import argparse
import itertools
import json
import logging
import math
import uuid
import warnings
from os import environ, listdir, makedirs
from os.path import basename, join
from pathlib import Path
from typing import List

import datasets
import numpy as np
import torch
import torch.nn.functional as F
import torch.utils.checkpoint
import transformers
from accelerate import Accelerator
from accelerate.logging import get_logger
from accelerate.utils import ProjectConfiguration, set_seed
from huggingface_hub import create_repo, upload_folder
from huggingface_hub.utils import insecure_hashlib
from PIL import Image
from torch import dtype
from torch.nn import Module
from torch.utils.data import Dataset
from torchvision import transforms
from tqdm.auto import tqdm
from transformers import AutoTokenizer, PretrainedConfig

import diffusers
from diffusers import (
    AutoencoderKL,
    DDPMScheduler,
    DiffusionPipeline,
    DPMSolverMultistepScheduler,
    UNet2DConditionModel,
)
from diffusers.optimization import get_scheduler
from diffusers.utils import check_min_version, is_wandb_available
from diffusers.utils.import_utils import is_xformers_available


if is_wandb_available():
    import wandb

# Will error if the minimal version of diffusers is not installed. Remove at your own risks.
check_min_version("0.13.0.dev0")

logger = get_logger(__name__)


def log_validation_images_to_tracker(
    images: List[np.array], label: str, validation_prompt: str, accelerator: Accelerator, epoch: int
):
    logger.info(f"Logging images to tracker for validation prompt: {validation_prompt}.")

    for tracker in accelerator.trackers:
        if tracker.name == "tensorboard":
            np_images = np.stack([np.asarray(img) for img in images])
            tracker.writer.add_images("validation", np_images, epoch, dataformats="NHWC")
        if tracker.name == "wandb":
            tracker.log(
                {
                    "validation": [
                        wandb.Image(image, caption=f"{label}_{epoch}_{i}: {validation_prompt}")
                        for i, image in enumerate(images)
                    ]
                }
            )


# TODO: Add `prompt_embeds` and `negative_prompt_embeds` parameters to the function when `pre_compute_text_embeddings`
#  argument is implemented.
def generate_validation_images(
    text_encoder: Module,
    tokenizer: Module,
    unet: Module,
    vae: Module,
    arguments: argparse.Namespace,
    accelerator: Accelerator,
    weight_dtype: dtype,
):
    logger.info("Running validation images.")

    pipeline_args = {}

    if text_encoder is not None:
        pipeline_args["text_encoder"] = accelerator.unwrap_model(text_encoder)

    if vae is not None:
        pipeline_args["vae"] = vae

    # create pipeline (note: unet and vae are loaded again in float32)
    pipeline = DiffusionPipeline.from_pretrained(
        arguments.pretrained_model_name_or_path,
        tokenizer=tokenizer,
        unet=accelerator.unwrap_model(unet),
        revision=arguments.revision,
        torch_dtype=weight_dtype,
        **pipeline_args,
    )

    # We train on the simplified learning objective. If we were previously predicting a variance, we need the
    # scheduler to ignore it
    scheduler_args = {}

    if "variance_type" in pipeline.scheduler.config:
        variance_type = pipeline.scheduler.config.variance_type

        if variance_type in ["learned", "learned_range"]:
            variance_type = "fixed_small"

        scheduler_args["variance_type"] = variance_type

    pipeline.scheduler = DPMSolverMultistepScheduler.from_config(pipeline.scheduler.config, **scheduler_args)
    pipeline = pipeline.to(accelerator.device)
    pipeline.set_progress_bar_config(disable=True)

    generator = (
        None if arguments.seed is None else torch.Generator(device=accelerator.device).manual_seed(arguments.seed)
    )

    images_sets = []
    for vp, nvi, vnp, vis, vgs in zip(
        arguments.validation_prompt,
        arguments.validation_number_images,
        arguments.validation_negative_prompt,
        arguments.validation_inference_steps,
        arguments.validation_guidance_scale,
    ):
        images = []
        if vp is not None:
            logger.info(
                f"Generating {nvi} images with prompt: '{vp}', negative prompt: '{vnp}', inference steps: {vis}, "
                f"guidance scale: {vgs}."
            )

            pipeline_args = {"prompt": vp, "negative_prompt": vnp, "num_inference_steps": vis, "guidance_scale": vgs}

            # run inference
            # TODO: it would be good to measure whether it's faster to run inference on all images at once, one at a
            #  time or in small batches
            for _ in range(nvi):
                with torch.autocast("cuda"):
                    image = pipeline(**pipeline_args, num_images_per_prompt=1, generator=generator).images[0]
                images.append(image)

        images_sets.append(images)

    del pipeline
    if torch.cuda.is_available():
        torch.cuda.empty_cache()

    return images_sets


def import_model_class_from_model_name_or_path(pretrained_model_name_or_path: str, revision: str):
    text_encoder_config = PretrainedConfig.from_pretrained(
        pretrained_model_name_or_path,
        subfolder="text_encoder",
        revision=revision,
    )
    model_class = text_encoder_config.architectures[0]

    if model_class == "CLIPTextModel":
        from transformers import CLIPTextModel

        return CLIPTextModel
    elif model_class == "RobertaSeriesModelWithTransformation":
        from diffusers.pipelines.alt_diffusion.modeling_roberta_series import RobertaSeriesModelWithTransformation

        return RobertaSeriesModelWithTransformation
    else:
        raise ValueError(f"{model_class} is not supported.")


