// /components/roles/roleService.js

const Role = require('./roleModel');
const AppError = require('../../utils/AppError');
const { parsePaginationAndSort, buildFilterQuery, calculateMeta } = require('../../utils/pagination');

const createRole = async (roleData) => {
  const existing = await Role.findOne({ name: roleData.name });
  if (existing) {
    throw new AppError('ROLE_ALREADY_EXISTS');
  }
  const role = await Role.create(roleData);
  return role;
};

const getRole = async (id) => {
  const role = await Role.findById(id);
  if (!role) {
    throw new AppError('ROLE_NOT_FOUND');
  }
  return role;
};

const getAllRoles = async (queryParams = {}) => {
  const { page, limit, skip, sort } = parsePaginationAndSort(queryParams);
  const filter = buildFilterQuery(queryParams, ['name', 'description']);

  const [roles, totalCount] = await Promise.all([
    Role.find(filter).sort(sort).skip(skip).limit(limit),
    Role.countDocuments(filter)
  ]);

  const meta = calculateMeta(totalCount, page, limit);
  return { data: roles, meta };
};

const updateRole = async (id, updateData) => {
  const role = await Role.findById(id);
  if (!role) {
    throw new AppError('ROLE_NOT_FOUND');
  }

  if (role.isSystem) {
    throw new AppError('SYSTEM_ROLE_PROTECTED');
  }

  if (updateData.name && updateData.name !== role.name) {
    const existing = await Role.findOne({ name: updateData.name });
    if (existing) {
      throw new AppError('ROLE_ALREADY_EXISTS');
    }
  }

  Object.assign(role, updateData);
  await role.save();
  return role;
};

const deleteRole = async (id) => {
  const role = await Role.findById(id);
  if (!role) {
    throw new AppError('ROLE_NOT_FOUND');
  }

  if (role.isSystem) {
    throw new AppError('SYSTEM_ROLE_PROTECTED');
  }

  await Role.findByIdAndDelete(id);
  return null;
};

const searchRoles = async (queryParams) => {
  return getAllRoles(queryParams);
};

module.exports = {
  createRole,
  getRole,
  getAllRoles,
  updateRole,
  deleteRole,
  searchRoles
};