#s file is modified from https://github.com/NVlabs/Sana

# Copyright 2024 NVIDIA CORPORATION & AFFILIATES
#
# 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.
#
# SPDX-License-Identifier: Apache-2.0

import os
import warnings
import pyrallis
from dataclasses import dataclass, field
from typing import Tuple, List
from PIL import Image

import torch
import torchvision.transforms as T

warnings.filterwarnings("ignore")  # ignore warning


from diffusion import DPMS
from model.builder import build_model, get_tokenizer_and_text_encoder, get_vae, vae_decode, vae_encode
from model.utils import get_weight_dtype, prepare_prompt_ar
from utils.config import BaseConfig, ModelConfig, AEConfig, TextEncoderConfig, SchedulerConfig, model_init_config
from utils.logger import get_root_logger

from tools.download import find_model


def read_image(image):
    if isinstance(image, str):
        assert os.path.exists(image), f"Image {image} does not exist."
        image = Image.open(image).convert("RGB")
        transform = T.Compose([T.ToTensor(), T.Normalize([0.5, 0.5, 0.5], [0.5, 0.5, 0.5])])
        image = transform(image)
    elif isinstance(image, Image.Image):
        transform = T.Compose([T.ToTensor(), T.Normalize([0.5, 0.5, 0.5], [0.5, 0.5, 0.5])])
        image = transform(image)
    elif isinstance(image, torch.Tensor):
        assert image.ndim == 3, "Image tensor should be 3D."
    else:
        raise TypeError("Unsupported image type. Expected str, PIL Image, or Tensor.")
    return image


def classify_height_width_bin(height: int, width: int, ratios: dict) -> Tuple[int, int]:
    """Returns binned height and width."""
    ar = float(height / width)
    closest_ratio = min(ratios.keys(), key=lambda ratio: abs(float(ratio) - ar))
    default_hw = ratios[closest_ratio]
    return int(default_hw[0]), int(default_hw[1])


@dataclass
class JodiInference(BaseConfig):
    model: ModelConfig
    vae: AEConfig
    text_encoder: TextEncoderConfig
    scheduler: SchedulerConfig
    config: str = "./configs/inference.yaml"
    conditions: List[str] = field(default_factory=list)
    work_dir: str = "output/"


class JodiPipeline:
    def __init__(
        self,
        config: str,
        device: torch.device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu"),
    ):
        super().__init__()
        config = pyrallis.load(JodiInference, open(config))
        self.config = config
        self.device = device
        self.logger = get_root_logger()
        self.progress_fn = lambda progress, desc: None

        # set some hyperparameters
        self.image_size = config.model.image_size
        self.latent_size = self.image_size // config.vae.vae_downsample_rate
        self.max_sequence_length = config.text_encoder.model_max_length
        self.flow_shift = config.scheduler.flow_shift

        self.weight_dtype = get_weight_dtype(config.model.mixed_precision)
        self.vae_dtype = get_weight_dtype(config.vae.weight_dtype)

        self.logger.info(f"flow_shift: {self.flow_shift}")
        self.logger.info(f"Inference with {self.weight_dtype}")

        self.num_conditions = len(config.conditions)

        # 1. build vae and text encoder
        self.vae = self.build_vae(config.vae)
        self.tokenizer, self.text_encoder = self.build_text_encoder(config.text_encoder)

        # 2. build Jodi
        self.model = self.build_jodi(config).to(self.device)

        # 3. pre-compute null embedding
        with torch.no_grad():
            null_caption_token = self.tokenizer(
                "", max_length=self.max_sequence_length, padding="max_length", truncation=True, return_tensors="pt"
            ).to(self.device)
            self.null_caption_embs = self.text_encoder(
                null_caption_token.input_ids, null_caption_token.attention_mask
            )[0]

