import os

import pytest
import torch
import torch.distributed as dist
from torch.testing import assert_close

import colossalai
from colossalai.logging import disable_existing_loggers
from colossalai.shardformer import PipelineGradientCheckpointConfig
from colossalai.shardformer.layer.utils import Randomizer
from colossalai.tensor.d_tensor.api import clear_layout_converter
from colossalai.testing import clear_cache_before_run, parameterize, rerun_if_address_is_in_use, spawn
from tests.kit.model_zoo import model_zoo
from tests.test_shardformer.test_model._utils import (
    build_model_from_hybrid_plugin,
    check_all_grad_tensors,
    check_loss,
    check_output_hidden_state,
    check_weight,
    get_grad_tensors_for_check,
    run_forward_backward_with_hybrid_plugin,
    unwrap_model,
)

os.environ["TRANSFORMERS_NO_ADVISORY_WARNINGS"] = "true"


def check_forward_backward(model_fn, data_gen_fn, output_transform_fn, loss_fn, test_config):
    enable_gradient_checkpointing = test_config.pop("enable_gradient_checkpointing", False)
    org_model, org_optimizer, sharded_model, sharded_optimizer, criterion, booster = build_model_from_hybrid_plugin(
        model_fn, loss_fn, test_config
    )
    if enable_gradient_checkpointing:
        # org_model.gradient_checkpointing_enable()
        sharded_model.unwrap().gradient_checkpointing_enable()

    org_loss, org_output, sharded_loss, sharded_output = run_forward_backward_with_hybrid_plugin(
        org_model, sharded_model, sharded_optimizer, data_gen_fn, output_transform_fn, criterion, booster
    )

    stage_manager = booster.plugin.stage_manager
    tp_group = booster.plugin.tp_group

    # unwrap model
    command_model = unwrap_model(org_model, "CohereModel", "model")
    shard_command_model = unwrap_model(sharded_model, "CohereModel", "model")

    row_layer_for_check = ["layers[0].self_attn.q_proj", "embed_tokens"]
    col_layer_for_check = ["layers[0].self_attn.o_proj"]
    # Here we check the grad of layernorm because an all-reduce operation should be performed during sequence parallelism
    norm_layer_for_check = ["layers[0].input_layernorm", "layers[1].input_layernorm"]

    # During pipeline parallelism, we cannot get the grad of norm layer during first stage, so we only check this when pp is not enbaled
    if stage_manager is None:
        norm_layer_for_check.append("norm")

    # Check the grad when using ZeRO-1 and ZeRO-2
    if (
        booster.plugin.zero_stage in [1, 2]
        and booster.plugin.shard_config.pipeline_stage_manager is None
        and booster.plugin.shard_config.enable_sequence_parallelism
        and booster.plugin.shard_config.sequence_parallelism_mode == "all_to_all"
    ):
        for p1, p2 in zip(command_model.parameters(), sharded_optimizer._master_param_groups_of_current_rank[0]):
            working_p = sharded_optimizer.master_to_working_param[id(p2)]
            grads = sharded_optimizer.get_partitioned_gradients_by_param_id(0, id(working_p))
            grad_index = (
                0 if sharded_optimizer._partition_grads else sharded_optimizer.pid_to_bucket_store[id(p2)].local_rank
            )
            grad = grads[grad_index]
            sharded_grad = p1.grad.view(-1).chunk(dist.get_world_size())[dist.get_rank()]
            assert_close(sharded_grad, grad[: sharded_grad.shape[0]], atol=5e-3, rtol=5e-3, check_dtype=False)

