# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project

import inspect
import json
import logging
import math
import os
from collections.abc import Iterable
from typing import Any, cast

import numpy as np
import PIL.Image
import torch
from diffusers.image_processor import VaeImageProcessor
from diffusers.models.autoencoders.autoencoder_kl_qwenimage import (
    AutoencoderKLQwenImage,
)
from diffusers.schedulers.scheduling_flow_match_euler_discrete import (
    FlowMatchEulerDiscreteScheduler,
)
from diffusers.utils.torch_utils import randn_tensor
from torch import nn
from transformers import Qwen2_5_VLForConditionalGeneration, Qwen2Tokenizer, Qwen2VLProcessor
from vllm.model_executor.models.utils import AutoWeightsLoader

from vllm_omni.diffusion.data import DiffusionOutput, OmniDiffusionConfig
from vllm_omni.diffusion.distributed.utils import get_local_device
from vllm_omni.diffusion.model_loader.diffusers_loader import DiffusersPipelineLoader
from vllm_omni.diffusion.models.interface import SupportImageInput
from vllm_omni.diffusion.models.qwen_image.cfg_parallel import (
    QwenImageCFGParallelMixin,
)
from vllm_omni.diffusion.models.qwen_image.pipeline_qwen_image import calculate_shift
from vllm_omni.diffusion.models.qwen_image.qwen_image_transformer import (
    QwenImageTransformer2DModel,
)
from vllm_omni.diffusion.request import OmniDiffusionRequest
from vllm_omni.diffusion.utils.tf_utils import get_transformer_config_kwargs
from vllm_omni.inputs.data import OmniTextPrompt
from vllm_omni.model_executor.model_loader.weight_utils import (
    download_weights_from_hf_specific,
)

logger = logging.getLogger(__name__)


def get_qwen_image_edit_pre_process_func(
    od_config: OmniDiffusionConfig,
):
    """Pre-processing function for QwenImageEditPipeline."""
    model_name = od_config.model
    if os.path.exists(model_name):
        model_path = model_name
    else:
        model_path = download_weights_from_hf_specific(model_name, None, ["*"])
    vae_config_path = os.path.join(model_path, "vae/config.json")
    with open(vae_config_path) as f:
        vae_config = json.load(f)
        vae_scale_factor = 2 ** len(vae_config["temporal_downsample"]) if "temporal_downsample" in vae_config else 8

    image_processor = VaeImageProcessor(vae_scale_factor=vae_scale_factor * 2, do_convert_rgb=True)
    latent_channels = vae_config.get("z_dim", 16)

    def pre_process_func(
        request: OmniDiffusionRequest,
    ):
        """Pre-process requests for QwenImageEditPipeline."""
        for i, prompt in enumerate(request.prompts):
            multi_modal_data = prompt.get("multi_modal_data", {}) if not isinstance(prompt, str) else None
            raw_image = multi_modal_data.get("image", None) if multi_modal_data is not None else None
            if isinstance(prompt, str):
                prompt = OmniTextPrompt(prompt=prompt)
            if "additional_information" not in prompt:
                prompt["additional_information"] = {}

            # Only handles single image
            if not raw_image:  # None or empty list
                raise ValueError("""Received no input image. This model requires one input image to run.""")
            elif isinstance(raw_image, list):
                if len(raw_image) > 1:
                    raise ValueError(
                        """Received multiple input images. Only a single image is supported by this model."""
                    )
                else:
                    raw_image = raw_image[0]

            if isinstance(raw_image, str):
                image = PIL.Image.open(raw_image)
            else:
                image = cast(PIL.Image.Image | torch.Tensor | np.ndarray, raw_image)

            image_size = image.size
            calculated_width, calculated_height = calculate_dimensions(1024 * 1024, image_size[0] / image_size[1])
            height = request.sampling_params.height or calculated_height
            width = request.sampling_params.width or calculated_width

            # Ensure dimensions are multiples of vae_scale_factor * 2
            multiple_of = vae_scale_factor * 2
            height = height // multiple_of * multiple_of
            width = width // multiple_of * multiple_of

