"""
Simple DROID Episode Visualizer

Just loads and displays DROID episodes to verify data format.
No tracking, no projection - pure visualization.
"""

import sys
import numpy as np
import tensorflow_datasets as tfds
from pathlib import Path
import argparse
import cv2
from tqdm import tqdm


def visualize_episode(droid_path: str, episode_index: int = 0, output_dir: str = '/tmp/droid_viz'):
    """
    Load and visualize a DROID episode.

    Args:
        droid_path: Path to DROID RLDS dataset
        episode_index: Which episode to visualize
        output_dir: Output directory for videos
    """
    print(f"Loading episode {episode_index} from {droid_path}...")

    # Load DROID
    builder = tfds.builder_from_directory(droid_path)
    dataset = builder.as_dataset(split='train')

    # Create output directory
    output_path = Path(output_dir)
    output_path.mkdir(parents=True, exist_ok=True)

    # Find episode
    for idx, episode in enumerate(dataset):
        if idx != episode_index:
            continue

        print(f"✓ Found episode {episode_index}")

        # Extract steps
        steps = list(episode['steps'])
        print(f"  Total steps: {len(steps)}")

        # Get metadata
        try:
            recording_path = episode['episode_metadata']['recording_folderpath'].numpy().decode('utf-8')
            print(f"  Recording: {recording_path}")
        except:
            recording_path = "unknown"

        try:
            language = steps[0]['language_instruction'].numpy().decode('utf-8')
            print(f"  Task: {language}")
        except:
            language = "No instruction"

        # Save info
        with open(output_path / 'episode_info.txt', 'w') as f:
            f.write(f"Episode: {episode_index}\n")
            f.write(f"Steps: {len(steps)}\n")
            f.write(f"Recording: {recording_path}\n")
            f.write(f"Task: {language}\n")

        # Process frames
        valid_frames_ext = []
        valid_frames_wrist = []

        print("\nProcessing frames...")
        for step_idx, step in enumerate(tqdm(steps)):
            # Try to decode images
            try:
                # Exterior camera
                img_ext_bytes = step['observation']['exterior_image_1_left'].numpy()
                img_ext = cv2.imdecode(np.frombuffer(img_ext_bytes, dtype=np.uint8), cv2.IMREAD_COLOR)

                # Wrist camera
                img_wrist_bytes = step['observation']['wrist_image_left'].numpy()
                img_wrist = cv2.imdecode(np.frombuffer(img_wrist_bytes, dtype=np.uint8), cv2.IMREAD_COLOR)

                if img_ext is not None and img_wrist is not None:
                    # Resize for consistency
                    img_ext = cv2.resize(img_ext, (448, 448))
                    img_wrist = cv2.resize(img_wrist, (448, 448))

                    # Add info text
                    cv2.putText(img_ext, f"Frame {step_idx}/{len(steps)}", (10, 30),
                               cv2.FONT_HERSHEY_SIMPLEX, 0.7, (255, 255, 255), 2)
                    cv2.putText(img_wrist, f"Frame {step_idx}/{len(steps)}", (10, 30),
                               cv2.FONT_HERSHEY_SIMPLEX, 0.7, (255, 255, 255), 2)

                    valid_frames_ext.append(img_ext)
                    valid_frames_wrist.append(img_wrist)
                else:
                    if step_idx == 0:
                        print(f"  ⚠ Frame {step_idx}: decode returned None")
            except Exception as e:
                if step_idx == 0:
                    print(f"  ⚠ Frame {step_idx}: decode failed - {e}")

        print(f"\n✓ Successfully decoded {len(valid_frames_ext)} frames out of {len(steps)}")

        if len(valid_frames_ext) == 0:
            print("✗ No valid frames found. This episode may be corrupted.")
            print("  Try a different episode with --episode-index N")
            return False

        # Save videos
        fourcc = cv2.VideoWriter_fourcc(*'mp4v')
        video_ext = cv2.VideoWriter(
            str(output_path / 'exterior_camera.mp4'),
            fourcc, 10, (448, 448)
        )
        video_wrist = cv2.VideoWriter(
            str(output_path / 'wrist_camera.mp4'),
            fourcc, 10, (448, 448)
        )

        for frame_ext, frame_wrist in zip(valid_frames_ext, valid_frames_wrist):
            video_ext.write(frame_ext)
            video_wrist.write(frame_wrist)

        video_ext.release()
        video_wrist.release()

        # Save first frame as image
        cv2.imwrite(str(output_path / 'frame_0_exterior.png'), valid_frames_ext[0])
        cv2.imwrite(str(output_path / 'frame_0_wrist.png'), valid_frames_wrist[0])

        print(f"\n✓ Saved videos to {output_path}:")
        print(f"  exterior_camera.mp4")
        print(f"  wrist_camera.mp4")
        print(f"  frame_0_exterior.png")
        print(f"  frame_0_wrist.png")

        # Print joint info
        try:
            joints = steps[0]['observation']['joint_position'].numpy()
            print(f"\n✓ Joint positions (first frame): {joints}")
            cart_pos = steps[0]['observation']['cartesian_position'].numpy()
            print(f"✓ Cartesian position (first frame): {cart_pos}")
        except Exception as e:
            print(f"⚠ Could not read robot state: {e}")

        return True

    print(f"✗ Episode {episode_index} not found in dataset")
    return False


def main():
    parser = argparse.ArgumentParser(description="Visualize DROID episode")

    parser.add_argument(
        '--droid-path',
        type=str,
        default='/mnt/kevin/data/droid/droid/1.0.0',
        help='Path to DROID RLDS dataset'
    )
    parser.add_argument(
        '--episode-index',
        type=int,
        default=0,
        help='Episode index to visualize (try different indices if one fails)'
    )
    parser.add_argument(
        '--output-dir',
        type=str,
        default='/tmp/droid_viz',
        help='Output directory'
    )

    args = parser.parse_args()

    print("=" * 60)
    print("DROID Episode Visualizer")
    print("=" * 60 + "\n")

    success = visualize_episode(args.droid_path, args.episode_index, args.output_dir)

    if not success:
        print("\nTry a different episode:")
        print("  python visualize_droid_episode.py --episode-index 1")
        print("  python visualize_droid_episode.py --episode-index 10")
        print("  python visualize_droid_episode.py --episode-index 100")
        return 1

    print("\n" + "=" * 60)
    print("Visualization Complete!")
    print("=" * 60)
    return 0


if __name__ == "__main__":
    sys.exit(main())