using System.Net.Http.Headers;
using System.Text;

namespace NejCommon.Utils;

public class HttpDebuggingHandler : DelegatingHandler
    {
        protected readonly ILogger Logger;
        public HttpDebuggingHandler(ILogger logger, HttpMessageHandler innerHandler = null)
            : base(innerHandler ?? new HttpClientHandler())
        {
            Logger = logger;
        }

        async protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
            CancellationToken cancellationToken)
        {
            var req = request;
            var id = Guid.NewGuid().ToString();
            var msg = $"[{id} -   Request]";

            StringBuilder output = new StringBuilder();

            output.AppendLine($"{msg}========Start==========");
            output.AppendLine($"{req.Method} {req.RequestUri.PathAndQuery} {req.RequestUri.Scheme}/{req.Version}");
            output.AppendLine($"Host: {req.RequestUri.Scheme}://{req.RequestUri.Host}");

            foreach (var header in req.Headers)
                output.AppendLine($"{header.Key}: {string.Join(", ", header.Value)}");

            if (req.Content != null)
            {
                foreach (var header in req.Content.Headers)
                    output.AppendLine($"{header.Key}: {string.Join(", ", header.Value)}");

                if (req.Content is StringContent || IsTextBasedContentType(req.Headers) ||
                    this.IsTextBasedContentType(req.Content.Headers))
                {
                    var result = await req.Content.ReadAsStringAsync();

                    output.AppendLine($"Content:");
                    output.AppendLine($"{result}");
                }
            }

            var start = DateTime.Now;

            var response = await base.SendAsync(request, cancellationToken).ConfigureAwait(false);

            var end = DateTime.Now;

            output.AppendLine($"Duration: {end - start}");
            output.AppendLine($"{msg}==========End==========");
            Logger.LogInformation(output.ToString());

            output.Clear();

            msg = $"[{id} - Response]";
            output.AppendLine($"{msg}=========Start=========");

            var resp = response;

            output.AppendLine(
                $"{req.RequestUri.Scheme.ToUpper()}/{resp.Version} {(int) resp.StatusCode} {resp.ReasonPhrase}");

            foreach (var header in resp.Headers)
                output.AppendLine($"{header.Key}: {string.Join(", ", header.Value)}");

            if (resp.Content != null)
            {
                foreach (var header in resp.Content.Headers)
                    output.AppendLine($"{header.Key}: {string.Join(", ", header.Value)}");

                if (resp.Content is StringContent || this.IsTextBasedContentType(resp.Headers) ||
                    this.IsTextBasedContentType(resp.Content.Headers))
                {
                    start = DateTime.Now;
                    var result = await resp.Content.ReadAsStringAsync();
                    end = DateTime.Now;

                    output.AppendLine($"Content:");
                    output.AppendLine($"{result}");
                    output.AppendLine($"Duration: {end - start}");
                }
            }

            output.AppendLine($"{msg}==========End==========");
            Logger.LogInformation(output.ToString());
            return response;
        }

        readonly string[] types = new[] {"html", "text", "xml", "json", "txt", "x-www-form-urlencoded"};

        bool IsTextBasedContentType(HttpHeaders headers)
        {
            IEnumerable<string> values;
            if (!headers.TryGetValues("Content-Type", out values))
                return false;
            var header = string.Join(" ", values).ToLowerInvariant();

            return types.Any(t => header.Contains(t));
        }
    }