import streamlit as st
import importlib
from fpdf import FPDF

# List of available modules with shorter names and icons
module_names = {
    "Bases": "presentation_bases",
    "Validity": "valid_invalid_numbers",
    "Conversion": "conversion_bases",
    "Grouping": "grouping_techniques",
    "Addition": "addition_bases",
    "2's Complement": "twos_complement",
    "Negative Numbers": "negative_binary",
    "Subtraction": "subtraction_bases",
}

# Initialize session state variables
if 'correct_count' not in st.session_state:
    st.session_state.correct_count = 0
if 'question_count' not in st.session_state:
    st.session_state.question_count = 0
if 'current_module' not in st.session_state:
    st.session_state.current_module = None
if 'question_queue' not in st.session_state:
    st.session_state.question_queue = []
if 'submitted' not in st.session_state:
    st.session_state.submitted = False
if 'current_question' not in st.session_state:
    st.session_state.current_question = None
if 'options' not in st.session_state:
    st.session_state.options = []
if 'correct_answer' not in st.session_state:
    st.session_state.correct_answer = None
if 'explanation' not in st.session_state:
    st.session_state.explanation = None
if 'selected_answer' not in st.session_state:
    st.session_state.selected_answer = None

# Handle Next and Previous question navigation
def navigate_question(direction):
    if direction == "next":
        st.session_state.question_count += 1
    elif direction == "prev" and st.session_state.question_count > 1:
        st.session_state.question_count -= 1
        st.session_state.submitted = False
        st.session_state.current_question = st.session_state.question_queue[st.session_state.question_count - 1][0]
        st.session_state.options = st.session_state.question_queue[st.session_state.question_count - 1][1]
        st.session_state.selected_answer = st.session_state.question_queue[st.session_state.question_count - 1][2]
        st.session_state.correct_answer = st.session_state.question_queue[st.session_state.question_count - 1][3]
        st.session_state.explanation = st.session_state.question_queue[st.session_state.question_count - 1][4]

def generate_pdf_report():
    pdf = FPDF()
    pdf.add_page()
    pdf.set_font("Arial", size=12)

    pdf.cell(200, 10, txt="Quiz Report", ln=True, align="C")
    pdf.ln(10)

    for idx, entry in enumerate(st.session_state.question_queue):
        question, options, selected, correct, explanation = entry
        pdf.multi_cell(0, 10, f"Q{idx+1}: {question}")
        for option in options:
            if option == correct:
                pdf.multi_cell(0, 10, f"{option} (Correct)")
            elif option == selected:
                pdf.multi_cell(0, 10, f"{option} (Your Choice)")
            else:
                pdf.multi_cell(0, 10, f"   {option}")
        pdf.multi_cell(0, 10, f"Explanation: {explanation}")
        pdf.ln(10)

    return pdf.output(dest='S').encode('utf-8')

# Streamlit interface
st.sidebar.title("Quiz Modules")
module_name = st.sidebar.radio("Choose a module:", list(module_names.keys()), index=0)

if module_name:
    module_file = module_names[module_name]
    try:
        module = importlib.import_module(f'modules.{module_file}')
        generate_question = module.generate_question
        title = getattr(module, 'title', f"{module_name} Module")
        description = getattr(module, 'description', "Description is not available")
        
        # Show module title and description
        st.title(title)
        st.write(description)

        if st.session_state.current_question is None or st.session_state.submitted:
            st.session_state.current_question, st.session_state.options, st.session_state.correct_answer, st.session_state.explanation = generate_question()
            st.session_state.submitted = False
            st.session_state.selected_answer = None

        if st.session_state.question_count > 0:
            correct_percentage = (st.session_state.correct_count / st.session_state.question_count) * 100
            st.write(f"**Correct Answers:** {st.session_state.correct_count}/{st.session_state.question_count} ({correct_percentage:.2f}%)")

        st.markdown(
            f"""
            <div style='border: 2px solid #ccc; padding: 15px; background-color: #f9f9f9;'>
            <strong>Question {st.session_state.question_count + 1}:</strong> {st.session_state.current_question}
            </div>
            """,
            unsafe_allow_html=True
        )

        st.session_state.selected_answer = st.radio("Choose an answer:", st.session_state.options)

        col1, col2, col3 = st.columns([1, 1, 3])
        with col1:
            if st.session_state.question_count > 0:
                if st.button("⬅️ Prev"):
                    navigate_question("prev")
        with col2:
            if st.button("Submit"):
                st.session_state.submitted = True
                st.session_state.question_queue.append((
                    st.session_state.current_question, 
                    st.session_state.options, 
                    st.session_state.selected_answer, 
                    st.session_state.correct_answer, 
                    st.session_state.explanation
                ))

                if st.session_state.selected_answer == st.session_state.correct_answer:
                    st.session_state.correct_count += 1
                    st.success("✅ Correct!")
                else:
                    st.error("❌ Incorrect.")
                st.write(f"**Explanation:** {st.session_state.explanation}")
                st.session_state.current_question = None

        if st.session_state.submitted:
            with col3:
                if st.button("➡️ Next"):
                    navigate_question("next")
                if st.session_state.question_count > 0:
                    pdf = generate_pdf_report()
                    st.download_button(
                        label="Download PDF Report 📄",
                        data=pdf,
                        file_name="quiz_report.pdf",
                        mime="application/pdf"
                    )

    except ModuleNotFoundError:
        st.error(f"The module '{module_name}' was not found. Please select another module.")