using System.Collections;
using System.IO;
using Meta.XR;
using UnityEngine;
using UnityEngine.UI;

public class PassthroughCameraRecorder : MonoBehaviour
{
    [Header("Camera")]
    [SerializeField] private PassthroughCameraAccess cameraAccess;
    [SerializeField] private RawImage optionalPreview;

    [Header("Recording")]
    [SerializeField, Range(0.2f, 10f)] private float savedFramesPerSecond = 2f;
    [SerializeField, Range(1, 100)] private int jpegQuality = 75;

    private Texture2D snapshotTexture;
    private Vector2Int snapshotResolution;
    private string cameraDirectory;
    private double nextCaptureTime;
    private int frameIndex;

    private IEnumerator Start()
    {
        while (XRSessionLogger.Instance == null ||
               string.IsNullOrEmpty(XRSessionLogger.Instance.SessionDirectory))
            yield return null;

        cameraDirectory = Path.Combine(XRSessionLogger.Instance.SessionDirectory, "camera");
        Directory.CreateDirectory(cameraDirectory);

        if (cameraAccess == null)
        {
            Debug.LogError("PassthroughCameraRecorder: cameraAccess is not assigned.");
            yield break;
        }

        while (!cameraAccess.IsPlaying)
            yield return null;

        if (optionalPreview != null)
            optionalPreview.texture = cameraAccess.GetTexture();

        nextCaptureTime = Time.realtimeSinceStartupAsDouble;
        Debug.Log("Passthrough camera recorder is ready.");
    }

    private void Update()
    {
        if (cameraAccess == null || !cameraAccess.IsPlaying ||
            XRSessionLogger.Instance == null || string.IsNullOrEmpty(cameraDirectory))
            return;

        if (!cameraAccess.IsUpdatedThisFrame)
            return;

        double now = Time.realtimeSinceStartupAsDouble;
        if (now < nextCaptureTime)
            return;

        nextCaptureTime = now + (1.0 / savedFramesPerSecond);
        CaptureFrame();
    }

    private void CaptureFrame()
    {
        Vector2Int resolution = cameraAccess.CurrentResolution;
        if (resolution.x <= 0 || resolution.y <= 0)
            return;

        EnsureSnapshotTexture(resolution);

        var pixels = cameraAccess.GetColors();
        if (!pixels.IsCreated || pixels.Length == 0)
            return;

        snapshotTexture.SetPixelData(pixels, 0);
        snapshotTexture.Apply(false, false);

        byte[] jpg = snapshotTexture.EncodeToJPG(jpegQuality);
        string filename = $"frame_{frameIndex:D6}.jpg";
        string fullPath = Path.Combine(cameraDirectory, filename);
        File.WriteAllBytes(fullPath, jpg);

        Pose cameraPose = cameraAccess.GetCameraPose();
        var intrinsics = cameraAccess.Intrinsics;

        XRSessionLogger.Instance.LogCameraFrame(
            cameraAccess.Timestamp,
            Path.Combine("camera", filename).Replace("\\", "/"),
            cameraPose,
            resolution,
            intrinsics.FocalLength,
            intrinsics.PrincipalPoint);

        frameIndex++;
    }

    private void EnsureSnapshotTexture(Vector2Int resolution)
    {
        if (snapshotTexture != null && snapshotResolution == resolution)
            return;

        if (snapshotTexture != null)
            Destroy(snapshotTexture);

        snapshotResolution = resolution;
        snapshotTexture = new Texture2D(
            resolution.x,
            resolution.y,
            TextureFormat.RGBA32,
            false);
    }

    private void OnDestroy()
    {
        if (snapshotTexture != null)
            Destroy(snapshotTexture);
    }
}