# Copyright 2023 The HuggingFace Team. 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.
from typing import Dict, List, Optional, Union

import safetensors
import torch
from torch import nn

from ..utils import (
    DIFFUSERS_CACHE,
    HF_HUB_OFFLINE,
    _get_model_file,
    is_accelerate_available,
    is_transformers_available,
    logging,
)


if is_transformers_available():
    from transformers import PreTrainedModel, PreTrainedTokenizer

if is_accelerate_available():
    from accelerate.hooks import AlignDevicesHook, CpuOffload, remove_hook_from_module

logger = logging.get_logger(__name__)

TEXT_INVERSION_NAME = "learned_embeds.bin"
TEXT_INVERSION_NAME_SAFE = "learned_embeds.safetensors"


def load_textual_inversion_state_dicts(pretrained_model_name_or_paths, **kwargs):
    cache_dir = kwargs.pop("cache_dir", DIFFUSERS_CACHE)
    force_download = kwargs.pop("force_download", False)
    resume_download = kwargs.pop("resume_download", False)
    proxies = kwargs.pop("proxies", None)
    local_files_only = kwargs.pop("local_files_only", HF_HUB_OFFLINE)
    use_auth_token = kwargs.pop("use_auth_token", None)
    revision = kwargs.pop("revision", None)
    subfolder = kwargs.pop("subfolder", None)
    weight_name = kwargs.pop("weight_name", None)
    use_safetensors = kwargs.pop("use_safetensors", None)

    allow_pickle = False
    if use_safetensors is None:
        use_safetensors = True
        allow_pickle = True

    user_agent = {
        "file_type": "text_inversion",
        "framework": "pytorch",
    }
    state_dicts = []
    for pretrained_model_name_or_path in pretrained_model_name_or_paths:
        if not isinstance(pretrained_model_name_or_path, (dict, torch.Tensor)):
            # 3.1. Load textual inversion file
            model_file = None

            # Let's first try to load .safetensors weights
            if (use_safetensors and weight_name is None) or (
                weight_name is not None and weight_name.endswith(".safetensors")
            ):
                try:
                    model_file = _get_model_file(
                        pretrained_model_name_or_path,
                        weights_name=weight_name or TEXT_INVERSION_NAME_SAFE,
                        cache_dir=cache_dir,
                        force_download=force_download,
                        resume_download=resume_download,
                        proxies=proxies,
                        local_files_only=local_files_only,
                        use_auth_token=use_auth_token,
                        revision=revision,
                        subfolder=subfolder,
                        user_agent=user_agent,
                    )
                    state_dict = safetensors.torch.load_file(model_file, device="cpu")
                except Exception as e:
                    if not allow_pickle:
                        raise e

                    model_file = None

            if model_file is None:
                model_file = _get_model_file(
                    pretrained_model_name_or_path,
                    weights_name=weight_name or TEXT_INVERSION_NAME,
                    cache_dir=cache_dir,
                    force_download=force_download,
                    resume_download=resume_download,
                    proxies=proxies,
                    local_files_only=local_files_only,
                    use_auth_token=use_auth_token,
                    revision=revision,
                    subfolder=subfolder,
                    user_agent=user_agent,
                )
                state_dict = torch.load(model_file, map_location="cpu")
        else:
            state_dict = pretrained_model_name_or_path

        state_dicts.append(state_dict)

    return state_dicts


class TextualInversionLoaderMixin:
    r"""
    Load Textual Inversion tokens and embeddings to the tokenizer and text encoder.
    """

    def maybe_convert_prompt(self, prompt: Union[str, List[str]], tokenizer: "PreTrainedTokenizer"):  # noqa: F821
        r"""
        Processes prompts that include a special token corresponding to a multi-vector textual inversion embedding to
        be replaced with multiple special tokens each corresponding to one of the vectors. If the prompt has no textual
        inversion token or if the textual inversion token is a single vector, the input prompt is returned.

        Parameters:
            prompt (`str` or list of `str`):
                The prompt or prompts to guide the image generation.
            tokenizer (`PreTrainedTokenizer`):
                The tokenizer responsible for encoding the prompt into input tokens.

        Returns:
            `str` or list of `str`: The converted prompt
        """
        if not isinstance(prompt, List):
            prompts = [prompt]
        else:
            prompts = prompt

        prompts = [self._maybe_convert_prompt(p, tokenizer) for p in prompts]

        if not isinstance(prompt, List):
            return prompts[0]

        return prompts

    def _maybe_convert_prompt(self, prompt: str, tokenizer: "PreTrainedTokenizer"):  # noqa: F821
        r"""
        Maybe convert a prompt into a "multi vector"-compatible prompt. If the prompt includes a token that corresponds
        to a multi-vector textual inversion embedding, this function will process the prompt so that the special token
        is replaced with multiple special tokens each corresponding to one of the vectors. If the prompt has no textual
        inversion token or a textual inversion token that is a single vector, the input prompt is simply returned.