def parse_args(input_args=None):
    parser = argparse.ArgumentParser(description="Simple example of a training script.")
    parser.add_argument(
        "--pretrained_model_name_or_path",
        type=str,
        default=None,
        required=True,
        help="Path to pretrained model or model identifier from huggingface.co/models.",
    )
    parser.add_argument(
        "--revision",
        type=str,
        default=None,
        required=False,
        help="Revision of pretrained model identifier from huggingface.co/models.",
    )
    parser.add_argument(
        "--tokenizer_name",
        type=str,
        default=None,
        help="Pretrained tokenizer name or path if not the same as model_name",
    )
    parser.add_argument(
        "--instance_data_dir",
        type=str,
        default=None,
        required=False,
        help="A folder containing the training data of instance images.",
    )
    parser.add_argument(
        "--class_data_dir",
        type=str,
        default=None,
        required=False,
        help="A folder containing the training data of class images.",
    )
    parser.add_argument(
        "--instance_prompt",
        type=str,
        default=None,
        required=False,
        help="The prompt with identifier specifying the instance",
    )
    parser.add_argument(
        "--class_prompt",
        type=str,
        default=None,
        help="The prompt to specify images in the same class as provided instance images.",
    )
    parser.add_argument(
        "--with_prior_preservation",
        default=False,
        action="store_true",
        help="Flag to add prior preservation loss.",
    )
    parser.add_argument("--prior_loss_weight", type=float, default=1.0, help="The weight of prior preservation loss.")
    parser.add_argument(
        "--num_class_images",
        type=int,
        default=100,
        help=(
            "Minimal class images for prior preservation loss. If there are not enough images already present in"
            " class_data_dir, additional images will be sampled with class_prompt."
        ),
    )
    parser.add_argument(
        "--output_dir",
        type=str,
        default="text-inversion-model",
        help="The output directory where the model predictions and checkpoints will be written.",
    )
    parser.add_argument("--seed", type=int, default=None, help="A seed for reproducible training.")
    parser.add_argument(
        "--resolution",
        type=int,
        default=512,
        help=(
            "The resolution for input images, all the images in the train/validation dataset will be resized to this"
            " resolution"
        ),
    )
    parser.add_argument(
        "--center_crop",
        default=False,
        action="store_true",
        help=(
            "Whether to center crop the input images to the resolution. If not set, the images will be randomly"
            " cropped. The images will be resized to the resolution first before cropping."
        ),
    )
    parser.add_argument("--train_text_encoder", action="store_true", help="Whether to train the text encoder")
    parser.add_argument(
        "--train_batch_size", type=int, default=4, help="Batch size (per device) for the training dataloader."
    )
    parser.add_argument(
        "--sample_batch_size", type=int, default=4, help="Batch size (per device) for sampling images."
    )
    parser.add_argument("--num_train_epochs", type=int, default=1)
    parser.add_argument(
        "--max_train_steps",
        type=int,
        default=None,
        help="Total number of training steps to perform.  If provided, overrides num_train_epochs.",
    )
    parser.add_argument(
        "--checkpointing_steps",
        type=int,
        default=500,
        help=(
            "Save a checkpoint of the training state every X updates. These checkpoints can be used both as final"
            " checkpoints in case they are better than the last checkpoint, and are also suitable for resuming"
            " training using `--resume_from_checkpoint`."
        ),
    )
    parser.add_argument(
        "--checkpoints_total_limit",
        type=int,
        default=None,
        help=(
            "Max number of checkpoints to store. Passed as `total_limit` to the `Accelerator` `ProjectConfiguration`."
            " See Accelerator::save_state https://huggingface.co/docs/accelerate/package_reference/accelerator#accelerate.Accelerator.save_state"
            " for more docs"
        ),
    )
    parser.add_argument(
        "--resume_from_checkpoint",
        type=str,
        default=None,
        help=(
            "Whether training should be resumed from a previous checkpoint. Use a path saved by"
            ' `--checkpointing_steps`, or `"latest"` to automatically select the last available checkpoint.'
        ),
    )
    parser.add_argument(
        "--gradient_accumulation_steps",
        type=int,
        default=1,
        help="Number of updates steps to accumulate before performing a backward/update pass.",
    )
    parser.add_argument(
        "--gradient_checkpointing",
        action="store_true",
        help="Whether or not to use gradient checkpointing to save memory at the expense of slower backward pass.",
    )
    parser.add_argument(
        "--learning_rate",
        type=float,
        default=5e-6,
        help="Initial learning rate (after the potential warmup period) to use.",
    )
    parser.add_argument(
        "--scale_lr",
        action="store_true",
        default=False,
        help="Scale the learning rate by the number of GPUs, gradient accumulation steps, and batch size.",
    )
    parser.add_argument(
        "--lr_scheduler",
        type=str,
        default="constant",
        help=(
            'The scheduler type to use. Choose between ["linear", "cosine", "cosine_with_restarts", "polynomial",'
            ' "constant", "constant_with_warmup"]'
        ),
    )
    parser.add_argument(
        "--lr_warmup_steps", type=int, default=500, help="Number of steps for the warmup in the lr scheduler."
    )
    parser.add_argument(
        "--lr_num_cycles",
        type=int,
