# Install bitsandbytes:
# `nvcc --version` to get CUDA version.
# `pip install -i https://test.pypi.org/simple/ bitsandbytes-cudaXXX` to install for current CUDA.
# Example Usage:
# Single GPU: torchrun --nproc_per_node=1 trainer/diffusers_trainer.py --model="CompVis/stable-diffusion-v1-4" --run_name="liminal" --dataset="liminal-dataset" --hf_token="hf_blablabla" --bucket_side_min=64 --use_8bit_adam=True --gradient_checkpointing=True --batch_size=1 --fp16=True --image_log_steps=250 --epochs=20 --resolution=768 --use_ema=True
# Multiple GPUs: torchrun --nproc_per_node=N trainer/diffusers_trainer.py --model="CompVis/stable-diffusion-v1-4" --run_name="liminal" --dataset="liminal-dataset" --hf_token="hf_blablabla" --bucket_side_min=64 --use_8bit_adam=True --gradient_checkpointing=True --batch_size=10 --fp16=True --image_log_steps=250 --epochs=20 --resolution=768 --use_ema=True

import argparse
import socket
import torch
import torchvision
import transformers
import diffusers
import os
import glob
import random
import tqdm
import resource
import psutil
import pynvml
import wandb
import gc
import time
import itertools
import numpy as np
import json
import re
import traceback
import shutil

try:
    pynvml.nvmlInit()
except pynvml.nvml.NVMLError_LibraryNotFound:
    pynvml = None

from typing import Iterable
from diffusers import AutoencoderKL, UNet2DConditionModel, DDPMScheduler, PNDMScheduler, DDIMScheduler, StableDiffusionPipeline
from diffusers.pipelines.stable_diffusion import StableDiffusionSafetyChecker
from diffusers.optimization import get_scheduler
from transformers import CLIPFeatureExtractor, CLIPTextModel, CLIPTokenizer
from PIL import Image, ImageOps
from PIL.Image import Image as Img

from typing import Dict, List, Generator, Tuple
from scipy.interpolate import interp1d

torch.backends.cuda.matmul.allow_tf32 = True

# defaults should be good for everyone
# TODO: add custom VAE support. should be simple with diffusers
bool_t = lambda x: x.lower() in ['true', 'yes', '1']
parser = argparse.ArgumentParser(description='Stable Diffusion Finetuner')
parser.add_argument('--model', type=str, default=None, required=True, help='The name of the model to use for finetuning. Could be HuggingFace ID or a directory')
parser.add_argument('--resume', type=str, default=None, help='The path to the checkpoint to resume from. If not specified, will create a new run.')
parser.add_argument('--run_name', type=str, default=None, required=True, help='Name of the finetune run.')
parser.add_argument('--dataset', type=str, default=None, required=True, help='The path to the dataset to use for finetuning.')
parser.add_argument('--num_buckets', type=int, default=16, help='The number of buckets.')
parser.add_argument('--bucket_side_min', type=int, default=256, help='The minimum side length of a bucket.')
parser.add_argument('--bucket_side_max', type=int, default=768, help='The maximum side length of a bucket.')
parser.add_argument('--lr', type=float, default=5e-6, help='Learning rate')
parser.add_argument('--epochs', type=int, default=10, help='Number of epochs to train for')
parser.add_argument('--batch_size', type=int, default=1, help='Batch size')
parser.add_argument('--use_ema', type=bool_t, default='False', help='Use EMA for finetuning')
parser.add_argument('--ucg', type=float, default=0.1, help='Percentage chance of dropping out the text condition per batch. Ranges from 0.0 to 1.0 where 1.0 means 100% text condition dropout.') # 10% dropout probability
parser.add_argument('--gradient_checkpointing', dest='gradient_checkpointing', type=bool_t, default='False', help='Enable gradient checkpointing')
parser.add_argument('--use_8bit_adam', dest='use_8bit_adam', type=bool_t, default='False', help='Use 8-bit Adam optimizer')
parser.add_argument('--adam_beta1', type=float, default=0.9, help='Adam beta1')
parser.add_argument('--adam_beta2', type=float, default=0.999, help='Adam beta2')
parser.add_argument('--adam_weight_decay', type=float, default=1e-2, help='Adam weight decay')
parser.add_argument('--adam_epsilon', type=float, default=1e-08, help='Adam epsilon')
parser.add_argument('--lr_scheduler', type=str, default='cosine', help='Learning rate scheduler [`cosine`, `linear`, `constant`]')
parser.add_argument('--lr_scheduler_warmup', type=float, default=0.05, help='Learning rate scheduler warmup steps. This is a percentage of the total number of steps in the training run. 0.1 means 10 percent of the total number of steps.')
parser.add_argument('--seed', type=int, default=42, help='Seed for random number generator, this is to be used for reproduceability purposes.')
parser.add_argument('--output_path', type=str, default='./output', help='Root path for all outputs.')
parser.add_argument('--save_steps', type=int, default=500, help='Number of steps to save checkpoints at.')
parser.add_argument('--resolution', type=int, default=512, help='Image resolution to train against. Lower res images will be scaled up to this resolution and higher res images will be scaled down.')
parser.add_argument('--shuffle', dest='shuffle', type=bool_t, default='True', help='Shuffle dataset')
parser.add_argument('--hf_token', type=str, default=None, required=False, help='A HuggingFace token is needed to download private models for training.')
parser.add_argument('--project_id', type=str, default='diffusers', help='Project ID for reporting to WandB')
parser.add_argument('--fp16', dest='fp16', type=bool_t, default='False', help='Train in mixed precision')
parser.add_argument('--image_log_steps', type=int, default=500, help='Number of steps to log images at.')
parser.add_argument('--image_log_amount', type=int, default=4, help='Number of images to log every image_log_steps')
parser.add_argument('--image_log_inference_steps', type=int, default=50, help='Number of inference steps to use to log images.')
parser.add_argument('--image_log_scheduler', type=str, default="PNDMScheduler", help='Number of inference steps to use to log images.')
parser.add_argument('--clip_penultimate', type=bool_t, default='False', help='Use penultimate CLIP layer for text embedding')
parser.add_argument('--output_bucket_info', type=bool_t, default='False', help='Outputs bucket information and exits')
parser.add_argument('--resize', type=bool_t, default='False', help="Resizes dataset's images to the appropriate bucket dimensions.")
parser.add_argument('--use_xformers', type=bool_t, default='False', help='Use memory efficient attention')
parser.add_argument('--wandb', dest='enablewandb', type=bool_t, default='True', help='Enable WeightsAndBiases Reporting')
parser.add_argument('--inference', dest='enableinference', type=bool_t, default='True', help='Enable Inference during training (Consumes 2GB of VRAM)')
parser.add_argument('--extended_validation', type=bool_t, default='False', help='Perform extended validation of images to catch truncated or corrupt images.')
parser.add_argument('--no_migration', type=bool_t, default='False', help='Do not perform migration of dataset while the `--resize` flag is active. Migration creates an adjacent folder to the dataset with <dataset_dirname>_cropped.')
parser.add_argument('--skip_validation', type=bool_t, default='False', help='Skip validation of images, useful for speeding up loading of very large datasets that have already been validated.')
parser.add_argument('--extended_mode_chunks', type=int, default=0, help='Enables extended mode for tokenization with given amount of maximum chunks. Values < 2 disable.')
parser.add_argument("--train_text_encoder", action="store_true", help="Whether to train the text encoder")


