# Last modified: 2025-01-14
#
# Copyright 2025 Ziyang Song, USTC. All rights reserved.
#
# This file has been modified from the original version.
# Original copyright (c) 2023 Bingxin Ke, ETH Zurich. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# --------------------------------------------------------------------------
# If you find this code useful, we kindly ask you to cite our paper in your work.
# Please find bibtex at: https://github.com/indu1ge/DepthMaster#-citation
# More information about the method can be found at https://indu1ge.github.io/DepthMaster_page
# --------------------------------------------------------------------------


from typing import Dict, Optional, Union

import numpy as np
import torch
from diffusers import (
    AutoencoderKL,
    DiffusionPipeline,
    # UNet2DConditionModel,
)
from depthmaster.modules.unet_2d_condition import UNet2DConditionModel
from diffusers.utils import BaseOutput
from PIL import Image
from torch.utils.data import DataLoader, TensorDataset
from torchvision.transforms import InterpolationMode
from torchvision.transforms.functional import pil_to_tensor, resize
from tqdm.auto import tqdm
from transformers import CLIPTextModel, CLIPTokenizer

from .util.image_util import (
    chw2hwc,
    colorize_depth_maps,
    get_tv_resample_method,
    resize_max_res,
)

class DepthMasterDepthOutput(BaseOutput):
    """
    Output class for monocular depth prediction pipeline.

    Args:
        depth_np (`np.ndarray`):
            Predicted depth map, with depth values in the range of [0, 1].
        depth_colored (`PIL.Image.Image`):
            Colorized depth map, with the shape of [3, H, W] and values in [0, 1].
        uncertainty (`None` or `np.ndarray`):
            Uncalibrated uncertainty(MAD, median absolute deviation) coming from ensembling.
    """

    depth_np: np.ndarray
    depth_colored: Union[None, Image.Image]
    uncertainty: Union[None, np.ndarray]


class DepthMasterPipeline(DiffusionPipeline):
    """
    Pipeline for monocular depth estimation using DepthMaster.

    This model inherits from [`DiffusionPipeline`]. Check the superclass documentation for the generic methods the
    library implements for all the pipelines (such as downloading or saving, running on a particular device, etc.)

    Args:
        unet (`UNet2DConditionModel`):
            Conditional U-Net to denoise the depth latent, conditioned on image latent.
        vae (`AutoencoderKL`):
            Variational Auto-Encoder (VAE) Model to encode and decode images and depth maps
            to and from latent representations.
        scheduler (`DDIMScheduler`):
            A scheduler to be used in combination with `unet` to denoise the encoded image latents.
        text_encoder (`CLIPTextModel`):
            Text-encoder, for empty text embedding.
        tokenizer (`CLIPTokenizer`):
            CLIP tokenizer.
        scale_invariant (`bool`, *optional*):
            A model property specifying whether the predicted depth maps are scale-invariant. This value must be set in
            the model config. When used together with the `shift_invariant=True` flag, the model is also called
            "affine-invariant". NB: overriding this value is not supported.
        shift_invariant (`bool`, *optional*):
            A model property specifying whether the predicted depth maps are shift-invariant. This value must be set in
            the model config. When used together with the `scale_invariant=True` flag, the model is also called
            "affine-invariant". NB: overriding this value is not supported.
        default_denoising_steps (`int`, *optional*):
            The minimum number of denoising diffusion steps that are required to produce a prediction of reasonable
            quality with the given model. This value must be set in the model config. When the pipeline is called
            without explicitly setting `num_inference_steps`, the default value is used. This is required to ensure
            reasonable results with various model flavors compatible with the pipeline, such as those relying on very
            short denoising schedules (`LCMScheduler`) and those with full diffusion schedules (`DDIMScheduler`).
        default_processing_resolution (`int`, *optional*):
            The recommended value of the `processing_resolution` parameter of the pipeline. This value must be set in
            the model config. When the pipeline is called without explicitly setting `processing_resolution`, the
            default value is used. This is required to ensure reasonable results with various model flavors trained
            with varying optimal processing resolution values.
    """

    rgb_latent_scale_factor = 0.18215
    depth_latent_scale_factor = 0.18215

    def __init__(
        self,
        unet: UNet2DConditionModel,
        vae: AutoencoderKL,
        text_encoder: CLIPTextModel,
        tokenizer: CLIPTokenizer,
        scale_invariant: Optional[bool] = True,
        shift_invariant: Optional[bool] = True,
        default_processing_resolution: Optional[int] = None,
    ):
        super().__init__()