        Parameters:
            prompt (`str`):
                The prompt to guide the image generation.
            tokenizer (`PreTrainedTokenizer`):
                The tokenizer responsible for encoding the prompt into input tokens.

        Returns:
            `str`: The converted prompt
        """
        tokens = tokenizer.tokenize(prompt)
        unique_tokens = set(tokens)
        for token in unique_tokens:
            if token in tokenizer.added_tokens_encoder:
                replacement = token
                i = 1
                while f"{token}_{i}" in tokenizer.added_tokens_encoder:
                    replacement += f" {token}_{i}"
                    i += 1

                prompt = prompt.replace(token, replacement)

        return prompt

    def _check_text_inv_inputs(self, tokenizer, text_encoder, pretrained_model_name_or_paths, tokens):
        if tokenizer is None:
            raise ValueError(
                f"{self.__class__.__name__} requires `self.tokenizer` or passing a `tokenizer` of type `PreTrainedTokenizer` for calling"
                f" `{self.load_textual_inversion.__name__}`"
            )

        if text_encoder is None:
            raise ValueError(
                f"{self.__class__.__name__} requires `self.text_encoder` or passing a `text_encoder` of type `PreTrainedModel` for calling"
                f" `{self.load_textual_inversion.__name__}`"
            )

        if len(pretrained_model_name_or_paths) > 1 and len(pretrained_model_name_or_paths) != len(tokens):
            raise ValueError(
                f"You have passed a list of models of length {len(pretrained_model_name_or_paths)}, and list of tokens of length {len(tokens)} "
                f"Make sure both lists have the same length."
            )

        valid_tokens = [t for t in tokens if t is not None]
        if len(set(valid_tokens)) < len(valid_tokens):
            raise ValueError(f"You have passed a list of tokens that contains duplicates: {tokens}")

    @staticmethod
    def _retrieve_tokens_and_embeddings(tokens, state_dicts, tokenizer):
        all_tokens = []
        all_embeddings = []
        for state_dict, token in zip(state_dicts, tokens):
            if isinstance(state_dict, torch.Tensor):
                if token is None:
                    raise ValueError(
                        "You are trying to load a textual inversion embedding that has been saved as a PyTorch tensor. Make sure to pass the name of the corresponding token in this case: `token=...`."
                    )
                loaded_token = token
                embedding = state_dict
            elif len(state_dict) == 1:
                # diffusers
                loaded_token, embedding = next(iter(state_dict.items()))
            elif "string_to_param" in state_dict:
                # A1111
                loaded_token = state_dict["name"]
                embedding = state_dict["string_to_param"]["*"]
            else:
                raise ValueError(
                    f"Loaded state dictonary is incorrect: {state_dict}. \n\n"
                    "Please verify that the loaded state dictionary of the textual embedding either only has a single key or includes the `string_to_param`"
                    " input key."
                )

            if token is not None and loaded_token != token:
                logger.info(f"The loaded token: {loaded_token} is overwritten by the passed token {token}.")
            else:
                token = loaded_token

            if token in tokenizer.get_vocab():
                raise ValueError(
                    f"Token {token} already in tokenizer vocabulary. Please choose a different token name or remove {token} and embedding from the tokenizer and text encoder."
                )

            all_tokens.append(token)
            all_embeddings.append(embedding)

        return all_tokens, all_embeddings

    @staticmethod
    def _extend_tokens_and_embeddings(tokens, embeddings, tokenizer):
        all_tokens = []
        all_embeddings = []

        for embedding, token in zip(embeddings, tokens):
            if f"{token}_1" in tokenizer.get_vocab():
                multi_vector_tokens = [token]
                i = 1
                while f"{token}_{i}" in tokenizer.added_tokens_encoder:
                    multi_vector_tokens.append(f"{token}_{i}")
                    i += 1

                raise ValueError(
                    f"Multi-vector Token {multi_vector_tokens} already in tokenizer vocabulary. Please choose a different token name or remove the {multi_vector_tokens} and embedding from the tokenizer and text encoder."
                )

            is_multi_vector = len(embedding.shape) > 1 and embedding.shape[0] > 1
            if is_multi_vector:
                all_tokens += [token] + [f"{token}_{i}" for i in range(1, embedding.shape[0])]
                all_embeddings += [e for e in embedding]  # noqa: C416
            else:
                all_tokens += [token]
                all_embeddings += [embedding[0]] if len(embedding.shape) > 1 else [embedding]

