# base class for platform strategies. this file defines the interface for strategies

import os
import re
from typing import Any, List, Optional, Tuple, Union

import numpy as np
import torch
from transformers import CLIPTokenizer, CLIPTextModel, CLIPTextModelWithProjection


# TODO remove circular import by moving ImageInfo to a separate file
# from library.train_util import ImageInfo

from library.utils import setup_logging

setup_logging()
import logging

logger = logging.getLogger(__name__)


class TokenizeStrategy:
    _strategy = None  # strategy instance: actual strategy class

    _re_attention = re.compile(
        r"""\\\(|
\\\)|
\\\[|
\\]|
\\\\|
\\|
\(|
\[|
:([+-]?[.\d]+)\)|
\)|
]|
[^\\()\[\]:]+|
:
""",
        re.X,
    )

    @classmethod
    def set_strategy(cls, strategy):
        if cls._strategy is not None:
            raise RuntimeError(f"Internal error. {cls.__name__} strategy is already set")
        cls._strategy = strategy

    @classmethod
    def get_strategy(cls) -> Optional["TokenizeStrategy"]:
        return cls._strategy

    def _load_tokenizer(
        self, model_class: Any, model_id: str, subfolder: Optional[str] = None, tokenizer_cache_dir: Optional[str] = None
    ) -> Any:
        tokenizer = None
        if tokenizer_cache_dir:
            local_tokenizer_path = os.path.join(tokenizer_cache_dir, model_id.replace("/", "_"))
            if os.path.exists(local_tokenizer_path):
                logger.info(f"load tokenizer from cache: {local_tokenizer_path}")
                tokenizer = model_class.from_pretrained(local_tokenizer_path)  # same for v1 and v2

        if tokenizer is None:
            tokenizer = model_class.from_pretrained(model_id, subfolder=subfolder)

        if tokenizer_cache_dir and not os.path.exists(local_tokenizer_path):
            logger.info(f"save Tokenizer to cache: {local_tokenizer_path}")
            tokenizer.save_pretrained(local_tokenizer_path)

        return tokenizer

    def tokenize(self, text: Union[str, List[str]]) -> List[torch.Tensor]:
        raise NotImplementedError

    def tokenize_with_weights(self, text: Union[str, List[str]]) -> Tuple[List[torch.Tensor], List[torch.Tensor]]:
        """
        returns: [tokens1, tokens2, ...], [weights1, weights2, ...]
        """
        raise NotImplementedError

    def _get_weighted_input_ids(
        self, tokenizer: CLIPTokenizer, text: str, max_length: Optional[int] = None
    ) -> Tuple[torch.Tensor, torch.Tensor]:
        """
        max_length includes starting and ending tokens.
        """

        def parse_prompt_attention(text):
            """
            Parses a string with attention tokens and returns a list of pairs: text and its associated weight.
            Accepted tokens are:
            (abc) - increases attention to abc by a multiplier of 1.1
            (abc:3.12) - increases attention to abc by a multiplier of 3.12
            [abc] - decreases attention to abc by a multiplier of 1.1
            \( - literal character '('
            \[ - literal character '['
            \) - literal character ')'
            \] - literal character ']'
            \\ - literal character '\'
            anything else - just text
            >>> parse_prompt_attention('normal text')
            [['normal text', 1.0]]
            >>> parse_prompt_attention('an (important) word')
            [['an ', 1.0], ['important', 1.1], [' word', 1.0]]
            >>> parse_prompt_attention('(unbalanced')
            [['unbalanced', 1.1]]
            >>> parse_prompt_attention('\(literal\]')
            [['(literal]', 1.0]]
            >>> parse_prompt_attention('(unnecessary)(parens)')
            [['unnecessaryparens', 1.1]]
            >>> parse_prompt_attention('a (((house:1.3)) [on] a (hill:0.5), sun, (((sky))).')
            [['a ', 1.0],
            ['house', 1.5730000000000004],
            [' ', 1.1],
            ['on', 1.0],
            [' a ', 1.1],
            ['hill', 0.55],
            [', sun, ', 1.1],
            ['sky', 1.4641000000000006],
            ['.', 1.1]]
            """

            res = []
            round_brackets = []
            square_brackets = []