        # unet = UNet2DConditionModel.from_pretrained('/zssd/szy/Marigold_rgb2d/ckpt/eval/unet')

        self.register_modules(
            unet=unet,
            vae=vae,
            text_encoder=text_encoder,
            tokenizer=tokenizer,
        )
        self.register_to_config(
            scale_invariant=scale_invariant,
            shift_invariant=shift_invariant,
            default_processing_resolution=default_processing_resolution,
        )

        self.scale_invariant = scale_invariant
        self.shift_invariant = shift_invariant
        self.default_processing_resolution = default_processing_resolution

        self.empty_text_embed = None

    @torch.no_grad()
    def __call__(
        self,
        input_image: Union[Image.Image, torch.Tensor],
        processing_res: Optional[int] = None,
        match_input_res: bool = True,
        resample_method: str = "bilinear",
        batch_size: int = 0,
        color_map: str = "Spectral",
        show_progress_bar: bool = True,
    ) -> DepthMasterDepthOutput:
        """
        Function invoked when calling the pipeline.

        Args:
            input_image (`Image`):
                Input RGB (or gray-scale) image.
            processing_res (`int`, *optional*, defaults to `None`):
                Effective processing resolution. When set to `0`, processes at the original image resolution. This
                produces crisper predictions, but may also lead to the overall loss of global context. The default
                value `None` resolves to the optimal value from the model config.
            match_input_res (`bool`, *optional*, defaults to `True`):
                Resize depth prediction to match input resolution.
                Only valid if `processing_res` > 0.
            resample_method: (`str`, *optional*, defaults to `bilinear`):
                Resampling method used to resize images and depth predictions. This can be one of `bilinear`, `bicubic` or `nearest`, defaults to: `bilinear`.
            batch_size (`int`, *optional*, defaults to `0`):
                Inference batch size, no bigger than `num_ensemble`.
                If set to 0, the script will automatically decide the proper batch size.
            show_progress_bar (`bool`, *optional*, defaults to `True`):
                Display a progress bar of diffusion denoising.
            color_map (`str`, *optional*, defaults to `"Spectral"`, pass `None` to skip colorized depth map generation):
                Colormap used to colorize the depth map.
        Returns:
            `DepthMasterDepthOutput`: Output class for DepthMaster monocular depth prediction pipeline, including:
            - **depth_np** (`np.ndarray`) Predicted depth map, with depth values in the range of [0, 1]
            - **depth_colored** (`PIL.Image.Image`) Colorized depth map, with the shape of [3, H, W] and values in [0, 1], None if `color_map` is `None`
        """
        # Model-specific optimal default values leading to fast and reasonable results.
        if processing_res is None:
            processing_res = self.default_processing_resolution

        assert processing_res >= 0

        resample_method: InterpolationMode = get_tv_resample_method(resample_method)

        # ----------------- Image Preprocess -----------------
        # Convert to torch tensor
        if isinstance(input_image, Image.Image):
            input_image = input_image.convert("RGB")
            # convert to torch tensor [H, W, rgb] -> [rgb, H, W]
            rgb = pil_to_tensor(input_image)
            rgb = rgb.unsqueeze(0)  # [1, rgb, H, W]
        elif isinstance(input_image, torch.Tensor):
            rgb = input_image
        else:
            raise TypeError(f"Unknown input type: {type(input_image) = }")
        input_size = rgb.shape
        assert (
            4 == rgb.dim() and 3 == input_size[-3]
        ), f"Wrong input shape {input_size}, expected [1, rgb, H, W]"
        # --------------- Image Processing ------------------------
        # Resize image
        if processing_res > 0:
            rgb = resize_max_res(
                rgb,
                max_edge_resolution=processing_res,
                resample_method=resample_method,
            )

        # Normalize rgb values
        rgb_norm: torch.Tensor = rgb / 255.0 * 2.0 - 1.0  #  [0, 255] -> [-1, 1]
        rgb_norm = rgb_norm.to(self.dtype)
        assert rgb_norm.min() >= -1.0 and rgb_norm.max() <= 1.0

        # ----------------- Predicting depth -----------------
        # Batch repeated input image
        duplicated_rgb = rgb_norm.expand(1, -1, -1, -1)
        single_rgb_dataset = TensorDataset(duplicated_rgb)
        # find the batch size
        if batch_size > 0:
            _bs = batch_size
        else:
            _bs = 1

        single_rgb_loader = DataLoader(
            single_rgb_dataset, batch_size=_bs, shuffle=False
        )