            # Store calculated dimensions in request
            prompt["additional_information"]["calculated_height"] = calculated_height
            prompt["additional_information"]["calculated_width"] = calculated_width
            request.sampling_params.height = height
            request.sampling_params.width = width

            # Preprocess image
            if image is not None and not (
                isinstance(image, torch.Tensor) and len(image.shape) > 1 and image.shape[1] == latent_channels
            ):
                image = image_processor.resize(image, calculated_height, calculated_width)
                prompt_image = image
                image = image_processor.preprocess(image, calculated_height, calculated_width)
                image = image.unsqueeze(2)

                # Store preprocessed image and prompt image in request
                prompt["additional_information"]["preprocessed_image"] = image
                prompt["additional_information"]["prompt_image"] = prompt_image
            request.prompts[i] = prompt
        return request

    return pre_process_func


def get_qwen_image_edit_post_process_func(
    od_config: OmniDiffusionConfig,
):
    """Post-processing function for QwenImageEditPipeline."""
    model_name = od_config.model
    if os.path.exists(model_name):
        model_path = model_name
    else:
        model_path = download_weights_from_hf_specific(model_name, None, ["*"])
    vae_config_path = os.path.join(model_path, "vae/config.json")
    with open(vae_config_path) as f:
        vae_config = json.load(f)
        vae_scale_factor = 2 ** len(vae_config["temporal_downsample"]) if "temporal_downsample" in vae_config else 8

    image_processor = VaeImageProcessor(vae_scale_factor=vae_scale_factor * 2, do_convert_rgb=True)

    def post_process_func(
        images: torch.Tensor,
    ):
        return image_processor.postprocess(images)

    return post_process_func


def calculate_dimensions(target_area: float, ratio: float):
    """Calculate width and height from target area and aspect ratio."""
    width = math.sqrt(target_area * ratio)
    height = width / ratio

    width = round(width / 32) * 32
    height = round(height / 32) * 32

    return width, height


def retrieve_timesteps(
    scheduler,
    num_inference_steps: int | None = None,
    device: str | torch.device | None = None,
    timesteps: list[int] | None = None,
    sigmas: list[float] | None = None,
    **kwargs,
) -> tuple[torch.Tensor, int]:
    r"""
    Calls the scheduler's `set_timesteps` method and retrieves timesteps from the scheduler after the call. Handles
    custom timesteps. Any kwargs will be supplied to `scheduler.set_timesteps`.
    """
    if timesteps is not None and sigmas is not None:
        raise ValueError("Only one of `timesteps` or `sigmas` can be passed. Please choose one to set custom values")
    if timesteps is not None:
        accepts_timesteps = "timesteps" in set(inspect.signature(scheduler.set_timesteps).parameters.keys())
        if not accepts_timesteps:
            raise ValueError(
                f"The current scheduler class {scheduler.__class__}'s `set_timesteps` does not support custom"
                f" timestep schedules. Please check whether you are using the correct scheduler."
            )
        scheduler.set_timesteps(timesteps=timesteps, device=device, **kwargs)
        timesteps = scheduler.timesteps
        num_inference_steps = len(timesteps)
    elif sigmas is not None:
        accept_sigmas = "sigmas" in set(inspect.signature(scheduler.set_timesteps).parameters.keys())
        if not accept_sigmas:
            raise ValueError(
                f"The current scheduler class {scheduler.__class__}'s `set_timesteps` does not support custom"
                f" sigmas schedules. Please check whether you are using the correct scheduler."
            )
        scheduler.set_timesteps(sigmas=sigmas, device=device, **kwargs)
        timesteps = scheduler.timesteps
        num_inference_steps = len(timesteps)
    else:
        scheduler.set_timesteps(num_inference_steps, device=device, **kwargs)
        timesteps = scheduler.timesteps
    return timesteps, num_inference_steps


def retrieve_latents(
    encoder_output: torch.Tensor, generator: torch.Generator | None = None, sample_mode: str = "argmax"
):
    """Retrieve latents from VAE encoder output."""
    if hasattr(encoder_output, "latent_dist"):
        return (
            encoder_output.latent_dist.mode()
            if sample_mode == "argmax"
            else encoder_output.latent_dist.sample(generator)
        )
    elif hasattr(encoder_output, "latents"):
        return encoder_output.latents
    else:
        raise AttributeError("Could not access latents of provided encoder_output")