        default=1,
        help="Number of hard resets of the lr in cosine_with_restarts scheduler.",
    )
    parser.add_argument("--lr_power", type=float, default=1.0, help="Power factor of the polynomial scheduler.")
    parser.add_argument(
        "--use_8bit_adam", action="store_true", help="Whether or not to use 8-bit Adam from bitsandbytes."
    )
    parser.add_argument("--adam_beta1", type=float, default=0.9, help="The beta1 parameter for the Adam optimizer.")
    parser.add_argument("--adam_beta2", type=float, default=0.999, help="The beta2 parameter for the Adam optimizer.")
    parser.add_argument("--adam_weight_decay", type=float, default=1e-2, help="Weight decay to use.")
    parser.add_argument("--adam_epsilon", type=float, default=1e-08, help="Epsilon value for the Adam optimizer")
    parser.add_argument("--max_grad_norm", default=1.0, type=float, help="Max gradient norm.")
    parser.add_argument("--push_to_hub", action="store_true", help="Whether or not to push the model to the Hub.")
    parser.add_argument("--hub_token", type=str, default=None, help="The token to use to push to the Model Hub.")
    parser.add_argument(
        "--hub_model_id",
        type=str,
        default=None,
        help="The name of the repository to keep in sync with the local `output_dir`.",
    )
    parser.add_argument(
        "--logging_dir",
        type=str,
        default="logs",
        help=(
            "[TensorBoard](https://www.tensorflow.org/tensorboard) log directory. Will default to"
            " *output_dir/runs/**CURRENT_DATETIME_HOSTNAME***."
        ),
    )
    parser.add_argument(
        "--allow_tf32",
        action="store_true",
        help=(
            "Whether or not to allow TF32 on Ampere GPUs. Can be used to speed up training. For more information, see"
            " https://pytorch.org/docs/stable/notes/cuda.html#tensorfloat-32-tf32-on-ampere-devices"
        ),
    )
    parser.add_argument(
        "--report_to",
        type=str,
        default="tensorboard",
        help=(
            'The integration to report the results and logs to. Supported platforms are `"tensorboard"`'
            ' (default), `"wandb"` and `"comet_ml"`. Use `"all"` to report to all integrations.'
        ),
    )
    parser.add_argument(
        "--validation_steps",
        type=int,
        default=None,
        help=(
            "Run validation every X steps. Validation consists of running the prompt(s) `validation_prompt` "
            "multiple times (`validation_number_images`) and logging the images."
        ),
    )
    parser.add_argument(
        "--validation_prompt",
        type=str,
        default=None,
        help="A prompt that is used during validation to verify that the model is learning. You can use commas to "
        "define multiple negative prompts. This parameter can be defined also within the file given by "
        "`concepts_list` parameter in the respective subject.",
    )
    parser.add_argument(
        "--validation_number_images",
        type=int,
        default=4,
        help="Number of images that should be generated during validation with the validation parameters given. This "
        "can be defined within the file given by `concepts_list` parameter in the respective subject.",
    )
    parser.add_argument(
        "--validation_negative_prompt",
        type=str,
        default=None,
        help="A negative prompt that is used during validation to verify that the model is learning. You can use commas"
        " to define multiple negative prompts, each one corresponding to a validation prompt. This parameter can "
        "be defined also within the file given by `concepts_list` parameter in the respective subject.",
    )
    parser.add_argument(
        "--validation_inference_steps",
        type=int,
        default=25,
        help="Number of inference steps (denoising steps) to run during validation. This can be defined within the "
        "file given by `concepts_list` parameter in the respective subject.",
    )
    parser.add_argument(
        "--validation_guidance_scale",
        type=float,
        default=7.5,
        help="To control how much the image generation process follows the text prompt. This can be defined within the "
        "file given by `concepts_list` parameter in the respective subject.",
    )
    parser.add_argument(
        "--mixed_precision",
        type=str,
        default=None,
        choices=["no", "fp16", "bf16"],
        help=(
            "Whether to use mixed precision. Choose between fp16 and bf16 (bfloat16). Bf16 requires PyTorch >="
            " 1.10.and an Nvidia Ampere GPU.  Default to the value of accelerate config of the current system or the"
            " flag passed with the `accelerate.launch` command. Use this argument to override the accelerate config."
        ),
    )
    parser.add_argument(
        "--prior_generation_precision",
        type=str,
        default=None,
        choices=["no", "fp32", "fp16", "bf16"],
        help=(
            "Choose prior generation precision between fp32, fp16 and bf16 (bfloat16). Bf16 requires PyTorch >="
            " 1.10.and an Nvidia Ampere GPU.  Default to  fp16 if a GPU is available else fp32."
        ),
    )
    parser.add_argument("--local_rank", type=int, default=-1, help="For distributed training: local_rank")
    parser.add_argument(
        "--enable_xformers_memory_efficient_attention", action="store_true", help="Whether or not to use xformers."
    )
    parser.add_argument(
        "--set_grads_to_none",
        action="store_true",
        help=(
            "Save more memory by using setting grads to None instead of zero. Be aware, that this changes certain"
            " behaviors, so disable this argument if it causes any problems. More info:"
            " https://pytorch.org/docs/stable/generated/torch.optim.Optimizer.zero_grad.html"
        ),
    )
    parser.add_argument(
        "--concepts_list",
        type=str,
        default=None,
        help="Path to json file containing a list of multiple concepts, will overwrite parameters like instance_prompt,"
        " class_prompt, etc.",
    )

