using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using BlueWest.Data;
using Microsoft.EntityFrameworkCore;

namespace BlueWest.WebApi.EF
{
    /// <summary>
    /// Currency table data extensions
    /// </summary>
    public static class CurrencyExtensions
    {
        
        /// <summary>
        /// Not found projection
        /// </summary>
        /// <returns></returns>
        public static (bool, Currency) NotFound() => (false, null);
        
        /// <summary>
        /// Add new Currency
        /// </summary>
        /// <param name="dbContext"></param>
        /// <param name="currencyToCreate"></param>
        /// <returns></returns>
        public static (bool, Currency) AddCurrency(this CountryDbContext dbContext, CurrencyCreate currencyToCreate)
        {
            var newCurrency = new Currency(currencyToCreate);
            dbContext.Add(newCurrency);
            var resultOperation = dbContext.SaveChanges() >= 0;
            return (resultOperation, newCurrency);
        }
        
        
        /// <summary>
        /// Updates currency
        /// </summary>
        /// <param name="dbContext"></param>
        /// <param name="currencyId"></param>
        /// <param name="currencyToUpdate"></param>
        /// <returns></returns>
        public static (bool, Currency) UpdateCurrency(this CountryDbContext dbContext, int currencyId, CurrencyUpdate currencyToUpdate)
        {
            var currency =  dbContext.Currencies.FirstOrDefault(x => x.Id == currencyId);
            if (currency == null) return NotFound();
            currency.Update(currencyToUpdate);
            dbContext.Update(currency);
            var resultOperation = dbContext.SaveChanges() >= 0;
            return (resultOperation, currency);

        }
        
        public static (bool, string, CountryUnique) AddCountry( 
            this CountryDbContext dbContext, 
            int currencyId, CountryCreate countryCreate,  
            Expression<Func<Country,bool>>[] duplicationValidations)
        {
            
            var currency = dbContext
                .Currencies
                .Where(data => data.Id == currencyId)
                .Include(o => o.Countries)
                .FirstOrDefault();
            
            
            // Check if currency exists
            if (currency == null) return (false, $"{nameof(Currency)}: {currencyId} - Not found.", null);

            // Check if there's currency with the same code
            foreach (var duplicationValidation in duplicationValidations)
            {
                var currencyToGet = dbContext.Countries.FirstOrDefault(duplicationValidation);
                if (currencyToGet != null) return Projection.ErrorMessage<CountryUnique>($"Duplication Validation failed: {duplicationValidation.Body}");
            }
            
            // Creates new currency
            var newCountry = new Country(countryCreate);
            currency.Countries.Add(newCountry);
            var success = dbContext.SaveChanges() >= 0;
            return Projection.Success(success, new CountryUnique(newCountry));
        }

    }
}