class QwenImageEditPipeline(nn.Module, SupportImageInput, QwenImageCFGParallelMixin):
    def __init__(
        self,
        *,
        od_config: OmniDiffusionConfig,
        prefix: str = "",
    ):
        super().__init__()
        self.od_config = od_config
        self.weights_sources = [
            DiffusersPipelineLoader.ComponentSource(
                model_or_path=od_config.model,
                subfolder="transformer",
                revision=None,
                prefix="transformer.",
                fall_back_to_pt=True,
            )
        ]
        self.device = get_local_device()
        model = od_config.model

        # Check if model is a local path
        local_files_only = os.path.exists(model)

        self.scheduler = FlowMatchEulerDiscreteScheduler.from_pretrained(
            model, subfolder="scheduler", local_files_only=local_files_only
        )
        self.text_encoder = Qwen2_5_VLForConditionalGeneration.from_pretrained(
            model, subfolder="text_encoder", local_files_only=local_files_only
        )

        self.vae = AutoencoderKLQwenImage.from_pretrained(model, subfolder="vae", local_files_only=local_files_only).to(
            self.device
        )
        transformer_kwargs = get_transformer_config_kwargs(od_config.tf_model_config, QwenImageTransformer2DModel)
        self.transformer = QwenImageTransformer2DModel(od_config=od_config, **transformer_kwargs)
        self.tokenizer = Qwen2Tokenizer.from_pretrained(model, subfolder="tokenizer", local_files_only=local_files_only)
        self.processor = Qwen2VLProcessor.from_pretrained(
            model, subfolder="processor", local_files_only=local_files_only
        )

        self.stage = None

        self.vae_scale_factor = 2 ** len(self.vae.temperal_downsample) if getattr(self, "vae", None) else 8
        self.latent_channels = self.vae.config.z_dim if getattr(self, "vae", None) else 16
        self.image_processor = VaeImageProcessor(vae_scale_factor=self.vae_scale_factor * 2, do_convert_rgb=True)
        self.tokenizer_max_length = 1024
        # Edit prompt template - different from generation template
        self.prompt_template_encode = "<|im_start|>system\nDescribe the key features of the input image (color, shape, size, texture, objects, background), then explain how the user's text instruction should alter or modify the image. Generate a new image that meets the user's requirements while maintaining consistency with the original input where appropriate.<|im_end|>\n<|im_start|>user\n<|vision_start|><|image_pad|><|vision_end|>{}<|im_end|>\n<|im_start|>assistant\n"  # noqa: E501
        self.prompt_template_encode_start_idx = 64
        self.default_sample_size = 128

    def check_inputs(
        self,
        prompt,
        height,
        width,
        image=None,
        negative_prompt=None,
        prompt_embeds=None,
        negative_prompt_embeds=None,
        prompt_embeds_mask=None,
        negative_prompt_embeds_mask=None,
        callback_on_step_end_tensor_inputs=None,
        max_sequence_length=None,
    ):
        if height % (self.vae_scale_factor * 2) != 0 or width % (self.vae_scale_factor * 2) != 0:
            logger.warning(
                f"`height` and `width` have to be divisible by {self.vae_scale_factor * 2} "
                f"but are {height} and {width}. Dimensions will be resized accordingly"
            )

        if prompt is not None and prompt_embeds is not None:
            raise ValueError(
                f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"
                " only forward one of the two."
            )
        elif prompt is None and prompt_embeds is None:
            raise ValueError(
                "Provide either `prompt` or `prompt_embeds`. Cannot leave both `prompt` and `prompt_embeds` undefined."
            )
        elif prompt is not None and (not isinstance(prompt, str) and not isinstance(prompt, list)):
            raise ValueError(f"`prompt` has to be of type `str` or `list` but is {type(prompt)}")

