using System.Globalization;
using System.Xml;
using Nop.Core;
using Nop.Core.Http;
using Nop.Services.Configuration;
using Nop.Services.Directory;
using Nop.Services.Localization;
using Nop.Services.Logging;
using Nop.Services.Plugins;

namespace Nop.Plugin.ExchangeRate.EcbExchange;

public class EcbExchangeRateProvider : BasePlugin, IExchangeRateProvider
{
    #region Fields

    protected readonly EcbExchangeRateSettings _ecbExchangeRateSettings;
    protected readonly IHttpClientFactory _httpClientFactory;
    protected readonly ILocalizationService _localizationService;
    protected readonly ILogger _logger;
    protected readonly ISettingService _settingService;

    #endregion

    #region Ctor

    public EcbExchangeRateProvider(EcbExchangeRateSettings ecbExchangeRateSettings,
        IHttpClientFactory httpClientFactory,
        ILocalizationService localizationService,
        ILogger logger,
        ISettingService settingService)
    {
        _ecbExchangeRateSettings = ecbExchangeRateSettings;
        _httpClientFactory = httpClientFactory;
        _localizationService = localizationService;
        _logger = logger;
        _settingService = settingService;
    }

    #endregion

    #region Methods

    /// <summary>
    /// Gets currency live rates
    /// </summary>
    /// <param name="exchangeRateCurrencyCode">Exchange rate currency code</param>
    /// <returns>
    /// A task that represents the asynchronous operation
    /// The task result contains the exchange rates
    /// </returns>
    public async Task<IList<Core.Domain.Directory.ExchangeRate>> GetCurrencyLiveRatesAsync(string exchangeRateCurrencyCode)
    {
        ArgumentNullException.ThrowIfNull(exchangeRateCurrencyCode);

        //add euro with rate 1
        var ratesToEuro = new List<Core.Domain.Directory.ExchangeRate>
        {
            new() {
                CurrencyCode = "EUR",
                Rate = 1,
                UpdatedOn = DateTime.UtcNow
            }
        };

        //get exchange rates to euro from European Central Bank
        try
        {
            var httpClient = _httpClientFactory.CreateClient(NopHttpDefaults.DefaultHttpClient);
            var stream = await httpClient.GetStreamAsync(_ecbExchangeRateSettings.EcbLink);

            //load XML document
            var document = new XmlDocument();
            document.Load(stream);

            //add namespaces
            var namespaces = new XmlNamespaceManager(document.NameTable);
            namespaces.AddNamespace("ns", "http://www.ecb.int/vocabulary/2002-08-01/eurofxref");
            namespaces.AddNamespace("gesmes", "http://www.gesmes.org/xml/2002-08-01");

            //get daily rates
            var dailyRates = document.SelectSingleNode("gesmes:Envelope/ns:Cube/ns:Cube", namespaces);
            if (!DateTime.TryParseExact(dailyRates.Attributes["time"].Value, "yyyy-MM-dd", null, DateTimeStyles.None, out var updateDate))
                updateDate = DateTime.UtcNow;

            foreach (XmlNode currency in dailyRates.ChildNodes)
            {
                //get rate
                if (!decimal.TryParse(currency.Attributes["rate"].Value, NumberStyles.Currency, CultureInfo.InvariantCulture, out var currencyRate))
                    continue;

                ratesToEuro.Add(new Core.Domain.Directory.ExchangeRate()
                {
                    CurrencyCode = currency.Attributes["currency"].Value,
                    Rate = currencyRate,
                    UpdatedOn = updateDate
                });
            }
        }
        catch (Exception ex)
        {
            await _logger.ErrorAsync("ECB exchange rate provider", ex);
        }

        //return result for the euro
        if (exchangeRateCurrencyCode.Equals("eur", StringComparison.InvariantCultureIgnoreCase))
            return ratesToEuro;

        //use only currencies that are supported by ECB
        var exchangeRateCurrency = ratesToEuro.FirstOrDefault(rate => rate.CurrencyCode.Equals(exchangeRateCurrencyCode, StringComparison.InvariantCultureIgnoreCase)) 
                                   ?? throw new NopException(await _localizationService.GetResourceAsync("Plugins.ExchangeRate.EcbExchange.Error"));

        //return result for the selected (not euro) currency
        return ratesToEuro.Select(rate => new Core.Domain.Directory.ExchangeRate
        {
            CurrencyCode = rate.CurrencyCode,
            Rate = Math.Round(rate.Rate / exchangeRateCurrency.Rate, 4),
            UpdatedOn = rate.UpdatedOn
        }).ToList();
    }

    /// <summary>
    /// Install the plugin
    /// </summary>
    /// <returns>A task that represents the asynchronous operation</returns>
    public override async Task InstallAsync()
    {
        //settings
        var defaultSettings = new EcbExchangeRateSettings
        {
            EcbLink = "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml"
        };
        await _settingService.SaveSettingAsync(defaultSettings);

        //locales
        await _localizationService.AddOrUpdateLocaleResourceAsync("Plugins.ExchangeRate.EcbExchange.Error", "You can use ECB (European central bank) exchange rate provider only when the primary exchange rate currency is supported by ECB");

        await base.InstallAsync();
    }

    /// <summary>
    /// Uninstall the plugin
    /// </summary>
    /// <returns>A task that represents the asynchronous operation</returns>
    public override async Task UninstallAsync()
    {
        //settings
        await _settingService.DeleteSettingAsync<EcbExchangeRateSettings>();

        //locales
        await _localizationService.DeleteLocaleResourceAsync("Plugins.ExchangeRate.EcbExchange.Error");

        await base.UninstallAsync();
    }

    #endregion
}