using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using gehGassi.Core.Interfaces;
using gehGassi.Domain.Common;
using gehGassi.Domain.Shop;
using Microsoft.EntityFrameworkCore;

namespace gehGassi.Core.Services
{
    /// <summary>
    /// Service der die Verwaltung von Versandkosten ermöglicht
    /// </summary>
    public class ShipmentCostService : ServiceBase<ShipmentCost>, IShipmentCostService
    {
        private readonly IShopSettingsService _shopSettingsService;

        /// <summary>
        /// Erstellt eine Instanz
        /// </summary>
        /// <param name="unitOfWork">Instanz eines IUnitOfWork</param>
        /// <param name="shopSettingsService">Instanz eines IShopSettingsService</param>
        public ShipmentCostService(IUnitOfWork unitOfWork, IShopSettingsService shopSettingsService) : base(unitOfWork)
        {
            _shopSettingsService = shopSettingsService;
        }

        /// <summary>
        /// Gibt eine gefilterte Liste von Versandkosten zurück
        /// </summary>
        /// <param name="filter">Filterbegriff der in bestimmten Feldern gesucht wird</param>
        /// <returns>List betroffener Versandkosten</returns>
        public IQueryable<ShipmentCost> Filter(string filter)
        {
            return Repository.Query(c => c.TargetCountryIso.Contains(filter));
        }

        /// <summary>
        /// Erstellen von Versandkosten
        /// </summary>
        /// <returns>Versandkosten</returns>
        public ShipmentCost Create()
        {
            var item = new ShipmentCost
            {
                
            };
            return item;
        }

        /// <summary>
        /// Gibt eine gefilterte Liste von Versandkosten zurück. Sucht nur im Land
        /// </summary>
        /// <param name="filter">Filterbegriff der in bestimmten Feldern gesucht wird</param>
        /// <returns>List betroffener Versandkosten</returns>
        public async Task<List<ShipmentCost>> SearchAsync(string filter)
        {
            return (await Repository.FindAsync(c => c.TargetCountryIso.Contains(filter)).ConfigureAwait(false)).ToList();
        }

        /// <summary>
        /// Berechnen der Versandkosten
        /// </summary>
        /// <param name="targetCountry">Zielland</param>
        /// <param name="weight">Gewicht</param>
        /// <param name="subtotal">Zwischensumme netto</param>
        /// <param name="additionalShipmentCosts">Summe der zusätzlichen Versandkosten je Produkt aber in Summe</param>
        /// <returns>Versandkosten netto</returns>
        public async Task<decimal> CalculateShipmentAsync(string targetCountry, decimal weight, decimal subtotal, decimal additionalShipmentCosts)
        {
            targetCountry = targetCountry.ToUpper();
            var result = 0M;
            var shopSettings = await _shopSettingsService.GetAsync();

            var rulesQuery = Repository.Query(c => (c.TargetCountryIso == "--" || c.TargetCountryIso == targetCountry));
            if (shopSettings.ShipmentCalculationType == ShipmentCalculationType.Weight)
            {
                rulesQuery = rulesQuery.Where(c => c.WeightFrom <= weight && c.WeightTo >= weight);
            }
            else
            {
                rulesQuery = rulesQuery.Where(c => c.SubtotalFrom <= subtotal && c.SubtotalTo >= subtotal);
            }
            
            var rules = await rulesQuery.ToListAsync();

            if (rules.Any())
            {
                //Wenn es mehrere Regeln gibt, dann jene für das Zielland wählen
                var ruleToAppy = rules.FirstOrDefault(c => c.TargetCountryIso == targetCountry) ?? rules.FirstOrDefault();
                if (ruleToAppy != null)
                {
                    if (shopSettings.ShipmentCalculationType == ShipmentCalculationType.Weight)
                    {
                        result = ruleToAppy.FixedPrice;
                    }
                    else
                    {
                        result = (subtotal / 100) * ruleToAppy.SubtotalPercent;
                    }
                }
            }

            result += additionalShipmentCosts;

            return result;
        }
    }
}