        if negative_prompt is not None and negative_prompt_embeds is not None:
            raise ValueError(
                f"Cannot forward both `negative_prompt`: {negative_prompt} and `negative_prompt_embeds`:"
                f" {negative_prompt_embeds}. Make sure to only forward one of the two."
            )

        if prompt_embeds is not None and prompt_embeds_mask is None:
            raise ValueError(
                "If `prompt_embeds` are provided, `prompt_embeds_mask` also have to be passed. "
                "Make sure to generate `prompt_embeds_mask` from the same text encoder "
                "that was used to generate `prompt_embeds`."
            )
        if negative_prompt_embeds is not None and negative_prompt_embeds_mask is None:
            raise ValueError(
                "If `negative_prompt_embeds` are provided, `negative_prompt_embeds_mask` also have to be passed. "
                "Make sure to generate `negative_prompt_embeds_mask` from the same text encoder "
                "that was used to generate `negative_prompt_embeds`."
            )

        if max_sequence_length is not None and max_sequence_length > 1024:
            raise ValueError(f"`max_sequence_length` cannot be greater than 1024 but is {max_sequence_length}")

    def _extract_masked_hidden(self, hidden_states: torch.Tensor, mask: torch.Tensor):
        bool_mask = mask.bool()
        valid_lengths = bool_mask.sum(dim=1)
        selected = hidden_states[bool_mask]
        split_result = torch.split(selected, valid_lengths.tolist(), dim=0)

        return split_result

    def _get_qwen_prompt_embeds(
        self,
        prompt: str | list[str] = None,
        image: torch.Tensor | None = None,
        dtype: torch.dtype | None = None,
    ):
        dtype = dtype or self.text_encoder.dtype

        prompt = [prompt] if isinstance(prompt, str) else prompt

        template = self.prompt_template_encode
        drop_idx = self.prompt_template_encode_start_idx
        txt = [template.format(e) for e in prompt]

        model_inputs = self.processor(
            text=txt,
            images=image,
            padding=True,
            return_tensors="pt",
        ).to(self.device)

        outputs = self.text_encoder(
            input_ids=model_inputs.input_ids,
            attention_mask=model_inputs.attention_mask,
            pixel_values=model_inputs.pixel_values,
            image_grid_thw=model_inputs.image_grid_thw,
            output_hidden_states=True,
        )

        hidden_states = outputs.hidden_states[-1]
        split_hidden_states = self._extract_masked_hidden(hidden_states, model_inputs.attention_mask)
        split_hidden_states = [e[drop_idx:] for e in split_hidden_states]
        attn_mask_list = [torch.ones(e.size(0), dtype=torch.long, device=e.device) for e in split_hidden_states]
        max_seq_len = max([e.size(0) for e in split_hidden_states])
        prompt_embeds = torch.stack(
            [torch.cat([u, u.new_zeros(max_seq_len - u.size(0), u.size(1))]) for u in split_hidden_states]
        )
        encoder_attention_mask = torch.stack(
            [torch.cat([u, u.new_zeros(max_seq_len - u.size(0))]) for u in attn_mask_list]
        )

        prompt_embeds = prompt_embeds.to(dtype=dtype, device=self.device)

        return prompt_embeds, encoder_attention_mask

    def _get_qwen_prompt_embeds(
        self,
        prompt: str | list[str] = None,
        image: PIL.Image.Image | torch.Tensor | None = None,
        dtype: torch.dtype | None = None,
    ):
        """Get prompt embeddings with image support for editing."""
        dtype = dtype or self.text_encoder.dtype

        prompt = [prompt] if isinstance(prompt, str) else prompt

        template = self.prompt_template_encode
        drop_idx = self.prompt_template_encode_start_idx
        txt = [template.format(e) for e in prompt]