args = parser.parse_args()

def setup():
    torch.distributed.init_process_group("nccl", init_method="env://")

def cleanup():
    torch.distributed.destroy_process_group()

def get_rank() -> int:
    if not torch.distributed.is_initialized():
        return 0
    return torch.distributed.get_rank()

def get_world_size() -> int:
    if not torch.distributed.is_initialized():
        return 1
    return torch.distributed.get_world_size()

def get_gpu_ram() -> str:
    """
    Returns memory usage statistics for the CPU, GPU, and Torch.

    :return:
    """
    gpu_str = ""
    torch_str = ""
    try:
        cudadev = torch.cuda.current_device()
        nvml_device = pynvml.nvmlDeviceGetHandleByIndex(cudadev)
        gpu_info = pynvml.nvmlDeviceGetMemoryInfo(nvml_device)
        gpu_total = int(gpu_info.total / 1E6)
        gpu_free = int(gpu_info.free / 1E6)
        gpu_used = int(gpu_info.used / 1E6)
        gpu_str = f"GPU: (U: {gpu_used:,}mb F: {gpu_free:,}mb " \
                  f"T: {gpu_total:,}mb) "
        torch_reserved_gpu = int(torch.cuda.memory.memory_reserved() / 1E6)
        torch_reserved_max = int(torch.cuda.memory.max_memory_reserved() / 1E6)
        torch_used_gpu = int(torch.cuda.memory_allocated() / 1E6)
        torch_max_used_gpu = int(torch.cuda.max_memory_allocated() / 1E6)
        torch_str = f"TORCH: (R: {torch_reserved_gpu:,}mb/"  \
                    f"{torch_reserved_max:,}mb, " \
                    f"A: {torch_used_gpu:,}mb/{torch_max_used_gpu:,}mb)"
    except AssertionError:
        pass
    cpu_maxrss = int(resource.getrusage(resource.RUSAGE_SELF).ru_maxrss / 1E3 +
                     resource.getrusage(
                         resource.RUSAGE_CHILDREN).ru_maxrss / 1E3)
    cpu_vmem = psutil.virtual_memory()
    cpu_free = int(cpu_vmem.free / 1E6)
    return f"CPU: (maxrss: {cpu_maxrss:,}mb F: {cpu_free:,}mb) " \
           f"{gpu_str}" \
           f"{torch_str}"

def _sort_by_ratio(bucket: tuple) -> float:
    return bucket[0] / bucket[1]

def _sort_by_area(bucket: tuple) -> float:
    return bucket[0] * bucket[1]

class Validation():
    def __init__(self, is_skipped: bool, is_extended: bool) -> None:
        if is_skipped:
            self.validate = self.__no_op
            return print("Validation: Skipped")

        if is_extended:
            self.validate = self.__extended_validate
            return print("Validation: Extended")

        self.validate = self.__validate
        print("Validation: Standard")

    def __validate(self, fp: str) -> bool:
        try:
            Image.open(fp)
            return True
        except:
            print(f'WARNING: Image cannot be opened: {fp}')
            return False

    def __extended_validate(self, fp: str) -> bool:
        try:
            Image.open(fp).load()
            return True
        except (OSError) as error:
            if 'truncated' in str(error):
                print(f'WARNING: Image truncated: {error}')
                return False
            print(f'WARNING: Image cannot be opened: {error}')
            return False
        except:
            print(f'WARNING: Image cannot be opened: {error}')
            return False

    def __no_op(self, fp: str) -> bool:
        return True

class Resize():
    def __init__(self, is_resizing: bool, is_not_migrating: bool) -> None:
        if not is_resizing:
            self.resize = self.__no_op
            return

        if not is_not_migrating:
            self.resize = self.__migration
            dataset_path = os.path.split(args.dataset)
            self.__directory = os.path.join(
                dataset_path[0],
                f'{dataset_path[1]}_cropped'
            )
            os.makedirs(self.__directory, exist_ok=True)
            return print(f"Resizing: Performing migration to '{self.__directory}'.")

