from flask import Blueprint, request, jsonify,g
from uuid import UUID
from db.model import db, User, Course, Enrollment,Chat
from utils.auth import auth_required
import requests
from sqlalchemy import desc

chat = Blueprint('chat', __name__)

SPAM_DETECTION_URL = "http://localhost:5000/test-spam"

@chat.route('/course/<uuid:course_id>/users', methods=['POST'])
def get_users_assigned_to_course(course_id: UUID):
    """
    Fetch all users assigned to a specific course.
    :param course_id: ID of the course to fetch users for (UUID).
    :return: JSON response with users assigned to the course.
    """
    try:
        # Query the course to ensure it exists
        course = Course.query.get(course_id)
        if not course:
            return jsonify({"error": "Course not found."}), 404

        # Get the list of users assigned to the course
        users = User.query.filter(User.enrollments.any(course_id=course_id)).all()

        # Prepare the response data
        user_data = [
            {
                "id": user.id,
                "email": user.email,
                "username": user.username,
                "firstName": user.firstName,
                "lastName": user.lastName,
            }
            for user in users
        ]

        return jsonify({"course": course.name, "users": user_data}), 200
    except Exception as e:
        return jsonify({"error": f"An error occurred: {str(e)}"}), 500


@chat.route('/course/<uuid:course_id>/chat', methods=['POST'])
def join_chat(course_id: UUID):
    """
    Allow users to join the chat only if they are enrolled in the course.
    :param course_id: ID of the course (UUID).
    :return: JSON response indicating whether the user can join or not.
    """
    try:
        # Get the user from the request (assume user_id is passed in the request body)
        user_id = request.json.get('user_id')
        if not user_id:
            return jsonify({"error": "User ID is required."}), 400

        # Query the user and ensure they exist
        user = User.query.get(user_id)
        if not user:
            return jsonify({"error": "User not found."}), 404

        # Check if the user is enrolled in the course
        enrollment = Enrollment.query.filter_by(userID=user_id, courseID=course_id).first()
        if not enrollment:
            return jsonify({"error": "User is not enrolled in this course."}), 403

        # If enrolled, allow the user to join the chat
        return jsonify({"message": f"User {user.username} is enrolled in the course and can join the chat."}), 200
    except Exception as e:
        return jsonify({"error": f"An error occurred: {str(e)}"}), 500


@chat.route("/send-message", methods=["POST"])
@auth_required()
def create_chat():
    """
    Create a chat message for a specific course.
    """
    current_user = g.current_user  # Fetch the logged-in user
    data = request.get_json()

    # Validate the payload
    course_id = data.get("course_id")
    message = data.get("message")

    if not course_id or not message:
        return jsonify({"error": "Course ID and message are required."}), 400

    try:
        # Call the spam detection service
        spam_response = requests.post(SPAM_DETECTION_URL, json={"test_message": message})
        if spam_response.status_code != 200:
            return jsonify({"error": "Failed to check message for spam."}), 500

        spam_score = int(spam_response.json().get("spam_score", 0))

        if spam_score > 6:
            return jsonify({"error": "This message contains suspicious links or is vulnerable."}), 400

        # Verify the course exists
        course = db.session.query(Course).filter_by(id=course_id).first()
        if not course:
            return jsonify({"error": "Invalid course ID."}), 404

        # Check if the user is enrolled in the course
        is_enrolled = db.session.query(Course).join(Enrollment).filter(
            Enrollment.userID == current_user.id,
            Enrollment.courseID == course_id
        ).first()

        if not is_enrolled:
            return jsonify({"error": "You are not enrolled in this course."}), 403

        # Create and save the chat message
        new_chat = Chat(
            textContent=message,
            userID=current_user.id,
            courseID=course_id,
        )
        db.session.add(new_chat)
        db.session.commit()

        return jsonify({"message": "Chat sent successfully.", "chat_id": str(new_chat.id)}), 201

    except Exception as e:
        return jsonify({"error": f"An error occurred: {str(e)}"}), 500

@chat.route("/get", methods=["GET"])
@auth_required()
def get_chat_history():
    """
    Fetch chat history for a course.
    """
    current_user = g.current_user  # Logged-in user
    course_id = request.args.get("course_id")
    limit = int(request.args.get("limit", 20))  # Default to 20 messages
    offset = int(request.args.get("offset", 0))  # Default to no offset (latest chats)

    if not course_id:
        return jsonify({"error": "Course ID is required."}), 400

    try:
        # Verify the course exists
        course = db.session.query(Course).filter_by(id=course_id).first()
        if not course:
            return jsonify({"error": "Invalid course ID."}), 404

        # Check if the user is enrolled in the course
        is_enrolled = db.session.query(Course).join(Enrollment).filter(
            Enrollment.userID == current_user.id,
            Enrollment.courseID == course_id
        ).first()

        if not is_enrolled:
            return jsonify({"error": "You are not enrolled in this course."}), 403

        # Fetch the latest chat messages with limit and offset
        chats = (
            db.session.query(Chat)
            .filter_by(courseID=course_id)
            .order_by(desc(Chat.chatDate))
            .offset(offset)
            .limit(limit)
            .all()
        )

        # Format the chat messages
        chat_history = [
            {
                "id": str(chat.id),
                "textContent": chat.textContent,
                "userID": str(chat.userID),
                "chatDate": chat.chatDate.isoformat(),
                "is_mine": chat.userID == current_user.id,
            }
            for chat in chats
        ]

        return jsonify({"chats": chat_history}), 200

    except Exception as e:
        return jsonify({"error": f"An error occurred: {str(e)}"}), 500