import os
import shutil
from copy import deepcopy
from typing import Tuple

import pytest
import torch
import torch.distributed
import torch.distributed as dist
from transformers import AutoConfig, AutoModel

import colossalai
from colossalai.booster.booster import Booster
from colossalai.booster.plugin.moe_hybrid_parallel_plugin import MoeHybridParallelPlugin
from colossalai.shardformer.layer.utils import Randomizer
from colossalai.testing import parameterize, rerun_if_address_is_in_use, spawn
from colossalai.testing.random import seed_all
from tests.test_moe.moe_utils import assert_loose_close, check_model_equal

NUM_BATCH = 8
NUM_TOK_PER_BATCH, NUM_EXPERTS = 64, 4
NUM_LAYERS = 4
HIDDEN_SIZE_PER_HEAD = 8
NUM_HEADS = 8
TOP_K = 2


def run_deepseek_commom(parallel_config: Tuple[int, ...]):
    Randomizer.reset_index()
    print(f"rank {dist.get_rank()} testing {parallel_config}")
    stage, ep_size, pp_size, tp_size, sp_size = parallel_config
    world_size = dist.get_world_size()
    rank = dist.get_rank()
    dtype, precision = torch.bfloat16, "bf16"
    torch.cuda.set_device(dist.get_rank())

    plugin = MoeHybridParallelPlugin(
        pp_size=pp_size,
        num_microbatches=pp_size,
        tp_size=tp_size,
        sp_size=sp_size,
        ep_size=ep_size,
        zero_stage=stage,
        enable_sequence_parallelism=sp_size > 1,
        sequence_parallelism_mode="all_to_all" if sp_size > 1 else None,
        overlap_communication=False,
        initial_scale=1,
        precision=precision,
        find_unused_parameters=True,
        enable_flash_attention=True,
    )
    dp_size = plugin.dp_size

    booster = Booster(plugin=plugin)

    assert pp_size <= NUM_LAYERS, "pp_size should be less than or equal to NUM_LAYERS"
    config = AutoConfig.from_pretrained(
        "deepseek-ai/deepseek-moe-16b-base",
        hidden_size=HIDDEN_SIZE_PER_HEAD * NUM_HEADS,
        intermediate_size=HIDDEN_SIZE_PER_HEAD * NUM_HEADS * 2,
        moe_intermediate_size=HIDDEN_SIZE_PER_HEAD * NUM_HEADS * 2,
        num_hidden_layers=4,
        num_attention_heads=NUM_HEADS,
        num_key_value_heads=NUM_HEADS,
        first_k_dense_replace=1,
        attn_implementation="flash_attention_2",
        torch_dtype="float16",
        n_routed_experts=NUM_EXPERTS,
        n_shared_experts=2,
        num_experts_per_tok=TOP_K,
        trust_remote_code=True,
    )

    # init model with the same seed
    seed_all(10086)

    torch_model = AutoModel.from_config(config, trust_remote_code=True).cuda().to(dtype)
    torch_optimizer = torch.optim.SGD(torch_model.parameters(), lr=1)

    parallel_model = deepcopy(torch_model)
    parallel_optimizer = torch.optim.SGD(parallel_model.parameters(), lr=1)
    parallel_model, parallel_optimizer, _, _, _ = booster.boost(parallel_model, parallel_optimizer)

    # create different input along dp axis
    seed_all(1453 + rank)

    torch_model.train()
    parallel_model.train()
    for _ in range(2):
        # gen random input
        input_embeddings = torch.rand(
            NUM_BATCH, NUM_TOK_PER_BATCH, HIDDEN_SIZE_PER_HEAD * NUM_HEADS, requires_grad=True
        ).cuda()
        dist.all_reduce(
            input_embeddings, group=plugin.pp_group
        )  # pp inputs except the first stage doesn't matter, but need to be replicate for torch model check

        dist.all_reduce(input_embeddings, group=plugin.tp_group)  # tp group duplicate input
        dist.all_reduce(input_embeddings, group=plugin.sp_group)  # sp group duplicate input

        # run the model with hybrid parallel
        if booster.plugin.stage_manager is not None:
            # for test with pp
            data_iter = iter([{"inputs_embeds": input_embeddings}])
            sharded_output = booster.execute_pipeline(
                data_iter,
                parallel_model,
                lambda x, y: x[0].mean(),
                parallel_optimizer,
                return_loss=True,
                return_outputs=True,
            )
            if booster.plugin.stage_manager.is_last_stage():
                parallel_output = sharded_output["loss"]
            else:
                parallel_output = torch.tensor(12345.0, device="cuda")