        self.resize = self.__no_migration

    def __no_migration(self, image_path: str, w: int, h: int) -> Img:
        return ImageOps.fit(
                Image.open(image_path),
                (w, h),
                bleed=0.0,
                centering=(0.5, 0.5),
                method=Image.Resampling.LANCZOS
            ).convert(mode='RGB')

    def __migration(self, image_path: str, w: int, h: int) -> Img:
        filename = re.sub('\.[^/.]+$', '', os.path.split(image_path)[1])

        image = ImageOps.fit(
                Image.open(image_path),
                (w, h),
                bleed=0.0,
                centering=(0.5, 0.5),
                method=Image.Resampling.LANCZOS
            ).convert(mode='RGB')

        image.save(
            os.path.join(f'{self.__directory}', f'{filename}.jpg'),
            optimize=True
        )

        try:
            shutil.copy(
                os.path.join(args.dataset, f'{filename}.txt'),
                os.path.join(self.__directory, f'{filename}.txt'),
                follow_symlinks=False
            )
        except (FileNotFoundError):
            f = open(
                os.path.join(self.__directory, f'{filename}.txt'),
                'w',
                encoding='UTF-8'
            )
            f.close()

        return image

    def __no_op(self, image_path: str, w: int, h: int) -> Img:
        return Image.open(image_path)

class ImageStore:
    def __init__(self, data_dir: str) -> None:
        self.data_dir = data_dir

        self.image_files = []
        [self.image_files.extend(glob.glob(f'{data_dir}' + '/*.' + e)) for e in ['jpg', 'jpeg', 'png', 'bmp', 'webp']]

        self.validator = Validation(
            args.skip_validation,
            args.extended_validation
        ).validate

        self.resizer = Resize(args.resize, args.no_migration).resize

        self.image_files = [x for x in self.image_files if self.validator(x)]

    def __len__(self) -> int:
        return len(self.image_files)

    # iterator returns images as PIL images and their index in the store
    def entries_iterator(self) -> Generator[Tuple[Tuple[int, int], int], None, None]:
        for f in range(len(self)):
            i = Image.open(self.image_files[f])
            width = i.width
            height = i.height
            del i
            yield (width, height), f

    # get image by index
    def get_image(self, ref: Tuple[int, int, int]) -> Img:
        return self.resizer(
            self.image_files[ref[0]],
            ref[1],
            ref[2]
        )

    # gets caption by removing the extension from the filename and replacing it with .txt
    def get_caption(self, ref: Tuple[int, int, int]) -> str:
        filename = re.sub('\.[^/.]+$', '', self.image_files[ref[0]]) + '.txt'
        with open(filename, 'r', encoding='UTF-8') as f:
            return f.read()


# ====================================== #
# Bucketing code stolen from hasuwoof:   #
# https://github.com/hasuwoof/huskystack #
# ====================================== #

class AspectBucket:
    def __init__(self, store: ImageStore,
                 num_buckets: int,
                 batch_size: int,
                 bucket_side_min: int = 256,
                 bucket_side_max: int = 768,
                 bucket_side_increment: int = 64,
                 max_image_area: int = 512 * 768,
                 max_ratio: float = 2):

        self.requested_bucket_count = num_buckets
        self.bucket_length_min = bucket_side_min
        self.bucket_length_max = bucket_side_max
        self.bucket_increment = bucket_side_increment
        self.max_image_area = max_image_area
        self.batch_size = batch_size
        self.total_dropped = 0

        if max_ratio <= 0:
            self.max_ratio = float('inf')
        else:
            self.max_ratio = max_ratio

        self.store = store
        self.buckets = []
        self._bucket_ratios = []
        self._bucket_interp = None
        self.bucket_data: Dict[tuple, List[int]] = dict()
        self.init_buckets()
        self.fill_buckets()

    def init_buckets(self):
        possible_lengths = list(range(self.bucket_length_min, self.bucket_length_max + 1, self.bucket_increment))
        possible_buckets = list((w, h) for w, h in itertools.product(possible_lengths, possible_lengths)
                        if w >= h and w * h <= self.max_image_area and w / h <= self.max_ratio)

        buckets_by_ratio = {}

        # group the buckets by their aspect ratios
        for bucket in possible_buckets:
            w, h = bucket
            # use precision to avoid spooky floats messing up your day
            ratio = '{:.4e}'.format(w / h)

            if ratio not in buckets_by_ratio:
                group = set()
                buckets_by_ratio[ratio] = group
            else:
                group = buckets_by_ratio[ratio]

            group.add(bucket)

        # now we take the list of buckets we generated and pick the largest by area for each (the first sorted)
        # then we put all of those in a list, sorted by the aspect ratio
        # the square bucket (LxL) will be the first
        unique_ratio_buckets = sorted([sorted(buckets, key=_sort_by_area)[-1]
                                       for buckets in buckets_by_ratio.values()], key=_sort_by_ratio)

        # how many buckets to create for each side of the distribution
        bucket_count_each = int(np.clip((self.requested_bucket_count + 1) / 2, 1, len(unique_ratio_buckets)))