    # Save gradient tensors for comparison between the original model and the sharded model before optimizer step.
    grads_to_check = {}
    if (stage_manager is None or stage_manager.is_first_stage(ignore_chunk=True)) and booster.plugin.zero_stage == 0:
        if test_config["precision"] == "fp32":
            atol, rtol = 1e-6, 1e-4
        else:
            atol, rtol = 5e-3, 5e-3
        row_layer_grads = get_grad_tensors_for_check(
            command_model,
            shard_command_model,
            row_layer_for_check,
            tp_group,
            atol=atol,
            rtol=rtol,
            dim=0,
            verbose=False,
        )
        col_layer_grads = get_grad_tensors_for_check(
            command_model,
            shard_command_model,
            col_layer_for_check,
            tp_group,
            atol=atol,
            rtol=rtol,
            dim=1,
            verbose=False,
        )
        norm_layer_grads = get_grad_tensors_for_check(
            command_model,
            shard_command_model,
            norm_layer_for_check,
            tp_group,
            atol=atol,
            rtol=rtol,
            dim=1,
            verbose=False,
        )
        grads_to_check.update(col_layer_grads)
        grads_to_check.update(row_layer_grads)
        grads_to_check.update(norm_layer_grads)

    # optimizer executes step
    org_optimizer.step()
    sharded_optimizer.step()

    # check last hidden state & loss
    if stage_manager is None or stage_manager.is_last_stage(ignore_chunk=True):
        if test_config["precision"] == "fp32":
            atol, rtol = 1e-5, 1e-3
        else:
            atol, rtol = 5e-3, 5e-3

        if org_model.__class__.__name__ == "CohereModel":
            check_output_hidden_state(
                org_output,
                sharded_output,
                stage_manager,
                atol=atol,
                rtol=rtol,
                shard_config=booster.plugin.shard_config,
            )

        check_loss(org_loss, sharded_loss, atol=atol, rtol=rtol)

    # check weights
    if stage_manager is None or stage_manager.is_first_stage(ignore_chunk=True):
        if test_config["precision"] == "fp32":
            atol, rtol = 5e-4, 1e-3
        else:
            atol, rtol = 5e-3, 5e-3
        check_weight(
            command_model,
            shard_command_model,
            col_layer_for_check,
            tp_group,
            atol=atol,
            rtol=rtol,
            dim=1,
            verbose=False,
        )

    # check grads
    check_all_grad_tensors(grads_to_check)

    torch.cuda.empty_cache()


@parameterize(
    "test_config",
    [
        {  # Ulysess + Flash attention
            "tp_size": 1,
            "pp_size": 2,
            "sp_size": 2,
            "num_microbatches": 2,
            "enable_sequence_parallelism": True,
            "sequence_parallelism_mode": "all_to_all",
            "enable_flash_attention": True,
            "use_lazy_init": True,
            "zero_stage": 1,
            "precision": "fp16",
            "initial_scale": 1,
        },
        {
            "tp_size": 2,
            "pp_size": 2,
            "sp_size": 2,
            "num_microbatches": 2,
            "enable_sequence_parallelism": True,
            "sequence_parallelism_mode": "split_gather",
            "enable_flash_attention": True,
            "use_lazy_init": True,
            "zero_stage": 1,
            "precision": "fp16",
            "initial_scale": 1,
        },
        {
            "tp_size": 2,
            "pp_size": 2,
            "sp_size": 2,
            "num_microbatches": 2,
            "enable_sequence_parallelism": True,
            "sequence_parallelism_mode": "ring",
            "enable_flash_attention": True,
            "use_lazy_init": True,
            "zero_stage": 1,
            "precision": "fp16",
            "initial_scale": 1,
        },
        {
            "tp_size": 2,
            "pp_size": 1,
            "num_microbatches": 1,
            "enable_sequence_parallelism": True,
            "sequence_parallelism_mode": "ring",
            "enable_flash_attention": True,
            "use_lazy_init": True,
            "zero_stage": 2,
            "precision": "fp16",
            "initial_scale": 1,
        },
        {
            "tp_size": 4,
            "pp_size": 1,
            "num_microbatches": 1,
            "enable_sequence_parallelism": True,
            "sequence_parallelism_mode": "all_to_all",
            "enable_flash_attention": False,
            "use_lazy_init": True,
            "precision": "fp16",
            "initial_scale": 1,
        },
        {
            "tp_size": 1,
            "pp_size": 1,
            "sp_size": 2,
            "num_microbatches": 1,
            "enable_sequence_parallelism": True,
            "sequence_parallelism_mode": "all_to_all",
            "use_lazy_init": True,
            "zero_stage": 2,
            "precision": "fp16",
            "initial_scale": 1,
        },
        {
            "tp_size": 2,
            "pp_size": 2,
            "num_microbatches": 2,
            "enable_all_optimization": True,
            "use_lazy_init": True,
            "precision": "fp16",
            "initial_scale": 1,
            "enable_gradient_checkpointing": True,
            "gradient_checkpoint_config": PipelineGradientCheckpointConfig(gradient_checkpointing_ratio=0.5),
        },
        {
            "tp_size": 1,
            "pp_size": 2,
            "num_microbatches": 4,
            "use_lazy_init": False,
            "precision": "fp32",
            "enable_gradient_checkpointing": True,
            "gradient_checkpoint_config": PipelineGradientCheckpointConfig(num_ckpt_layers_per_stage=[4, 0]),
        },
        {
            "tp_size": 2,
            "pp_size": 1,
            "enable_all_optimization": True,
            "use_lazy_init": True,
            "zero_stage": 2,
            "precision": "fp16",
            "initial_scale": 1,
        },
        {
            "tp_size": 1,
            "pp_size": 2,
            "num_microbatches": 2,
            "enable_all_optimization": True,
            "use_lazy_init": True,
            "zero_stage": 1,
            "precision": "fp16",
            "initial_scale": 1,
        },
    ],
)
def run_command_test(test_config):
    sub_model_zoo = model_zoo.get_sub_registry("transformers_command", "transformers_command_for_causal_lm")