        # Use processor to handle both text and image inputs
        model_inputs = self.processor(
            text=txt,
            images=image,
            padding=True,
            return_tensors="pt",
        ).to(self.device)

        outputs = self.text_encoder(
            input_ids=model_inputs.input_ids,
            attention_mask=model_inputs.attention_mask,
            pixel_values=model_inputs.pixel_values,
            image_grid_thw=model_inputs.image_grid_thw,
            output_hidden_states=True,
        )

        hidden_states = outputs.hidden_states[-1]
        split_hidden_states = self._extract_masked_hidden(hidden_states, model_inputs.attention_mask)
        split_hidden_states = [e[drop_idx:] for e in split_hidden_states]
        attn_mask_list = [torch.ones(e.size(0), dtype=torch.long, device=e.device) for e in split_hidden_states]
        max_seq_len = max([e.size(0) for e in split_hidden_states])
        prompt_embeds = torch.stack(
            [torch.cat([u, u.new_zeros(max_seq_len - u.size(0), u.size(1))]) for u in split_hidden_states]
        )
        encoder_attention_mask = torch.stack(
            [torch.cat([u, u.new_zeros(max_seq_len - u.size(0))]) for u in attn_mask_list]
        )

        prompt_embeds = prompt_embeds.to(dtype=dtype)

        return prompt_embeds, encoder_attention_mask

    def encode_prompt(
        self,
        prompt: str | list[str],
        image: torch.Tensor | None = None,
        num_images_per_prompt: int = 1,
        prompt_embeds: torch.Tensor | None = None,
        prompt_embeds_mask: torch.Tensor | None = None,
        max_sequence_length: int = 1024,
    ):
        r"""

        Args:
            prompt (`str` or `list[str]`, *optional*):
                prompt to be encoded
            image (`torch.Tensor`, *optional*):
                image to be encoded
            num_images_per_prompt (`int`):
                number of images that should be generated per prompt
            prompt_embeds (`torch.Tensor`, *optional*):
                Pre-generated text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not
                provided, text embeddings will be generated from `prompt` input argument.
        """

        prompt = [prompt] if isinstance(prompt, str) else prompt
        batch_size = len(prompt) if prompt_embeds is None else prompt_embeds.shape[0]

        if prompt_embeds is None:
            prompt_embeds, prompt_embeds_mask = self._get_qwen_prompt_embeds(prompt, image)

        _, seq_len, _ = prompt_embeds.shape
        prompt_embeds = prompt_embeds.repeat(1, num_images_per_prompt, 1)
        prompt_embeds = prompt_embeds.view(batch_size * num_images_per_prompt, seq_len, -1)
        prompt_embeds_mask = prompt_embeds_mask.repeat(1, num_images_per_prompt, 1)
        prompt_embeds_mask = prompt_embeds_mask.view(batch_size * num_images_per_prompt, seq_len)

        return prompt_embeds, prompt_embeds_mask

    @staticmethod
    def _pack_latents(latents, batch_size, num_channels_latents, height, width):
        latents = latents.view(batch_size, num_channels_latents, height // 2, 2, width // 2, 2)
        latents = latents.permute(0, 2, 4, 1, 3, 5)
        latents = latents.reshape(batch_size, (height // 2) * (width // 2), num_channels_latents * 4)

        return latents

    @staticmethod
    def _unpack_latents(latents, height, width, vae_scale_factor):
        batch_size, num_patches, channels = latents.shape

        # VAE applies 8x compression on images but we must also account for packing which requires
        # latent height and width to be divisible by 2.
        height = 2 * (int(height) // (vae_scale_factor * 2))
        width = 2 * (int(width) // (vae_scale_factor * 2))

        latents = latents.view(batch_size, height // 2, width // 2, channels // 4, 2, 2)
        latents = latents.permute(0, 3, 1, 4, 2, 5)

        latents = latents.reshape(batch_size, channels // (2 * 2), 1, height, width)

        return latents

    def _encode_vae_image(self, image: torch.Tensor, generator: torch.Generator):
        if isinstance(generator, list):
            image_latents = [
                retrieve_latents(self.vae.encode(image[i : i + 1]), generator=generator[i], sample_mode="argmax")
                for i in range(image.shape[0])
            ]
            image_latents = torch.cat(image_latents, dim=0)
        else:
            image_latents = retrieve_latents(self.vae.encode(image), generator=generator, sample_mode="argmax")
        latents_mean = (
            torch.tensor(self.vae.config.latents_mean)
            .view(1, self.latent_channels, 1, 1, 1)
            .to(image_latents.device, image_latents.dtype)
        )
        latents_std = (
            torch.tensor(self.vae.config.latents_std)
            .view(1, self.latent_channels, 1, 1, 1)
            .to(image_latents.device, image_latents.dtype)
        )
        image_latents = (image_latents - latents_mean) / latents_std

