using AngleSharp;
using AngleSharp.Parser.Html;
using NLog;
using System;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace Sony.Filtr.SpotifyWebAPI
{
    public class InternalSpotifyApiClient
    {
        private readonly HttpClient _apiRequestClient = new HttpClient();
        private readonly Logger _logger;
        private DateTime? _accessTokenExpiresOn;

        private bool TokenIsExpired => _accessTokenExpiresOn <= DateTime.UtcNow;

        public InternalSpotifyApiClient()
        { }

        public InternalSpotifyApiClient(Logger logger)
        {
            _logger = logger;
        }

        public async Task<ArtistInfoRootObject> GetArtistInfoAsync(string artistId)
        {
            if (TokenIsExpired)
                await GetScrapedTokenAsync();

            try
            {
                return await FetchArtistInfoAsync(artistId);
            }
            catch (UnauthorizedAccessException e)
            {
                _logger?.Error(e, "Unauthorized request to internal API - invalidating token.");
                _accessTokenExpiresOn = DateTime.UtcNow;

                await GetScrapedTokenAsync();

                return await FetchArtistInfoAsync(artistId);
            }
        }

        private async Task<ArtistInfoRootObject> FetchArtistInfoAsync(string artistId)
        {
            var artistInfoUrl = new Flurl.Url("https://spclient.wg.spotify.com/open-backend-2/v1/artists/").AppendPathSegment(artistId);
            var response = await _apiRequestClient.GetAsync(artistInfoUrl);

            if (response.StatusCode == HttpStatusCode.Unauthorized)
                throw new UnauthorizedAccessException();

            response.EnsureSuccessStatusCode();

            return await response.Content.ReadAsAsync<ArtistInfoRootObject>();
        }

        private async Task GetScrapedTokenAsync()
        {
            _logger?.Info("Scraping access token");
            using (var httpClient = new HttpClient())
            {
                //try get latest version of chrome as the server blacklists old version numbers
                var chromeVersionNumber = await GetChromeVersionNumber(httpClient);

                // User agent needs to be browser to force correct rendering, including "Set-Cookie" header with token.
                httpClient.DefaultRequestHeaders.UserAgent.ParseAdd($"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/{chromeVersionNumber} Safari/537.36");

                // TODO: Just a random artist ID used here, should use something safer.
                var response = await httpClient.GetAsync("https://open.spotify.com/artist/3jOstUTkEu2JkjvRdBA5Gu");

                if (response.Headers.TryGetValues("Set-Cookie", out var cookieHeaderValues))
                {
                    var tokenValue = cookieHeaderValues.FirstOrDefault(v => v.StartsWith("wp_access_token"));

                    if (!string.IsNullOrWhiteSpace(tokenValue))
                    {
                        var token = tokenValue.Substring(tokenValue.IndexOf("wp_access_token=", StringComparison.Ordinal) + "wp_access_token=".Length).Split(';').FirstOrDefault();
                        Console.WriteLine("Token: " + token);

                        _apiRequestClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
                        //the access token expires 3300 seconds after creation
                        //set an expiry time to know when and avoid making unauthorized requests
                        _accessTokenExpiresOn = DateTime.UtcNow.AddSeconds(3295);

                        _logger?.Info($"New token set to: { token }");
                    }
                }
            }
        }

        private async Task<string> GetChromeVersionNumber(HttpClient httpClient)
        {
            var wikipediaVersionHtml = await httpClient.GetStringAsync("https://en.wikipedia.org/wiki/Google_Chrome_version_history");
            var htmlDocument = new HtmlParser(new Configuration().WithCss()).Parse(wikipediaVersionHtml);

            var innerHtmlFromTdWithVersionNumber = htmlDocument.All.FirstOrDefault(x =>
                x.LocalName == "td"
                && x.OuterHtml.Contains("a0e75a")
                && x.InnerHtml.Any(y => char.IsDigit(y))
            )?.InnerHtml;

            var chromeVersionNumber = "72.0.3578.98";
            if (!string.IsNullOrEmpty(innerHtmlFromTdWithVersionNumber))
            {
                chromeVersionNumber = Regex.Replace(innerHtmlFromTdWithVersionNumber, @"\t|\n|\r", "");
                _logger?.Info($"Scraped Chrome version number: {chromeVersionNumber}");
            }
            else
            {
                _logger?.Warn($"Could not scrape Chrome version number! Using default {chromeVersionNumber}");
            }

            return chromeVersionNumber;
        }

        public class ArtistInfoRootObject
        {
            public string bio { get; set; }
            public Headerimage[] headerImages { get; set; }
            public Artistinsights artistInsights { get; set; }
        }

        public class Artistinsights
        {
            public string artist_gid { get; set; }
            public Autobiography autobiography { get; set; }
            public string biography { get; set; }
            public Header_Image header_image { get; set; }
            public Image[] images { get; set; }
            public int global_chart_position { get; set; }
            public long monthly_listeners { get; set; }
            public long monthly_listeners_delta { get; set; }
            public int follower_count { get; set; }
            public int following_count { get; set; }
            public Playlists playlists { get; set; }
            public City[] cities { get; set; }
        }

        public class Autobiography
        {
            public string[] urls { get; set; }
            public Links links { get; set; }
        }

        public class Links
        {
            public string twitter { get; set; }
            public string instagram { get; set; }
            public string wikipedia { get; set; }
            public string facebook { get; set; }
        }

        public class Header_Image
        {
            public string id { get; set; }
            public string uri { get; set; }
            public int width { get; set; }
            public int height { get; set; }
        }

        public class Playlists
        {
            public Entry[] entries { get; set; }
        }

        public class Entry
        {
            public string uri { get; set; }
            public string name { get; set; }
            public string image_url { get; set; }
            public Owner owner { get; set; }
            public int listeners { get; set; }
        }

        public class Owner
        {
            public string name { get; set; }
            public string uri { get; set; }
        }

        public class Image
        {
            public string id { get; set; }
            public string uri { get; set; }
            public int width { get; set; }
            public int height { get; set; }
        }

        public class City
        {
            public string country { get; set; }
            public string region { get; set; }
            public string city { get; set; }
            public int listeners { get; set; }
        }

        public class Headerimage
        {
            public string url { get; set; }
        }

    }
}