            round_bracket_multiplier = 1.1
            square_bracket_multiplier = 1 / 1.1

            def multiply_range(start_position, multiplier):
                for p in range(start_position, len(res)):
                    res[p][1] *= multiplier

            for m in TokenizeStrategy._re_attention.finditer(text):
                text = m.group(0)
                weight = m.group(1)

                if text.startswith("\\"):
                    res.append([text[1:], 1.0])
                elif text == "(":
                    round_brackets.append(len(res))
                elif text == "[":
                    square_brackets.append(len(res))
                elif weight is not None and len(round_brackets) > 0:
                    multiply_range(round_brackets.pop(), float(weight))
                elif text == ")" and len(round_brackets) > 0:
                    multiply_range(round_brackets.pop(), round_bracket_multiplier)
                elif text == "]" and len(square_brackets) > 0:
                    multiply_range(square_brackets.pop(), square_bracket_multiplier)
                else:
                    res.append([text, 1.0])

            for pos in round_brackets:
                multiply_range(pos, round_bracket_multiplier)

            for pos in square_brackets:
                multiply_range(pos, square_bracket_multiplier)

            if len(res) == 0:
                res = [["", 1.0]]

            # merge runs of identical weights
            i = 0
            while i + 1 < len(res):
                if res[i][1] == res[i + 1][1]:
                    res[i][0] += res[i + 1][0]
                    res.pop(i + 1)
                else:
                    i += 1

            return res

        def get_prompts_with_weights(text: str, max_length: int):
            r"""
            Tokenize a list of prompts and return its tokens with weights of each token. max_length does not include starting and ending token.

            No padding, starting or ending token is included.
            """
            truncated = False

            texts_and_weights = parse_prompt_attention(text)
            tokens = []
            weights = []
            for word, weight in texts_and_weights:
                # tokenize and discard the starting and the ending token
                token = tokenizer(word).input_ids[1:-1]
                tokens += token
                # copy the weight by length of token
                weights += [weight] * len(token)
                # stop if the text is too long (longer than truncation limit)
                if len(tokens) > max_length:
                    truncated = True
                    break
            # truncate
            if len(tokens) > max_length:
                truncated = True
                tokens = tokens[:max_length]
                weights = weights[:max_length]
            if truncated:
                logger.warning("Prompt was truncated. Try to shorten the prompt or increase max_embeddings_multiples")
            return tokens, weights

        def pad_tokens_and_weights(tokens, weights, max_length, bos, eos, pad):
            r"""
            Pad the tokens (with starting and ending tokens) and weights (with 1.0) to max_length.
            """
            tokens = [bos] + tokens + [eos] + [pad] * (max_length - 2 - len(tokens))
            weights = [1.0] + weights + [1.0] * (max_length - 1 - len(weights))
            return tokens, weights

        if max_length is None:
            max_length = tokenizer.model_max_length

        tokens, weights = get_prompts_with_weights(text, max_length - 2)
        tokens, weights = pad_tokens_and_weights(
            tokens, weights, max_length, tokenizer.bos_token_id, tokenizer.eos_token_id, tokenizer.pad_token_id
        )
        return torch.tensor(tokens).unsqueeze(0), torch.tensor(weights).unsqueeze(0)

    def _get_input_ids(
        self, tokenizer: CLIPTokenizer, text: str, max_length: Optional[int] = None, weighted: bool = False
    ) -> torch.Tensor:
        """
        for SD1.5/2.0/SDXL
        TODO support batch input
        """
        if max_length is None:
            max_length = tokenizer.model_max_length - 2

        if weighted:
            input_ids, weights = self._get_weighted_input_ids(tokenizer, text, max_length)
        else:
            input_ids = tokenizer(text, padding="max_length", truncation=True, max_length=max_length, return_tensors="pt").input_ids