    if input_args:
        args = parser.parse_args(input_args)
    else:
        args = parser.parse_args()

    if not args.concepts_list and (not args.instance_data_dir or not args.instance_prompt):
        raise ValueError(
            "You must specify either instance parameters (data directory, prompt, etc.) or use "
            "the `concept_list` parameter and specify them within the file."
        )

    if args.concepts_list:
        if args.instance_prompt:
            raise ValueError("If you are using `concepts_list` parameter, define the instance prompt within the file.")
        if args.instance_data_dir:
            raise ValueError(
                "If you are using `concepts_list` parameter, define the instance data directory within the file."
            )
        if args.validation_steps and (args.validation_prompt or args.validation_negative_prompt):
            raise ValueError(
                "If you are using `concepts_list` parameter, define validation parameters for "
                "each subject within the file:\n - `validation_prompt`."
                "\n - `validation_negative_prompt`.\n - `validation_guidance_scale`."
                "\n - `validation_number_images`.\n - `validation_prompt`."
                "\n - `validation_inference_steps`.\nThe `validation_steps` parameter is the only one "
                "that needs to be defined outside the file."
            )

    env_local_rank = int(environ.get("LOCAL_RANK", -1))
    if env_local_rank != -1 and env_local_rank != args.local_rank:
        args.local_rank = env_local_rank

    if args.with_prior_preservation:
        if not args.concepts_list:
            if not args.class_data_dir:
                raise ValueError("You must specify a data directory for class images.")
            if not args.class_prompt:
                raise ValueError("You must specify prompt for class images.")
        else:
            if args.class_data_dir:
                raise ValueError(
                    "If you are using `concepts_list` parameter, define the class data directory within the file."
                )
            if args.class_prompt:
                raise ValueError(
                    "If you are using `concepts_list` parameter, define the class prompt within the file."
                )
    else:
        # logger is not available yet
        if not args.class_data_dir:
            warnings.warn(
                "Ignoring `class_data_dir` parameter, you need to use it together with `with_prior_preservation`."
            )
        if not args.class_prompt:
            warnings.warn(
                "Ignoring `class_prompt` parameter, you need to use it together with `with_prior_preservation`."
            )

    return args


class DreamBoothDataset(Dataset):
    """
    A dataset to prepare the instance and class images with the prompts for fine-tuning the model.
    It pre-processes the images and then tokenizes prompts.
    """

    def __init__(
        self,
        instance_data_root,
        instance_prompt,
        tokenizer,
        class_data_root=None,
        class_prompt=None,
        size=512,
        center_crop=False,
    ):
        self.size = size
        self.center_crop = center_crop
        self.tokenizer = tokenizer

        self.instance_data_root = []
        self.instance_images_path = []
        self.num_instance_images = []
        self.instance_prompt = []
        self.class_data_root = [] if class_data_root is not None else None
        self.class_images_path = []
        self.num_class_images = []
        self.class_prompt = []
        self._length = 0

        for i in range(len(instance_data_root)):
            self.instance_data_root.append(Path(instance_data_root[i]))
            if not self.instance_data_root[i].exists():
                raise ValueError("Instance images root doesn't exists.")

            self.instance_images_path.append(list(Path(instance_data_root[i]).iterdir()))
            self.num_instance_images.append(len(self.instance_images_path[i]))
            self.instance_prompt.append(instance_prompt[i])
            self._length += self.num_instance_images[i]

            if class_data_root is not None:
                self.class_data_root.append(Path(class_data_root[i]))
                self.class_data_root[i].mkdir(parents=True, exist_ok=True)
                self.class_images_path.append(list(self.class_data_root[i].iterdir()))
                self.num_class_images.append(len(self.class_images_path))
                if self.num_class_images[i] > self.num_instance_images[i]:
                    self._length -= self.num_instance_images[i]
                    self._length += self.num_class_images[i]
                self.class_prompt.append(class_prompt[i])

        self.image_transforms = transforms.Compose(
            [
                transforms.Resize(size, interpolation=transforms.InterpolationMode.BILINEAR),
                transforms.CenterCrop(size) if center_crop else transforms.RandomCrop(size),
                transforms.ToTensor(),
                transforms.Normalize([0.5], [0.5]),
            ]
        )

    def __len__(self):
        return self._length

    def __getitem__(self, index):
        example = {}
        for i in range(len(self.instance_images_path)):
            instance_image = Image.open(self.instance_images_path[i][index % self.num_instance_images[i]])
            if not instance_image.mode == "RGB":
                instance_image = instance_image.convert("RGB")
            example[f"instance_images_{i}"] = self.image_transforms(instance_image)
            example[f"instance_prompt_ids_{i}"] = self.tokenizer(
                self.instance_prompt[i],
                truncation=True,
                padding="max_length",
                max_length=self.tokenizer.model_max_length,
                return_tensors="pt",
            ).input_ids

        if self.class_data_root:
            for i in range(len(self.class_data_root)):
                class_image = Image.open(self.class_images_path[i][index % self.num_class_images[i]])
                if not class_image.mode == "RGB":
                    class_image = class_image.convert("RGB")
                example[f"class_images_{i}"] = self.image_transforms(class_image)
                example[f"class_prompt_ids_{i}"] = self.tokenizer(
                    self.class_prompt[i],
                    truncation=True,
                    padding="max_length",
                    max_length=self.tokenizer.model_max_length,
                    return_tensors="pt",
                ).input_ids

        return example


def collate_fn(num_instances, examples, with_prior_preservation=False):
    input_ids = []
    pixel_values = []

    for i in range(num_instances):
        input_ids += [example[f"instance_prompt_ids_{i}"] for example in examples]
        pixel_values += [example[f"instance_images_{i}"] for example in examples]

