from flask import Blueprint, request, jsonify
from werkzeug.utils import secure_filename
from sqlalchemy.sql import func
import os
import uuid
from db.model import db, Course, Category, User
from utils.utils import random_string_generator
from constants import *
from config import *

course = Blueprint('course', __name__)

@course.route('/create/course', methods=['POST'])
def create_course():
    """
    Endpoint to create a new course.
    Ensures strict adherence to the Course model, with file handling and default behaviors.
    """
    try:
        # Retrieve form data
        data = request.form
        name :str= data.get('name', '').strip()
        category_id :str = data.get('category_id', '').strip()
        description :str= data.get('description', '')
        is_active :bool = bool(int(data.get('is_active', 0)))
        published_status :int = data.get('published_status', int(PublishedStatus.DRAFT.value)) # Defaults to DRAFT
        author_id :str = data.get('author_id', '').strip()

        # Validate required fields
        if not name or not category_id or not author_id:
            return jsonify({"error": "Missing required fields: 'name', 'category_id', or 'author_id'."}), 400

        # Validate category existence
        category :str= Category.query.get(category_id)
        if not category:
            return jsonify({"error": "Category not found."}), 404

        # Validate author existence
        author :str = User.query.get(author_id)
        if not author:
            return jsonify({"error": "Author not found."}), 404

        # File handling
        uploaded_cover_image = request.files.get('cover')
        uploaded_file = request.files.get('pdf')

        cover_filename_image :str= ''
        pdf_file_filename :str= ''
        if uploaded_cover_image is not None:
            cover_filename_image :str = random_string_generator(10) + os.path.splitext(uploaded_cover_image.filename)[-1]
            uploaded_cover_image.save(os.path.join(USER_UPLOADS_DIR, cover_filename_image))

        if uploaded_file is not None:
            pdf_file_filename :str= random_string_generator(10) + os.path.splitext(uploaded_file.filename)[-1]
            uploaded_file.save( os.path.join(USER_UPLOADS_DIR, pdf_file_filename))

        # Default to DRAFT if critical content is missing
        if not uploaded_cover_image or not uploaded_file:
            published_status :int= int(PublishedStatus.DRAFT.value)

        # Create new course
        new_course = Course(
            name=name,
            categoryID=uuid.UUID(category_id),
            description=description,
            isActive=is_active,
            publishedStatus=int(published_status),
            coverImage=cover_filename_image,
            serverFilename=pdf_file_filename,
            authorID=uuid.UUID(author_id),
            creationDate=func.now(),
        )

        # Save the course to the database
        db.session.add(new_course)
        db.session.commit()

        return jsonify({"message": "Course created successfully.", "course_id": str(new_course.id)}), 201

    except Exception as e:
        # Rollback in case of an error
        db.session.rollback()
        return jsonify({"error": f"An error occurred: {str(e)}"}), 500