        if max_length > tokenizer.model_max_length:
            input_ids = input_ids.squeeze(0)
            iids_list = []
            if tokenizer.pad_token_id == tokenizer.eos_token_id:
                # v1
                # 77以上の時は "<BOS> .... <EOS> <EOS> <EOS>" でトータル227とかになっているので、"<BOS>...<EOS>"の三連に変換する
                # 1111氏のやつは , で区切る、とかしているようだが　とりあえず単純に
                for i in range(1, max_length - tokenizer.model_max_length + 2, tokenizer.model_max_length - 2):  # (1, 152, 75)
                    ids_chunk = (
                        input_ids[0].unsqueeze(0),
                        input_ids[i : i + tokenizer.model_max_length - 2],
                        input_ids[-1].unsqueeze(0),
                    )
                    ids_chunk = torch.cat(ids_chunk)
                    iids_list.append(ids_chunk)
            else:
                # v2 or SDXL
                # 77以上の時は "<BOS> .... <EOS> <PAD> <PAD>..." でトータル227とかになっているので、"<BOS>...<EOS> <PAD> <PAD> ..."の三連に変換する
                for i in range(1, max_length - tokenizer.model_max_length + 2, tokenizer.model_max_length - 2):
                    ids_chunk = (
                        input_ids[0].unsqueeze(0),  # BOS
                        input_ids[i : i + tokenizer.model_max_length - 2],
                        input_ids[-1].unsqueeze(0),
                    )  # PAD or EOS
                    ids_chunk = torch.cat(ids_chunk)

                    # 末尾が <EOS> <PAD> または <PAD> <PAD> の場合は、何もしなくてよい
                    # 末尾が x <PAD/EOS> の場合は末尾を <EOS> に変える（x <EOS> なら結果的に変化なし）
                    if ids_chunk[-2] != tokenizer.eos_token_id and ids_chunk[-2] != tokenizer.pad_token_id:
                        ids_chunk[-1] = tokenizer.eos_token_id
                    # 先頭が <BOS> <PAD> ... の場合は <BOS> <EOS> <PAD> ... に変える
                    if ids_chunk[1] == tokenizer.pad_token_id:
                        ids_chunk[1] = tokenizer.eos_token_id

                    iids_list.append(ids_chunk)

            input_ids = torch.stack(iids_list)  # 3,77

            if weighted:
                weights = weights.squeeze(0)
                new_weights = torch.ones(input_ids.shape)
                for i in range(1, max_length - tokenizer.model_max_length + 2, tokenizer.model_max_length - 2):
                    b = i // (tokenizer.model_max_length - 2)
                    new_weights[b, 1 : 1 + tokenizer.model_max_length - 2] = weights[i : i + tokenizer.model_max_length - 2]
                weights = new_weights

        if weighted:
            return input_ids, weights
        return input_ids


class TextEncodingStrategy:
    _strategy = None  # strategy instance: actual strategy class

    @classmethod
    def set_strategy(cls, strategy):
        if cls._strategy is not None:
            raise RuntimeError(f"Internal error. {cls.__name__} strategy is already set")
        cls._strategy = strategy

    @classmethod
    def get_strategy(cls) -> Optional["TextEncodingStrategy"]:
        return cls._strategy

    def encode_tokens(
        self, tokenize_strategy: TokenizeStrategy, models: List[Any], tokens: List[torch.Tensor]
    ) -> List[torch.Tensor]:
        """
        Encode tokens into embeddings and outputs.
        :param tokens: list of token tensors for each TextModel
        :return: list of output embeddings for each architecture
        """
        raise NotImplementedError

    def encode_tokens_with_weights(
        self, tokenize_strategy: TokenizeStrategy, models: List[Any], tokens: List[torch.Tensor], weights: List[torch.Tensor]
    ) -> List[torch.Tensor]:
        """
        Encode tokens into embeddings and outputs.
        :param tokens: list of token tensors for each TextModel
        :param weights: list of weight tensors for each TextModel
        :return: list of output embeddings for each architecture
        """
        raise NotImplementedError


class TextEncoderOutputsCachingStrategy:
    _strategy = None  # strategy instance: actual strategy class

    def __init__(
        self,
        cache_to_disk: bool,
        batch_size: Optional[int],
        skip_disk_cache_validity_check: bool,
        is_partial: bool = False,
        is_weighted: bool = False,
    ) -> None:
        self._cache_to_disk = cache_to_disk
        self._batch_size = batch_size
        self.skip_disk_cache_validity_check = skip_disk_cache_validity_check
        self._is_partial = is_partial
        self._is_weighted = is_weighted

    @classmethod
    def set_strategy(cls, strategy):
        if cls._strategy is not None:
            raise RuntimeError(f"Internal error. {cls.__name__} strategy is already set")
        cls._strategy = strategy

