G_new = nx.read_gml("karate_club.gml")
    st.write("Graph read back from 'karate_club.gml'.")
    nx.draw(G_new, with_labels=True)
    st.pyplot(plt)

def display_simple_graph():
    st.title("Basic: Simple graph")
    G = nx.complete_graph(5)
    nx.draw(G, with_labels=True)
    st.pyplot(plt)

def display_simple_directed_graph():
    st.title("Basic: Simple graph Directed")
    G = nx.complete_graph(5, nx.DiGraph())
    nx.draw(G, with_labels=True)
    st.pyplot(plt)

def display_custom_node_position():
    st.title("Drawing: Custom Node Position")
    pos = {"A": (1, 2), "B": (2, 3), "C": (3, 1)}
    G = nx.Graph(pos)
    nx.draw(G, pos=pos, with_labels=True)
    st.pyplot(plt)


# Call the appropriate function based on sidebar selection
if sidebar_option == "Basic: Properties":
    display_basic_properties()
elif sidebar_option == "Basic: Read and write graphs":
    display_read_write_graph()
elif sidebar_option == "Basic: Simple graph":
    display_simple_graph()
elif sidebar_option == "Basic: Simple graph Directed":
    display_simple_directed_graph()
elif sidebar_option == "Drawing: Custom Node Position":
    display_custom_node_position()
elif sidebar_option == "Drawing: Chess Masters":
    display_chess_masters_graph()
else:
    st.write("Please select a valid option from the sidebar.")