import torch.nn as nn

import colossalai.shardformer.layer as col_nn

from .._utils import getattr_, setattr_
from ..modeling.blip2 import forward_fn
from .base_policy import ModulePolicyDescription, Policy, SubModuleReplacementDescription

__all__ = ['BlipPolicy', 'BlipModelPolicy']


class BlipPolicy(Policy):

    def config_sanity_check(self):
        pass

    def preprocess(self):
        # reshape the embedding layer
        r"""
        Reshape the Embedding layer to make the embedding dimension divisible by world_size
        """
        # TODO:
        vocab_size = self.model.config.qformer_config.vocab_size
        world_size = self.shard_config.tensor_parallel_size
        if vocab_size % world_size != 0:
            new_vocab_size = vocab_size + world_size - vocab_size % world_size
            self.model.resize_token_embeddings(new_vocab_size)
        return self.model

    def module_policy(self):
        from transformers.models.blip_2.modeling_blip_2 import (
            Blip2Attention,
            Blip2EncoderLayer,
            Blip2QFormerLayer,
            Blip2QFormerModel,
            Blip2VisionModel,
        )
        from transformers.models.opt.modeling_opt import OPTDecoderLayer, OPTForCausalLM

        policy = {}

        if self.shard_config.enable_tensor_parallelism:
            policy[Blip2EncoderLayer] = ModulePolicyDescription(attribute_replacement={
                "self_attn.num_heads":
                    self.model.config.vision_config.num_attention_heads // self.shard_config.tensor_parallel_size,
                "self_attn.embed_dim":
                    self.model.config.vision_config.hidden_size // self.shard_config.tensor_parallel_size,
            },
                                                                sub_module_replacement=[
                                                                    SubModuleReplacementDescription(
                                                                        suffix="self_attn.dropout",
                                                                        target_module=col_nn.DropoutForParallelInput,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="self_attn.qkv",
                                                                        target_module=col_nn.FusedLinear1D_Col,
                                                                        kwargs={
                                                                            "n_fused": 3,
                                                                        }),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="self_attn.projection",
                                                                        target_module=col_nn.Linear1D_Row,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="mlp.fc1",
                                                                        target_module=col_nn.Linear1D_Col,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="mlp.fc2",
                                                                        target_module=col_nn.Linear1D_Row,
                                                                    ),
                                                                ])

            policy[Blip2QFormerModel] = ModulePolicyDescription(sub_module_replacement=[
                SubModuleReplacementDescription(
                    suffix="dropout",
                    target_module=col_nn.DropoutForParallelInput,
                ),
            ])

            policy[Blip2QFormerLayer] = ModulePolicyDescription(attribute_replacement={
                "attention.attention.num_attention_heads":
                    self.model.config.qformer_config.num_attention_heads // self.shard_config.tensor_parallel_size,
                "attention.attention.all_head_size":
                    self.model.config.qformer_config.hidden_size // self.shard_config.tensor_parallel_size,
                "crossattention.attention.num_attention_heads":
                    self.model.config.qformer_config.num_attention_heads // self.shard_config.tensor_parallel_size,
                "crossattention.attention.all_head_size":
                    self.model.config.qformer_config.hidden_size // self.shard_config.tensor_parallel_size,
            },
                                                                sub_module_replacement=[
                                                                    SubModuleReplacementDescription(
                                                                        suffix="attention.attention.query",
                                                                        target_module=col_nn.Linear1D_Col,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="attention.attention.key",
                                                                        target_module=col_nn.Linear1D_Col,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="attention.attention.value",
                                                                        target_module=col_nn.Linear1D_Col,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="attention.attention.dropout",
                                                                        target_module=col_nn.DropoutForParallelInput,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="attention.output.dense",
                                                                        target_module=col_nn.Linear1D_Row,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="attention.output.dropout",
                                                                        target_module=col_nn.DropoutForParallelInput,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="crossattention.attention.query",
                                                                        target_module=col_nn.Linear1D_Col,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="crossattention.attention.key",
                                                                        target_module=col_nn.Linear1D_Col,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="crossattention.attention.value",
                                                                        target_module=col_nn.Linear1D_Col,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="crossattention.attention.dropout",
                                                                        target_module=col_nn.DropoutForParallelInput,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="crossattention.output.dense",
                                                                        target_module=col_nn.Linear1D_Row,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="crossattention.output.dropout",
                                                                        target_module=col_nn.DropoutForParallelInput,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="intermediate_query.dense",
                                                                        target_module=col_nn.Linear1D_Col,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="output_query.dense",
                                                                        target_module=col_nn.Linear1D_Row,
                                                                    ),
                                                                    SubModuleReplacementDescription(
                                                                        suffix="output_query.dropout",
                                                                        target_module=col_nn.DropoutForParallelInput,
                                                                    )
                                                                ])

