using System.Globalization;
using System.Net;
using System.Xml.Linq;
using Google.Cloud.BigQuery.V2;
using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json.Linq;

namespace OSAFeedXML
{
    public class Function1
    {
        private readonly ILogger _logger;
        private readonly IBigQuery _bq;
        private readonly string DomainRedirect, ShortDescription, Title;

        public Function1(ILoggerFactory loggerFactory, IBigQuery bq)
        {
            _logger = loggerFactory.CreateLogger<Function1>();
            DomainRedirect = Environment.GetEnvironmentVariable("DOMAIN_REDIRECT") ?? throw new Exception("Brak domeny przekierowania.");
            ShortDescription = Environment.GetEnvironmentVariable("SHORT_DESCRIPTION") ?? throw new Exception("Brak krótkiego opisu.");
            Title = Environment.GetEnvironmentVariable("TITLE") ?? throw new Exception("Brak tytułu.");
            _bq = bq;
        }

        [Function("getfeeds")]
        public HttpResponseData Run([HttpTrigger(AuthorizationLevel.Anonymous, "get")] HttpRequestData req)
        {
            try
            {
            var queryParams = System.Web.HttpUtility.ParseQueryString(req.Url.Query);
            var sourceParam = queryParams["source"];
            var destinationList = new List<Destinations>();
            Boolean.TryParse(queryParams["withoutbg"], out var withoutbg);

            if (sourceParam != null)
            {
                var sources = sourceParam.Split(',');
                destinationList = sources
                    .Select(src => Enum.TryParse(typeof(Destinations), src, true, out var result) ? result : null)
                    .Where(v => v != null)
                    .Cast<Destinations>()
                    .ToList();
            }
            else
            {
                destinationList = new List<Destinations>() { Destinations.google, Destinations.facebook };
            }

            var result = _bq.GetDataBigQuery(destinationList, withoutbg);

            var jsonArray = new JArray(
                ((BigQueryResults)result).Select(row => new JObject(
                    row.Schema.Fields.Select(field => new JProperty(field.Name, JToken.FromObject(row[field.Name] ?? string.Empty)))
                    ))
                );

            JArray products = JArray.Parse(jsonArray.ToString());

            XNamespace g = "http://base.google.com/ns/1.0";

            XDocument xmlDoc = new XDocument(
            new XElement("rss", new XAttribute("version", "2.0"),
                new XAttribute(XNamespace.Xmlns + "g", g),
                new XElement("channel",
                    new XElement("title", Title),
                    new XElement("link", DomainRedirect),
                    new XElement("description", ShortDescription),
                    from product in products
                    select new XElement("item",
                        new XElement(g + "id", product["id"]?.ToString()),
                        new XElement(g + "title", product["title"]?.ToString()),
                        new XElement(g + "description", product["description"]?.ToString()),
                        new XElement(g + "link", product["link"]?.ToString()),
                        new XElement(g + "image_link", product["image_link"]?.ToString()),
                        new XElement(g + "availability", product["availability"]?.ToString()),
                        new XElement(g + "price", FormatPrice(product["price"] ?? 0)),
                        new XElement(g + "brand", product["brand"]?.ToString()),
                        new XElement(g + "gtin", product["gtin"]?.ToString()),
                        new XElement(g + "mpn", product["mpn"]?.ToString()),
                        new XElement(g + "product_type", product["product_type"]?.ToString()),
                        new XElement(g + "google_product_category", product["google_product_category"]?.ToString()),
                        new XElement(g + "unit_pricing_measure", product["unit_pricing_measure"]?.ToString()),
                        new XElement(g + "condition", product["condition"]?.ToString()),
                        product["gtin"]?.ToString() == "" ? new XElement(g + "identifier_exists", "no") : new XElement(g + "identifier_exists", "yes")
                    )
                )
            )
            );


            var response = req.CreateResponse(HttpStatusCode.OK);
            response.Headers.Add("Content-Type", "text/xml; charset=utf-8");

            response.WriteString(xmlDoc.ToString());

            return response;
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, ex.Message);
                return req.CreateResponse(HttpStatusCode.InternalServerError);
            }
        }

        static string FormatPrice(JToken priceToken)
        {
            if (priceToken == null || string.IsNullOrWhiteSpace(priceToken.ToString()))
            {
                return "0.00 PLN";
            }

            decimal price = priceToken.Value<decimal>();
            return price.ToString("0.00", CultureInfo.InvariantCulture) + " PLN";
        }
    }
}