    # Concat class and instance examples for prior preservation.
    # We do this to avoid doing two forward passes.
    if with_prior_preservation:
        for i in range(num_instances):
            input_ids += [example[f"class_prompt_ids_{i}"] for example in examples]
            pixel_values += [example[f"class_images_{i}"] for example in examples]

    pixel_values = torch.stack(pixel_values)
    pixel_values = pixel_values.to(memory_format=torch.contiguous_format).float()

    input_ids = torch.cat(input_ids, dim=0)

    batch = {
        "input_ids": input_ids,
        "pixel_values": pixel_values,
    }
    return batch


class PromptDataset(Dataset):
    """A simple dataset to prepare the prompts to generate class images on multiple GPUs."""

    def __init__(self, prompt, num_samples):
        self.prompt = prompt
        self.num_samples = num_samples

    def __len__(self):
        return self.num_samples

    def __getitem__(self, index):
        example = {}
        example["prompt"] = self.prompt
        example["index"] = index
        return example


def main(args):
    if args.report_to == "wandb" and args.hub_token is not None:
        raise ValueError(
            "You cannot use both --report_to=wandb and --hub_token due to a security risk of exposing your token."
            " Please use `huggingface-cli login` to authenticate with the Hub."
        )

    logging_dir = Path(args.output_dir, args.logging_dir)
    accelerator_project_config = ProjectConfiguration(
        total_limit=args.checkpoints_total_limit, project_dir=args.output_dir, logging_dir=logging_dir
    )
    accelerator = Accelerator(
        gradient_accumulation_steps=args.gradient_accumulation_steps,
        mixed_precision=args.mixed_precision,
        log_with=args.report_to,
        project_config=accelerator_project_config,
    )

    # Disable AMP for MPS.
    if torch.backends.mps.is_available():
        accelerator.native_amp = False

    if args.report_to == "wandb":
        if not is_wandb_available():
            raise ImportError("Make sure to install wandb if you want to use it for logging during training.")

    # Currently, it's not possible to do gradient accumulation when training two models with accelerate.accumulate
    # This will be enabled soon in accelerate. For now, we don't allow gradient accumulation when training two models.
    # TODO (patil-suraj): Remove this check when gradient accumulation with two models is enabled in accelerate.
    if args.train_text_encoder and args.gradient_accumulation_steps > 1 and accelerator.num_processes > 1:
        raise ValueError(
            "Gradient accumulation is not supported when training the text encoder in distributed training. "
            "Please set gradient_accumulation_steps to 1. This feature will be supported in the future."
        )

    instance_data_dir = []
    instance_prompt = []
    class_data_dir = [] if args.with_prior_preservation else None
    class_prompt = [] if args.with_prior_preservation else None
    if args.concepts_list:
        with open(args.concepts_list, "r") as f:
            concepts_list = json.load(f)

        if args.validation_steps:
            args.validation_prompt = []
            args.validation_number_images = []
            args.validation_negative_prompt = []
            args.validation_inference_steps = []
            args.validation_guidance_scale = []

        for concept in concepts_list:
            instance_data_dir.append(concept["instance_data_dir"])
            instance_prompt.append(concept["instance_prompt"])

            if args.with_prior_preservation:
                try:
                    class_data_dir.append(concept["class_data_dir"])
                    class_prompt.append(concept["class_prompt"])
                except KeyError:
                    raise KeyError(
                        "`class_data_dir` or `class_prompt` not found in concepts_list while using "
                        "`with_prior_preservation`."
                    )
            else:
                if "class_data_dir" in concept:
                    warnings.warn(
                        "Ignoring `class_data_dir` key, to use it you need to enable `with_prior_preservation`."
                    )
                if "class_prompt" in concept:
                    warnings.warn(
                        "Ignoring `class_prompt` key, to use it you need to enable `with_prior_preservation`."
                    )

            if args.validation_steps:
                args.validation_prompt.append(concept.get("validation_prompt", None))
                args.validation_number_images.append(concept.get("validation_number_images", 4))
                args.validation_negative_prompt.append(concept.get("validation_negative_prompt", None))
                args.validation_inference_steps.append(concept.get("validation_inference_steps", 25))
                args.validation_guidance_scale.append(concept.get("validation_guidance_scale", 7.5))
    else:
        # Parse instance and class inputs, and double check that lengths match
        instance_data_dir = args.instance_data_dir.split(",")
        instance_prompt = args.instance_prompt.split(",")
        assert all(
            x == len(instance_data_dir) for x in [len(instance_data_dir), len(instance_prompt)]
        ), "Instance data dir and prompt inputs are not of the same length."

        if args.with_prior_preservation:
            class_data_dir = args.class_data_dir.split(",")
            class_prompt = args.class_prompt.split(",")
            assert all(
                x == len(instance_data_dir)
                for x in [len(instance_data_dir), len(instance_prompt), len(class_data_dir), len(class_prompt)]
            ), "Instance & class data dir or prompt inputs are not of the same length."