        return image_latents

    def prepare_latents(
        self,
        image,
        batch_size,
        num_channels_latents,
        height,
        width,
        dtype,
        device,
        generator,
        latents=None,
    ):
        # VAE applies 8x compression on images but we must also account for packing which requires
        # latent height and width to be divisible by 2.
        height = 2 * (int(height) // (self.vae_scale_factor * 2))
        width = 2 * (int(width) // (self.vae_scale_factor * 2))

        shape = (batch_size, 1, num_channels_latents, height, width)

        image_latents = None
        if image is not None:
            image = image.to(device=device, dtype=dtype)
            if image.shape[1] != self.latent_channels:
                image_latents = self._encode_vae_image(image=image, generator=generator)
            else:
                image_latents = image
            if batch_size > image_latents.shape[0] and batch_size % image_latents.shape[0] == 0:
                # expand init_latents for batch_size
                additional_image_per_prompt = batch_size // image_latents.shape[0]
                image_latents = torch.cat([image_latents] * additional_image_per_prompt, dim=0)
            elif batch_size > image_latents.shape[0] and batch_size % image_latents.shape[0] != 0:
                raise ValueError(
                    f"Cannot duplicate `image` of batch size {image_latents.shape[0]} to {batch_size} text prompts."
                )
            else:
                image_latents = torch.cat([image_latents], dim=0)

            image_latent_height, image_latent_width = image_latents.shape[3:]
            image_latents = self._pack_latents(
                image_latents, batch_size, num_channels_latents, image_latent_height, image_latent_width
            )

        if isinstance(generator, list) and len(generator) != batch_size:
            raise ValueError(
                f"You have passed a list of generators of length {len(generator)}, but requested an effective batch"
                f" size of {batch_size}. Make sure the batch size matches the length of the generators."
            )
        if latents is None:
            latents = randn_tensor(shape, generator=generator, device=device, dtype=dtype)
            latents = self._pack_latents(latents, batch_size, num_channels_latents, height, width)
        else:
            latents = latents.to(device=device, dtype=dtype)

        return latents, image_latents

    def prepare_timesteps(self, num_inference_steps, sigmas, image_seq_len):
        sigmas = np.linspace(1.0, 1 / num_inference_steps, num_inference_steps) if sigmas is None else sigmas
        mu = calculate_shift(
            image_seq_len,
            self.scheduler.config.get("base_image_seq_len", 256),
            self.scheduler.config.get("max_image_seq_len", 4096),
            self.scheduler.config.get("base_shift", 0.5),
            self.scheduler.config.get("max_shift", 1.15),
        )
        timesteps, num_inference_steps = retrieve_timesteps(
            self.scheduler,
            num_inference_steps,
            sigmas=sigmas,
            mu=mu,
        )
        return timesteps, num_inference_steps

