import gradio as gr
import random
import json
from fpdf import FPDF
import os

# Load question bank
with open("questions.json", "r", encoding="utf-8") as f:
    question_bank = json.load(f)

# Function to get random 50 questions
def get_random_questions():
    return random.sample(question_bank, 50)

# Function to evaluate answers (handles single or multiple-correct formats)
def evaluate_test(student_name, father_name, roll_no, answers, questions):
    # answers: list of 50 selected option strings (or None)
    attempted = sum(1 for a in answers if a is not None and a != "")
    correct = 0
    for q, ans in zip(questions, answers):
        if ans is None or ans == "":
            continue
        correct_key = q.get("answer")
        # support either a single string or a list of accepted answers
        if isinstance(correct_key, list):
            if ans in correct_key:
                correct += 1
        else:
            if ans == correct_key:
                correct += 1

    total = len(questions) if questions else 0
    percentage = (correct / total) * 100 if total > 0 else 0.0

    # Generate PDF report (safe encoding)
    pdf = FPDF()
    pdf.add_page()
    pdf.set_font("Arial", size=12)
    pdf.cell(200, 10, txt="Test Report - Class 6 General Knowledge", ln=True, align="C")
    pdf.ln(10)

    # Use latin-1 replacement to avoid crashes for non-latin characters
    def safe_text(t):
        return str(t).encode("latin-1", "replace").decode("latin-1")

    pdf.cell(200, 8, txt=safe_text(f"Student Name: {student_name}"), ln=True)
    pdf.cell(200, 8, txt=safe_text(f"Father's Name: {father_name}"), ln=True)
    pdf.cell(200, 8, txt=safe_text(f"Roll No: {roll_no}"), ln=True)
    pdf.ln(6)
    pdf.cell(200, 8, txt=f"Total Questions: {total}", ln=True)
    pdf.cell(200, 8, txt=f"Attempted: {attempted}", ln=True)
    pdf.cell(200, 8, txt=f"Correct: {correct}", ln=True)
    pdf.cell(200, 8, txt=f"Percentage: {percentage:.2f}%", ln=True)

    # Save file
    safe_roll = roll_no if roll_no else "student"
    file_name = f"{safe_roll}_result.pdf"
    # ensure unique filename to avoid race conditions
    idx = 0
    base_name = file_name
    while os.path.exists(file_name):
        idx += 1
        file_name = f"{safe_roll}_result_{idx}.pdf"

    pdf.output(file_name)

    result_summary = (
        f"Student: {student_name}\n"
        f"Father's Name: {father_name}\n"
        f"Roll No: {roll_no}\n\n"
        f"Attempted: {attempted}\n"
        f"Correct: {correct}\n"
        f"Percentage: {percentage:.2f}%"
    )

    return result_summary, file_name

# Build Gradio interface using Blocks
def build_interface():
    def run_test(*args):
        """
        args layout:
        0: student_name
        1: father_name
        2: roll_no
        3..52: answer values for Q1..Q50
        53: questions state (list of 50 question dicts)
        """
        if len(args) < 4:
            return "Invalid input.", None

        student_name = args[0]
        father_name = args[1]
        roll_no = args[2]
        # answers are args[3] .. args[-2], last arg is questions
        if len(args) < 5:
            # no answers provided
            answers = []
            questions = []
        else:
            questions = args[-1]
            answers = list(args[3:-1])

        # Safety: if questions is a single dict (shouldn't be) or None, handle gracefully
        if not isinstance(questions, list):
            questions = list(questions) if questions else []

        return evaluate_test(student_name, father_name, roll_no, answers, questions)

    def update_questions_ui(questions):
        """Return 50 gr.update objects to populate radio labels and choices."""
        updates = []
        for i, q in enumerate(questions):
            updates.append(
                gr.update(label=f"Q{i+1}: {q.get('question','')}", choices=q.get("options", []), value=None)
            )
        return updates

    with gr.Blocks() as demo:
        gr.Markdown("## Class 6 General Knowledge Test (GFT/O Exam)")
        gr.Markdown("Answer 50 random questions and get your result in PDF.")

        student_name = gr.Textbox(label="Student Name")
        father_name = gr.Textbox(label="Father's Name")
        roll_no = gr.Textbox(label="Roll No")

        # State to store current random questions (list of 50 question dicts)
        question_state = gr.State(get_random_questions())

        # Create 50 radio inputs
        answer_inputs = []
        with gr.Accordion("Questions", open=True):
            for i in range(50):
                r = gr.Radio(label=f"Q{i+1}", choices=[])
                answer_inputs.append(r)

        output_text = gr.Textbox(label="Result Summary")
        output_file = gr.File(label="Download Result PDF")

        submit_btn = gr.Button("Submit Test", variant="primary")
        new_test_btn = gr.Button("New Test", variant="secondary")

        # On load, populate the 50 radios using the question_state
        demo.load(update_questions_ui, inputs=question_state, outputs=answer_inputs)

        # Submit test -> run_test which parses args and calls evaluate_test
        submit_btn.click(
            run_test,
            inputs=[student_name, father_name, roll_no] + answer_inputs + [question_state],
            outputs=[output_text, output_file],
        )

        # New Test -> generate fresh questions and update state + radios
        def refresh():
            qs = get_random_questions()
            # return list whose first element will set question_state, followed by 50 radio updates
            return [qs] + update_questions_ui(qs)

        new_test_btn.click(
            refresh,
            inputs=None,
            outputs=[question_state] + answer_inputs,
        )

    return demo

demo = build_interface()

if __name__ == "__main__":
    demo.launch()