from pathlib import Path
from importlib import import_module

import torch

import ignite
import ignite.distributed as idist
from ignite.utils import manual_seed, setup_logger

import fire
from omegaconf import OmegaConf


def log_basic_info(logger, config):
    logger.info(f"Train {config.name}")
    logger.info(f"- PyTorch version: {torch.__version__}")
    logger.info(f"- Ignite version: {ignite.__version__}")
    if idist.get_world_size() > 1:
        logger.info("Distributed setting:\n")
        idist.show_config()


def running(local_rank, config, task, backup_config=False, setup_output_dir=False, setup_random_seed=False):
    logger = setup_logger(name=config.name, distributed_rank=local_rank, **config.log.logger)
    log_basic_info(logger, config)

    if setup_random_seed:
        manual_seed(config.misc.random_seed + idist.get_rank())
    if setup_output_dir:
        output_dir = Path(config.result_dir) / config.name if config.output_dir is None else config.output_dir
        config.output_dir = str(output_dir)
        if idist.get_rank() == 0:
            if not output_dir.exists():
                output_dir.mkdir(parents=True)
                logger.info(f"mkdir -p {output_dir}")
            logger.info(f"output path: {config.output_dir}")
            if backup_config:
                with open(output_dir / "config.yml", "w+") as f:
                    print(config.pretty(), file=f)

    OmegaConf.set_readonly(config, True)

    engine = import_module(f"engine.{config.engine}")
    engine.run(task, config, logger)


def run(task, config: str, *omega_options, **kwargs):
    omega_options = [str(o) for o in omega_options]
    conf = OmegaConf.merge(OmegaConf.load(config), OmegaConf.from_cli(omega_options))
    backend = kwargs.get("backend", "nccl")
    backup_config = kwargs.get("backup_config", False)
    setup_output_dir = kwargs.get("setup_output_dir", False)
    setup_random_seed = kwargs.get("setup_random_seed", False)
    with idist.Parallel(backend=backend) as parallel:
        parallel.run(running, conf, task, backup_config=backup_config, setup_output_dir=setup_output_dir,
                     setup_random_seed=setup_random_seed)


if __name__ == '__main__':
    fire.Fire(run)