            policy[OPTDecoderLayer] = ModulePolicyDescription(attribute_replacement={
                "self_attn.embed_dim":
                    self.model.config.text_config.hidden_size // self.shard_config.tensor_parallel_size,
                "self_attn.num_heads":
                    self.model.config.text_config.num_attention_heads // self.shard_config.tensor_parallel_size
            },
                                                              sub_module_replacement=[
                                                                  SubModuleReplacementDescription(
                                                                      suffix="self_attn.q_proj",
                                                                      target_module=col_nn.Linear1D_Col,
                                                                  ),
                                                                  SubModuleReplacementDescription(
                                                                      suffix="self_attn.k_proj",
                                                                      target_module=col_nn.Linear1D_Col,
                                                                  ),
                                                                  SubModuleReplacementDescription(
                                                                      suffix="self_attn.v_proj",
                                                                      target_module=col_nn.Linear1D_Col,
                                                                  ),
                                                                  SubModuleReplacementDescription(
                                                                      suffix="self_attn.out_proj",
                                                                      target_module=col_nn.Linear1D_Row,
                                                                  ),
                                                                  SubModuleReplacementDescription(
                                                                      suffix="fc1",
                                                                      target_module=col_nn.Linear1D_Col,
                                                                  ),
                                                                  SubModuleReplacementDescription(
                                                                      suffix="fc2",
                                                                      target_module=col_nn.Linear1D_Row,
                                                                  )
                                                              ])

            policy[OPTForCausalLM] = ModulePolicyDescription(sub_module_replacement=[
                SubModuleReplacementDescription(
                    suffix="model.decoder.embed_tokens",
                    target_module=col_nn.VocabParallelEmbedding1D,
                ),
                SubModuleReplacementDescription(
                    suffix="lm_head",
                    target_module=col_nn.Linear1D_Col,
                    kwargs={"gather_output": True},
                ),
            ])

            policy[Blip2Attention] = ModulePolicyDescription(method_replacement={"forward": forward_fn()})

        # optimization configuration
        if self.shard_config.enable_fused_normalization:
            # Handle Blip2EncoderLayer layer
            self.append_or_create_submodule_replacement(description=[
                SubModuleReplacementDescription(
                    suffix="layer_norm1",
                    target_module=col_nn.FusedLayerNorm,
                ),
                SubModuleReplacementDescription(
                    suffix="layer_norm2",
                    target_module=col_nn.FusedLayerNorm,
                )
            ],
                                                        policy=policy,
                                                        target_key=Blip2EncoderLayer)

            # handle Blip2VisionModel layer
            self.append_or_create_submodule_replacement(description=[
                SubModuleReplacementDescription(
                    suffix="post_layernorm",
                    target_module=col_nn.FusedLayerNorm,
                )
            ],
                                                        policy=policy,
                                                        target_key=Blip2VisionModel)

            # handle Blip2VisionModel layer
            self.append_or_create_submodule_replacement(
                description=[SubModuleReplacementDescription(
                    suffix="layernorm",
                    target_module=col_nn.FusedLayerNorm,
                )],
                policy=policy,
                target_key=Blip2QFormerModel)

            # handle Blip2QFormerLayer layer
            self.append_or_create_submodule_replacement(description=[
                SubModuleReplacementDescription(
                    suffix="attention.output.LayerNorm",
                    target_module=col_nn.FusedLayerNorm,
                ),
                SubModuleReplacementDescription(
                    suffix="crossattention.output.LayerNorm",
                    target_module=col_nn.FusedLayerNorm,
                ),
                SubModuleReplacementDescription(
                    suffix="output_query.LayerNorm",
                    target_module=col_nn.FusedLayerNorm,
                )
            ],
                                                        policy=policy,
                                                        target_key=Blip2QFormerLayer)

            # handle OPTForCausalLM layer
            self.append_or_create_submodule_replacement(description=[
                SubModuleReplacementDescription(
                    suffix="model.decoder.final_layer_norm",
                    target_module=col_nn.FusedLayerNorm,
                )
            ],
                                                        policy=policy,
                                                        target_key=OPTForCausalLM)

            # handle OPTDecoderLayer layer
            self.append_or_create_submodule_replacement(description=[
                SubModuleReplacementDescription(
                    suffix="self_attn_layer_norm",
                    target_module=col_nn.FusedLayerNorm,
                ),
                SubModuleReplacementDescription(
                    suffix="final_layer_norm",
                    target_module=col_nn.FusedLayerNorm,
                )
            ],
                                                        policy=policy,
                                                        target_key=OPTDecoderLayer)

        return policy

    def postprocess(self):
        binding_map = {
            'language_model.model.decoder.embed_tokens': 'language_model.lm_head',
        }

        for k, v in binding_map.items():
            src_mod = getattr_(self.model, k)
            dst_mod = getattr_(self.model, v)
            dst_mod.weight = src_mod.weight

        return self.model


# Blip2Model
class Blip2ModelPolicy(BlipPolicy):

    def __init__(self) -> None:
        super().__init__()


# Blip2ForConditionalGeneration
class Blip2ForConditionalGenerationPolicy(BlipPolicy):

    def __init__(self) -> None:
        super().__init__()