    @property
    def guidance_scale(self):
        return self._guidance_scale

    @property
    def attention_kwargs(self):
        return self._attention_kwargs

    @property
    def num_timesteps(self):
        return self._num_timesteps

    @property
    def current_timestep(self):
        return self._current_timestep

    @property
    def interrupt(self):
        return self._interrupt

    def forward(
        self,
        req: OmniDiffusionRequest,
        prompt: str | list[str] | None = None,
        negative_prompt: str | list[str] | None = None,
        image: PIL.Image.Image | torch.Tensor | None = None,
        true_cfg_scale: float = 4.0,
        height: int | None = None,
        width: int | None = None,
        num_inference_steps: int = 50,
        sigmas: list[float] | None = None,
        guidance_scale: float = 1.0,
        num_images_per_prompt: int = 1,
        generator: torch.Generator | list[torch.Generator] | None = None,
        latents: torch.Tensor | None = None,
        prompt_embeds: torch.Tensor | None = None,
        prompt_embeds_mask: torch.Tensor | None = None,
        negative_prompt_embeds: torch.Tensor | None = None,
        negative_prompt_embeds_mask: torch.Tensor | None = None,
        output_type: str | None = "pil",
        attention_kwargs: dict[str, Any] | None = None,
        callback_on_step_end_tensor_inputs: list[str] = ["latents"],
        max_sequence_length: int = 512,
    ) -> DiffusionOutput:
        """Forward pass for image editing."""
        # TODO: In online mode, sometimes it receives [{"negative_prompt": None}, {...}], so cannot use .get("...", "")
        # TODO: May be some data formatting operations on the API side. Hack for now.
        if len(req.prompts) > 1:
            logger.warning(
                """This model only supports a single prompt, not a batched request.""",
                """Taking only the first image for now.""",
            )
        first_prompt = req.prompts[0]
        prompt = first_prompt if isinstance(first_prompt, str) else (first_prompt.get("prompt") or "")
        negative_prompt = None if isinstance(first_prompt, str) else first_prompt.get("negative_prompt")
        if negative_prompt is None:
            logger.warning(
                "negative_prompt is not set. The official Qwen-Image-Edit model "
                "may produce lower-quality results without a negative_prompt. "
                "Qwen official repository recommends to use whitespace string as negative_prompt. "
                "Note: some distilled variants may not be affected by this."
            )

        # Get preprocessed image from request (pre-processing is done in DiffusionEngine)
        if not isinstance(first_prompt, str) and "preprocessed_image" in (
            additional_information := first_prompt.get("additional_information", {})
        ):
            prompt_image = additional_information.get("prompt_image")
            image = additional_information.get("preprocessed_image")
            calculated_height = additional_information.get("calculated_height")
            calculated_width = additional_information.get("calculated_width")
            height = req.sampling_params.height
            width = req.sampling_params.width
        else:
            # fallback to run pre-processing in pipeline (debug only)
            image_size = image[0].size if isinstance(image, list) else image.size
            calculated_width, calculated_height, _ = calculate_dimensions(1024 * 1024, image_size[0] / image_size[1])
            height = height or calculated_height
            width = width or calculated_width

            multiple_of = self.vae_scale_factor * 2
            width = width // multiple_of * multiple_of
            height = height // multiple_of * multiple_of

            if image is not None and not (isinstance(image, torch.Tensor) and image.size(1) == self.latent_channels):
                image = self.image_processor.resize(image, calculated_height, calculated_width)
                prompt_image = image
                image = self.image_processor.preprocess(image, calculated_height, calculated_width)
                image = image.unsqueeze(2)

        num_inference_steps = req.sampling_params.num_inference_steps or num_inference_steps
        sigmas = req.sampling_params.sigmas or sigmas
        max_sequence_length = req.sampling_params.max_sequence_length or max_sequence_length
        generator = req.sampling_params.generator or generator
        true_cfg_scale = req.sampling_params.true_cfg_scale or true_cfg_scale
        if req.sampling_params.guidance_scale_provided:
            guidance_scale = req.sampling_params.guidance_scale
        num_images_per_prompt = (
            req.sampling_params.num_outputs_per_prompt
            if req.sampling_params.num_outputs_per_prompt > 0
            else num_images_per_prompt
        )

        # 1. check inputs
        # 2. encode prompts
        # 3. prepare latents and timesteps
        # 4. diffusion process
        # 5. decode latents
        # 6. post-process outputs
        self.check_inputs(
            prompt,
            height,
            width,
            image,
            negative_prompt,
            prompt_embeds,
            negative_prompt_embeds,
            prompt_embeds_mask,
            negative_prompt_embeds_mask,
            callback_on_step_end_tensor_inputs,
            max_sequence_length,
        )

        self._guidance_scale = guidance_scale
        self._attention_kwargs = attention_kwargs
        self._current_timestep = None
        self._interrupt = False