        if args.validation_steps:
            validation_prompts = args.validation_prompt.split(",")
            num_of_validation_prompts = len(validation_prompts)
            args.validation_prompt = validation_prompts
            args.validation_number_images = [args.validation_number_images] * num_of_validation_prompts

            negative_validation_prompts = [None] * num_of_validation_prompts
            if args.validation_negative_prompt:
                negative_validation_prompts = args.validation_negative_prompt.split(",")
                while len(negative_validation_prompts) < num_of_validation_prompts:
                    negative_validation_prompts.append(None)
            args.validation_negative_prompt = negative_validation_prompts

            assert num_of_validation_prompts == len(
                negative_validation_prompts
            ), "The length of negative prompts for validation is greater than the number of validation prompts."
            args.validation_inference_steps = [args.validation_inference_steps] * num_of_validation_prompts
            args.validation_guidance_scale = [args.validation_guidance_scale] * num_of_validation_prompts

    # Make one log on every process with the configuration for debugging.
    logging.basicConfig(
        format="%(asctime)s - %(levelname)s - %(name)s - %(message)s",
        datefmt="%m/%d/%Y %H:%M:%S",
        level=logging.INFO,
    )
    logger.info(accelerator.state, main_process_only=False)
    if accelerator.is_local_main_process:
        datasets.utils.logging.set_verbosity_warning()
        transformers.utils.logging.set_verbosity_warning()
        diffusers.utils.logging.set_verbosity_info()
    else:
        datasets.utils.logging.set_verbosity_error()
        transformers.utils.logging.set_verbosity_error()
        diffusers.utils.logging.set_verbosity_error()

    # If passed along, set the training seed now.
    if args.seed is not None:
        set_seed(args.seed)

    # Generate class images if prior preservation is enabled.
    if args.with_prior_preservation:
        for i in range(len(class_data_dir)):
            class_images_dir = Path(class_data_dir[i])
            if not class_images_dir.exists():
                class_images_dir.mkdir(parents=True)
            cur_class_images = len(list(class_images_dir.iterdir()))

            if cur_class_images < args.num_class_images:
                torch_dtype = torch.float16 if accelerator.device.type == "cuda" else torch.float32
                if args.prior_generation_precision == "fp32":
                    torch_dtype = torch.float32
                elif args.prior_generation_precision == "fp16":
                    torch_dtype = torch.float16
                elif args.prior_generation_precision == "bf16":
                    torch_dtype = torch.bfloat16
                pipeline = DiffusionPipeline.from_pretrained(
                    args.pretrained_model_name_or_path,
                    torch_dtype=torch_dtype,
                    safety_checker=None,
                    revision=args.revision,
                )
                pipeline.set_progress_bar_config(disable=True)

                num_new_images = args.num_class_images - cur_class_images
                logger.info(f"Number of class images to sample: {num_new_images}.")

                sample_dataset = PromptDataset(class_prompt[i], num_new_images)
                sample_dataloader = torch.utils.data.DataLoader(sample_dataset, batch_size=args.sample_batch_size)

                sample_dataloader = accelerator.prepare(sample_dataloader)
                pipeline.to(accelerator.device)

                for example in tqdm(
                    sample_dataloader, desc="Generating class images", disable=not accelerator.is_local_main_process
                ):
                    images = pipeline(example["prompt"]).images

                    for ii, image in enumerate(images):
                        hash_image = insecure_hashlib.sha1(image.tobytes()).hexdigest()
                        image_filename = (
                            class_images_dir / f"{example['index'][ii] + cur_class_images}-{hash_image}.jpg"
                        )
                        image.save(image_filename)

                # Clean up the memory deleting one-time-use variables.
                del pipeline
                del sample_dataloader
                del sample_dataset
                if torch.cuda.is_available():
                    torch.cuda.empty_cache()

    # Handle the repository creation
    if accelerator.is_main_process:
        if args.output_dir is not None:
            makedirs(args.output_dir, exist_ok=True)

        if args.push_to_hub:
            repo_id = create_repo(
                repo_id=args.hub_model_id or Path(args.output_dir).name, exist_ok=True, token=args.hub_token
            ).repo_id

    # Load the tokenizer
    tokenizer = None
    if args.tokenizer_name:
        tokenizer = AutoTokenizer.from_pretrained(args.tokenizer_name, revision=args.revision, use_fast=False)
    elif args.pretrained_model_name_or_path:
        tokenizer = AutoTokenizer.from_pretrained(
            args.pretrained_model_name_or_path,
            subfolder="tokenizer",
            revision=args.revision,
            use_fast=False,
        )

    # import correct text encoder class
    text_encoder_cls = import_model_class_from_model_name_or_path(args.pretrained_model_name_or_path, args.revision)

    # Load scheduler and models
    noise_scheduler = DDPMScheduler.from_pretrained(args.pretrained_model_name_or_path, subfolder="scheduler")
    text_encoder = text_encoder_cls.from_pretrained(
        args.pretrained_model_name_or_path, subfolder="text_encoder", revision=args.revision
    )
    vae = AutoencoderKL.from_pretrained(args.pretrained_model_name_or_path, subfolder="vae", revision=args.revision)
    unet = UNet2DConditionModel.from_pretrained(
        args.pretrained_model_name_or_path, subfolder="unet", revision=args.revision
    )

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

    if args.enable_xformers_memory_efficient_attention:
        if is_xformers_available():
            unet.enable_xformers_memory_efficient_attention()
        else:
            raise ValueError("xformers is not available. Make sure it is installed correctly")