        # we know that the requested_bucket_count must be an odd number, so the indices we calculate
        # will include the square bucket and some linearly spaced buckets along the distribution
        indices = {*np.linspace(0, len(unique_ratio_buckets) - 1, bucket_count_each, dtype=int)}

        # make the buckets, make sure they are unique (to remove the duplicated square bucket), and sort them by ratio
        # here we add the portrait buckets by reversing the dimensions of the landscape buckets we generated above
        buckets = sorted({*(unique_ratio_buckets[i] for i in indices),
                          *(tuple(reversed(unique_ratio_buckets[i])) for i in indices)}, key=_sort_by_ratio)

        self.buckets = buckets

        # cache the bucket ratios and the interpolator that will be used for calculating the best bucket later
        # the interpolator makes a 1d piecewise interpolation where the input (x-axis) is the bucket ratio,
        # and the output is the bucket index in the self.buckets array
        # to find the best fit we can just round that number to get the index
        self._bucket_ratios = [w / h for w, h in buckets]
        self._bucket_interp = interp1d(self._bucket_ratios, list(range(len(buckets))), assume_sorted=True,
                                       fill_value=None)

        for b in buckets:
            self.bucket_data[b] = []

    def get_batch_count(self):
        return sum(len(b) // self.batch_size for b in self.bucket_data.values())

    def get_bucket_info(self):
        return json.dumps({ "buckets": self.buckets, "bucket_ratios": self._bucket_ratios })

    def get_batch_iterator(self) -> Generator[Tuple[Tuple[int, int, int]], None, None]:
        """
        Generator that provides batches where the images in a batch fall on the same bucket

        Each element generated will be:
            (index, w, h)

        where each image is an index into the dataset
        :return:
        """
        max_bucket_len = max(len(b) for b in self.bucket_data.values())
        index_schedule = list(range(max_bucket_len))
        random.shuffle(index_schedule)

        bucket_len_table = {
            b: len(self.bucket_data[b]) for b in self.buckets
        }

        bucket_schedule = []
        for i, b in enumerate(self.buckets):
            bucket_schedule.extend([i] * (bucket_len_table[b] // self.batch_size))

        random.shuffle(bucket_schedule)

        bucket_pos = {
            b: 0 for b in self.buckets
        }

        total_generated_by_bucket = {
            b: 0 for b in self.buckets
        }

        for bucket_index in bucket_schedule:
            b = self.buckets[bucket_index]
            i = bucket_pos[b]
            bucket_len = bucket_len_table[b]

            batch = []
            while len(batch) != self.batch_size:
                # advance in the schedule until we find an index that is contained in the bucket
                k = index_schedule[i]
                if k < bucket_len:
                    entry = self.bucket_data[b][k]
                    batch.append(entry)

                i += 1

            total_generated_by_bucket[b] += self.batch_size
            bucket_pos[b] = i
            yield [(idx, *b) for idx in batch]

    def fill_buckets(self):
        entries = self.store.entries_iterator()
        total_dropped = 0

        for entry, index in tqdm.tqdm(entries, total=len(self.store)):
            if not self._process_entry(entry, index):
                total_dropped += 1

        for b, values in self.bucket_data.items():
            # shuffle the entries for extra randomness and to make sure dropped elements are also random
            random.shuffle(values)

            # make sure the buckets have an exact number of elements for the batch
            to_drop = len(values) % self.batch_size
            self.bucket_data[b] = list(values[:len(values) - to_drop])
            total_dropped += to_drop

        self.total_dropped = total_dropped

    def _process_entry(self, entry: Tuple[int, int], index: int) -> bool:
        aspect = entry[0] / entry[1] # width / height

        if aspect > self.max_ratio or (1 / aspect) > self.max_ratio:
            return False

        best_bucket = self._bucket_interp(aspect)

        if best_bucket is None:
            return False

        bucket = self.buckets[round(float(best_bucket))]

        self.bucket_data[bucket].append(index)

        return True

class AspectBucketSampler(torch.utils.data.Sampler):
    def __init__(self, bucket: AspectBucket, num_replicas: int = 1, rank: int = 0):
        super().__init__(None)
        self.bucket = bucket
        self.num_replicas = num_replicas
        self.rank = rank

    def __iter__(self):
        # subsample the bucket to only include the elements that are assigned to this rank
        indices = self.bucket.get_batch_iterator()
        indices = list(indices)[self.rank::self.num_replicas]
        return iter(indices)

    def __len__(self):
        return self.bucket.get_batch_count() // self.num_replicas

class AspectDataset(torch.utils.data.Dataset):
    def __init__(self, store: ImageStore, tokenizer: CLIPTokenizer, text_encoder: CLIPTextModel, device: torch.device, ucg: float = 0.1):
        self.store = store
        self.tokenizer = tokenizer
        self.text_encoder = text_encoder
        self.device = device
        self.ucg = ucg

        if type(self.text_encoder) is torch.nn.parallel.DistributedDataParallel:
            self.text_encoder = self.text_encoder.module

        self.transforms = torchvision.transforms.Compose([
            torchvision.transforms.RandomHorizontalFlip(p=0.5),
            torchvision.transforms.ToTensor(),
            torchvision.transforms.Normalize([0.5], [0.5])
        ])

    def __len__(self):
        return len(self.store)

    def __getitem__(self, item: Tuple[int, int, int]):
        return_dict = {'pixel_values': None, 'input_ids': None}

        image_file = self.store.get_image(item)