    @property
    def base_ratios(self):
        return {
            "0.25": [512.0, 2048.0],  # 1:4
            "0.33": [576.0, 1728.0],  # 1:3
            "0.4": [640.0, 1600.0],   # 2:5
            "0.5": [704.0, 1408.0],   # 1:2
            "0.67": [768.0, 1152.0],  # 2:3
            "0.75": [864.0, 1152.0],  # 3:4
            "0.82": [896.0, 1088.0],  # 5:6
            "1.0": [1024.0, 1024.0],  # 1:1
            "1.21": [1088.0, 896.0],  # 6:5
            "1.33": [1152.0, 864.0],  # 4:3
            "1.5": [1152.0, 768.0],   # 3:2
            "2.0": [1408.0, 704.0],   # 2:1
            "2.5": [1600.0, 640.0],   # 5:2
            "3.0": [1728.0, 576.0],   # 3:1
            "4.0": [2048.0, 512.0],   # 4:1
        }

    def build_vae(self, config):
        vae = get_vae(config.vae_type, config.vae_pretrained, self.device).to(self.vae_dtype)
        return vae

    def build_text_encoder(self, config):
        tokenizer, text_encoder = get_tokenizer_and_text_encoder(name=config.text_encoder_name, device=self.device)
        return tokenizer, text_encoder

    def build_jodi(self, config):
        # model setting
        model_kwargs = model_init_config(config, latent_size=self.latent_size)
        model = build_model(
            config.model.model,
            use_fp32_attention=config.model.get("fp32_attention", False) and config.model.mixed_precision != "bf16",
            num_conditions=self.num_conditions,
            **model_kwargs,
        )
        self.logger.info(f"use_fp32_attention: {model.fp32_attention}")
        self.logger.info(
            f"{model.__class__.__name__}:{config.model.model},"
            f"Model Parameters: {sum(p.numel() for p in model.parameters()):,}"
        )
        return model

    def from_pretrained(self, model_path):
        state_dict = find_model(model_path)
        state_dict = state_dict.get("state_dict", state_dict)
        if "pos_embed" in state_dict:
            del state_dict["pos_embed"]
        missing, unexpected = self.model.load_state_dict(state_dict, strict=False)
        self.model.eval().to(self.weight_dtype)

        self.logger.info(f"Generating sample from ckpt: {model_path}")
        self.logger.warning(f"Missing keys: {missing}")
        self.logger.warning(f"Unexpected keys: {unexpected}")

    def register_progress_bar(self, progress_fn=None):
        self.progress_fn = progress_fn if progress_fn is not None else self.progress_fn

    @torch.inference_mode()
    def __call__(
        self,
        images,
        role,
        prompt="",
        height=1024,
        width=1024,
        negative_prompt="",
        num_inference_steps=20,
        guidance_scale=4.5,
        num_images_per_prompt=1,
        generator=None,
        latents=None,
    ):
        ori_height, ori_width = height, width
        height, width = classify_height_width_bin(height, width, ratios=self.base_ratios)
        latent_size_h, latent_size_w = (
            height // self.config.vae.vae_downsample_rate,
            width // self.config.vae.vae_downsample_rate,
        )

        # pre-compute negative embedding
        if negative_prompt != "":
            null_caption_token = self.tokenizer(
                negative_prompt,
                max_length=self.max_sequence_length,
                padding="max_length",
                truncation=True,
                return_tensors="pt",
            ).to(self.device)
            self.null_caption_embs = self.text_encoder(
                null_caption_token.input_ids, null_caption_token.attention_mask
            )[0]

        # compute clean_x
        if len(images) != 1 + self.num_conditions:
            raise ValueError(f"Number of images {len(images)} != {1 + self.num_conditions}.")
        if len(role) != 1 + self.num_conditions:
            raise ValueError(f"Number of roles {len(role)} != {1 + self.num_conditions}.")
        clean_x = [
            torch.zeros(
                1,
                self.config.vae.vae_latent_dim,
                latent_size_h,
                latent_size_w,
                device=self.device,
                dtype=self.vae_dtype,
            )
        ] * (self.num_conditions + 1)
        for i, image in enumerate(images):
            if role[i] == 1:
                assert image is not None
                image = read_image(image).unsqueeze(0).to(self.device, self.vae_dtype)

