Quote-Generator-Client/lib/providers/render_provider.dart

import "dart:async";
import "dart:io";
import "dart:typed_data";
import "dart:ui" as ui;

import "package:flutter/material.dart";
import "package:flutter/rendering.dart";
import "package:path/path.dart" as path;
import "package:path_provider/path_provider.dart";
import "package:quotegen_client/services/quote_api_v2.dart";
import "package:video_player/video_player.dart";


class RenderProvider extends ChangeNotifier {

  Uint8List? postPreviewImage;
  String? postPreviewContentType;

  int renderProgress = 0;
  String renderStatus = "idle";
  String renderStage = "idle";

  VideoPlayerController? videoController;
  bool videoLoadFailed = false;

  StreamSubscription? _sseSubscription;
  bool _disposed = false;


  void clearRender() {
    if (postPreviewImage == null && renderStatus == "idle") return;

    videoController?.dispose();
    videoController = null;

    postPreviewImage = null;
    postPreviewContentType = null;
    renderStatus = "idle";
    renderProgress = 0;
    renderStage = "idle";
    videoLoadFailed = false;

    if (!_disposed) notifyListeners();
  }

  Future<void> renderOutput(String? sessionId, bool isVideoInForm, {GlobalKey? previewKey}) async {
    if (!_disposed) {
      renderProgress = 0;
      renderStatus = "pending";
      renderStage = "idle";
      notifyListeners();
    }

    if (isVideoInForm) {
      // video still goes through the server, so no session means theres genuinely nothing we can do
      if (sessionId == null) {
        print("Cant render video, session isnt ready (or never got created)");
        if (!_disposed) {
          renderStatus = "failed";
          notifyListeners();
        }
        return;
      }

      print("Starting video render for session: $sessionId");

      if (!_disposed) {
        renderStatus = "rendering";
        renderStage = "rendering";
        notifyListeners();
      }

      // cancel any existing sub before starting new one
      await _sseSubscription?.cancel();

      _sseSubscription = QuoteGeneratorApiV2.watchRenderProgress(sessionId).listen(
        (progress) {
          print("Render progress: ${progress.status} - ${progress.stage} - ${progress.progress}%");

          if (_disposed) return;

          renderProgress = progress.progress;
          renderStatus = progress.status;
          renderStage = progress.stage ?? "idle";
          notifyListeners();

          if (progress.isComplete) {
            print("Render complete, fetching media...");
            fetchRenderedMedia(sessionId);
          } else if (progress.isFailed) {
            print("Render failed: ${progress.error}");
            if (!_disposed) {
              renderStatus = "failed";
              notifyListeners();
            }
          }
        },
        onError: (error) {
          print("Error watching render progress: $error");
        },
      );

      try {
        await QuoteGeneratorApiV2.generateMedia(sessionId);
      } catch (e) {
        print("Error starting render: $e");
      }

      return;
    }

    // image render - grab it straight off the live preview widget, dont need the server for this bit anymore
    try {
      if (previewKey == null) {
        throw Exception("no preview key given, cant capture anything");
      }

      // renderStatus flipped to pending up top already, which swaps the ui back to the live
      // tweet card - just gotta wait for that frame to actually paint before we grab it
      await WidgetsBinding.instance.endOfFrame;

      final bytes = await _capturePreview(previewKey);

      if (_disposed) return;

      videoController?.dispose();
      videoController = null;

      postPreviewImage = bytes;
      postPreviewContentType = "image/png";
      videoLoadFailed = false;
      renderStatus = "completed";
      renderProgress = 100;
      renderStage = "completed";
      notifyListeners();

    } catch (e) {
      print("Error rendering: $e");
      if (!_disposed) {
        renderStatus = "failed";
        notifyListeners();
      }
    }
  }

  // rasterizes a repaint boundary to png, scaled to a fixed resolution regardless of its onscreen size
  Future<Uint8List> _capturePreview(GlobalKey key, {double targetSize = 1080}) async {
    final renderObj = key.currentContext?.findRenderObject();

    if (renderObj is! RenderRepaintBoundary) {
      throw Exception("preview widget isnt mounted, nothing to capture");
    }

    final logicalSize = renderObj.size;
    final pixelRatio = logicalSize.shortestSide == 0 ? 1.0 : targetSize / logicalSize.shortestSide;

    final image = await renderObj.toImage(pixelRatio: pixelRatio);
    final byteData = await image.toByteData(format: ui.ImageByteFormat.png);
    image.dispose();

    if (byteData == null) {
      throw Exception("failed to encode captured png");
    }

    return byteData.buffer.asUint8List();
  }

  Future<void> fetchRenderedMedia(String sessionId) async {
    try {
      MediaResponse media = await QuoteGeneratorApiV2.generateMedia(sessionId);

      if (_disposed) return;

      videoController?.dispose();
      videoController = null;

      postPreviewImage = media.bytes;
      postPreviewContentType = media.contentType;
      videoLoadFailed = false;
      renderStatus = "completed";
      renderProgress = 100;
      renderStage = "completed";
      notifyListeners();

      if (media.isVideo) {
        await initializeVideoPlayer(media.bytes);
      }

    } catch (e) {
      print("Error fetching rendered media: $e");
      if (!_disposed) {
        renderStatus = "failed";
        notifyListeners();
      }
    }
  }

  Future<void> initializeVideoPlayer(Uint8List videoBytes) async {
    try {
      videoLoadFailed = false;

      final tempDir = await getTemporaryDirectory();
      final videoPath = path.join(tempDir.path, "preview_video_${DateTime.now().millisecondsSinceEpoch}.mp4");
      final file = File(videoPath);
      await file.writeAsBytes(videoBytes);

      print("Video saved to: $videoPath (${videoBytes.length} bytes)");

      videoController = VideoPlayerController.file(file);

      videoController!.addListener(() {
        if (!_disposed) notifyListeners();
      });

      await videoController!.initialize();

      videoController!.setLooping(true);
      videoController!.play();

      if (!_disposed) {
        videoLoadFailed = false;
        notifyListeners();
      }
    } catch (e) {
      print("Error initializing video player: $e");
      if (!_disposed) {
        videoLoadFailed = true;
        notifyListeners();
      }
    }
  }

  @override
  void dispose() {
    _disposed = true;
    _sseSubscription?.cancel();
    videoController?.dispose();
    super.dispose();
  }
}