        return_dict['pixel_values'] = self.transforms(image_file)
        if random.random() > self.ucg:
            caption_file = self.store.get_caption(item)
        else:
            caption_file = ''

        return_dict['input_ids'] = caption_file
        return return_dict

    def collate_fn(self, examples):
            pixel_values = torch.stack([example['pixel_values'] for example in examples if example is not None])
            pixel_values.to(memory_format=torch.contiguous_format).float()

            if args.extended_mode_chunks < 2:
                max_length = self.tokenizer.model_max_length - 2
                input_ids = [self.tokenizer([example['input_ids']], truncation=True, return_length=True, return_overflowing_tokens=False, padding=False, add_special_tokens=False, max_length=max_length).input_ids for example in examples if example is not None]
            else:
                max_length = self.tokenizer.model_max_length
                max_chunks = args.extended_mode_chunks
                input_ids = [self.tokenizer([example['input_ids']], truncation=True, return_length=True, return_overflowing_tokens=False, padding=False, add_special_tokens=False, max_length=(max_length * max_chunks) - (max_chunks * 2)).input_ids[0] for example in examples if example is not None]

            tokens = input_ids

            if args.extended_mode_chunks < 2:
                for i, x in enumerate(input_ids):
                    for j, y in enumerate(x):
                        input_ids[i][j] = [self.tokenizer.bos_token_id, *y, *np.full((self.tokenizer.model_max_length - len(y) - 1), self.tokenizer.eos_token_id)]

                if args.clip_penultimate:
                    input_ids = [self.text_encoder.text_model.final_layer_norm(self.text_encoder(torch.asarray(input_id).to(self.device), output_hidden_states=True)['hidden_states'][-2])[0] for input_id in input_ids]
                else:
                    input_ids = [self.text_encoder(torch.asarray(input_id).to(self.device), output_hidden_states=True).last_hidden_state[0] for input_id in input_ids]
            else:
                max_standard_tokens = max_length - 2
                max_chunks = args.extended_mode_chunks
                max_len = np.ceil(max(len(x) for x in input_ids) / max_standard_tokens).astype(int).item() * max_standard_tokens
                if max_len > max_standard_tokens:
                    z = None
                    for i, x in enumerate(input_ids):
                        if len(x) < max_len:
                            input_ids[i] = [*x, *np.full((max_len - len(x)), self.tokenizer.eos_token_id)]
                    batch_t = torch.tensor(input_ids)
                    chunks = [batch_t[:, i:i + max_standard_tokens] for i in range(0, max_len, max_standard_tokens)]
                    for chunk in chunks:
                        chunk = torch.cat((torch.full((chunk.shape[0], 1), self.tokenizer.bos_token_id), chunk, torch.full((chunk.shape[0], 1), self.tokenizer.eos_token_id)), 1)
                        if z is None:
                            if args.clip_penultimate:
                                z = self.text_encoder.text_model.final_layer_norm(self.text_encoder(chunk.to(self.device), output_hidden_states=True)['hidden_states'][-2])
                            else:
                                z = self.text_encoder(chunk.to(self.device), output_hidden_states=True).last_hidden_state
                        else:
                            if args.clip_penultimate:
                                z = torch.cat((z, self.text_encoder.text_model.final_layer_norm(self.text_encoder(chunk.to(self.device), output_hidden_states=True)['hidden_states'][-2])), dim=-2)
                            else:
                                z = torch.cat((z, self.text_encoder(chunk.to(self.device), output_hidden_states=True).last_hidden_state), dim=-2)
                    input_ids = z
                else:
                    for i, x in enumerate(input_ids):
                        input_ids[i] = [self.tokenizer.bos_token_id, *x, *np.full((self.tokenizer.model_max_length - len(x) - 1), self.tokenizer.eos_token_id)]
                    if args.clip_penultimate:    
                        input_ids = self.text_encoder.text_model.final_layer_norm(self.text_encoder(torch.asarray(input_ids).to(self.device), output_hidden_states=True)['hidden_states'][-2])
                    else:
                        input_ids = self.text_encoder(torch.asarray(input_ids).to(self.device), output_hidden_states=True).last_hidden_state
            input_ids = torch.stack(tuple(input_ids))

            return {
                'pixel_values': pixel_values,
                'input_ids': input_ids,
                'tokens': tokens
            }

# Adapted from torch-ema https://github.com/fadel/pytorch_ema/blob/master/torch_ema/ema.py#L14
class EMAModel:
    """
    Exponential Moving Average of models weights
    """

    def __init__(self, parameters: Iterable[torch.nn.Parameter], decay=0.9999):
        parameters = list(parameters)
        self.shadow_params = [p.clone().detach() for p in parameters]

        self.decay = decay
        self.optimization_step = 0

    def get_decay(self, optimization_step):
        """
        Compute the decay factor for the exponential moving average.
        """
        value = (1 + optimization_step) / (10 + optimization_step)
        return 1 - min(self.decay, value)

    @torch.no_grad()
    def step(self, parameters):
        parameters = list(parameters)

        self.optimization_step += 1
        self.decay = self.get_decay(self.optimization_step)

        for s_param, param in zip(self.shadow_params, parameters):
            if param.requires_grad:
                tmp = self.decay * (s_param - param)
                s_param.sub_(tmp)
            else:
                s_param.copy_(param)

        torch.cuda.empty_cache()

    def copy_to(self, parameters: Iterable[torch.nn.Parameter]) -> None:
        """
        Copy current averaged parameters into given collection of parameters.
        Args:
            parameters: Iterable of `torch.nn.Parameter`; the parameters to be
                updated with the stored moving averages. If `None`, the
                parameters with which this `ExponentialMovingAverage` was
                initialized will be used.
        """
        parameters = list(parameters)
        for s_param, param in zip(self.shadow_params, parameters):
            param.data.copy_(s_param.data)