            # broadcast along pp axis
            dist.broadcast(
                parallel_output, src=dist.get_process_group_ranks(plugin.pp_group)[-1], group=plugin.pp_group
            )
        else:
            # for test without pp
            parallel_output = parallel_model(inputs_embeds=input_embeddings.to(dtype)).last_hidden_state.mean()
            parallel_optimizer.backward(parallel_output)
        parallel_optimizer.step()
        parallel_optimizer.zero_grad()
        dist.all_reduce(parallel_output, group=plugin.mixed_dp_group)

        # ===================================================================================
        # run normal model with all dp(different) inputs
        all_inputs = [torch.empty_like(input_embeddings) for _ in range(dp_size)]
        dist.all_gather(all_inputs, input_embeddings, group=plugin.mixed_dp_group)
        torch_output_sum = 0
        for input_data_ in all_inputs:
            torch_output = torch_model(inputs_embeds=input_data_.to(dtype)).last_hidden_state.mean()
            torch_output.backward()
            torch_output_sum += torch_output.detach()
        # avg dp grads follows zero optimizer
        for p in torch_model.parameters():
            if p.grad is not None:
                p.grad /= dp_size
        torch_optimizer.step()
        torch_optimizer.zero_grad()

        assert_loose_close(parallel_output, torch_output_sum, dtype=dtype)

    # use checkpoint to load sharded zero model
    model_dir = "./test_deepseek"
    if rank == world_size - 1:
        os.makedirs(model_dir, exist_ok=True)

    dist.barrier()
    booster.save_model(parallel_model, model_dir, shard=True)
    dist.barrier()

    saved_model = AutoModel.from_pretrained(model_dir, trust_remote_code=True).cuda()
    check_model_equal(torch_model, saved_model, dtype=dtype)
    dist.barrier()

    if rank == world_size - 1:
        shutil.rmtree(model_dir)

    print(f"rank {dist.get_rank()} passed {parallel_config}")


@parameterize(
    "config",
    [
        # DDP: ep == 1 since ep * moe_dp == dp == moe_dp; sp == 1 since sp * dp == moe_dp == dp
        (0, 1, 4, 1, 1),
        (0, 1, 1, 4, 1),
        (0, 1, 2, 2, 1),
        # zero 1
        (1, 4, 1, 1, 1),
        (1, 1, 4, 1, 1),
        (1, 1, 1, 4, 1),
        (1, 2, 1, 1, 2),
        # zero 2
        (2, 4, 1, 1, 1),
        (2, 1, 4, 1, 1),
        (2, 1, 1, 4, 1),
        (2, 2, 1, 1, 2),
    ],
)
def run_deepseek_test(config: Tuple[int, ...]):
    run_deepseek_commom(config)


@parameterize(
    "config",
    [
        # DDP: ep == 1 since ep * moe_dp == dp == moe_dp; sp == 1 since sp * dp == moe_dp == dp
        (0, 1, 2, 4, 1),
        (0, 1, 4, 2, 1),
        (0, 1, 1, 4, 1),
        # (0, 1, 4, 1, 1),  # todo: failed pass, need to be fixed
        (0, 1, 2, 1, 1),
        # zero 1:
        (1, 2, 1, 1, 2),
        (1, 2, 1, 4, 1),
        (1, 1, 1, 2, 2),
        (1, 2, 2, 2, 1),
        # zero 2
        (2, 2, 1, 1, 2),
        (2, 2, 1, 4, 1),
        (2, 1, 1, 2, 2),
        (2, 2, 2, 2, 1),
    ],
)
def run_deepseek_3d_test(config: Tuple[int, ...]):
    run_deepseek_commom(config)


def check_deepseek(rank, world_size, port):
    colossalai.launch(rank=rank, world_size=world_size, host="localhost", port=port, backend="nccl")
    run_deepseek_test()


def check_deepseek_3d(rank, world_size, port):
    colossalai.launch(rank=rank, world_size=world_size, host="localhost", port=port, backend="nccl")
    run_deepseek_3d_test()


@pytest.mark.dist
@pytest.mark.parametrize("world_size", [4])
@rerun_if_address_is_in_use()
def test_deepseek(world_size):
    spawn(check_deepseek, world_size)


@pytest.mark.largedist
@pytest.mark.parametrize("world_size", [8])
@rerun_if_address_is_in_use()
def test_deepseek_3d(world_size):
    spawn(check_deepseek_3d, world_size)


if __name__ == "__main__":
    test_deepseek(world_size=8)
    test_deepseek_3d(world_size=8)
