import streamlit as st

class FormHelper:
    def __init__(self):
        """Initializes the FormHelper with default session state values."""
        if "exam_loaded" not in st.session_state:
            st.session_state.exam_loaded = False
        if "exam_started" not in st.session_state:
            st.session_state.exam_started = False
        if "current_form" not in st.session_state:
            st.session_state.current_form = "about"

    def show_about_page(self):
        """Displays the About page."""
        st.title("About This App")
        st.write("This is a dummy app for demonstrating form management in Streamlit.")

    def show_load_exam_page(self):
        """Displays the Load Exam page and handles exam loading."""
        st.title("Load Exam")
        st.write("Simulating exam loading...")
        if st.button("Exam Loaded"):
            st.session_state.exam_loaded = True
            st.session_state.current_form = "take_exam"
            st.rerun()

    def show_take_exam_page(self):
        """Displays the Take Exam page with dummy questions and handles exam finishing."""
        st.title("Take Exam")
        st.session_state.exam_started = True
        st.write("Displaying exam questions here...")
        for i in range(5):
            st.write(f"Question {i+1}: What is the capital of France?")
            st.radio(f"Select answer for question {i+1}", ("Berlin", "Paris", "Madrid", "Rome"))
        if st.button("Finish Exam"):
            st.session_state.exam_started = False
            st.session_state.current_form = "view_result"
            st.rerun()
        if st.button("End Exam Early"):
            st.session_state.exam_started = False
            st.session_state.current_form = "view_result"
            st.rerun()

    def show_view_result_page(self):
        """Displays the View Result page with dummy results and handles exam retake/reload."""
        st.title("View Result")
        st.write("Displaying exam results here...")
        st.write("You answered 3 out of 5 questions correctly.")
        if st.button("Retake Exam"):
            st.session_state.current_form = "take_exam"
            st.rerun()
        if st.button("Load Another Exam"):
            st.session_state.exam_loaded = False
            st.session_state.current_form = "load_exam"
            st.rerun()

    def show_sidebar(self):
        """Displays the sidebar with navigation buttons."""
        with st.sidebar:
            st.title("Navigation")
            if st.button("About"):
                st.session_state.current_form = "about"
                st.rerun()
            if not st.session_state.exam_started:
                if st.button("Load Exam"):
                    st.session_state.current_form = "load_exam"
                    st.rerun()
            if st.session_state.exam_loaded and st.session_state.exam_started:
                if st.button("Take Exam"):
                    st.session_state.current_form = "take_exam"
                    st.rerun()
            if "current_form" in st.session_state and st.session_state.current_form == "view_result":
                if st.button("View Result"):
                    st.session_state.current_form = "view_result"
                    st.rerun()

    def run(self):
        """Runs the app by displaying the appropriate page based on the current form."""
        self.show_sidebar()
        if st.session_state.current_form == "about":
            self.show_about_page()
        elif st.session_state.current_form == "load_exam":
            self.show_load_exam_page()
        elif st.session_state.current_form == "take_exam":
            self.show_take_exam_page()
        elif st.session_state.current_form == "view_result":
            self.show_view_result_page()