from typing import Optional

import torch
import torch.distributed as dist

import colossalai
from colossalai.booster import Booster
from colossalai.booster.plugin import LowLevelZeroPlugin
from colossalai.nn.optimizer import HybridAdam
from colossalai.testing import parameterize, rerun_if_address_is_in_use, spawn
from tests.kit.model_zoo import model_zoo

# These models are not compatible with AMP
_AMP_ERR_MODELS = ['timm_convit', 'dlrm', 'deepfm_interactionarch', 'deepfm_simpledeepfmnn`']
# These models have no parameters
_LOW_LEVEL_ZERO_ERR_MODELS = ['dlrm_interactionarch']
# These models will get stuck
_STUCK_MODELS = [
    'diffusers_vq_model', 'transformers_albert', 'transformers_albert_for_pretraining', 'transformers_bert',
    'transformers_bert_for_pretraining', 'transformers_gpt_double_heads'
]


def run_fn(stage, model_fn, data_gen_fn, output_transform_fn) -> Optional[str]:
    try:
        plugin = LowLevelZeroPlugin(stage=stage, max_norm=1.0, initial_scale=2**5)
        booster = Booster(plugin=plugin)
        model = model_fn()
        optimizer = HybridAdam(model.parameters(), lr=1e-3)
        criterion = lambda x: x.mean()
        data = data_gen_fn()

        data = {
            k: v.to('cuda') if torch.is_tensor(v) or 'Tensor' in v.__class__.__name__ else v for k, v in data.items()
        }

        model, optimizer, criterion, _, _ = booster.boost(model, optimizer, criterion)

        output = model(**data)
        output = output_transform_fn(output)
        output_key = list(output.keys())[0]
        loss = criterion(output[output_key])

        booster.backward(loss, optimizer)
        optimizer.step()

    except Exception as e:
        return repr(e)


@parameterize('stage', [2])
def check_low_level_zero_plugin(stage: int, early_stop: bool = True):
    """check low level zero plugin over model zoo

    Args:
        stage (int), stage of low level zero plugin
        early_stop (bool, optional): Whether to stop when getting the first error. Defaults to True.
    """
    passed_models = []
    failed_info = {}    # (model_name, error) pair
    ignore_models = _AMP_ERR_MODELS + _LOW_LEVEL_ZERO_ERR_MODELS + _STUCK_MODELS
    skipped_models = []

    for name, (model_fn, data_gen_fn, output_transform_fn, _) in model_zoo.items():
        # FIXME(ver217): fix these models
        if name in ignore_models:
            skipped_models.append(name)
            continue
        err = run_fn(stage, model_fn, data_gen_fn, output_transform_fn)
        torch.cuda.empty_cache()

        if err is None:
            passed_models.append(name)
        else:
            failed_info[name] = err
            if early_stop:
                break

    if dist.get_rank() == 0:
        print(f'Passed models({len(passed_models)}): {passed_models}\n\n')
        print(f'Failed models({len(failed_info)}): {list(failed_info.keys())}\n\n')
        print(f'Skipped models({len(skipped_models)}): {skipped_models}\n\n')
    assert len(failed_info) == 0, '\n'.join([f'{k}: {v}' for k, v in failed_info.items()])


def run_dist(rank, world_size, port, early_stop: bool = True):
    # init dist env
    colossalai.launch(config=dict(), rank=rank, world_size=world_size, port=port, host='localhost')
    check_low_level_zero_plugin(early_stop=early_stop)


@rerun_if_address_is_in_use()
def test_low_level_zero_plugin(early_stop: bool = True):
    spawn(run_dist, 2, early_stop=early_stop)


if __name__ == '__main__':
    test_low_level_zero_plugin(early_stop=False)
