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

namespace gehGassi.Core.Services
{
    /// <summary>
    /// Service der die Verwaltung von Coin-Konten, Transaktionen und Monats- und Jahresstatistiken realisiert
    /// </summary>
    public class CoinsService : ServiceBase<CoinsAccount>, ICoinsService
    {
        private readonly IRepository<CoinsTransaction> _transactionRepository;
        private readonly IRepository<CoinsPerMonth> _perMonthRepository;
        private readonly IRepository<CoinsPerMonthWithNames> _perMonthNamesRepository;
        private readonly IRepository<CoinsPerYear> _perYearRepository;
        private readonly IRepository<CoinsPerYearWithNames> _perYearNamesRepository;

        /// <summary>
        /// Erstellt eine Instanz
        /// </summary>
        /// <param name="unitOfWork">Instanz eines IUnitOfWork</param>
        public CoinsService(IUnitOfWork unitOfWork) : base(unitOfWork)
        {
            _transactionRepository = unitOfWork.GetRepository<CoinsTransaction>();
            _perMonthRepository = unitOfWork.GetRepository<CoinsPerMonth>();
            _perMonthNamesRepository = unitOfWork.GetRepository<CoinsPerMonthWithNames>();
            _perYearRepository = unitOfWork.GetRepository<CoinsPerYear>();
            _perYearNamesRepository = unitOfWork.GetRepository<CoinsPerYearWithNames>();
        }

        /// <summary>
        /// Gibt einen Coin-Account zurück oder erstellt einen neuen wenn noch nicht vorhanden
        /// </summary>
        /// <param name="appUserId">Id des AppUsers</param>
        /// <param name="appUserType">Typ des AppUsers</param>
        /// <returns>CoinAccount</returns>
        public async Task<CoinsAccount> GetOrCreateAsync(string appUserId, AppUserType appUserType)
        {
            var account = await Repository.FirstOrDefaultAsync(c => c.AppUserId == appUserId && c.AppUserType == appUserType);

            if (account == null)
            {
                account = new CoinsAccount()
                {
                    Id = Guid.NewGuid().ToString("N"),
                    AppUserId = appUserId,
                    AppUserType = appUserType,
                    Balance = 0,
                    Created = DateTimeOffset.UtcNow,
                    UpdatedAt = DateTimeOffset.UtcNow
                };
                Repository.Add(account);
                await CommitAsync("System");
            }

            return account;
        }

        /// <summary>
        /// Einzahlen einer Coins-Summe auf das passende Konto eines AppUsers
        /// </summary>
        /// <param name="appUserId">Id des AppUsers</param>
        /// <param name="appUserType">Typ des AppUsers</param>
        /// <param name="ammount">Coins-Betrag der eingezahlt werden soll</param>
        /// <param name="walkId">Optional: Id des Walks auf den sich die Transaktion bezieht</param>
        /// <returns>Transaktion</returns>
        public async Task<CoinsTransaction> DepositAsync(string appUserId, AppUserType appUserType, decimal ammount, string walkId)
        {
            var account = await GetOrCreateAsync(appUserId, appUserType);
            
            //Transaktion anlegen
            var transaction = new CoinsTransaction()
            {
                TransactionType = CoinsTransactionType.Deposit,
                AccountId = account.Id,
                Ammount = ammount,
                WalkId = walkId,
                Created = DateTimeOffset.UtcNow
            };
            _transactionRepository.Add(transaction);

            account.Balance += ammount;

            //Punkte für das Monatskonto
            var coinsPerMonth = await GetOrCreateCoinsPerMonthAsync(appUserId, appUserType, DateTimeOffset.UtcNow);
            coinsPerMonth.Balance += ammount;
            coinsPerMonth.LastUpdate = DateTimeOffset.UtcNow;

            //Punkte für das Jahreskonto
            var coinsPerYear = await GetOrCreateCoinsPerYearAsync(appUserId, appUserType, DateTimeOffset.UtcNow);
            coinsPerYear.Balance += ammount;
            coinsPerYear.LastUpdate = DateTimeOffset.UtcNow;

            await CommitAsync("System");

            return transaction;
        }

        /// <summary>
        /// Abbuchen einer Coins-Summe von dem passenden Konto eines AppUsers
        /// </summary>
        /// <param name="appUserId">Id des AppUsers</param>
        /// <param name="appUserType">Typ des AppUsers</param>
        /// <param name="ammount">Coins-Betrag der eingezahlt werden soll</param>
        /// <returns>CoinsTransaction</returns>
        public async Task<CoinsTransaction> WithdrawAsync(string appUserId, AppUserType appUserType, decimal ammount)
        {
            var account = await GetOrCreateAsync(appUserId, appUserType);

            if (account.Balance < ammount)
                return null;

