# pylint: skip-file
import os

rank = os.environ.get('RANK', -1)
print("rank:", rank)
print("world_size:", os.environ.get("WORLD_SIZE", -1))
print("local_rank:", os.environ.get("LOCAL_RANK", -1))
# run in remote
if rank != -1:
    os.system(
        "pip3 install https://automl-nni.oss-cn-beijing.aliyuncs.com/nni/hpo_tools/hpo_tools-0.2.1-py3-none-any.whl")
    # 鍒ゆ柇 Torch 鏄惁宸茬粡瀹夎
    try:
        import torch
    except ImportError:
        # 濡傛灉鏈畨瑁咃紝鍒欎娇鐢� pip 瀹夎 Torch
        os.system("pip3 install torch torchvision --trusted-host yum.tbsite.net -i http://yum.tbsite.net/pypi/simple/")

import logging
import pathlib
import argparse

import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim
from torchvision import datasets, transforms
from torch.optim.lr_scheduler import StepLR
import torch.distributed as dist

logger = logging.getLogger('mnist_AutoML')


def init_distributed_mode(args):
    """initilize DDP."""
    if "RANK" in os.environ and "WORLD_SIZE" in os.environ:
        args['rank'] = int(os.environ["RANK"])
        args['world_size'] = int(os.environ["WORLD_SIZE"])

    elif "SLURM_PROCID" in os.environ:
        args['rank'] = int(os.environ["SLURM_PROCID"])

    elif hasattr(args, "rank"):
        pass
    else:
        print("Not using distributed mode")
        args['distributed'] = False
        return

    args['distributed'] = True
    if torch.cuda.device_count() > 0:
        args['local_rank'] = args['rank'] % torch.cuda.device_count()
    if args['use_cuda']:
        torch.cuda.set_device(args['local_rank'])
    print(
        f"| distributed init (rank {args['rank']}): {args['dist_url']}, "
        f"local rank:{args['local_rank']}, world size:{args['world_size']}",
        flush=True)
    dist.init_process_group(backend=args['backend'],
                            init_method=args['dist_url'],
                            world_size=args['world_size'],
                            rank=args['rank'])
    print("init success")


class Net(nn.Module):
    def __init__(self):
        super(Net, self).__init__()
        self.conv1 = nn.Conv2d(1, 32, 3, 1)
        self.conv2 = nn.Conv2d(32, 64, 3, 1)
        self.dropout1 = nn.Dropout(0.25)
        self.dropout2 = nn.Dropout(0.5)
        self.fc1 = nn.Linear(9216, 128)
        self.fc2 = nn.Linear(128, 10)

    def forward(self, x):
        x = self.conv1(x)
        x = F.relu(x)
        x = self.conv2(x)
        x = F.relu(x)
        x = F.max_pool2d(x, 2)
        x = self.dropout1(x)
        x = torch.flatten(x, 1)
        x = self.fc1(x)
        x = F.relu(x)
        x = self.dropout2(x)
        x = self.fc2(x)
        output = F.log_softmax(x, dim=1)
        return output


def train(args, model, device, train_loader, optimizer, epoch):
    model.train()
    for batch_idx, (data, target) in enumerate(train_loader):
        data, target = data.to(device), target.to(device)
        optimizer.zero_grad()
        output = model(data)
        loss = F.nll_loss(output, target)
        loss.backward()
        optimizer.step()
        if args['distributed']:
            if dist.get_rank() == 0:
                if batch_idx % args['log_interval'] == 0:
                    print('Train Epoch: {}/{} [{}/{} ({:.0f}%)]\tLoss: {:.6f}'.format(
                        epoch, batch_idx,
                        dist.get_world_size() * batch_idx * len(data), len(train_loader.dataset),
                        100. * batch_idx / len(train_loader), loss.item()))
        else:
            if batch_idx % args['log_interval'] == 0:
                print('Train Epoch: {}/{} [{}/{} ({:.0f}%)]\tLoss: {:.6f}'.format(epoch, batch_idx,
                                                                                  batch_idx * len(data),
                                                                                  len(train_loader.dataset),
                                                                                  100. * batch_idx / len(train_loader),
                                                                                  loss.item()))
        if args['dry_run']:
            break


def test(model, device, test_loader):
    model.eval()
    test_loss = 0
    correct = 0
    with torch.no_grad():
        for data, target in test_loader:
            data, target = data.to(device), target.to(device)
            output = model(data)
            test_loss += F.nll_loss(output, target, reduction='sum').item()  # sum up batch loss
            pred = output.argmax(dim=1, keepdim=True)  # get the index of the max log-probability
            correct += pred.eq(target.view_as(pred)).sum().item()

    test_loss /= len(test_loader.dataset)
    accuracy = 100. * correct / len(test_loader.dataset)
    print('\nTest set: Average loss: {:.4f}, Accuracy: {}/{} ({:.0f}%)\n'.format(
        test_loss, correct, len(test_loader.dataset), 100. * correct / len(test_loader.dataset)))