    # From CompVis LitEMA implementation
    def store(self, parameters):
        """
        Save the current parameters for restoring later.
        Args:
          parameters: Iterable of `torch.nn.Parameter`; the parameters to be
            temporarily stored.
        """
        self.collected_params = [param.clone() for param in parameters]

    def restore(self, parameters):
        """
        Restore the parameters stored with the `store` method.
        Useful to validate the model with EMA parameters without affecting the
        original optimization process. Store the parameters before the
        `copy_to` method. After validation (or model saving), use this to
        restore the former parameters.
        Args:
          parameters: Iterable of `torch.nn.Parameter`; the parameters to be
            updated with the stored parameters.
        """
        for c_param, param in zip(self.collected_params, parameters):
            param.data.copy_(c_param.data)

        del self.collected_params
        gc.collect()

    def to(self, device=None, dtype=None) -> None:
        r"""Move internal buffers of the ExponentialMovingAverage to `device`.
        Args:
            device: like `device` argument to `torch.Tensor.to`
        """
        # .to() on the tensors handles None correctly
        self.shadow_params = [
            p.to(device=device, dtype=dtype) if p.is_floating_point() else p.to(device=device)
            for p in self.shadow_params
        ]

def main():
    rank = get_rank()
    world_size = get_world_size()
    torch.cuda.set_device(rank)

    if rank == 0:
        os.makedirs(args.output_path, exist_ok=True)
        
        mode = 'disabled'
        if args.enablewandb:
            mode = 'online'
        if args.hf_token is not None:
            os.environ['HF_API_TOKEN'] = args.hf_token
            args.hf_token = None
        run = wandb.init(project=args.project_id, name=args.run_name, config=vars(args), dir=args.output_path+'/wandb', mode=mode)

        # Inform the user of host, and various versions -- useful for debugging issues.
        print("RUN_NAME:", args.run_name)
        print("HOST:", socket.gethostname())
        print("CUDA:", torch.version.cuda)
        print("TORCH:", torch.__version__)
        print("TRANSFORMERS:", transformers.__version__)
        print("DIFFUSERS:", diffusers.__version__)
        print("MODEL:", args.model)
        print("FP16:", args.fp16)
        print("RESOLUTION:", args.resolution)


    if args.hf_token is not None:
        print('It is recommended to set the HF_API_TOKEN environment variable instead of passing it as a command line argument since WandB will automatically log it.')
    else:
        try:
            args.hf_token = os.environ['HF_API_TOKEN']
            print("HF Token set via enviroment variable")
        except Exception:
            print("No HF Token detected in arguments or enviroment variable, setting it to none (as in string)")
            args.hf_token = "none"

    device = torch.device('cuda')

    print("DEVICE:", device)

    # setup fp16 stuff
    scaler = torch.cuda.amp.GradScaler(enabled=args.fp16)

    # Set seed
    torch.manual_seed(args.seed)
    random.seed(args.seed)
    np.random.seed(args.seed)
    print('RANDOM SEED:', args.seed)

    if args.resume:
        args.model = args.resume
    
    tokenizer = CLIPTokenizer.from_pretrained(args.model, subfolder='tokenizer', use_auth_token=args.hf_token)
    text_encoder = CLIPTextModel.from_pretrained(args.model, subfolder='text_encoder', use_auth_token=args.hf_token)
    vae = AutoencoderKL.from_pretrained(args.model, subfolder='vae', use_auth_token=args.hf_token)
    unet = UNet2DConditionModel.from_pretrained(args.model, subfolder='unet', use_auth_token=args.hf_token)

    # Freeze vae and text_encoder
    vae.requires_grad_(False)
    if not args.train_text_encoder:
        text_encoder.requires_grad_(False)

    if args.gradient_checkpointing:
        unet.enable_gradient_checkpointing()
        if args.train_text_encoder:
            text_encoder.gradient_checkpointing_enable()

    if args.use_xformers:
        unet.set_use_memory_efficient_attention_xformers(True)

    # "The “safer” approach would be to move the model to the device first and create the optimizer afterwards."
    weight_dtype = torch.float16 if args.fp16 else torch.float32

    # move models to device
    vae = vae.to(device, dtype=weight_dtype)
    unet = unet.to(device, dtype=torch.float32)
    text_encoder = text_encoder.to(device, dtype=weight_dtype if not args.train_text_encoder else torch.float32)

    unet = torch.nn.parallel.DistributedDataParallel(
        unet,
        device_ids=[rank],
        output_device=rank,
        gradient_as_bucket_view=True
    )

    if args.train_text_encoder:
        text_encoder = torch.nn.parallel.DistributedDataParallel(
            text_encoder,
            device_ids=[rank],
            output_device=rank,
            gradient_as_bucket_view=True
        )

    if args.use_8bit_adam: # Bits and bytes is only supported on certain CUDA setups, so default to regular adam if it fails.
        try:
            import bitsandbytes as bnb
            optimizer_cls = bnb.optim.AdamW8bit
        except:
            print('bitsandbytes not supported, using regular Adam optimizer')
            optimizer_cls = torch.optim.AdamW
    else:
        optimizer_cls = torch.optim.AdamW