        if prompt is not None and isinstance(prompt, str):
            batch_size = 1
        elif prompt is not None and isinstance(prompt, list):
            batch_size = len(prompt)
        else:
            batch_size = prompt_embeds.shape[0]

        has_neg_prompt = negative_prompt is not None or (
            negative_prompt_embeds is not None and negative_prompt_embeds_mask is not None
        )

        do_true_cfg = true_cfg_scale > 1 and has_neg_prompt
        self.check_cfg_parallel_validity(true_cfg_scale, has_neg_prompt)

        prompt_embeds, prompt_embeds_mask = self.encode_prompt(
            prompt=prompt,
            image=prompt_image,  # Use resized image for prompt encoding
            prompt_embeds=prompt_embeds,
            prompt_embeds_mask=prompt_embeds_mask,
            num_images_per_prompt=num_images_per_prompt,
            max_sequence_length=max_sequence_length,
        )

        if do_true_cfg:
            negative_prompt_embeds, negative_prompt_embeds_mask = self.encode_prompt(
                prompt=negative_prompt,
                image=prompt_image,  # Use same resized image for negative prompt encoding
                prompt_embeds=negative_prompt_embeds,
                prompt_embeds_mask=negative_prompt_embeds_mask,
                num_images_per_prompt=num_images_per_prompt,
                max_sequence_length=max_sequence_length,
            )

        num_channels_latents = self.transformer.in_channels // 4
        # random noise latents, and image latents encoded by vae
        latents, image_latents = self.prepare_latents(
            image,
            batch_size * num_images_per_prompt,
            num_channels_latents,
            height,
            width,
            prompt_embeds.dtype,
            self.device,
            generator,
            latents,
        )
        img_shapes = [
            [
                (1, height // self.vae_scale_factor // 2, width // self.vae_scale_factor // 2),
                (1, calculated_height // self.vae_scale_factor // 2, calculated_width // self.vae_scale_factor // 2),
            ]
        ] * batch_size

        timesteps, num_inference_steps = self.prepare_timesteps(num_inference_steps, sigmas, latents.shape[1])
        self._num_timesteps = len(timesteps)

        # handle guidance
        if self.transformer.guidance_embeds:
            guidance = torch.full([1], guidance_scale, dtype=torch.float32)
            guidance = guidance.expand(latents.shape[0])
        else:
            guidance = None

        if self.attention_kwargs is None:
            self._attention_kwargs = {}

        txt_seq_lens = prompt_embeds_mask.sum(dim=1).tolist() if prompt_embeds_mask is not None else None
        negative_txt_seq_lens = (
            negative_prompt_embeds_mask.sum(dim=1).tolist() if negative_prompt_embeds_mask is not None else None
        )

        latents = self.diffuse(
            prompt_embeds,
            prompt_embeds_mask,
            negative_prompt_embeds,
            negative_prompt_embeds_mask,
            latents,
            img_shapes,
            txt_seq_lens,
            negative_txt_seq_lens,
            timesteps,
            do_true_cfg,
            guidance,
            true_cfg_scale,
            image_latents=image_latents,
            cfg_normalize=True,
            additional_transformer_kwargs={
                "return_dict": False,
                "attention_kwargs": self.attention_kwargs,
            },
        )

        self._current_timestep = None
        if output_type == "latent":
            image = latents
        else:
            latents = self._unpack_latents(latents, height, width, self.vae_scale_factor)
            latents = latents.to(self.vae.dtype)
            latents_mean = (
                torch.tensor(self.vae.config.latents_mean)
                .view(1, self.vae.config.z_dim, 1, 1, 1)
                .to(latents.device, latents.dtype)
            )
            latents_std = 1.0 / torch.tensor(self.vae.config.latents_std).view(1, self.vae.config.z_dim, 1, 1, 1).to(
                latents.device, latents.dtype
            )
            latents = latents / latents_std + latents_mean
            image = self.vae.decode(latents, return_dict=False)[0][:, :, 0]

        return DiffusionOutput(output=image)

    def load_weights(self, weights: Iterable[tuple[str, torch.Tensor]]) -> set[str]:
        loader = AutoWeightsLoader(self)
        return loader.load_weights(weights)