    for name, (model_fn, data_gen_fn, output_transform_fn, loss_fn, _) in sub_model_zoo.items():
        try:
            check_forward_backward(model_fn, data_gen_fn, output_transform_fn, loss_fn, test_config)
        except Exception as e:
            print(f"Failed test config: {test_config}")
            raise e

    clear_layout_converter()
    Randomizer.reset_index()
    torch.cuda.empty_cache()


@parameterize(
    "test_config",
    [
        {
            "tp_size": 2,
            "pp_size": 2,
            "num_microbatches": 4,
            "enable_all_optimization": False,
            "use_lazy_init": False,
            "precision": "fp32",
            "initial_scale": 1,
        },
        {
            "tp_size": 2,
            "pp_size": 2,
            "num_microbatches": 4,
            "enable_all_optimization": False,
            "use_lazy_init": False,
            "precision": "fp16",
            "zero_stage": 1,
            "initial_scale": 1,
        },
        {
            "tp_size": 2,
            "pp_size": 2,
            "pp_style": "interleaved",
            "num_model_chunks": 2,
            "num_microbatches": 4,
            "enable_all_optimization": False,
            "precision": "fp16",
            "zero_stage": 1,
            "initial_scale": 1,
            "enable_gradient_checkpointing": True,
            "gradient_checkpoint_config": PipelineGradientCheckpointConfig(
                num_ckpt_layers_per_stage=[0, 1, 2, 2],
            ),
        },
    ],
)
def run_command_3d_test(test_config):
    sub_model_zoo = model_zoo.get_sub_registry("transformers_command", "transformers_command_for_causal_lm")

    for name, (model_fn, data_gen_fn, output_transform_fn, loss_fn, _) in sub_model_zoo.items():
        check_forward_backward(model_fn, data_gen_fn, output_transform_fn, loss_fn, test_config)

    clear_layout_converter()
    Randomizer.reset_index()
    torch.cuda.empty_cache()


def check_command(rank, world_size, port):
    disable_existing_loggers()
    colossalai.launch(rank=rank, world_size=world_size, host="localhost", port=port, backend="nccl")
    run_command_test()


def check_command_3d(rank, world_size, port):
    disable_existing_loggers()
    colossalai.launch(rank=rank, world_size=world_size, host="localhost", port=port, backend="nccl")
    run_command_3d_test()


@pytest.mark.dist
@rerun_if_address_is_in_use()
@clear_cache_before_run()
def test_command():
    spawn(check_command, 4)


@pytest.mark.largedist
@rerun_if_address_is_in_use()
@clear_cache_before_run()
def test_command_3d():
    spawn(check_command_3d, 8)


if __name__ == "__main__":
    test_command()
    test_command_3d()
