using Fragalytics.Web;
using Fragalytics.Web.Models;
using Microsoft.Extensions.Options;

namespace Fragalytics.RenderWorker.Services;

public sealed class SampleCopyRenderBackend : IClipRenderBackend
{
    private readonly FragalyticsOptions _options;

    public SampleCopyRenderBackend(IOptions<FragalyticsOptions> options)
    {
        _options = options.Value;
    }

    public string Name => RenderBackendNames.SampleCopy;

    public async Task<RenderedClipResult> RenderAsync(ClipJobRecord clipJob, CancellationToken cancellationToken)
    {
        if (string.IsNullOrWhiteSpace(_options.RenderWorker.SampleClipPath))
        {
            throw new InvalidOperationException("Fragalytics:RenderWorker:SampleClipPath is not configured.");
        }

        var sampleClipPath = Path.GetFullPath(_options.RenderWorker.SampleClipPath);
        if (!File.Exists(sampleClipPath))
        {
            throw new FileNotFoundException("Configured sample clip was not found.", sampleClipPath);
        }

        var tempDirectory = Path.GetFullPath(_options.RenderWorker.TempDirectory);
        Directory.CreateDirectory(tempDirectory);

        var extension = Path.GetExtension(sampleClipPath);
        var outputPath = Path.Combine(tempDirectory, $"clipjob_{clipJob.Id}_{DateTimeOffset.UtcNow.ToUnixTimeMilliseconds()}{extension}");

        await using var input = File.OpenRead(sampleClipPath);
        await using var output = File.Create(outputPath);
        await input.CopyToAsync(output, cancellationToken);

        return new RenderedClipResult
        {
            FilePath = outputPath,
            FileName = Path.GetFileName(sampleClipPath),
            ContentType = ClipMediaFormats.InferContentType(extension)
        };
    }
}