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

    # Enable TF32 for faster training on Ampere GPUs,
    # cf https://pytorch.org/docs/stable/notes/cuda.html#tensorfloat-32-tf32-on-ampere-devices
    if args.allow_tf32:
        torch.backends.cuda.matmul.allow_tf32 = True

    if args.scale_lr:
        args.learning_rate = (
            args.learning_rate * args.gradient_accumulation_steps * args.train_batch_size * accelerator.num_processes
        )

    # Use 8-bit Adam for lower memory usage or to fine-tune the model in 16GB GPUs
    if args.use_8bit_adam:
        try:
            import bitsandbytes as bnb
        except ImportError:
            raise ImportError(
                "To use 8-bit Adam, please install the bitsandbytes library: `pip install bitsandbytes`."
            )

        optimizer_class = bnb.optim.AdamW8bit
    else:
        optimizer_class = torch.optim.AdamW

    # Optimizer creation
    params_to_optimize = (
        itertools.chain(unet.parameters(), text_encoder.parameters()) if args.train_text_encoder else unet.parameters()
    )
    optimizer = optimizer_class(
        params_to_optimize,
        lr=args.learning_rate,
        betas=(args.adam_beta1, args.adam_beta2),
        weight_decay=args.adam_weight_decay,
        eps=args.adam_epsilon,
    )

    # Dataset and DataLoaders creation:
    train_dataset = DreamBoothDataset(
        instance_data_root=instance_data_dir,
        instance_prompt=instance_prompt,
        class_data_root=class_data_dir,
        class_prompt=class_prompt,
        tokenizer=tokenizer,
        size=args.resolution,
        center_crop=args.center_crop,
    )

    train_dataloader = torch.utils.data.DataLoader(
        train_dataset,
        batch_size=args.train_batch_size,
        shuffle=True,
        collate_fn=lambda examples: collate_fn(len(instance_data_dir), examples, args.with_prior_preservation),
        num_workers=1,
    )

    # Scheduler and math around the number of training steps.
    overrode_max_train_steps = False
    num_update_steps_per_epoch = math.ceil(len(train_dataloader) / args.gradient_accumulation_steps)
    if args.max_train_steps is None:
        args.max_train_steps = args.num_train_epochs * num_update_steps_per_epoch
        overrode_max_train_steps = True

    lr_scheduler = get_scheduler(
        args.lr_scheduler,
        optimizer=optimizer,
        num_warmup_steps=args.lr_warmup_steps * accelerator.num_processes,
        num_training_steps=args.max_train_steps * accelerator.num_processes,
        num_cycles=args.lr_num_cycles,
        power=args.lr_power,
    )

    # Prepare everything with our `accelerator`.
    if args.train_text_encoder:
        unet, text_encoder, optimizer, train_dataloader, lr_scheduler = accelerator.prepare(
            unet, text_encoder, optimizer, train_dataloader, lr_scheduler
        )
    else:
        unet, optimizer, train_dataloader, lr_scheduler = accelerator.prepare(
            unet, optimizer, train_dataloader, lr_scheduler
        )

    # For mixed precision training we cast the text_encoder and vae weights to half-precision
    # as these models are only used for inference, keeping weights in full precision is not required.
    weight_dtype = torch.float32
    if accelerator.mixed_precision == "fp16":
        weight_dtype = torch.float16
    elif accelerator.mixed_precision == "bf16":
        weight_dtype = torch.bfloat16

    # Move vae and text_encoder to device and cast to weight_dtype
    vae.to(accelerator.device, dtype=weight_dtype)
    if not args.train_text_encoder:
        text_encoder.to(accelerator.device, dtype=weight_dtype)

    # We need to recalculate our total training steps as the size of the training dataloader may have changed.
    num_update_steps_per_epoch = math.ceil(len(train_dataloader) / args.gradient_accumulation_steps)
    if overrode_max_train_steps:
        args.max_train_steps = args.num_train_epochs * num_update_steps_per_epoch
    # Afterwards we recalculate our number of training epochs
    args.num_train_epochs = math.ceil(args.max_train_steps / num_update_steps_per_epoch)

    # We need to initialize the trackers we use, and also store our configuration.
    # The trackers initialize automatically on the main process.
    if accelerator.is_main_process:
        accelerator.init_trackers("dreambooth", config=vars(args))

    # Train!
    total_batch_size = args.train_batch_size * accelerator.num_processes * args.gradient_accumulation_steps

    logger.info("***** Running training *****")
    logger.info(f"  Num examples = {len(train_dataset)}")
    logger.info(f"  Num batches each epoch = {len(train_dataloader)}")
    logger.info(f"  Num Epochs = {args.num_train_epochs}")
    logger.info(f"  Instantaneous batch size per device = {args.train_batch_size}")
    logger.info(f"  Total train batch size (w. parallel, distributed & accumulation) = {total_batch_size}")
    logger.info(f"  Gradient Accumulation steps = {args.gradient_accumulation_steps}")
    logger.info(f"  Total optimization steps = {args.max_train_steps}")
    global_step = 0
    first_epoch = 0