    @classmethod
    def get_strategy(cls) -> Optional["TextEncoderOutputsCachingStrategy"]:
        return cls._strategy

    @property
    def cache_to_disk(self):
        return self._cache_to_disk

    @property
    def batch_size(self):
        return self._batch_size

    @property
    def is_partial(self):
        return self._is_partial

    @property
    def is_weighted(self):
        return self._is_weighted

    def get_outputs_npz_path(self, image_abs_path: str) -> str:
        raise NotImplementedError

    def load_outputs_npz(self, npz_path: str) -> List[np.ndarray]:
        raise NotImplementedError

    def is_disk_cached_outputs_expected(self, npz_path: str) -> bool:
        raise NotImplementedError

    def cache_batch_outputs(
        self, tokenize_strategy: TokenizeStrategy, models: List[Any], text_encoding_strategy: TextEncodingStrategy, batch: List
    ):
        raise NotImplementedError


class LatentsCachingStrategy:
    # TODO commonize utillity functions to this class, such as npz handling etc.

    _strategy = None  # strategy instance: actual strategy class

    def __init__(self, cache_to_disk: bool, batch_size: int, skip_disk_cache_validity_check: bool) -> None:
        self._cache_to_disk = cache_to_disk
        self._batch_size = batch_size
        self.skip_disk_cache_validity_check = skip_disk_cache_validity_check

    @classmethod
    def set_strategy(cls, strategy):
        if cls._strategy is not None:
            raise RuntimeError(f"Internal error. {cls.__name__} strategy is already set")
        cls._strategy = strategy

    @classmethod
    def get_strategy(cls) -> Optional["LatentsCachingStrategy"]:
        return cls._strategy

    @property
    def cache_to_disk(self):
        return self._cache_to_disk

    @property
    def batch_size(self):
        return self._batch_size

    @property
    def cache_suffix(self):
        raise NotImplementedError

    def get_image_size_from_disk_cache_path(self, absolute_path: str, npz_path: str) -> Tuple[Optional[int], Optional[int]]:
        w, h = os.path.splitext(npz_path)[0].split("_")[-2].split("x")
        return int(w), int(h)

    def get_latents_npz_path(self, absolute_path: str, image_size: Tuple[int, int]) -> str:
        raise NotImplementedError

    def is_disk_cached_latents_expected(
        self, bucket_reso: Tuple[int, int], npz_path: str, flip_aug: bool, alpha_mask: bool
    ) -> bool:
        raise NotImplementedError

    def cache_batch_latents(self, model: Any, batch: List, flip_aug: bool, alpha_mask: bool, random_crop: bool):
        raise NotImplementedError

    def _default_is_disk_cached_latents_expected(
        self,
        latents_stride: int,
        bucket_reso: Tuple[int, int],
        npz_path: str,
        flip_aug: bool,
        alpha_mask: bool,
        multi_resolution: bool = False,
    ):
        if not self.cache_to_disk:
            return False
        if not os.path.exists(npz_path):
            return False
        if self.skip_disk_cache_validity_check:
            return True

        expected_latents_size = (bucket_reso[1] // latents_stride, bucket_reso[0] // latents_stride)  # bucket_reso is (W, H)

        # e.g. "_32x64", HxW
        key_reso_suffix = f"_{expected_latents_size[0]}x{expected_latents_size[1]}" if multi_resolution else ""

        try:
            npz = np.load(npz_path)
            if "latents" + key_reso_suffix not in npz:
                return False
            if flip_aug and "latents_flipped" + key_reso_suffix not in npz:
                return False
            if alpha_mask and "alpha_mask" + key_reso_suffix not in npz:
                return False
        except Exception as e:
            logger.error(f"Error loading file: {npz_path}")
            raise e

        return True

    # TODO remove circular dependency for ImageInfo
    def _default_cache_batch_latents(
        self,
        encode_by_vae,
        vae_device,
        vae_dtype,
        image_infos: List,
        flip_aug: bool,
        alpha_mask: bool,
        random_crop: bool,
        multi_resolution: bool = False,
    ):
        """
        Default implementation for cache_batch_latents. Image loading, VAE, flipping, alpha mask handling are common.
        """
        from library import train_util  # import here to avoid circular import

        img_tensor, alpha_masks, original_sizes, crop_ltrbs = train_util.load_images_and_masks_for_caching(
            image_infos, alpha_mask, random_crop
        )
        img_tensor = img_tensor.to(device=vae_device, dtype=vae_dtype)

        with torch.no_grad():
            latents_tensors = encode_by_vae(img_tensor).to("cpu")
        if flip_aug:
            img_tensor = torch.flip(img_tensor, dims=[3])
            with torch.no_grad():
                flipped_latents = encode_by_vae(img_tensor).to("cpu")
        else:
            flipped_latents = [None] * len(latents_tensors)

