using AutoScan.Interfaces;
using AutoScan.Options;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using System.Diagnostics;

namespace AutoScan.Implementations;

public class Snapshoter : ISnapshoter
{
    private readonly IDVRConnector _dvrConnector;
    private readonly AutoScanOptions _options;
    private readonly ILogger<Snapshoter> _logger;   

    public Snapshoter(IDVRConnector dvrConnector, IOptions<AutoScanOptions> options, ILogger<Snapshoter> logger)
    {
        _dvrConnector = dvrConnector;
        _options = options.Value;
        _logger = logger;
    }

    public async Task<string?> TakeSnapshot()
    {
        try
        {
            if (_options.Scanner?.FFMpeg is null)
            {
                _logger.LogError("FFMpeg path is not set in the options");
                return null;
            }
            
            var timer = new Stopwatch();
            timer.Start();
            var outputDir = _options.Scanner?.SnapshotFolder;
            if (string.IsNullOrEmpty(outputDir))
            {
                _logger.LogError("Snapshot folder is not set in the options");
                return null;
            }
            var outputPath = Path.Combine(outputDir, "snp.jpeg");
            //create if doesnt exists
            if (!Directory.Exists(outputDir))
            {
                Directory.CreateDirectory(outputDir);
            }
            var originalFeed = await _dvrConnector.GetVideoStream();
            var ffmArgs = $"-y -rtsp_transport tcp -i \"{originalFeed}\" -ss 00:00:00.500 -frames:v 1 {outputPath}";
            

            var process = new Process
            {
                StartInfo = new ProcessStartInfo
                {
                    //To change this, I need to make sure ffmpeg is installed
                    FileName = _options.Scanner?.FFMpeg,
                    Arguments = ffmArgs,
                    RedirectStandardOutput = true,
                    RedirectStandardError = true,
                    UseShellExecute = false,
                    CreateNoWindow = true,
                }
            };
            process.Start();
            
            var timeoutSignal = new CancellationTokenSource(TimeSpan.FromSeconds(6));
            try 
            {
                await process.WaitForExitAsync(timeoutSignal.Token);
            } catch (OperationCanceledException)
            {
                _logger.LogError("Taking snapshot timed out");
                process.Kill();
                return null;
            }
            
            // you can read the output here.
            // var output = await process.StandardOutput.ReadToEndAsync();
            // var error = await process.StandardError.ReadToEndAsync();
            timer.Stop();
            _logger.LogDebug("Taking snapshot took {Elapsed} ms", timer.ElapsedMilliseconds);

            if (process.ExitCode != 0)
            {
                _logger.LogError("Error taking snapshot, exit code: {ExitCode}", process.ExitCode);
                return string.Empty;
            }

            return outputPath;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error taking snapshot");
            return null;
        }
    }
}