using System.Collections;
using System.Diagnostics;
using System.IO;
using UnityEngine;

public class FFmpegVideoRecorder : MonoBehaviour
{
    public Camera targetCamera; // Assign your camera in the Inspector
    public int outputWidth = 1920; // Output video width
    public int outputHeight = 1080; // Output video height
    public int outputFrameRate = 30; // Output video frame rate
    public string ffmpegPath = "ffmpeg"; // Path to the FFmpeg binary
    public string outputFilePath = "output.mp4"; // Path to save the video

    private RenderTexture renderTexture;
    private Texture2D frameTexture;
    private Process ffmpegProcess;
    private BinaryWriter ffmpegInputStream;

    private void Start()
    {
        // Setup FFmpeg process
        StartFFmpeg();

        // Create a RenderTexture and Texture2D for capturing frames
        renderTexture = new RenderTexture(outputWidth, outputHeight, 24);
        frameTexture = new Texture2D(outputWidth, outputHeight, TextureFormat.RGB24, false);
        
        // Set the camera's target texture to render to the RenderTexture
        targetCamera.targetTexture = renderTexture;
    }

    private void LateUpdate()
    {
        // Capture the camera's current frame
        RenderTexture currentRT = RenderTexture.active;
        RenderTexture.active = renderTexture;
        targetCamera.Render();

        // Read the pixels from the RenderTexture into the Texture2D
        frameTexture.ReadPixels(new Rect(0, 0, outputWidth, outputHeight), 0, 0);
        frameTexture.Apply();

        // Write the frame's raw RGB data to the FFmpeg input stream
        byte[] frameData = frameTexture.GetRawTextureData();
        if (ffmpegInputStream != null)
        {
            ffmpegInputStream.Write(frameData);
        }

        // Restore the previous active RenderTexture
        RenderTexture.active = currentRT;
    }

    private void OnApplicationQuit()
    {
        StopFFmpeg();

        // Clean up temporary objects
        if (renderTexture != null)
        {
            RenderTexture.ReleaseTemporary(renderTexture);
        }
        if (frameTexture != null)
        {
            Destroy(frameTexture);
        }
    }

    private void StartFFmpeg()
    {
        var ffmpegStartInfo = new ProcessStartInfo
        {
            FileName = ffmpegPath,
            Arguments = $"-y -f rawvideo -vcodec rawvideo -pix_fmt rgb24 -s {outputWidth}x{outputHeight} -r {outputFrameRate} -i - -an -vcodec libx264 -pix_fmt yuv420p \"{outputFilePath}\"",
            UseShellExecute = false,
            RedirectStandardInput = true,
            RedirectStandardOutput = false,
            RedirectStandardError = true, // Optional: Redirect standard error for debugging
            CreateNoWindow = true
        };

        ffmpegProcess = new Process
        {
            StartInfo = ffmpegStartInfo
        };

        ffmpegProcess.Start();

        // Attach the input stream
        ffmpegInputStream = new BinaryWriter(ffmpegProcess.StandardInput.BaseStream);
    }

    private void StopFFmpeg()
    {
        if (ffmpegInputStream != null)
        {
            try
            {
                // Close the input stream
                ffmpegInputStream.Close();
            }
            catch
            {
                // Ignore any errors when closing the stream
            }
            ffmpegInputStream = null;
        }

        if (ffmpegProcess != null)
        {
            try
            {
                // Wait for the FFmpeg process to exit
                ffmpegProcess.WaitForExit();
            }
            catch
            {
                // Ignore any errors when waiting for the process
            }
            finally
            {
                ffmpegProcess.Close();
            }

            ffmpegProcess = null;
        }
    }
}