                image_height, image_width = image.shape[-2:]
                if height / image_height > width / image_width:
                    resize_size = height, int(image_width * height / image_height)
                else:
                    resize_size = int(image_height * width / image_width), width

                resize_and_crop = T.Compose([
                    T.Resize(resize_size, interpolation=T.InterpolationMode.BILINEAR, antialias=True),
                    T.CenterCrop((height, width)),
                ])
                image = resize_and_crop(image)
                clean_x[i] = vae_encode(
                    self.config.vae.vae_type, self.vae, image, self.config.vae.sample_posterior, self.device
                )
        clean_x = torch.stack(clean_x, dim=1)  # (1, 1+K, 32, 32, 32)
        role = torch.tensor(role).unsqueeze(0)  # (1, 1+K)
        role = role.to(dtype=torch.long, device=self.device)

        prompts = [
            prepare_prompt_ar(prompt, self.base_ratios, device=self.device, show=False)[0].strip()
            for _ in range(num_images_per_prompt)
        ]

        with torch.no_grad():
            # prepare text feature
            if not self.config.text_encoder.chi_prompt:
                max_length_all = self.config.text_encoder.model_max_length
                prompts_all = prompts
            else:
                chi_prompt = "\n".join(self.config.text_encoder.chi_prompt)
                prompts_all = [chi_prompt + prompt for prompt in prompts]
                num_chi_prompt_tokens = len(self.tokenizer.encode(chi_prompt))
                max_length_all = (
                    num_chi_prompt_tokens + self.config.text_encoder.model_max_length - 2
                )  # magic number 2: [bos], [_]

            caption_token = self.tokenizer(
                prompts_all,
                max_length=max_length_all,
                padding="max_length",
                truncation=True,
                return_tensors="pt",
            ).to(device=self.device)
            select_index = [0] + list(range(-self.config.text_encoder.model_max_length + 1, 0))
            caption_embs = self.text_encoder(caption_token.input_ids, caption_token.attention_mask)[0][:, None][
                :, :, select_index
            ].to(self.weight_dtype)
            emb_masks = caption_token.attention_mask[:, select_index]
            null_y = self.null_caption_embs.repeat(len(prompts), 1, 1)[:, None].to(self.weight_dtype)

            n = len(prompts)
            if latents is None:
                z = torch.randn(
                    n,
                    1 + self.num_conditions,
                    self.config.vae.vae_latent_dim,
                    latent_size_h,
                    latent_size_w,
                    generator=generator,
                    device=self.device,
                )
            else:
                assert latents.shape == (
                    n,
                    1 + self.num_conditions,
                    self.config.vae.vae_latent_dim,
                    latent_size_h,
                    latent_size_w,
                )
                z = latents.to(self.device)
            role = role.repeat(n, 1)
            clean_x = clean_x.repeat(n, 1, 1, 1, 1)

            model_kwargs = dict(mask=emb_masks, role=role, clean_x=clean_x)
            scheduler = DPMS(
                self.model,
                condition=caption_embs,
                uncondition=null_y,
                cfg_scale=guidance_scale,
                model_type="flow",
                model_kwargs=model_kwargs,
                schedule="FLOW",
            )
            scheduler.register_progress_bar(self.progress_fn)
            sample = scheduler.sample(
                z,
                steps=num_inference_steps,
                order=2,
                skip_type="time_uniform_flow",
                method="multistep",
                flow_shift=self.flow_shift,
            )

        sample = torch.where(torch.eq(role, 1)[:, :, None, None, None], clean_x, sample)
        sample = sample.to(self.vae_dtype)
        sample = torch.unbind(sample, dim=1)
        with torch.no_grad():
            sample = [vae_decode(self.config.vae.vae_type, self.vae, s) for s in sample]
        resize = T.Resize((ori_height, ori_width), interpolation=T.InterpolationMode.BILINEAR)
        sample = [resize(s).clamp(-1, 1) for s in sample]
        return sample