import streamlit as st
import matplotlib.pyplot as plt
import networkx as nx
import numpy as np

# Define available colors
colors = [
    "#FF9999", "#99FF99", "#9999FF", "#FFCC99", "#FFFF99",
    "#CC99FF", "#66CCCC", "#FF6666", "#66FF66", "#6666FF"
]

# Define time slots and days
time_slots = ["08:30-10:00", "10:05-11:35", "11:40-13:10", "13:15-14:45", "14:50-16:20", "16:25-17:55","18:00-19:30"]
days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"]

st.title("Timetable Scheduling using Graph Coloring")

# User input for timetable slots
user_slots = {}
for day in days:
    user_slots[day] = []
    st.subheader(f"Select slots for {day}")
    for slot in time_slots:
        subject = st.text_input(f"Enter subject for {slot} on {day}", key=f"{day}-{slot}")
        if subject:
            user_slots[day].append((slot, subject))

# Create graph representation
G = nx.Graph()
for day in user_slots:
    for slot, subject in user_slots[day]:
        G.add_node((day, slot, subject))

# Add edges for overlapping subjects (same time slots across days)
for day1 in user_slots:
    for day2 in user_slots:
        if day1 != day2:
            for (slot1, subject1) in user_slots[day1]:
                for (slot2, subject2) in user_slots[day2]:
                    if slot1 == slot2:
                        G.add_edge((day1, slot1, subject1), (day2, slot2, subject2))

# Apply Welsh-Powell Graph Coloring Algorithm
sorted_nodes = sorted(G.nodes, key=lambda x: G.degree(x), reverse=True)  # Sort nodes by degree

subject_color = {}
used_colors = set()
color_map = {}

for node in sorted_nodes:
    day, slot, subject = node

    # If subject already has a color, use it
    if subject in subject_color:
        color_map[node] = subject_color[subject]
    else:
        # Find a color that hasn't been used yet
        for color in colors:
            if color not in used_colors:
                subject_color[subject] = color
                color_map[node] = color
                used_colors.add(color)
                break
        else:
            st.error("Not enough colors for the number of unique subjects. Please add more colors.")

# Convert to timetable format for visualization
timetable = {day: {slot: None for slot in time_slots} for day in days}
for (day, slot, subject), color in color_map.items():
    timetable[day][slot] = (subject, color)

# Plot the timetable
fig, ax = plt.subplots(figsize=(12, 6))
ax.set_xticks(np.arange(len(days)) + 0.5)
ax.set_yticks(np.arange(len(time_slots)) + 0.5)
ax.set_xticklabels(days, fontsize=12)
ax.set_yticklabels(time_slots, fontsize=12)
ax.set_xlim(0, len(days))
ax.set_ylim(0, len(time_slots))
ax.invert_yaxis()

# Draw timetable slots
for i, day in enumerate(days):
    for j, slot in enumerate(time_slots):
        subject_info = timetable[day].get(slot)
        if subject_info:
            subject, color = subject_info
            ax.add_patch(plt.Rectangle((i, j), 1, 1, color=color, edgecolor="black"))
            ax.text(i + 0.5, j + 0.5, subject, ha='center', va='center', fontsize=10, fontweight='bold')

plt.title("Colored Timetable using Graph Coloring", fontsize=14)
plt.grid(True, linestyle="--", alpha=0.6)
st.pyplot(fig)