import asyncio
import os
import uuid
import re
import glob
from sqlmodel import Session, select, delete
from datetime import datetime

import fitz  # PyMuPDF
from database import engine, init_db
import models

def parse_pdf(filepath):
    doc = fitz.open(filepath)
    text = ""
    for page in doc:
        text += page.get_text() + "\n"
        
    q_block = text.split("Questions\n")[-1].split("Answer Key\n")[0]
    q_pattern = re.compile(r'^(\d+)\.\s+(.*?)(?=^\d+\.\s+|\Z)', re.DOTALL | re.MULTILINE)
    
    questions_dict = {}
    for match in q_pattern.finditer(q_block):
        q_num = int(match.group(1))
        if 1 <= q_num <= 15:
            questions_dict[q_num] = match.group(2).strip()

    answers_dict = {}
    if "Answer Key\n" in text:
        a_block = text.split("Answer Key\n")[-1]
        a_pattern = re.compile(r'^(\d+)\s+(.*?)(?=^\d+\s+|\Z)', re.DOTALL | re.MULTILINE)
        for match in a_pattern.finditer(a_block):
            q_num = int(match.group(1))
            if 1 <= q_num <= 15:
                # Some answers might get overwritten if footer matches the same number, but 
                # answers are strictly linear 1 to 15, so we only take the first match.
                if q_num not in answers_dict:
                    answers_dict[q_num] = match.group(2).strip()
            
    return questions_dict, answers_dict

async def seed_pdfs():
    admin_id_str = "b0e17378-864d-439e-8806-708dc48a891b"
    pdf_files = glob.glob('/app/pdfs_to_parse/*.pdf')
    
    if not pdf_files:
        print("No PDFs found in /app/pdfs_to_parse/")
        return

    with Session(engine) as session:
        admin = session.exec(select(models.User).limit(1)).first()
        admin_id = admin.id if admin else uuid.UUID(admin_id_str)

        statement = select(models.Test).where(models.Test.type == "DPS")
        old_tests = session.exec(statement).all()
        for t in old_tests:
            session.delete(t)
        session.commit()

        for pdf_path in pdf_files:
            filename = os.path.basename(pdf_path)
            subject = "Physics"
            topic = "General"
            if "phy" in filename.lower():
                subject = "Physics"
                topic = "Laws of Motion"
            elif "che" in filename.lower():
                subject = "Chemistry"
                topic = "Chemical Bonding"
            elif "mth" in filename.lower():
                subject = "Mathematics"
                topic = "Calculus"
            elif "bio" in filename.lower():
                subject = "Biology"
                topic = "Genetics"

            print(f"Parsing {filename}...")
            q_dict, a_dict = parse_pdf(pdf_path)
            print(f"Found {len(q_dict)} questions and {len(a_dict)} answers.")

            if not q_dict:
                continue

            question_ids = []
            for i in range(1, 16):
                if i not in q_dict:
                    continue
                q_text = q_dict[i].replace('\x00', '')
                ans_text = a_dict.get(i, "Solution not provided in PDF.").replace('\x00', '')
                
                options = {
                    "A": "Correct Answer - Refer to Solution Key below",
                    "B": "Incorrect Placeholder",
                    "C": "Incorrect Placeholder",
                    "D": "Incorrect Placeholder"
                }

                new_q = models.Question(
                    subject=subject,
                    topic=topic,
                    subtopic="General",
                    difficulty="Medium",
                    type=models.QuestionTypeEnum.NUMERICAL,
                    question_text=q_text,
                    options=None,
                    correct_answer={"value": "Subjective input"},
                    solution_text=ans_text,
                    language=models.MediumEnum.ENGLISH,
                    exam=models.ExamEnum.JEE_MAIN,
                    created_by=admin_id
                )
                session.add(new_q)
                session.flush()
                question_ids.append(str(new_q.id))
                
            if question_ids:
                test_obj = models.Test(
                    title=f"DPP: {subject} - {topic}",
                    type="DPS",
                    exam_pattern=models.ExamEnum.JEE_MAIN,
                    sections={
                        "Section 1": {
                            "questions": question_ids,
                            "time_limit": 45
                        }
                    },
                    total_time=45,
                    difficulty="Medium",
                    scheduled_date=datetime.utcnow(),
                    is_active=True,
                    created_by=admin_id
                )
                session.add(test_obj)
                session.commit()
                print(f"Successfully created DPP Test: {test_obj.title} with {len(question_ids)} questions.")

if __name__ == "__main__":
    asyncio.run(seed_pdfs())