            //Transaktion anlegen
            var transaction = new CoinsTransaction()
            {
                TransactionType = CoinsTransactionType.Withdrawal,
                AccountId = account.Id,
                Ammount = ammount,
                WalkId = string.Empty,
                Created = DateTimeOffset.UtcNow
            };
            _transactionRepository.Add(transaction);

            account.Balance -= ammount;

            await CommitAsync("System");

            return transaction;
        }

        /// <summary>
        /// Gibt den Coins-Stand eines AppUsers für einen Monat zurück
        /// </summary>
        /// <param name="appUserId">Id des AppUsers</param>
        /// <param name="appUserType">Typ des AppUsers</param>
        /// <param name="date">Datum</param>
        /// <returns>CoinsPerMonth</returns>
        public async Task<CoinsPerMonth> GetOrCreateCoinsPerMonthAsync(string appUserId, AppUserType appUserType, DateTimeOffset date)
        {
            var coinsPerMonth = await _perMonthRepository.FirstOrDefaultAsync(c => c.AppUserId == appUserId && c.AppUserType == appUserType && c.Year == date.Year && c.Month == date.Month);

            if (coinsPerMonth == null)
            {
                coinsPerMonth = new CoinsPerMonth()
                {
                    AppUserId = appUserId,
                    AppUserType = appUserType,
                    Year = date.Year,
                    Month = date.Month,
                    Balance = 0,
                    LastUpdate = DateTimeOffset.UtcNow
                };
                //Keine Wertung rückwirkend erstellen
                if (date.Year == DateTimeOffset.UtcNow.Year && date.Month == DateTimeOffset.UtcNow.Month)
                {
                    _perMonthRepository.Add(coinsPerMonth);
                    await CommitAsync("System");
                }
            }

            return coinsPerMonth;
        }

        /// <summary>
        /// Gibt den Coins-Stand eines AppUsers für ein Jahr zurück
        /// </summary>
        /// <param name="appUserId">Id des AppUsers</param>
        /// <param name="appUserType">Typ des AppUsers</param>
        /// <param name="date">Datum</param>
        /// <returns>CoinsPerYear</returns>
        public async Task<CoinsPerYear> GetOrCreateCoinsPerYearAsync(string appUserId, AppUserType appUserType, DateTimeOffset date)
        {
            var coinsPerYear = await _perYearRepository.FirstOrDefaultAsync(c => c.AppUserId == appUserId && c.AppUserType == appUserType && c.Year == date.Year);

            if (coinsPerYear == null)
            {
                coinsPerYear = new CoinsPerYear()
                {
                    AppUserId = appUserId,
                    AppUserType = appUserType,
                    Year = date.Year,
                    Balance = 0,
                    LastUpdate = DateTimeOffset.UtcNow
                };
                //Keine Wertung rückwirkend erstellen
                if (date.Year == DateTimeOffset.UtcNow.Year)
                {
                    _perYearRepository.Add(coinsPerYear);
                    await CommitAsync("System");
                }
            }

            return coinsPerYear;
        }

        /// <summary>
        /// Gibt die Top X der Coins je Monat für ein Jahr und Monat zurück.
        /// Sortiert nach Coins absteigend und bei Gleichstand nach LastUpdate aufsteigend
        /// </summary>
        /// <param name="count">Anzalh Datensätze</param>
        /// <param name="appUserType">Typ des AppUsers</param>
        /// <param name="year">Jahr</param>
        /// <param name="month">Monat</param>
        /// <param name="minBalance">Mindest-Wert der erreicht werden musste</param>
        /// <returns>Liste CoinsPerMonthWithNames</returns>
        public async Task<List<CoinsPerMonthWithNames>> GetMonthlyTopAsync(int count, AppUserType appUserType, int year, int month, decimal minBalance)
        {
            var coins = await _perMonthNamesRepository.QueryView(c => c.AppUserType == appUserType && c.Year == year && c.Month == month && c.Balance >= minBalance).OrderByDescending(c => c.Balance).ThenBy(c => c.LastUpdate).Take(count).ToListAsync();
            return coins;
        }

        /// <summary>
        /// Gibt die Top X der Coins je Jahr zurück.
        /// Sortiert nach Coins absteigend und bei Gleichstand nach LastUpdate aufsteigend
        /// </summary>
        /// <param name="count">Anzalh Datensätze</param>
        /// <param name="appUserType">Typ des AppUsers</param>
        /// <param name="year">Jahr</param>
        /// <param name="minBalance">Mindest-Wert der erreicht werden musste</param>
        /// <returns>Liste CoinsPerMonthWithNames</returns>
        public async Task<List<CoinsPerYearWithNames>> GetYearlyTopAsync(int count, AppUserType appUserType, int year, decimal minBalance)
        {
            var coins = await _perYearNamesRepository.QueryView(c => c.AppUserType == appUserType && c.Year == year && c.Balance >= minBalance).OrderByDescending(c => c.Balance).ThenBy(c => c.LastUpdate).Take(count).ToListAsync();
            return coins;
        }
    }
}