using System;
using System.Collections.Generic;
using System.Linq;
using Database.Models;
using Database.Repository;

namespace Pos.Service
{
    public class ProductGroupService
    {
        private readonly ProductGroupRepository _productGroupRepository =
            new ProductGroupRepository();

        public List<ProductGroupEntity> GetProductGroups()
        {
            return _productGroupRepository.GetAll();
        }

        public bool HasProductGroups()
        {
            return _productGroupRepository.Any();
        }

        public void AddProductGroup(string name)
        {
            _productGroupRepository.Add(ValidateName(name));
            CacheService.Invalidate();
        }

        public void RenameProductGroup(int productGroupId, string name)
        {
            ValidateId(productGroupId);
            _productGroupRepository.Edit(
                ValidateName(name),
                productGroupId);
            CacheService.Invalidate();
        }

        public void ArchiveProductGroup(int productGroupId)
        {
            ValidateId(productGroupId);
            _productGroupRepository.Archive(productGroupId);
            CacheService.Invalidate();
        }

        public void UpdateOrder(IReadOnlyList<int> orderedProductGroupIds)
        {
            ValidateOrder(orderedProductGroupIds);
            _productGroupRepository.SetOrder(orderedProductGroupIds);
            CacheService.Invalidate();
        }

        private static string ValidateName(string name)
        {
            if (string.IsNullOrWhiteSpace(name))
                throw new ArgumentException(
                    "Produktgruppen skal have et navn.",
                    nameof(name));

            return name.Trim();
        }

        private static void ValidateId(int productGroupId)
        {
            if (productGroupId <= 0)
                throw new ArgumentOutOfRangeException(nameof(productGroupId));
        }

        private static void ValidateOrder(IReadOnlyList<int> orderedIds)
        {
            if (orderedIds == null)
                throw new ArgumentNullException(nameof(orderedIds));

            if (orderedIds.Any(id => id <= 0))
                throw new ArgumentException(
                    "Rækkefølgen indeholder et ugyldigt id.",
                    nameof(orderedIds));

            if (orderedIds.Distinct().Count() != orderedIds.Count)
                throw new ArgumentException(
                    "Rækkefølgen indeholder dubletter.",
                    nameof(orderedIds));
        }
    }
}