        # for info, latents, flipped_latent, alpha_mask in zip(image_infos, latents_tensors, flipped_latents, alpha_masks):
        for i in range(len(image_infos)):
            info = image_infos[i]
            latents = latents_tensors[i]
            flipped_latent = flipped_latents[i]
            alpha_mask = alpha_masks[i]
            original_size = original_sizes[i]
            crop_ltrb = crop_ltrbs[i]

            latents_size = latents.shape[1:3]  # H, W
            key_reso_suffix = f"_{latents_size[0]}x{latents_size[1]}" if multi_resolution else ""  # e.g. "_32x64", HxW

            if self.cache_to_disk:
                self.save_latents_to_disk(
                    info.latents_npz, latents, original_size, crop_ltrb, flipped_latent, alpha_mask, key_reso_suffix
                )
            else:
                info.latents_original_size = original_size
                info.latents_crop_ltrb = crop_ltrb
                info.latents = latents
                if flip_aug:
                    info.latents_flipped = flipped_latent
                info.alpha_mask = alpha_mask

    def load_latents_from_disk(
        self, npz_path: str, bucket_reso: Tuple[int, int]
    ) -> Tuple[Optional[np.ndarray], Optional[List[int]], Optional[List[int]], Optional[np.ndarray], Optional[np.ndarray]]:
        """
        for SD/SDXL/SD3.0
        """
        return self._default_load_latents_from_disk(None, npz_path, bucket_reso)

    def _default_load_latents_from_disk(
        self, latents_stride: Optional[int], npz_path: str, bucket_reso: Tuple[int, int]
    ) -> Tuple[Optional[np.ndarray], Optional[List[int]], Optional[List[int]], Optional[np.ndarray], Optional[np.ndarray]]:
        if latents_stride is None:
            key_reso_suffix = ""
        else:
            latents_size = (bucket_reso[1] // latents_stride, bucket_reso[0] // latents_stride)  # bucket_reso is (W, H)
            key_reso_suffix = f"_{latents_size[0]}x{latents_size[1]}"  # e.g. "_32x64", HxW

        npz = np.load(npz_path)
        if "latents" + key_reso_suffix not in npz:
            raise ValueError(f"latents{key_reso_suffix} not found in {npz_path}")

        latents = npz["latents" + key_reso_suffix]
        original_size = npz["original_size" + key_reso_suffix].tolist()
        crop_ltrb = npz["crop_ltrb" + key_reso_suffix].tolist()
        flipped_latents = npz["latents_flipped" + key_reso_suffix] if "latents_flipped" + key_reso_suffix in npz else None
        alpha_mask = npz["alpha_mask" + key_reso_suffix] if "alpha_mask" + key_reso_suffix in npz else None
        return latents, original_size, crop_ltrb, flipped_latents, alpha_mask

    def save_latents_to_disk(
        self,
        npz_path,
        latents_tensor,
        original_size,
        crop_ltrb,
        flipped_latents_tensor=None,
        alpha_mask=None,
        key_reso_suffix="",
    ):
        kwargs = {}

        if os.path.exists(npz_path):
            # load existing npz and update it
            npz = np.load(npz_path)
            for key in npz.files:
                kwargs[key] = npz[key]

        kwargs["latents" + key_reso_suffix] = latents_tensor.float().cpu().numpy()
        kwargs["original_size" + key_reso_suffix] = np.array(original_size)
        kwargs["crop_ltrb" + key_reso_suffix] = np.array(crop_ltrb)
        if flipped_latents_tensor is not None:
            kwargs["latents_flipped" + key_reso_suffix] = flipped_latents_tensor.float().cpu().numpy()
        if alpha_mask is not None:
            kwargs["alpha_mask" + key_reso_suffix] = alpha_mask.float().cpu().numpy()
        np.savez(npz_path, **kwargs)
