import argparse
import torch

import torch.multiprocessing as mp
import torch.distributed as dist

from utils.init import initialize_from_env
from models.setup import setup_model, setup_data
from tasks.stage_2 import train as train_stage_2


parser = argparse.ArgumentParser(description='Main script for v2dial')
parser.add_argument(
    '--model',
    type=str,
    default='v2dial/stage_2',
    help='model name to train or test')

parser.add_argument(
    '--mode',
    type=str,
    default='train',
    help='train, generate or debug'
    )

parser.add_argument(
    '--eval_dir',
    type=str,
    default='eval_dir',
)

parser.add_argument(
    '--wandb_mode',
    type=str,
    default='online',
    choices=['online', 'offline', 'disabled', 'run', 'dryrun']
)

parser.add_argument(
    '--wandb_project',
    type=str,
    default='V2Dial'
)

parser.add_argument(
    '--tag',
    type=str,
    default='experiment_tag',
    help="Tag to differentiate the models"
)

parser.add_argument(
    '--medium',
    type=str,
    default='avsd',
    help="Medium of the test dataset"
)

parser.add_argument(
    '--start_idx_gen',
    type=int,
    default=0,
    help="The start index for generation"
)

parser.add_argument(
    '--end_idx_gen',
    type=int,
    default=10,
    help="The end index for generation"
)

parser.add_argument(
    '--gen_subset_num',
    type=int,
    default=1,
    help="The index of the test split for generation"
)

parser.add_argument('--ssh', action='store_true',
                    help='whether or not we are executing command via ssh. '
                         'If set to True, we will not log.info anything to screen and only redirect them to log file')


def main(gpu, config, args):
    
    config['gpu'] = gpu
    if config['distributed']:
        dist.init_process_group(
            backend='nccl',
            world_size=config['num_gpus'],
            rank=gpu
        )
        torch.cuda.set_device(gpu)
    
    device = torch.device(f'cuda:{gpu}')
    if config.use_cpu:
        device = torch.device('cpu')
    config['device'] = device
    
    if config['training']:
        train_dataloaders, val_dataloaders = setup_data(config)

    ( 
         model, model_without_ddp, optimizer, scheduler, scaler, start_epoch, global_step, config
    ) = setup_model(config)

    if config['training']:
        train_stage_2(
            model,
            model_without_ddp,
            train_dataloaders,
            val_dataloaders,
            optimizer,
            global_step,
            scheduler,
            scaler,
            start_epoch,
            config
        )

    if config['distributed']:
        dist.destroy_process_group()

if __name__ == '__main__':
    args = parser.parse_args()
    
    # initialization
    model, stage = args.model.split('/')
    config = initialize_from_env(model, args.mode, stage, args.eval_dir, tag=args.tag)
    config['wandb_enabled'] = args.wandb_mode == 'online'
    config['training'] = args.mode == 'train'
    config['generating'] = args.mode == 'generate'
    config['debugging'] = args.mode == 'debug'

    config['wandb_mode'] = args.wandb_mode
    config['medium'] = args.medium
    config['start_idx_gen'] = args.start_idx_gen
    config['end_idx_gen'] = args.end_idx_gen

    if config['num_gpus'] > 1:
        config['distributed'] = True
        mp.spawn(main, nprocs=config['num_gpus'], args=(config, args))
    else:
        config['distributed'] = False
        main(0, config, args)