import streamlit as st
import pandas as pd
from fpdf import FPDF
import datetime

# Initialize session state
def init_session_state():
    if "study_data" not in st.session_state:
        st.session_state.study_data = pd.DataFrame(columns=["Subject", "Topic", "Goal", "Progress (%)"])
    if "calendar_data" not in st.session_state:
        st.session_state.calendar_data = pd.DataFrame({"Day": ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"], "Planned Topic": ["" for _ in range(7)]})

# PDF Generation
def generate_pdf(df):
    pdf = FPDF()
    pdf.add_page()
    pdf.set_font("Arial", size=12)
    pdf.cell(200, 10, txt="Study Plan Report", ln=True, align='C')
    pdf.ln(10)

    for i, row in df.iterrows():
        pdf.multi_cell(0, 10, f"Subject: {row['Subject']}\nTopic: {row['Topic']}\nGoal: {row['Goal']}\nProgress: {row['Progress (%)']}%\n")
        pdf.ln(1)

    file_path = "study_report.pdf"
    pdf.output(file_path)
    return file_path

def main():
    st.set_page_config(page_title="Study Planner", layout="wide")
    st.title("📚 Smart Study Planner")

    init_session_state()

    st.sidebar.markdown("---")
    st.sidebar.header("📂 Upload Your Study Plan (optional)")
    uploaded_plan = st.sidebar.file_uploader("Upload Study CSV", type=["csv"])
    uploaded_calendar = st.sidebar.file_uploader("Upload Calendar CSV", type=["csv"])

    # Handle uploads
    if uploaded_plan:
        st.session_state.study_data = pd.read_csv(uploaded_plan)
    if uploaded_calendar:
        st.session_state.calendar_data = pd.read_csv(uploaded_calendar)

    if st.sidebar.button("🔁 Reset All"):
        st.session_state.study_data = pd.DataFrame(columns=["Subject", "Topic", "Goal", "Progress (%)"])
        st.session_state.calendar_data = pd.DataFrame({"Day": ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"], "Planned Topic": ["" for _ in range(7)]})
        st.sidebar.success("Planner has been reset.")

    with st.sidebar:
        st.header("➕ Add Study Task")
        subject = st.text_input("Subject")
        topic = st.text_input("Topic")
        goal = st.text_area("Goal Description")
        progress = st.slider("Progress (%)", 0, 100, 0)

        if st.button("Add Task"):
            if subject and topic:
                new_row = {"Subject": subject, "Topic": topic, "Goal": goal, "Progress (%)": progress}
                st.session_state.study_data = pd.concat([
                    st.session_state.study_data,
                    pd.DataFrame([new_row])
                ], ignore_index=True)
                st.success("Task added!")
            else:
                st.error("Subject and Topic are required.")

    df = st.session_state.study_data
    calendar_df = st.session_state.calendar_data

    st.subheader("🎯 Study Summary by Subject")
    if not df.empty:
        subjects = df["Subject"].unique()
        cols = st.columns(len(subjects))
        colors = ["#fca311", "#a1c181", "#f28482", "#8ecae6", "#ffb703"]

        for i, subject in enumerate(subjects):
            sub_df = df[df["Subject"] == subject]
            avg_progress = int(sub_df["Progress (%)"].mean())
            with cols[i % len(cols)]:
                st.markdown(f"""
                    <div style='padding: 1em; border-radius: 10px; background-color: {colors[i % len(colors)]}; color: black'>
                        <h4>{subject}</h4>
                        <p>Topics: {len(sub_df)}</p>
                        <p>Avg. Progress: {avg_progress}%</p>
                    </div>
                """, unsafe_allow_html=True)

    st.subheader("📅 Weekly Study Calendar")
    days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]
    calendar_data = []
    for day in days:
        default_topic = calendar_df.set_index("Day").get("Planned Topic", {}).get(day, "")
        topic = st.text_input(f"{day}", value=default_topic)
        calendar_data.append({"Day": day, "Planned Topic": topic})

    if st.button("Save Weekly Plan"):
        st.session_state.calendar_data = pd.DataFrame(calendar_data)
        st.success("Weekly calendar saved.")

    st.markdown("---")
    st.subheader("📋 All Study Tasks (Editable)")
    if not df.empty:
        edited_df = st.data_editor(df, num_rows="dynamic", use_container_width=True)
        st.session_state.study_data = edited_df

        st.markdown("---")
        st.subheader("📊 Progress Summary")
        summary = edited_df.groupby("Subject")["Progress (%)"].mean().reset_index()
        st.bar_chart(summary.set_index("Subject"))

        st.markdown("---")
        st.subheader("📤 Export Options")

        csv = df.to_csv(index=False).encode("utf-8")
        st.download_button("⬇️ Download CSV", data=csv, file_name="study_data.csv", mime="text/csv")

        if st.button("📄 Generate PDF Report"):
            file_path = generate_pdf(edited_df)
            with open(file_path, "rb") as f:
                st.download_button("📥 Download PDF", f, file_name="study_plan_report.pdf")
    else:
        st.info("No tasks added yet.")

if __name__ == "__main__":
    main()