# Copyright (c) Alibaba, Inc. and its affiliates.
# Copyright 2023-present the HuggingFace Inc. team.
import os.path
from dataclasses import asdict, dataclass, field
from functools import partial, reduce
from typing import Dict, Optional

import json
import peft
import torch
import torch.nn
from packaging import version
from peft import (AdaLoraConfig, BOFTConfig, IA3Config, LoftQConfig, LoHaConfig, LoKrConfig, LoraModel, OFTConfig,
                  PeftConfig, PeftModel, PeftModelForCausalLM, PeftModelForSeq2SeqLM,
                  PeftModelForSequenceClassification, PeftModelForTokenClassification, PrefixTuningConfig,
                  PromptEncoderConfig, PromptLearningConfig, PromptTuningConfig, VeraConfig, get_peft_config,
                  get_peft_model, get_peft_model_state_dict)
from peft.config import PeftConfigMixin
from peft.tuners.lora import Embedding
from transformers import Trainer

from swift import get_logger
from swift.hub.snapshot_download import snapshot_download

logger = get_logger()
dispatchers = []


@dataclass
class LoraConfig(peft.LoraConfig):
    lora_dtype: str = field(
        default=None, metadata={'help': 'The lora dtype, default None means following the original layer\'s dtype'})

    lorap_lr_ratio: float = field(default=2.0**4, metadata={'help': 'The lr ratio of lora_B in lora+'})

    lorap_emb_lr: float = field(default=1e-6, metadata={'help': 'The lr for embedding in lora+'})

    def to_peft_config(self) -> peft.LoraConfig:
        _dict = asdict(self)
        _dict.pop('lora_dtype')
        _dict.pop('lorap_lr_ratio')
        _dict.pop('lorap_emb_lr')
        return peft.LoraConfig(**_dict)

    def save_pretrained(self, save_directory: str, **kwargs) -> None:
        self.to_peft_config().save_pretrained(save_directory, **kwargs)
        additional_args = {
            'lora_dtype': self.lora_dtype,
            'lorap_lr_ratio': self.lorap_lr_ratio,
            'lorap_emb_lr': self.lorap_emb_lr,
        }
        with open(os.path.join(save_directory, 'additional_config.json'), 'w') as f:
            json.dump(additional_args, f)

    @classmethod
    def from_pretrained(cls, pretrained_model_name_or_path: str, subfolder: Optional[str] = None, **kwargs):
        if hasattr(PeftConfigMixin, 'from_pretrained_origin'):
            self = PeftConfigMixin.from_pretrained_origin(pretrained_model_name_or_path, subfolder, **kwargs)
        else:
            self = super(LoraConfig, cls).from_pretrained(pretrained_model_name_or_path, subfolder, **kwargs)

        if type(self) == peft.LoraConfig:
            self = LoraConfig(**self.to_dict())

        if os.path.isfile(os.path.join(pretrained_model_name_or_path, 'additional_config.json')):
            with open(os.path.join(pretrained_model_name_or_path, 'additional_config.json'), 'r') as f:
                _json = json.load(f)
                for key, value in _json.items():
                    setattr(self, key, value)

        return self


def _create_and_replace_hook(self, *args, **kwargs):
    target = None
    if 'target' in kwargs:
        target = kwargs['target']
    else:
        for arg in args:
            if isinstance(arg, torch.nn.Module):
                target = arg
                break

    if target and target.__class__.__name__ == 'NonDynamicallyQuantizableLinear':
        return

    return self._create_and_replace_origin(*args, **kwargs)


def _convert_dtype(target: torch.nn.Module, adapter_name: str, lora_dtype: str):
    if lora_dtype == 'fp32':
        torch_dtype = torch.float32
    elif lora_dtype == 'fp16':
        torch_dtype = torch.float16
    elif lora_dtype == 'bf16':
        torch_dtype = torch.bfloat16
    else:
        torch_dtype = None

    if torch_dtype is not None:
        if hasattr(target, 'lora_A') and adapter_name in target.lora_A:
            target.lora_A[adapter_name].to(torch_dtype)
            target.lora_B[adapter_name].to(torch_dtype)
        if hasattr(target, 'lora_embedding_A') and adapter_name in target.lora_embedding_A:
            target.lora_embedding_A[adapter_name].to(torch_dtype)
            target.lora_embedding_B[adapter_name].to(torch_dtype)


def create_optimizer_param_groups(self: PeftModel, **defaults):
    if not isinstance(self.peft_config[self.active_adapter],
                      LoraConfig) or self.peft_config[self.active_adapter].lorap_lr_ratio is None:
        return None

    def get_module(name):
        parent_idx = 2 if 'lora' in name else 1
        module_names = name.split(sep='.')[:-parent_idx]
        module = reduce(getattr, module_names, self.base_model)
        return module