    # Potentially load in the weights and states from a previous save
    if args.resume_from_checkpoint:
        if args.resume_from_checkpoint != "latest":
            path = basename(args.resume_from_checkpoint)
        else:
            # Get the mos recent checkpoint
            dirs = listdir(args.output_dir)
            dirs = [d for d in dirs if d.startswith("checkpoint")]
            dirs = sorted(dirs, key=lambda x: int(x.split("-")[1]))
            path = dirs[-1] if len(dirs) > 0 else None

        if path is None:
            accelerator.print(
                f"Checkpoint '{args.resume_from_checkpoint}' does not exist. Starting a new training run."
            )
            args.resume_from_checkpoint = None
        else:
            accelerator.print(f"Resuming from checkpoint {path}")
            accelerator.load_state(join(args.output_dir, path))
            global_step = int(path.split("-")[1])

            resume_global_step = global_step * args.gradient_accumulation_steps
            first_epoch = global_step // num_update_steps_per_epoch
            resume_step = resume_global_step % (num_update_steps_per_epoch * args.gradient_accumulation_steps)

    # Only show the progress bar once on each machine.
    progress_bar = tqdm(range(global_step, args.max_train_steps), disable=not accelerator.is_local_main_process)
    progress_bar.set_description("Steps")

    for epoch in range(first_epoch, args.num_train_epochs):
        unet.train()
        if args.train_text_encoder:
            text_encoder.train()
        for step, batch in enumerate(train_dataloader):
            # Skip steps until we reach the resumed step
            if args.resume_from_checkpoint and epoch == first_epoch and step < resume_step:
                if step % args.gradient_accumulation_steps == 0:
                    progress_bar.update(1)
                continue

            with accelerator.accumulate(unet):
                # Convert images to latent space
                latents = vae.encode(batch["pixel_values"].to(dtype=weight_dtype)).latent_dist.sample()
                latents = latents * vae.config.scaling_factor

                # Sample noise that we'll add to the latents
                noise = torch.randn_like(latents)
                bsz = latents.shape[0]
                # Sample a random timestep for each image
                time_steps = torch.randint(
                    0, noise_scheduler.config.num_train_timesteps, (bsz,), device=latents.device
                )
                time_steps = time_steps.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, time_steps)

                # Get the text embedding for conditioning
                encoder_hidden_states = text_encoder(batch["input_ids"])[0]

                # Predict the noise residual
                model_pred = unet(noisy_latents, time_steps, encoder_hidden_states).sample

                # Get the target for loss depending on the prediction type
                if noise_scheduler.config.prediction_type == "epsilon":
                    target = noise
                elif noise_scheduler.config.prediction_type == "v_prediction":
                    target = noise_scheduler.get_velocity(latents, noise, time_steps)
                else:
                    raise ValueError(f"Unknown prediction type {noise_scheduler.config.prediction_type}")

                if args.with_prior_preservation:
                    # Chunk the noise and model_pred into two parts and compute the loss on each part separately.
                    model_pred, model_pred_prior = torch.chunk(model_pred, 2, dim=0)
                    target, target_prior = torch.chunk(target, 2, dim=0)

                    # Compute instance loss
                    loss = F.mse_loss(model_pred.float(), target.float(), reduction="mean")

                    # Compute prior loss
                    prior_loss = F.mse_loss(model_pred_prior.float(), target_prior.float(), reduction="mean")

                    # Add the prior loss to the instance loss.
                    loss = loss + args.prior_loss_weight * prior_loss
                else:
                    loss = F.mse_loss(model_pred.float(), target.float(), reduction="mean")

                accelerator.backward(loss)
                if accelerator.sync_gradients:
                    params_to_clip = (
                        itertools.chain(unet.parameters(), text_encoder.parameters())
                        if args.train_text_encoder
                        else unet.parameters()
                    )
                    accelerator.clip_grad_norm_(params_to_clip, args.max_grad_norm)
                optimizer.step()
                lr_scheduler.step()
                optimizer.zero_grad(set_to_none=args.set_grads_to_none)

            # Checks if the accelerator has performed an optimization step behind the scenes
            if accelerator.sync_gradients:
                progress_bar.update(1)
                global_step += 1

                if accelerator.is_main_process:
                    if global_step % args.checkpointing_steps == 0:
                        save_path = join(args.output_dir, f"checkpoint-{global_step}")
                        accelerator.save_state(save_path)
                        logger.info(f"Saved state to {save_path}")

                    if (
                        args.validation_steps
                        and any(args.validation_prompt)
                        and global_step % args.validation_steps == 0
                    ):
                        images_set = generate_validation_images(
                            text_encoder, tokenizer, unet, vae, args, accelerator, weight_dtype
                        )
                        for images, validation_prompt in zip(images_set, args.validation_prompt):
                            if len(images) > 0:
                                label = str(uuid.uuid1())[:8]  # generate an id for different set of images
                                log_validation_images_to_tracker(
                                    images, label, validation_prompt, accelerator, global_step
                                )

            logs = {"loss": loss.detach().item(), "lr": lr_scheduler.get_last_lr()[0]}
            progress_bar.set_postfix(**logs)
            accelerator.log(logs, step=global_step)

            if global_step >= args.max_train_steps:
                break

    # Create the pipeline using the trained modules and save it.
    accelerator.wait_for_everyone()
    if accelerator.is_main_process:
        pipeline = DiffusionPipeline.from_pretrained(
            args.pretrained_model_name_or_path,
            unet=accelerator.unwrap_model(unet),
            text_encoder=accelerator.unwrap_model(text_encoder),
            revision=args.revision,
        )
        pipeline.save_pretrained(args.output_dir)

        if args.push_to_hub:
            upload_folder(
                repo_id=repo_id,
                folder_path=args.output_dir,
                commit_message="End of training",
                ignore_patterns=["step_*", "epoch_*"],
            )

    accelerator.end_training()


if __name__ == "__main__":
    args = parse_args()
    main(args)
