# =================================================================================== #
# ImageNet CLIP Feature Extraction - Download-First Strategy
# Author:AbstractPhil
# 
# Description: Should sufficiently handle preparing imagenet from a repo of choice.
# Formatted for colab - uses userdata to set HF_TOKEN with userdata.get('HF_TOKEN')
# Should run as-is without hassle, but it's a little time consuming.
#
# License: MIT
# =================================================================================== #

import os, json, datetime, time
from pathlib import Path
from typing import Dict, List, Union, Optional, Generator
import torch
import torch.nn.functional as F
from datasets import Dataset, DatasetDict, Features, Value, Sequence
from transformers import CLIPModel
from huggingface_hub import HfApi, HfFolder, create_repo
from google.colab import userdata

# Set your HF_TOKEN here.
HF_TOKEN = userdata.get('HF_TOKEN') # set to os.environ or whatever you want to use.
os.environ["HF_TOKEN"] = HF_TOKEN

import torchvision.transforms.functional as TF
from torch.utils.data import DataLoader


# Configuration for ImageNet-scale processing
CONFIG = {
    "device": "cuda" if torch.cuda.is_available() else "cpu",
    "batch_size": 256,  # A100 can handle much larger batches
    "generator_chunk_size": 5000,  # Process and yield in chunks
    "prefetch_factor": 16,  # DataLoader prefetch
    "persistent_workers": True,  # Keep workers alive
    "num_workers": 2,  # Parallel data loading

    "image_size": 224,
    "vector_dim": 768,
    "normalize_on_gpu": True,
    "clip_mean": (0.48145466, 0.4578275, 0.40821073),
    "clip_std": (0.26862954, 0.26130258, 0.27577711),

    # Memory management for ImageNet scale
    "max_memory_gb": 64,  # Adjust based on available RAM
    "memory_cleanup_interval": 10000,  # Clean memory every N images

    # Output configuration
    "upload_to_hub": False, # set to true if you wish to upload to your repo
    "repo_id": "",          #"AbstractPhil/imagenet-clip-features", # change this to your HF repo, you can't upload to mine.
    "generator_version": "2.0.0",  # Must be x.y.z format

    # Download-first strategy (optimized for multiple models)
    "download_first": True,  # Download entire dataset before processing
    "cache_dir": "./imagenet_cache",  # Where to cache downloaded data
    "keep_dataset_in_memory": False,  # False to save RAM

    "imagenet_repo": "benjamin-paine/imagenet-1k-256x256",
}

# Extended list of CLIP models to process
CLIP_MODELS = [
    # OpenAI CLIP models
    #{"repo_id": "openai/clip-vit-base-patch32", "short_name": "clip_vit_b32", "dim": 512},
    # {"repo_id": "openai/clip-vit-base-patch16", "short_name": "clip_vit_b16", "dim": 512},

    #{"repo_id": "laion/CLIP-ViT-B-32-laion2B-s34B-b79K", "short_name": "clip_vit_laion_b32", "dim": 512},
    #{"repo_id": "openai/clip-vit-large-patch14", "short_name": "clip_vit_l14", "dim": 768},
    #{"repo_id": "openai/clip-vit-large-patch14-336", "short_name": "clip_vit_l14_336", "dim": 768},

    # LAION CLIP models (if you want to add them)
    {"repo_id": "laion/CLIP-ViT-H-14-laion2B-s32B-b79K", "short_name": "clip_vit_laion_h14", "dim": 1024},
    #{"repo_id": "laion/CLIP-ViT-g-14-laion2B-s12B-b42K", "short_name": "clip_vit_laion_g14", "dim": 1024},
    # {"repo_id": "laion/CLIP-ViT-bigG-14-laion2B-39B-b160k", "short_name": "clip_vit_laion_bigg14", "dim": 1280},

    # You can add more models here
]

TARGET_SPLITS = ["train", "validation", "test"]


class ImageNetClipFeatureExtractor:
    """
    Production-ready CLIP feature extractor optimized for processing multiple models.
    Uses download-first strategy for maximum throughput.
    """

    def __init__(self, config: dict):
        self.cfg = config
        self.device = torch.device(config["device"])
        self._setup_preprocessing()
        self.hf_token = os.environ.get("HF_TOKEN") or userdata.get('HF_TOKEN')
        self.datasets_cache = {}  # Cache loaded datasets

    def _setup_preprocessing(self):
        self._mean = torch.tensor(self.cfg["clip_mean"]).view(1, 3, 1, 1)
        self._std = torch.tensor(self.cfg["clip_std"]).view(1, 3, 1, 1)