    param_groups = {
        'groupA': {},
        'groupB': {},
        'groupB_no_decay': {},
        'embedding': {},
    }

    decay_parameters = Trainer.get_decay_parameter_names(None, self.base_model)
    for name, param in self.base_model.named_parameters():
        if not param.requires_grad:
            continue

        module = get_module(name)
        if isinstance(module, Embedding):
            param_groups['embedding'][name] = param
        elif 'lora_B' in name or param.ndim == 1:
            if name in decay_parameters:
                param_groups['groupB'][name] = param
            else:
                param_groups['groupB_no_decay'][name] = param
        else:
            param_groups['groupA'][name] = param

    lr = defaults['lr']
    weight_decay = defaults.get('weight_decay', 0.0)

    param_groups = [
        {
            'params': list(param_groups['groupA'].values()),
            'weight_decay': weight_decay,
            'lr': lr,
        },
        {
            'params': list(param_groups['embedding'].values()),
            'weight_decay': weight_decay,
            'lr': self.peft_config[self.active_adapter].lorap_emb_lr,
        },
        {
            'params': list(param_groups['groupB'].values()),
            'weight_decay': weight_decay,
            'lr': lr * self.peft_config[self.active_adapter].lorap_lr_ratio,
        },
        {
            'params': list(param_groups['groupB_no_decay'].values()),
            'weight_decay': 0.0,
            'lr': lr * self.peft_config[self.active_adapter].lorap_lr_ratio,
        },
    ]
    return param_groups


def adalora_forward(self, *args, **kwargs):
    from peft.utils.integrations import gather_params_ctx
    outputs = self.model.forward(*args, **kwargs)

    if (getattr(outputs, 'loss', None) is not None) and isinstance(outputs.loss, torch.Tensor):
        # Calculate the orthogonal regularization
        orth_reg_weight = self.peft_config[self.trainable_adapter_name].orth_reg_weight

        if orth_reg_weight <= 0:
            raise ValueError('orth_reg_weight should be greater than 0. ')

        regu_loss = 0
        num_param = 0
        for n, p in self.model.named_parameters():
            if ('lora_A' in n or 'lora_B' in n) and self.trainable_adapter_name in n:
                if p.shape == torch.Size([0]):
                    with gather_params_ctx(p, fwd_module=self):
                        para_cov = p @ p.T if 'lora_A' in n else p.T @ p
                else:
                    para_cov = p @ p.T if 'lora_A' in n else p.T @ p
                I = torch.eye(*para_cov.size(), out=torch.empty_like(para_cov))  # noqa: E741
                I.requires_grad = False
                num_param += 1
                if isinstance(regu_loss, torch.Tensor):
                    regu_loss = regu_loss.to(para_cov.device)
                regu_loss += torch.norm(para_cov - I, p='fro')
        if num_param > 0:
            regu_loss = regu_loss / num_param
        else:
            regu_loss = 0
        if isinstance(regu_loss, torch.Tensor) and isinstance(outputs.loss, torch.Tensor):
            regu_loss = regu_loss.to(outputs.loss.device)
        outputs.loss += orth_reg_weight * regu_loss
    return outputs


def adalora_mask_to_budget(self, model, budget):
    value_ipt = {}
    vector_ipt = {}
    triplet_ipt = {}
    # Get the importance score for A, E, B
    for n, p in model.named_parameters():
        if f'lora_A.{self.adapter_name}' in n:
            entry_ipt = self._element_score(n)
            comb_ipt = torch.mean(entry_ipt, dim=1, keepdim=True)
            name_m = n.replace('lora_A', '%s')
            if name_m not in vector_ipt:
                vector_ipt[name_m] = [comb_ipt]
            else:
                vector_ipt[name_m].append(comb_ipt)
        if f'lora_B.{self.adapter_name}' in n:
            entry_ipt = self._element_score(n)
            comb_ipt = torch.mean(entry_ipt, dim=0, keepdim=False).view(-1, 1)
            name_m = n.replace('lora_B', '%s')
            if name_m not in vector_ipt:
                vector_ipt[name_m] = [comb_ipt]
            else:
                vector_ipt[name_m].append(comb_ipt)
        if f'lora_E.{self.adapter_name}' in n:
            entry_ipt = self._element_score(n)
            name_m = n.replace('lora_E', '%s')
            value_ipt[name_m] = entry_ipt

    all_score = []
    # Calculate the score for each triplet
    for name_m in vector_ipt:
        ipt_E = value_ipt[name_m]
        ipt_AB = torch.cat(vector_ipt[name_m], dim=1)
        sum_ipt = self._combine_ipt(ipt_E, ipt_AB)
        name_E = name_m % 'lora_E'
        triplet_ipt[name_E] = sum_ipt.view(-1, 1)
        sum_ipt = sum_ipt.view(-1)
        if all_score:
            sum_ipt = sum_ipt.to(all_score[0].device)
        all_score.append(sum_ipt)