    """
    optimizer = optimizer_cls(
        unet.parameters(),
        lr=args.lr,
        betas=(args.adam_beta1, args.adam_beta2),
        eps=args.adam_epsilon,
        weight_decay=args.adam_weight_decay,
    )
    """

    optimizer_parameters = unet.parameters() if not args.train_text_encoder else itertools.chain(unet.parameters(), text_encoder.parameters())

    # Create distributed optimizer
    from torch.distributed.optim import ZeroRedundancyOptimizer
    optimizer = ZeroRedundancyOptimizer(
        optimizer_parameters,
        optimizer_class=optimizer_cls,
        parameters_as_bucket_view=True,
        lr=args.lr,
        betas=(args.adam_beta1, args.adam_beta2),
        eps=args.adam_epsilon,
        weight_decay=args.adam_weight_decay,
    )


    noise_scheduler = DDPMScheduler.from_pretrained(
        args.model,
        subfolder='scheduler',
        use_auth_token=args.hf_token,
    )

    # load dataset
    store = ImageStore(args.dataset)
    dataset = AspectDataset(store, tokenizer, text_encoder, device, ucg=args.ucg)
    bucket = AspectBucket(store, args.num_buckets, args.batch_size, args.bucket_side_min, args.bucket_side_max, 64, args.resolution * args.resolution, 2.0)
    sampler = AspectBucketSampler(bucket=bucket, num_replicas=world_size, rank=rank)

    print(f'STORE_LEN: {len(store)}')

    if args.output_bucket_info:
        print(bucket.get_bucket_info())
        exit(0)

    train_dataloader = torch.utils.data.DataLoader(
        dataset,
        batch_sampler=sampler,
        num_workers=0,
        collate_fn=dataset.collate_fn
    )
    
    # Migrate dataset
    if args.resize and not args.no_migration:
        for _, batch in enumerate(train_dataloader):
            continue
        print(f"Completed resize and migration to '{args.dataset}_cropped' please relaunch the trainer without the --resize argument and train on the migrated dataset.")
        exit(0)

    # create ema
    if args.use_ema:
        ema_unet = EMAModel(unet.parameters())

    print(get_gpu_ram())

    num_steps_per_epoch = len(train_dataloader)
    progress_bar = tqdm.tqdm(range(args.epochs * num_steps_per_epoch), desc="Total Steps", leave=False)
    global_step = 0

    if args.resume:
        target_global_step = int(args.resume.split('_')[-1])
        print(f'resuming from {args.resume}...')

    lr_scheduler = get_scheduler(
        args.lr_scheduler,
        optimizer=optimizer,
        num_warmup_steps=int(args.lr_scheduler_warmup * num_steps_per_epoch * args.epochs),
        num_training_steps=args.epochs * num_steps_per_epoch,
        #last_epoch=(global_step // num_steps_per_epoch) - 1,
    )

    def save_checkpoint(global_step):
        if rank == 0:
            if args.use_ema:
                ema_unet.store(unet.parameters())
                ema_unet.copy_to(unet.parameters())
            pipeline = StableDiffusionPipeline(
                text_encoder=text_encoder if type(text_encoder) is not torch.nn.parallel.DistributedDataParallel else text_encoder.module,
                vae=vae,
                unet=unet.module,
                tokenizer=tokenizer,
                scheduler=PNDMScheduler.from_pretrained(args.model, subfolder="scheduler", use_auth_token=args.hf_token),
                safety_checker=StableDiffusionSafetyChecker.from_pretrained("CompVis/stable-diffusion-safety-checker"),
                feature_extractor=CLIPFeatureExtractor.from_pretrained("openai/clip-vit-base-patch32"),
            )
            print(f'saving checkpoint to: {args.output_path}/{args.run_name}_{global_step}')
            pipeline.save_pretrained(f'{args.output_path}/{args.run_name}_{global_step}')

            if args.use_ema:
                ema_unet.restore(unet.parameters())

    # train!
    try:
        loss = torch.tensor(0.0, device=device, dtype=weight_dtype)
        for epoch in range(args.epochs):
            unet.train()
            if args.train_text_encoder:
                text_encoder.train()
            for _, batch in enumerate(train_dataloader):
                if args.resume and global_step < target_global_step:
                    if rank == 0:
                        progress_bar.update(1)
                    global_step += 1
                    continue
                
                b_start = time.perf_counter()
                latents = vae.encode(batch['pixel_values'].to(device, dtype=weight_dtype)).latent_dist.sample()
                latents = latents * 0.18215

                # Sample noise
                noise = torch.randn_like(latents)
                bsz = latents.shape[0]
                # Sample a random timestep for each image
                timesteps = torch.randint(0, noise_scheduler.num_train_timesteps, (bsz,), device=latents.device)
                timesteps = timesteps.long()

                # Add noise to the latents according to the noise magnitude at each timestep
                # (this is the forward diffusion process)
                noisy_latents = noise_scheduler.add_noise(latents, noise, timesteps)

                # Get the embedding for conditioning
                encoder_hidden_states = batch['input_ids']

                if noise_scheduler.config.prediction_type == "epsilon":
                    target = noise
                elif noise_scheduler.config.prediction_type == "v_prediction":
                    target = noise_scheduler.get_velocity(latents, noise, timesteps)
                else:
                    raise ValueError(f"Unknown prediction type: {noise_scheduler.config.prediction_type}")

                if not args.train_text_encoder:
                    with unet.join():
                        # Predict the noise residual and compute loss
                        with torch.autocast('cuda', enabled=args.fp16):
                            noise_pred = unet(noisy_latents, timesteps, encoder_hidden_states).sample
                            
