using System;
using System.IO;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using MalwareMultiScan.Shared.Interfaces;
using Microsoft.AspNetCore.Http;

namespace MalwareMultiScan.Backends.Backends.Abstracts
{
    public abstract class AbstractScanBackend : IScanBackend
    {
        public virtual string Name => throw new NotImplementedException();
        
        public virtual DateTime DatabaseLastUpdate => throw new NotImplementedException();
        
        public virtual Task<string[]> ScanAsync(string path, CancellationToken cancellationToken)
        {
            throw new NotImplementedException();
        }

        public async Task<string[]> ScanAsync(Uri uri, CancellationToken cancellationToken)
        {
            using var httpClient = new HttpClient();
            await using var uriStream = await httpClient.GetStreamAsync(uri);
            
            return await ScanAsync(uriStream, cancellationToken);
        }

        public async Task<string[]> ScanAsync(IFormFile file, CancellationToken cancellationToken)
        {
            await using var fileStream = file.OpenReadStream();
            
            return await ScanAsync(fileStream, cancellationToken);
        }

        public async Task<string[]> ScanAsync(Stream stream, CancellationToken cancellationToken)
        {
            var tempFile = Path.GetTempFileName();

            try
            {
                await using (var tempFileStream = File.OpenWrite(tempFile))
                    await stream.CopyToAsync(tempFileStream, cancellationToken);

                return await ScanAsync(tempFile, cancellationToken);
            }
            finally
            {
                File.Delete(tempFile);
            }
        }
    }
}