    def _download_datasets(self):
        """
        Pre-download all datasets once before processing any models.
        This is called once and datasets are reused for all models.
        """
        from datasets import load_dataset

        print("=" * 60)
        print("📥 DOWNLOADING IMAGENET DATASET")
        print("=" * 60)

        for split in TARGET_SPLITS:
            if split not in self.datasets_cache:
                print(f"\n[⏬] Downloading {split} split to {self.cfg['cache_dir']}...")
                start_time = time.time()

                dataset = load_dataset(
                    imagenet_repo, #small tweak to allow setting your own imagenet target repo.
                    split=split,
                    cache_dir=self.cfg["cache_dir"],
                    keep_in_memory=self.cfg["keep_dataset_in_memory"],
                    num_proc=None  # Disable the progress bar noise
                )

                download_time = time.time() - start_time
                print(f"[✅] Downloaded {len(dataset)} {split} images in {download_time/60:.1f} minutes")
                if download_time > 0:
                    print(f"[📊] Download speed: {len(dataset)/download_time:.1f} images/sec")

                self.datasets_cache[split] = dataset

        print("\n[✅] All datasets downloaded and cached!")
        print("=" * 60)

    def _gpu_preprocess(self, images: torch.Tensor) -> torch.Tensor:
        """Memory-efficient GPU preprocessing."""
        if images.dtype != torch.float32:
            images = images.float()

        # Handle both 0-1 and 0-255 ranges
        if images.max() > 1.5:
            images = images / 255.0

        # Resize if needed
        if images.shape[-1] != self.cfg["image_size"]:
            images = F.interpolate(
                images,
                size=(self.cfg["image_size"], self.cfg["image_size"]),
                mode="bilinear",
                align_corners=False
            )

        # Normalize
        if self.cfg["normalize_on_gpu"]:
            mean = self._mean.to(images.device, dtype=images.dtype)
            std = self._std.to(images.device, dtype=images.dtype)
            images = (images - mean) / std

        return images

    def _collate_fn(self, batch):
        """Custom collate function for DataLoader."""
        import hashlib
        images = []
        labels = []
        image_ids = []

        for item in batch:
            image = item['image']
            if image.mode != 'RGB':
                image = image.convert('RGB')

            # Convert to tensor [3, H, W]
            image_tensor = TF.to_tensor(image)

            # Generate SHA256 hash of the image
            image_bytes = image.tobytes()
            sha256_hash = hashlib.sha256(image_bytes).hexdigest()

            images.append(image_tensor)
            labels.append(item.get('label', -1))
            image_ids.append(sha256_hash)

        return {
            'images': torch.stack(images),
            'labels': labels,
            'image_ids': image_ids
        }

    def _imagenet_generator_optimized(self, split: str, model_id: str) -> Generator[Dict, None, None]:
        """
        Optimized generator using pre-downloaded data and DataLoader for parallel loading.
        """
        # Use cached dataset
        dataset = self.datasets_cache[split]

        # Create DataLoader for efficient parallel loading
        dataloader = DataLoader(
            dataset,
            batch_size=self.cfg["batch_size"],
            shuffle=False,  # Keep order for reproducibility
            num_workers=self.cfg["num_workers"],
            prefetch_factor=self.cfg["prefetch_factor"],
            persistent_workers=self.cfg["persistent_workers"],
            collate_fn=self._collate_fn,
            pin_memory=True  # Faster GPU transfer
        )

        # Load CLIP model
        print(f"\n[🤖] Loading {model_id}")
        model = CLIPModel.from_pretrained(model_id).to(self.device)
        model.eval()

        # Setup for chunked processing
        chunk_buffer = []
        timestamp = datetime.datetime.now(datetime.timezone.utc)
        images_processed = 0
        start_time = time.time()
        last_print_time = start_time
        print_interval = 10  # Print progress every 10 seconds

        try:
            with torch.no_grad():
                for batch_idx, batch in enumerate(dataloader):
                    # Move batch to GPU
                    image_batch = batch['images'].to(self.device, non_blocking=True)
                    labels = batch['labels']
                    image_ids = batch['image_ids']

                    # Preprocess on GPU
                    image_batch = self._gpu_preprocess(image_batch)

                    # Extract features
                    features = model.get_image_features(pixel_values=image_batch)
                    features = features / features.norm(dim=-1, keepdim=True)

                    # Create records
                    for img_id, label, feature_vec in zip(image_ids, labels, features):
                        chunk_buffer.append({
                            "image_id": img_id,  # Now using SHA256 hash
                            "label": int(label),
                            "clip_model": model_id,
                            "clip_features": feature_vec.detach().cpu().float().numpy().tolist(),
                            "vector_dim": features.shape[-1],
                            "timestamp": timestamp,
                        })

                    images_processed += len(image_ids)