                        loss = torch.nn.functional.mse_loss(noise_pred.float(), target.float(), reduction="mean")

                        # backprop and update
                        scaler.scale(loss).backward()
                        torch.nn.utils.clip_grad_norm_(unet.parameters(), 1.0)
                        scaler.step(optimizer)
                        scaler.update()
                        lr_scheduler.step()
                        optimizer.zero_grad()
                else:
                    with unet.join(), text_encoder.join():
                        # Predict the noise residual and compute loss
                        with torch.autocast('cuda', enabled=args.fp16):
                            noise_pred = unet(noisy_latents, timesteps, encoder_hidden_states).sample
                            
                        loss = torch.nn.functional.mse_loss(noise_pred.float(), target.float(), reduction="mean")

                        # backprop and update
                        scaler.scale(loss).backward()
                        torch.nn.utils.clip_grad_norm_(unet.parameters(), 1.0)
                        torch.nn.utils.clip_grad_norm_(text_encoder.parameters(), 1.0)
                        scaler.step(optimizer)
                        scaler.update()
                        lr_scheduler.step()
                        optimizer.zero_grad()                    

                # Update EMA
                if args.use_ema:
                    ema_unet.step(unet.parameters())

                # perf
                b_end = time.perf_counter()
                seconds_per_step = b_end - b_start
                steps_per_second = 1 / seconds_per_step
                rank_images_per_second = args.batch_size * steps_per_second
                world_images_per_second = rank_images_per_second * world_size
                samples_seen = global_step * args.batch_size * world_size

                # get global loss for logging
                torch.distributed.all_reduce(loss, op=torch.distributed.ReduceOp.SUM)
                loss = loss / world_size

                if rank == 0:
                    progress_bar.update(1)
                    global_step += 1
                    logs = {
                        "train/loss": loss.detach().item(),
                        "train/lr": lr_scheduler.get_last_lr()[0],
                        "train/epoch": epoch,
                        "train/step": global_step,
                        "train/samples_seen": samples_seen,
                        "perf/rank_samples_per_second": rank_images_per_second,
                        "perf/global_samples_per_second": world_images_per_second,
                    }
                    progress_bar.set_postfix(logs)
                    run.log(logs, step=global_step)

                if global_step % args.save_steps == 0 and global_step > 0:
                    save_checkpoint(global_step)
                if args.enableinference:
                    if global_step % args.image_log_steps == 0 and global_step > 0:
                        if rank == 0:
                            # get prompt from random batch
                            prompt = tokenizer.decode(batch['tokens'][random.randint(0, len(batch['tokens'])-1)])

                            if args.image_log_scheduler == 'DDIMScheduler':
                                print('using DDIMScheduler scheduler')
                                scheduler = DDIMScheduler.from_pretrained(args.model, subfolder="scheduler", use_auth_token=args.hf_token)
                            else:
                                print('using PNDMScheduler scheduler')
                                scheduler=PNDMScheduler.from_pretrained(args.model, subfolder="scheduler", use_auth_token=args.hf_token)

                            pipeline = StableDiffusionPipeline(
                                text_encoder=text_encoder if type(text_encoder) is not torch.nn.parallel.DistributedDataParallel else text_encoder.module,
                                vae=vae,
                                unet=unet.module,
                                tokenizer=tokenizer,
                                scheduler=scheduler,
                                safety_checker=None, # disable safety checker to save memory
                                feature_extractor=CLIPFeatureExtractor.from_pretrained("openai/clip-vit-base-patch32"),
                            ).to(device)
                            # inference
                            if args.enablewandb:
                                images = []
                            else:
                                saveInferencePath = args.output_path + "/inference"
                                os.makedirs(saveInferencePath, exist_ok=True)
                            with torch.no_grad():
                                with torch.autocast('cuda', enabled=args.fp16):
                                    for _ in range(args.image_log_amount):
                                        if args.enablewandb:
                                            images.append(
                                                wandb.Image(pipeline(
                                                    prompt, num_inference_steps=args.image_log_inference_steps
                                                ).images[0],
                                                caption=prompt)
                                            )
                                        else:
                                            from datetime import datetime
                                            images = pipeline(prompt, num_inference_steps=args.image_log_inference_steps).images[0]
                                            filenameImg = str(time.time_ns()) + ".png"
                                            filenameTxt = str(time.time_ns()) + ".txt"
                                            images.save(saveInferencePath + "/" + filenameImg)
                                            with open(saveInferencePath + "/" + filenameTxt, 'a') as f:
                                                f.write('Used prompt: ' + prompt + '\n')
                                                f.write('Generated Image Filename: ' + filenameImg + '\n')
                                                f.write('Generated at: ' + str(global_step) + ' steps' + '\n')
                                                f.write('Generated at: ' + str(datetime.now().strftime('%Y-%m-%d %H:%M:%S'))+ '\n')

                            # log images under single caption
                            if args.enablewandb:
                                run.log({'images': images}, step=global_step)

                            # cleanup so we don't run out of memory
                            del pipeline
                            gc.collect()
    except Exception as e:
        print(f'Exception caught on rank {rank} at step {global_step}, saving checkpoint...\n{e}\n{traceback.format_exc()}')
        pass

    save_checkpoint(global_step)

    cleanup()

    print(get_gpu_ram())
    print('Done!')

if __name__ == "__main__":
    setup()
    main()