import hmac
from datetime import datetime
import pytz
from flask import request, jsonify, current_app
from app.models import db, Deck, Course, Password
from . import internal_bp


@internal_bp.route('/register-deck', methods=['POST'])
def register_deck():
    # Verify shared secret
    token = request.headers.get('X-Internal-Token', '')
    if not hmac.compare_digest(token, current_app.config['INTERNAL_TOKEN']):
        return jsonify({'error': 'Unauthorized'}), 401

    data = request.get_json()
    if not data:
        return jsonify({'error': 'Invalid JSON'}), 400

    for field in ('course', 'deck', 'name'):
        if not data.get(field):
            return jsonify({'error': f'Missing required field: {field}'}), 400

    # Look up course by folder name
    course = db.session.execute(
        db.select(Course).where(Course.folder == data['course'])
    ).scalar_one_or_none()
    if not course:
        return jsonify({'error': f"Course '{data['course']}' not found"}), 404

    # Upsert deck
    # NOTE: Deck.__init__ takes course= (object), not course_id=
    deck = db.session.execute(
        db.select(Deck).where(
            Deck.deck == data['deck'],
            Deck.course_id == course.id
        )
    ).scalar_one_or_none()

    if deck:
        deck.name        = data['name']
        deck.description = data['description']
        deck.export_file = data.get('export_file') or None
    else:
        deck = Deck(
            name        = data['name'],
            deck        = data['deck'],
            course      = course,           # pass object, not course_id
            description = data['description'],
            index_file  = data.get('index_file', 'index.html'),
            export_file = data.get('export_file') or None,
        )
        db.session.add(deck)
        db.session.flush()  # populate deck.id before linking password

    # Upsert password if provided
    if data.get('password'):
        expires_at = None
        if data.get('password_expires'):
            try:
                # Parse ISO string and convert to UTC naive (matches UTCDateTime model)
                expires_at = datetime.fromisoformat(
                    data['password_expires'].replace('Z', '+00:00')
                ).astimezone(pytz.utc)
            except ValueError:
                current_app.logger.warning(
                    f"Invalid password_expires format: {data['password_expires']}"
                )

        existing_pw = db.session.execute(
            db.select(Password).where(Password.value == data['password'])
        ).scalar_one_or_none()

        if existing_pw:
            existing_pw.expires_at = expires_at
            if deck not in existing_pw.decks:
                existing_pw.decks.append(deck)
        else:
            pw = Password(value=data['password'], expires_at=expires_at)
            pw.decks.append(deck)
            db.session.add(pw)

    db.session.commit()
    current_app.logger.info(
        f"Registered deck '{data['deck']}' for course '{data['course']}'"
    )
    return jsonify({'status': 'ok', 'deck': data['deck']}), 200