        # Predict depth maps (batched)
        depth_pred_ls = []
        if show_progress_bar:
            iterable = tqdm(
                single_rgb_loader, desc=" " * 2 + "Inference batches", leave=False
            )
        else:
            iterable = single_rgb_loader
        for batch in iterable:
            (batched_img,) = batch  # here the image is still around 0-1
            depth_pred_raw = self.single_infer(
                rgb_in=batched_img,
            )
            depth_pred_ls.append(depth_pred_raw.detach())
        depth_preds = torch.concat(depth_pred_ls, dim=0)
        torch.cuda.empty_cache()  # clear vram cache for ensembling

        depth_pred = depth_preds
        pred_uncert = None

        # Resize back to original resolution
        if match_input_res:
            depth_pred = resize(
                depth_pred,
                input_size[-2:],
                interpolation=resample_method,
                antialias=True,
            )

        # Convert to numpy
        depth_pred = depth_pred.squeeze()
        depth_pred = depth_pred.cpu().numpy()
        if pred_uncert is not None:
            pred_uncert = pred_uncert.squeeze().cpu().numpy()

        # Clip output range
        depth_pred = depth_pred.clip(0, 1)

        # Colorize
        if color_map is not None:
            depth_colored = colorize_depth_maps(
                depth_pred, 0, 1, cmap=color_map
            ).squeeze()  # [3, H, W], value in (0, 1)
            depth_colored = (depth_colored * 255).astype(np.uint8)
            depth_colored_hwc = chw2hwc(depth_colored)
            depth_colored_img = Image.fromarray(depth_colored_hwc)
        else:
            depth_colored_img = None

        return DepthMasterDepthOutput(
            depth_np=depth_pred,
            depth_colored=depth_colored_img,
            uncertainty=pred_uncert,
        )


    def encode_empty_text(self):
        """
        Encode text embedding for empty prompt
        """
        prompt = ""
        text_inputs = self.tokenizer(
            prompt,
            padding="do_not_pad",
            max_length=self.tokenizer.model_max_length,
            truncation=True,
            return_tensors="pt",
        )
        text_input_ids = text_inputs.input_ids.to(self.text_encoder.device) #[1,2]
        self.empty_text_embed = self.text_encoder(text_input_ids)[0].to(self.dtype) #[1,2,1024]

    @torch.no_grad()
    def single_infer(
        self,
        rgb_in: torch.Tensor,
    ) -> torch.Tensor:
        """
        Perform an individual depth prediction without ensembling.

        Args:
            rgb_in (`torch.Tensor`):
                Input RGB image.
        Returns:
            `torch.Tensor`: Predicted depth map.
        """
        device = self.device
        rgb_in = rgb_in.to(device)

        # Encode image
        rgb_latent = self.encode_rgb(rgb_in) # 1/8 Resolution with a channel nums of 4. 


        # Batched empty text embedding
        if self.empty_text_embed is None:
            self.encode_empty_text()
        batch_empty_text_embed = self.empty_text_embed.repeat(
            (rgb_latent.shape[0], 1, 1)
        ).to(device)  # [B, 2, 1024]


        unet_output = self.unet(
                rgb_latent,
                1,
                encoder_hidden_states=batch_empty_text_embed,
            ).sample  # [B, 4, h, w]

        torch.cuda.empty_cache()
        depth = self.decode_depth(unet_output) # [B, 1, h, w]

        # clip prediction
        depth = torch.clip(depth, -1.0, 1.0)
        # shift to [0, 1]
        depth = (depth + 1.0) / 2.0

        return depth

    def encode_rgb(self, rgb_in: torch.Tensor) -> torch.Tensor:
        """
        Encode RGB image into latent.

        Args:
            rgb_in (`torch.Tensor`):
                Input RGB image to be encoded.

        Returns:
            `torch.Tensor`: Image latent.
        """
        # encode
        h = self.vae.encoder(rgb_in)
        moments = self.vae.quant_conv(h)
        mean, logvar = torch.chunk(moments, 2, dim=1)
        # scale latent
        rgb_latent = mean * self.rgb_latent_scale_factor
        return rgb_latent

    def decode_depth(self, depth_latent: torch.Tensor) -> torch.Tensor:
        """
        Decode depth latent into depth map.

        Args:
            depth_latent (`torch.Tensor`):
                Depth latent to be decoded.

        Returns:
            `torch.Tensor`: Decoded depth map.
        """
        # scale latent
        depth_latent = depth_latent / self.depth_latent_scale_factor
        # decode
        z = self.vae.post_quant_conv(depth_latent)
        stacked = self.vae.decoder(z)
        # mean of output channels
        depth_mean = stacked.mean(dim=1, keepdim=True)
        return depth_mean