                    # Print progress at regular time intervals
                    current_time = time.time()
                    if current_time - last_print_time >= print_interval:
                        elapsed = current_time - start_time
                        speed = images_processed / elapsed
                        eta = (len(dataset) - images_processed) / speed
                        print(f"[⚡] Progress: {images_processed}/{len(dataset)} "
                              f"({100*images_processed/len(dataset):.1f}%) | "
                              f"Speed: {speed:.1f} img/sec | "
                              f"ETA: {eta/60:.1f} min")
                        last_print_time = current_time

                    # Yield chunk when it reaches configured size
                    if len(chunk_buffer) >= self.cfg["generator_chunk_size"]:
                        elapsed = time.time() - start_time
                        speed = images_processed / elapsed
                        print(f"[📦] Yielding chunk of {len(chunk_buffer)} features | "
                              f"Progress: {images_processed}/{len(dataset)} "
                              f"({100*images_processed/len(dataset):.1f}%)")
                        yield from chunk_buffer
                        chunk_buffer = []

                    # Memory cleanup at configured interval
                    if images_processed % self.cfg["memory_cleanup_interval"] == 0:
                        torch.cuda.empty_cache()

                # Yield remaining chunk buffer
                if chunk_buffer:
                    print(f"[📦] Final chunk of {len(chunk_buffer)} features")
                    yield from chunk_buffer

                # Final stats
                total_time = time.time() - start_time
                print(f"\n[✅] Processed {images_processed} images in {total_time/60:.1f} minutes")
                print(f"[📊] Average speed: {images_processed/total_time:.1f} images/sec")

        finally:
            del model
            torch.cuda.empty_cache()

    def extract_and_upload(self, model_config: dict, split: str = "train"):
        """
        Extract features using optimized generator and upload to HuggingFace.
        Returns the dataset if upload fails for retry purposes.
        """
        model_id = model_config["repo_id"]
        short_name = model_config["short_name"]

        print("\n" + "=" * 60)
        print(f"⚙️  PROCESSING: {short_name} - {split}")
        print("=" * 60)

        # Define dataset features
        features = Features({
            "image_id": Value("string"),
            "label": Value("int32"),
            "clip_model": Value("string"),
            "clip_features": Sequence(Value("float32")),
            "vector_dim": Value("int32"),
            "timestamp": Value("timestamp[ns]"),
        })

        # Suppress the "Generating split" progress bar
        import sys
        import io
        old_stderr = sys.stderr
        sys.stderr = io.StringIO()

        try:
            # Create dataset from generator
            dataset = Dataset.from_generator(
                lambda: self._imagenet_generator_optimized(split, model_id),
                features=features,
                writer_batch_size=self.cfg["generator_chunk_size"],
                split=split
            )
        except Exception as e:
            raise Exception(e)
        #finally:
        #    # Restore stderr
        #    sys.stderr = old_stderr
        #    return

        # Add metadata
        dataset.info.description = f"CLIP features for ImageNet-1k 256x256 {split} using {model_id}"
        dataset.info.version = self.cfg["generator_version"]

        # Save to disk before upload (safety backup)
        temp_path = f"./temp_dataset_{short_name}_{split}"
        print(f"[💾] Saving dataset to {temp_path} for safety...")
        dataset.save_to_disk(temp_path)

        # Upload to HuggingFace
        split_name = f"{short_name}_{split}"

        print(f"\n[📤] Uploading {split_name} to {self.cfg['repo_id']}")
        try:
            dataset.push_to_hub(
                self.cfg["repo_id"],
                split=split_name,
                token=self.hf_token,
                commit_message=f"Add {split_name} CLIP features",
                max_shard_size="500MB"
            )
            print(f"[✅] Successfully uploaded {split_name}")

            # Clean up temp file on success
            import shutil
            shutil.rmtree(temp_path, ignore_errors=True)
            return None

        except Exception as e:
            print(f"[❌] Upload failed for {split_name}: {e}")
            print(f"[💡] Dataset saved at {temp_path} - you can retry upload with:")
            print(f"    from datasets import load_from_disk")
            print(f"    dataset = load_from_disk('{temp_path}')")
            print(f"    dataset.push_to_hub('{self.cfg['repo_id']}', split='{split_name}', ...)")
            return dataset  # Return dataset for potential retry

    def extract_all_models(self, models_to_process=None):
        """
        Extract features for all models and splits.