    return accuracy


def get_params():
    # Training settings
    parser = argparse.ArgumentParser(description='PyTorch MNIST Example')
    parser.add_argument("--data_dir", type=str, default='../data/mnist/', help="data directory")
    parser.add_argument('--batch_size',
                        type=int,
                        default=256,
                        metavar='N',
                        help='input batch size for training (default: 64)')
    parser.add_argument('--test-batch-size',
                        type=int,
                        default=1000,
                        metavar='N',
                        help='input batch size for testing (default: 1000)')
    parser.add_argument('--epochs', type=int, default=5, metavar='N', help='number of epochs to train (default: 14)')
    parser.add_argument('--lr', type=float, default=1.0, metavar='LR', help='learning rate (default: 1.0)')
    parser.add_argument('--gamma', type=float, default=0.7, metavar='M', help='Learning rate step gamma (default: 0.7)')
    parser.add_argument('--no-cuda', action='store_true', default=False, help='disables CUDA training')
    parser.add_argument('--dry-run', action='store_true', default=False, help='quickly check a single pass')
    parser.add_argument('--seed', type=int, default=1, metavar='S', help='random seed (default: 1)')
    parser.add_argument('--log-interval',
                        type=int,
                        default=10,
                        metavar='N',
                        help='how many batches to wait before logging training status')
    parser.add_argument('--save_model', type=str, default='../model', help='For Saving the current Model')

    parser.add_argument('--local_rank', type=int, help='local rank, will passed by ddp')
    parser.add_argument("--world-size", default=1, type=int, help="number of distributed processes")
    parser.add_argument("--dist-url", default="env://", type=str, help="url used to set up distributed training")
    parser.add_argument("--metric_filepath", default="../metric", type=str, help="oss dir to store the metric file")
    parser.add_argument("--stdout_filepath", default="../stdout", type=str, help="oss dir to store the metric file")
    parser.add_argument('--backend',
                        type=str,
                        help='Distributed backend',
                        choices=[dist.Backend.GLOO, dist.Backend.NCCL, dist.Backend.MPI],
                        default=dist.Backend.GLOO)
    args, _ = parser.parse_known_args()
    return args


def main(args):
    print(args['batch_size'])
    print(args['no_cuda'])
    use_cuda = not args['no_cuda'] and torch.cuda.is_available()
    args['use_cuda'] = use_cuda

    init_distributed_mode(args)

    torch.manual_seed(args['seed'])

    device = torch.device("cuda" if use_cuda else "cpu")
    print("device:", device)

    train_kwargs = {'batch_size': args['batch_size']}
    test_kwargs = {'batch_size': args['test_batch_size']}
    if use_cuda:
        cuda_kwargs = {
            'num_workers': 1,
            'pin_memory': True,
        }
        train_kwargs.update(cuda_kwargs)
        test_kwargs.update(cuda_kwargs)

    transform = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.1307,), (0.3081,))])
    dataset_train = datasets.MNIST(args['data_dir'], train=True, download=True, transform=transform)
    dataset_val = datasets.MNIST(args['data_dir'], train=False, transform=transform)
    if args['distributed']:
        train_sampler = torch.utils.data.distributed.DistributedSampler(dataset_train, shuffle=True)
    else:
        train_sampler = torch.utils.data.RandomSampler(dataset_train)
    test_sampler = torch.utils.data.SequentialSampler(dataset_val)

    train_loader = torch.utils.data.DataLoader(dataset_train, sampler=train_sampler, **train_kwargs)
    test_loader = torch.utils.data.DataLoader(dataset_val, sampler=test_sampler, **test_kwargs)

    model = Net().to(device)
    model_without_ddp = model
    if args['distributed']:
        if use_cuda:
            model = torch.nn.parallel.DistributedDataParallel(model,
                                                              device_ids=[args['local_rank']],
                                                              output_device=args['local_rank'])
        else:
            model = torch.nn.parallel.DistributedDataParallel(model)
        model_without_ddp = model.module

    optimizer = optim.Adadelta(model.parameters(), lr=args['lr'])

    scheduler = StepLR(optimizer, step_size=1, gamma=args['gamma'])
    for epoch in range(1, args['epochs'] + 1):
        if args['distributed']:
            train_sampler.set_epoch(epoch)
        train(args, model, device, train_loader, optimizer, epoch)
        if args['distributed']:
            # Only run validation on GPU 0 process, for simplity, so we do not run validation on multi gpu.
            if dist.get_rank() == 0:
                test_acc = test(model_without_ddp, device, test_loader)
        else:
            test_acc = test(model, device, test_loader)
        scheduler.step()

        if (args['distributed'] and dist.get_rank() == 0) or not args['distributed']:
            print(f'validation: accuracy={test_acc}')

    if args['save_model']:
        # only save model on 0 process.
        if (args['distributed'] and dist.get_rank() == 0) or not args['distributed']:
            pathlib.Path(args['save_model']).mkdir(parents=True, exist_ok=True)
            path = os.path.join(args['save_model'], "mnist_cnn.pt")
            torch.save(model.state_dict(), path)

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


if __name__ == '__main__':
    args = get_params()
    print("args:", args)
    main(vars(args))