        return all_tokens, all_embeddings

    def load_textual_inversion(
        self,
        pretrained_model_name_or_path: Union[str, List[str], Dict[str, torch.Tensor], List[Dict[str, torch.Tensor]]],
        token: Optional[Union[str, List[str]]] = None,
        tokenizer: Optional["PreTrainedTokenizer"] = None,  # noqa: F821
        text_encoder: Optional["PreTrainedModel"] = None,  # noqa: F821
        **kwargs,
    ):
        r"""
        Load Textual Inversion embeddings into the text encoder of [`StableDiffusionPipeline`] (both 🤗 Diffusers and
        Automatic1111 formats are supported).

        Parameters:
            pretrained_model_name_or_path (`str` or `os.PathLike` or `List[str or os.PathLike]` or `Dict` or `List[Dict]`):
                Can be either one of the following or a list of them:

                    - A string, the *model id* (for example `sd-concepts-library/low-poly-hd-logos-icons`) of a
                      pretrained model hosted on the Hub.
                    - A path to a *directory* (for example `./my_text_inversion_directory/`) containing the textual
                      inversion weights.
                    - A path to a *file* (for example `./my_text_inversions.pt`) containing textual inversion weights.
                    - A [torch state
                      dict](https://pytorch.org/tutorials/beginner/saving_loading_models.html#what-is-a-state-dict).

            token (`str` or `List[str]`, *optional*):
                Override the token to use for the textual inversion weights. If `pretrained_model_name_or_path` is a
                list, then `token` must also be a list of equal length.
            text_encoder ([`~transformers.CLIPTextModel`], *optional*):
                Frozen text-encoder ([clip-vit-large-patch14](https://huggingface.co/openai/clip-vit-large-patch14)).
                If not specified, function will take self.tokenizer.
            tokenizer ([`~transformers.CLIPTokenizer`], *optional*):
                A `CLIPTokenizer` to tokenize text. If not specified, function will take self.tokenizer.
            weight_name (`str`, *optional*):
                Name of a custom weight file. This should be used when:

                    - The saved textual inversion file is in 🤗 Diffusers format, but was saved under a specific weight
                      name such as `text_inv.bin`.
                    - The saved textual inversion file is in the Automatic1111 format.
            cache_dir (`Union[str, os.PathLike]`, *optional*):
                Path to a directory where a downloaded pretrained model configuration is cached if the standard cache
                is not used.
            force_download (`bool`, *optional*, defaults to `False`):
                Whether or not to force the (re-)download of the model weights and configuration files, overriding the
                cached versions if they exist.
            resume_download (`bool`, *optional*, defaults to `False`):
                Whether or not to resume downloading the model weights and configuration files. If set to `False`, any
                incompletely downloaded files are deleted.
            proxies (`Dict[str, str]`, *optional*):
                A dictionary of proxy servers to use by protocol or endpoint, for example, `{'http': 'foo.bar:3128',
                'http://hostname': 'foo.bar:4012'}`. The proxies are used on each request.
            local_files_only (`bool`, *optional*, defaults to `False`):
                Whether to only load local model weights and configuration files or not. If set to `True`, the model
                won't be downloaded from the Hub.
            use_auth_token (`str` or *bool*, *optional*):
                The token to use as HTTP bearer authorization for remote files. If `True`, the token generated from
                `diffusers-cli login` (stored in `~/.huggingface`) is used.
            revision (`str`, *optional*, defaults to `"main"`):
                The specific model version to use. It can be a branch name, a tag name, a commit id, or any identifier
                allowed by Git.
            subfolder (`str`, *optional*, defaults to `""`):
                The subfolder location of a model file within a larger model repository on the Hub or locally.
            mirror (`str`, *optional*):
                Mirror source to resolve accessibility issues if you're downloading a model in China. We do not
                guarantee the timeliness or safety of the source, and you should refer to the mirror site for more
                information.

