/***********************************************************************************************************************************************************************
 * File Name: purchasable.util.js
 * Type of Program: Utility
 * Description: Resolves a Product's polymorphic target (purchasable_type +
 *              purchasable_id → Course | Unit | Lesson) and the checkout
 *              route for it. Products.mdl.js can't express a single
 *              Sequelize association across three different target models,
 *              so this is the shared lookup every consumer (access checks,
 *              admin product CRUD, client checkout) goes through instead.
 *
 * Author: Kenneth Obsequio (@lash0000)
 * Date Created: Aug. 1, 2026
 ***********************************************************************************************************************************************************************/
'use strict';

const { Course } = require('../models/courses/courses.mdl');
const Unit        = require('../models/courses/units.mdl');
const Lesson       = require('../models/courses/lessons.mdl');

const TYPE_MODELS = { course: Course, unit: Unit, lesson: Lesson };
const TYPE_PK      = { course: 'course_id', unit: 'unit_id', lesson: 'lesson_id' };

function getPurchasableModel(type) {
  return TYPE_MODELS[type] ?? null;
}

// Returns the target row (needs at least uuid/course_id + subscription for
// callers), or null if the type is unknown or the row doesn't exist.
async function resolvePurchasable(type, id) {
  const Model = TYPE_MODELS[type];
  if (!Model) return null;
  return Model.findOne({ where: { [TYPE_PK[type]]: id, deletedAt: null } });
}

// Course checkout stays keyed by numeric course_id (existing convention);
// Unit/Lesson checkout is keyed by uuid, matching how /units/:uuid and
// /lessons/:uuid already work everywhere else in the standalone consumption paths.
function checkoutPath(type, record) {
  if (type === 'course') return `/course/${record.course_id}/checkout`;
  if (type === 'unit')   return `/units/${record.uuid}/checkout`;
  if (type === 'lesson') return `/lessons/${record.uuid}/checkout`;
  return null;
}

module.exports = { getPurchasableModel, resolvePurchasable, checkoutPath };