    # Get the threshold by ranking ipt
    mask_threshold = torch.kthvalue(
        torch.cat(all_score),
        k=self.init_bgt - budget,
    )[0].item()

    rank_pattern = {}
    # Mask the unimportant triplets
    with torch.no_grad():
        for n, p in model.named_parameters():
            if f'lora_E.{self.adapter_name}' in n:
                p.masked_fill_(triplet_ipt[n] <= mask_threshold, 0.0)
                rank_pattern[n] = (~(triplet_ipt[n] <= mask_threshold)).view(-1).tolist()
    return rank_pattern


def hot_patch_peft_module():
    from peft.tuners.lora import LoraLayer

    # Fix Lora does not support NonDynamicallyQuantizableLinear
    LoraModel._create_and_replace_origin = LoraModel._create_and_replace
    LoraModel._create_and_replace = _create_and_replace_hook

    # Support type conversion
    def init(self, model: torch.nn.Module, config: Dict[str, LoraConfig], adapter_name):
        self.__init_origin__(model, config, adapter_name)
        if isinstance(self.active_adapter, list):
            self.active_adapter = self.active_adapter[0]
        active_config = config[self.active_adapter] if isinstance(config, dict) else config
        if hasattr(active_config, 'lora_dtype'):
            for name, module in model.named_modules():
                if isinstance(module, LoraLayer):
                    _convert_dtype(module, self.active_adapter, active_config.lora_dtype)

    LoraModel.__init_origin__ = LoraModel.__init__
    LoraModel.__init__ = init

    # Support LoRA+
    PeftModel.create_optimizer_param_groups = create_optimizer_param_groups

    PeftConfigMixin.from_pretrained_origin = PeftConfigMixin.from_pretrained
    PeftConfigMixin.from_pretrained = LoraConfig.from_pretrained

    # Compatible with SwiftModel
    def dummy_function(*args, **kwargs):
        logger.warn(f'The function {kwargs["func"]} has no effects, consider using other functions.')

    PeftModel.activate_adapter = PeftModel.set_adapter
    PeftModel.deactivate_adapter = partial(dummy_function, func='deactivate_adapter')
    PeftModel.set_active_adapters = partial(dummy_function, func='set_active_adapters')

    # Fix adalora does not support device_map
    from peft.tuners.adalora import AdaLoraModel, RankAllocator
    AdaLoraModel.forward = adalora_forward
    RankAllocator.mask_to_budget = adalora_mask_to_budget


def get_wrapped_class(module_class):
    """Get a custom wrapper class for peft classes to download the models from the ModelScope hub

    Args:
        module_class: The actual module class

    Returns:
        The wrapper
    """

    class PeftWrapper(module_class):

        @classmethod
        def from_pretrained(cls, model, model_id, *args, revision: Optional[str] = None, **kwargs):
            if not os.path.exists(model_id):
                model_id = snapshot_download(model_id, revision=revision)
            return module_class.from_pretrained(model, model_id, *args, **kwargs)

    PeftWrapper.__name__ = module_class.__name__
    return PeftWrapper


def wrap_module(module):
    if not hasattr(module, 'from_pretrained'):
        return module

    return get_wrapped_class(module)


hot_patch_peft_module()
PeftModel = wrap_module(PeftModel)
PeftConfig = wrap_module(PeftConfig)
PeftModelForSeq2SeqLM = wrap_module(PeftModelForSeq2SeqLM)
PeftModelForSequenceClassification = wrap_module(PeftModelForSequenceClassification)
PeftModelForTokenClassification = wrap_module(PeftModelForTokenClassification)
PeftModelForCausalLM = wrap_module(PeftModelForCausalLM)
PromptEncoderConfig = wrap_module(PromptEncoderConfig)
PromptTuningConfig = wrap_module(PromptTuningConfig)
PrefixTuningConfig = wrap_module(PrefixTuningConfig)
PromptLearningConfig = wrap_module(PromptLearningConfig)
LoraConfig = wrap_module(LoraConfig)
AdaLoraConfig = wrap_module(AdaLoraConfig)
IA3Config = wrap_module(IA3Config)
LoHaConfig = wrap_module(LoHaConfig)
LoKrConfig = wrap_module(LoKrConfig)
LoftQConfig = wrap_module(LoftQConfig)
OFTConfig = wrap_module(OFTConfig)
BOFTConfig = wrap_module(BOFTConfig)
VeraConfig = wrap_module(VeraConfig)
OFTConfig = wrap_module(OFTConfig)
get_peft_config = get_peft_config
get_peft_model_state_dict = get_peft_model_state_dict
get_peft_model = get_peft_model
