// (c) Copyright Ascensio System SIA 2010-2022
//
// This program is a free software product.
// You can redistribute it and/or modify it under the terms
// of the GNU Affero General Public License (AGPL) version 3 as published by the Free Software
// Foundation. In accordance with Section 7(a) of the GNU AGPL its Section 15 shall be amended
// to the effect that Ascensio System SIA expressly excludes the warranty of non-infringement of
// any third-party rights.
//
// This program is distributed WITHOUT ANY WARRANTY, without even the implied warranty
// of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE. For details, see
// the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
//
// You can contact Ascensio System SIA at Lubanas st. 125a-25, Riga, Latvia, EU, LV-1021.
//
// The  interactive user interfaces in modified source and object code versions of the Program must
// display Appropriate Legal Notices, as required under Section 5 of the GNU AGPL version 3.
//
// Pursuant to Section 7(b) of the License you must retain the original Product logo when
// distributing the program. Pursuant to Section 7(e) we decline to grant you any rights under
// trademark law for use of our trademarks.
//
// All the Product's GUI elements, including illustrations and icon sets, as well as technical writing
// content are licensed under the terms of the Creative Commons Attribution-ShareAlike 4.0
// International. See the License terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode

namespace ASC.Webhooks.Service;

[Singletone]
public class WebhookSender
{
    private readonly IHttpClientFactory _clientFactory;
    private readonly ILogger _log;
    public int? RepeatCount { get; init; }
    private readonly IServiceScopeFactory _scopeFactory;

    public WebhookSender(ILoggerProvider options, IServiceScopeFactory scopeFactory, Settings settings, IHttpClientFactory clientFactory)
    {
        _log = options.CreateLogger("ASC.Webhooks.Core");
        _scopeFactory = scopeFactory;
        RepeatCount = settings.RepeatCount;
        _clientFactory = clientFactory;
    }

    public async Task Send(WebhookRequest webhookRequest, CancellationToken cancellationToken)
    {
        using var scope = _scopeFactory.CreateScope();
        var dbWorker = scope.ServiceProvider.GetRequiredService<DbWorker>();

        var entry = dbWorker.ReadFromJournal(webhookRequest.Id);
        var id = entry.Id;
        var requestURI = entry.Uri;
        var secretKey = entry.SecretKey;
        var data = entry.Payload;

        var response = new HttpResponseMessage();
        var request = new HttpRequestMessage();

        for (var i = 0; i < RepeatCount; i++)
        {
            try
            {
                request = new HttpRequestMessage(HttpMethod.Post, requestURI);
                request.Headers.Add("Accept", "*/*");
                request.Headers.Add("Secret", "SHA256=" + GetSecretHash(secretKey, data));

                request.Content = new StringContent(
                    data,
                    Encoding.UTF8,
                    "application/json");

                var httpClient = _clientFactory.CreateClient();
                response = await httpClient.SendAsync(request, cancellationToken);

                if (response.IsSuccessStatusCode)
                {
                    UpdateDb(dbWorker, id, response, request, ProcessStatus.Success);
                    _log.DebugResponse(response);
                    break;
                }
                else if (i == RepeatCount - 1)
                {
                    UpdateDb(dbWorker, id, response, request, ProcessStatus.Failed);
                    _log.DebugResponse(response);
                }
            }
            catch (Exception ex)
            {
                if (i == RepeatCount - 1)
                {
                    UpdateDb(dbWorker, id, response, request, ProcessStatus.Failed);
                }

                _log.ErrorWithException(ex);
                continue;
            }
        }
    }

    private string GetSecretHash(string secretKey, string body)
    {
        string computedSignature;
        var secretBytes = Encoding.UTF8.GetBytes(secretKey);

        using (var hasher = new HMACSHA256(secretBytes))
        {
            var data = Encoding.UTF8.GetBytes(body);
            computedSignature = BitConverter.ToString(hasher.ComputeHash(data));
        }

        return computedSignature;
    }

    private void UpdateDb(DbWorker dbWorker, int id, HttpResponseMessage response, HttpRequestMessage request, ProcessStatus status)
    {
        var responseHeaders = JsonSerializer.Serialize(response.Headers.ToDictionary(r => r.Key, v => v.Value));
        var requestHeaders = JsonSerializer.Serialize(request.Headers.ToDictionary(r => r.Key, v => v.Value));
        string responsePayload;

        using (var streamReader = new StreamReader(response.Content.ReadAsStream()))
        {
            var responseContent = streamReader.ReadToEnd();
            responsePayload = JsonSerializer.Serialize(responseContent);
        }

        dbWorker.UpdateWebhookJournal(id, status, responsePayload, responseHeaders, requestHeaders);
    }
}