        Args:
            models_to_process: List of model configs to process (default: all)
        """
        # Ensure repo exists
        if self.hf_token:
            try:
                create_repo(self.cfg["repo_id"], repo_type="dataset", exist_ok=True, token=self.hf_token)
                print(f"[✅] Repository ready: {self.cfg['repo_id']}")
            except Exception as e:
                print(f"[⚠️] Repo creation warning: {e}")

        # Download all data first (once for all models)
        self._download_datasets()

        # Process specified models or all
        models = models_to_process or CLIP_MODELS
        total_combinations = len(models) * 2  # train + validation

        print("\n" + "=" * 60)
        print(f"📋 PROCESSING PLAN: {len(models)} models × 2 splits = {total_combinations} tasks")
        print("=" * 60)

        # Keep track of failed uploads for retry
        failed_uploads = []

        for i, model_config in enumerate(models, 1):
            print(f"\n[{i}/{len(models)}] Model: {model_config['short_name']}")

            for split in TARGET_SPLITS: #"train", "test"]:
                try:
                    dataset = self.extract_and_upload(model_config, split)
                    if dataset is not None:
                        # Upload failed but we have the dataset
                        failed_uploads.append({
                            'model': model_config['short_name'],
                            'split': split,
                            'dataset': dataset,
                            'path': f"./temp_dataset_{model_config['short_name']}_{split}"
                        })
                except Exception as e:
                    print(f"[❌] Failed {model_config['short_name']} {split}: {e}")
                    continue

            # Cleanup between models
            torch.cuda.empty_cache()

        print("\n" + "=" * 60)
        if failed_uploads:
            print(f"⚠️  PROCESSING COMPLETE WITH {len(failed_uploads)} FAILED UPLOADS")
            print("\nFailed uploads saved to disk:")
            for failure in failed_uploads:
                print(f"  - {failure['model']}_{failure['split']}: {failure['path']}")
            print("\nYou can retry these uploads after fixing the issue.")
        else:
            print("🎉 ALL PROCESSING COMPLETE!")
        print("=" * 60)

        return failed_uploads  # Return list of failed uploads for retry


# ============================================================
# Utility Functions
# ============================================================

def estimate_processing_time(num_models=len(CLIP_MODELS)):
    """
    Estimate total processing time for all models.
    """
    print("=" * 60)
    print("⏱️  TIME ESTIMATES")
    print("=" * 60)

    # Dataset sizes
    train_size = 1_281_167
    val_size = 50_000
    total_images = train_size + val_size

    # Time estimates
    download_time_min = 60  # minutes
    download_time_max = 120

    # Processing speeds (images/sec)
    speed_min = 800
    speed_max = 1200

    print(f"\n📊 Dataset sizes:")
    print(f"  - Train: {train_size:,} images")
    print(f"  - Validation: {val_size:,} images")
    print(f"  - Total per model: {total_images:,} images")

    print(f"\n⏬ Download time (one-time):")
    print(f"  - Estimated: {download_time_min}-{download_time_max} minutes")

    print(f"\n🚀 Processing speed:")
    print(f"  - Expected: {speed_min}-{speed_max} images/sec")

    # Per model
    time_per_model_min = total_images / speed_max / 60
    time_per_model_max = total_images / speed_min / 60

    print(f"\n⏱️  Per model:")
    print(f"  - Processing time: {time_per_model_min:.1f}-{time_per_model_max:.1f} minutes")

    # Total
    total_min = download_time_min + (num_models * time_per_model_min)
    total_max = download_time_max + (num_models * time_per_model_max)

    print(f"\n🎯 Total for {num_models} models:")
    print(f"  - Total time: {total_min:.1f}-{total_max:.1f} minutes")
    print(f"  - Or: {total_min/60:.1f}-{total_max/60:.1f} hours")

    print("\n💡 Tips:")
    print("  - Processing is GPU-bound, so better GPUs = faster")
    print("  - A100/H100 can use batch_size=1024+ for more speed")
    print("  - Multiple GPUs can process different models in parallel")
    print("=" * 60)


# ============================================================
# Main Execution
# ============================================================
"""
Main execution for multi-model ImageNet CLIP feature extraction.
"""
# Show time estimates
estimate_processing_time()

# Confirm settings
print(f"\n🔧 Current configuration:")
print(f"  - Batch size: {CONFIG['batch_size']}")
print(f"  - Chunk size: {CONFIG['generator_chunk_size']}")
print(f"  - Workers: {CONFIG['num_workers']}")
print(f"  - Models to process: {len(CLIP_MODELS)}")

# Option to process subset of models
# For testing, you might want to start with just one:
# test_models = CLIP_MODELS[:1]  # Just first model
# extractor.extract_all_models(models_to_process=test_models)

# Run extraction
extractor = ImageNetClipFeatureExtractor(CONFIG)
extractor.extract_all_models()  # Process all models