        Example:

        To load a Textual Inversion embedding vector in 🤗 Diffusers format:

        ```py
        from diffusers import StableDiffusionPipeline
        import torch

        model_id = "runwayml/stable-diffusion-v1-5"
        pipe = StableDiffusionPipeline.from_pretrained(model_id, torch_dtype=torch.float16).to("cuda")

        pipe.load_textual_inversion("sd-concepts-library/cat-toy")

        prompt = "A <cat-toy> backpack"

        image = pipe(prompt, num_inference_steps=50).images[0]
        image.save("cat-backpack.png")
        ```

        To load a Textual Inversion embedding vector in Automatic1111 format, make sure to download the vector first
        (for example from [civitAI](https://civitai.com/models/3036?modelVersionId=9857)) and then load the vector
        locally:

        ```py
        from diffusers import StableDiffusionPipeline
        import torch

        model_id = "runwayml/stable-diffusion-v1-5"
        pipe = StableDiffusionPipeline.from_pretrained(model_id, torch_dtype=torch.float16).to("cuda")

        pipe.load_textual_inversion("./charturnerv2.pt", token="charturnerv2")

        prompt = "charturnerv2, multiple views of the same character in the same outfit, a character turnaround of a woman wearing a black jacket and red shirt, best quality, intricate details."

        image = pipe(prompt, num_inference_steps=50).images[0]
        image.save("character.png")
        ```

        """
        # 1. Set correct tokenizer and text encoder
        tokenizer = tokenizer or getattr(self, "tokenizer", None)
        text_encoder = text_encoder or getattr(self, "text_encoder", None)

        # 2. Normalize inputs
        pretrained_model_name_or_paths = (
            [pretrained_model_name_or_path]
            if not isinstance(pretrained_model_name_or_path, list)
            else pretrained_model_name_or_path
        )
        tokens = [token] if not isinstance(token, list) else token
        if tokens[0] is None:
            tokens = tokens * len(pretrained_model_name_or_paths)

        # 3. Check inputs
        self._check_text_inv_inputs(tokenizer, text_encoder, pretrained_model_name_or_paths, tokens)

        # 4. Load state dicts of textual embeddings
        state_dicts = load_textual_inversion_state_dicts(pretrained_model_name_or_paths, **kwargs)

        # 4.1 Handle the special case when state_dict is a tensor that contains n embeddings for n tokens
        if len(tokens) > 1 and len(state_dicts) == 1:
            if isinstance(state_dicts[0], torch.Tensor):
                state_dicts = list(state_dicts[0])
                if len(tokens) != len(state_dicts):
                    raise ValueError(
                        f"You have passed a state_dict contains {len(state_dicts)} embeddings, and list of tokens of length {len(tokens)} "
                        f"Make sure both have the same length."
                    )

        # 4. Retrieve tokens and embeddings
        tokens, embeddings = self._retrieve_tokens_and_embeddings(tokens, state_dicts, tokenizer)

        # 5. Extend tokens and embeddings for multi vector
        tokens, embeddings = self._extend_tokens_and_embeddings(tokens, embeddings, tokenizer)

        # 6. Make sure all embeddings have the correct size
        expected_emb_dim = text_encoder.get_input_embeddings().weight.shape[-1]
        if any(expected_emb_dim != emb.shape[-1] for emb in embeddings):
            raise ValueError(
                "Loaded embeddings are of incorrect shape. Expected each textual inversion embedding "
                "to be of shape {input_embeddings.shape[-1]}, but are {embeddings.shape[-1]} "
            )

        # 7. Now we can be sure that loading the embedding matrix works
        # < Unsafe code:

        # 7.1 Offload all hooks in case the pipeline was cpu offloaded before make sure, we offload and onload again
        is_model_cpu_offload = False
        is_sequential_cpu_offload = False
        for _, component in self.components.items():
            if isinstance(component, nn.Module):
                if hasattr(component, "_hf_hook"):
                    is_model_cpu_offload = isinstance(getattr(component, "_hf_hook"), CpuOffload)
                    is_sequential_cpu_offload = isinstance(getattr(component, "_hf_hook"), AlignDevicesHook)
                    logger.info(
                        "Accelerate hooks detected. Since you have called `load_textual_inversion()`, the previous hooks will be first removed. Then the textual inversion parameters will be loaded and the hooks will be applied again."
                    )
                    remove_hook_from_module(component, recurse=is_sequential_cpu_offload)

        # 7.2 save expected device and dtype
        device = text_encoder.device
        dtype = text_encoder.dtype

        # 7.3 Increase token embedding matrix
        text_encoder.resize_token_embeddings(len(tokenizer) + len(tokens))
        input_embeddings = text_encoder.get_input_embeddings().weight

        # 7.4 Load token and embedding
        for token, embedding in zip(tokens, embeddings):
            # add tokens and get ids
            tokenizer.add_tokens(token)
            token_id = tokenizer.convert_tokens_to_ids(token)
            input_embeddings.data[token_id] = embedding
            logger.info(f"Loaded textual inversion embedding for {token}.")

        input_embeddings.to(dtype=dtype, device=device)

        # 7.5 Offload the model again
        if is_model_cpu_offload:
            self.enable_model_cpu_offload()
        elif is_sequential_cpu_offload:
            self.enable_sequential_cpu_offload()

        # / Unsafe Code >
