import streamlit as st
import sys, os

# ✅ FIX: Add project root first
sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from config import APP_TITLE, APP_ICON, MAX_QUESTIONS

# ✅ FIRST Streamlit call
st.set_page_config(
    page_title=APP_TITLE,
    page_icon=APP_ICON,
    layout="centered",
)   

# Add project root to path
sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from src.evaluator import score_quiz
from app.components import (
    render_question_card,
    render_result_card,
    render_score_summary
)

# ─────────────────────────────────────────────
#  CACHE MODEL (important for performance)
# ─────────────────────────────────────────────

@st.cache_resource
def load_pipeline():
    from src.mcq_builder import build_quiz
    return build_quiz

build_quiz = load_pipeline()


# ─────────────────────────────────────────────
#  SESSION STATE
# ─────────────────────────────────────────────

def init_state():
    defaults = {
        "screen": "input",
        "mcqs": [],
        "current_q": 0,
        "user_answers": [],
        "quiz_result": None,
    }
    for k, v in defaults.items():
        if k not in st.session_state:
            st.session_state[k] = v

init_state()


# ─────────────────────────────────────────────
#  RESET
# ─────────────────────────────────────────────

def reset():
    st.session_state.screen = "input"
    st.session_state.mcqs = []
    st.session_state.current_q = 0
    st.session_state.user_answers = []
    st.session_state.quiz_result = None


# ─────────────────────────────────────────────
#  SCREEN 1: INPUT
# ─────────────────────────────────────────────

def screen_input():
    st.title(f"{APP_ICON} {APP_TITLE}")
    st.write("Paste text to generate MCQs")

    passage = st.text_area(
        "Your passage",
        height=250,
        placeholder="Paste content here..."
    )

    num_questions = st.slider(
        "Number of questions",
        3,
        MAX_QUESTIONS,
        5
    )

    if st.button("Generate Quiz", type="primary"):

        if not passage or len(passage.split()) < 30:
            st.warning("Enter at least 30 words")
            return

        with st.spinner("Generating questions..."):

            try:
                mcqs = build_quiz(passage, num_questions=num_questions)
            except Exception as e:
                st.error(f"Error: {e}")
                return

        if not mcqs:
            st.error("Failed to generate questions")
            return

        st.session_state.mcqs = mcqs
        st.session_state.user_answers = [-1] * len(mcqs)
        st.session_state.current_q = 0
        st.session_state.screen = "quiz"

        st.rerun()


# ─────────────────────────────────────────────
#  SCREEN 2: QUIZ
# ─────────────────────────────────────────────

def screen_quiz():
    mcqs = st.session_state.mcqs
    current = st.session_state.current_q
    total = len(mcqs)

    mcq = mcqs[current]

    st.progress(current / total, text=f"Q {current+1}/{total}")

    selected_label = render_question_card(mcq, current)

    col1, col2, col3 = st.columns([1, 2, 1])

    # Previous
    with col1:
        if current > 0:
            if st.button("← Prev"):
                st.session_state.current_q -= 1
                st.rerun()

    # Next / Submit
    with col3:
        if selected_label:
            idx = ord(selected_label) - ord("A")
            st.session_state.user_answers[current] = idx

        if current < total - 1:
            if st.button("Next →", type="primary"):
                if selected_label is None:
                    st.warning("Select an answer")
                else:
                    st.session_state.current_q += 1
                    st.rerun()
        else:
            if st.button("Submit", type="primary"):
                result = score_quiz(
                    st.session_state.mcqs,
                    st.session_state.user_answers
                )
                st.session_state.quiz_result = result
                st.session_state.screen = "results"
                st.rerun()

    # Quit
    with col2:
        if st.button("Quit"):
            reset()
            st.rerun()


# ─────────────────────────────────────────────
#  SCREEN 3: RESULTS
# ─────────────────────────────────────────────

def screen_results():
    result = st.session_state.quiz_result

    st.title("Quiz Complete")

    render_score_summary(result)

    for i, r in enumerate(result["results"]):
        render_result_card(r, i + 1)

    col1, col2 = st.columns(2)

    with col1:
        if st.button("New Quiz"):
            reset()
            st.rerun()

    with col2:
        if st.button("Retry"):
            st.session_state.user_answers = [-1] * len(st.session_state.mcqs)
            st.session_state.current_q = 0
            st.session_state.screen = "quiz"
            st.rerun()


# ─────────────────────────────────────────────
#  ROUTER
# ─────────────────────────────────────────────

if st.session_state.screen == "input":
    screen_input()

elif st.session_state.screen == "quiz":
    screen_quiz()

elif st.session_state.screen == "results":
    screen_results()