ParadoxSaveParser/ParadoxSaveParser.WebAPI/Routes/GetSaveFileHandler.cs

using System.Net;
using ParadoxSaveParser.WebAPI.Database;
using ParadoxSaveParser.WebAPI.HttpHelpers;

namespace ParadoxSaveParser.WebAPI.Routes;

internal class GetSaveFileHandler : RouteHandlerBase
{
    public GetSaveFileHandler(CancellationToken cancelAllToken)
        : base(cancelAllToken)
    {
    }

    public override async Task<HttpStatusCode> HandleRequest(
        HttpListenerContext ctx, ContextLogger requestLogger)
    {
        var idOrError = RequestHelper.GetQueryValue(ctx, "id");
        if (idOrError.HasError)
            return await ReturnHelper.ResponseError(ctx, requestLogger, _cancelAllToken, idOrError.Error!);
        string id = idOrError.Value!;

        var meta = await Program.DB.GetMetadata(id);
        if(meta is null)
            return await ReturnHelper.ResponseError(ctx, requestLogger, _cancelAllToken,
                new ErrorMessage(HttpStatusCode.NotFound,
                    $"Save with id {id} not found"));
        // file is being uploaded (Initialized) or was deleted (Error)
        if(meta.status is SaveFileProcessingStatus.Initialized or SaveFileProcessingStatus.Error)
            return await ReturnHelper.ResponseError(ctx, requestLogger, _cancelAllToken,
                new ErrorMessage(HttpStatusCode.BadRequest,
                    $"Save with id {id} has status {meta.status}"));

        IOPath saveFilePath = meta.GetSaveFilePath();
        if (!File.Exists(saveFilePath))
            return await ReturnHelper.ResponseError(ctx, requestLogger, _cancelAllToken,
                new ErrorMessage(HttpStatusCode.InternalServerError,
                    $"Save with id {id} not found")
            );

        await using var saveFile = File.OpenRead(saveFilePath);

        return await ReturnHelper.ResponseStream(ctx, requestLogger, _cancelAllToken,
            saveFile, contentType: "application/zstd");
    }
}