Musify/backend/Musify.Infrastructure/MassTransit/Activities/Files/DownloadFileFromUrlActivity.cs

using MassTransit;
using Microsoft.Extensions.Logging;
using Musify.Infrastructure.MassTransit.Arguments;
using Musify.Infrastructure.MassTransit.Logs;

namespace Musify.Infrastructure.MassTransit.Activities.Files
{
    internal class DownloadFileFromUrlActivity(
        IHttpClientFactory httpClientFactory,
        ILogger<DownloadFileFromUrlActivity> logger)
        : IActivity<DownloadFileFromUrlArguments, DownloadFileFromUrlLog>
    {
        public const string ExecuteEndpointName = "download-file-from-url";

        public async Task<ExecutionResult> Execute(ExecuteContext<DownloadFileFromUrlArguments> executeContext)
        {
            var destinationPath = executeContext.GetVariable<string>(executeContext.Arguments.DestinationFilePathVariable);
            ArgumentNullException.ThrowIfNull(destinationPath, nameof(destinationPath));

            try
            {
                var httpClient = httpClientFactory.CreateClient();

                using var response = await httpClient.GetAsync(
                    executeContext.Arguments.SourceUrl,
                    HttpCompletionOption.ResponseHeadersRead,
                    executeContext.CancellationToken);
                response.EnsureSuccessStatusCode();

                var destinationDirectory = Path.GetDirectoryName(destinationPath);
                if (!string.IsNullOrWhiteSpace(destinationDirectory))
                    Directory.CreateDirectory(destinationDirectory);

                await using (var destinationStream = File.Create(destinationPath))
                {
                    await response.Content.CopyToAsync(destinationStream, executeContext.CancellationToken);
                }

                logger.LogInformation("Downloaded {SourceUrl} to {DestinationPath}",
                    executeContext.Arguments.SourceUrl, destinationPath);

                return executeContext.Completed(new DownloadFileFromUrlLog(
                    executeContext.Arguments.SourceUrl,
                    destinationPath));
            }
            catch (Exception exception)
            {
                logger.LogError(exception, "Failed to download file from {SourceUrl}", executeContext.Arguments.SourceUrl);
                throw;
            }
        }

        public Task<CompensationResult> Compensate(CompensateContext<DownloadFileFromUrlLog> compensateContext)
        {
            try
            {
                if (File.Exists(compensateContext.Log.DestinationFilePath))
                    File.Delete(compensateContext.Log.DestinationFilePath);
                return Task.FromResult(compensateContext.Compensated());
            }
            catch (Exception exception)
            {
                logger.LogError(exception, "Failed to compensate downloaded file {DestinationFilePath}",
                    compensateContext.Log.DestinationFilePath);
                return Task.FromResult(compensateContext.Failed(exception));
            }
        }
    }
}