import os
os.environ["KMP_DUPLICATE_LIB_OK"]  =  "TRUE"

import argparse
import datetime
import numpy as np
import time
import torch
import torch.backends.cudnn as cudnn
import json
import yaml
from pathlib import Path
from timm.data import Mixup
from timm.models import create_model
from timm.loss import LabelSmoothingCrossEntropy, SoftTargetCrossEntropy
from timm.scheduler import create_scheduler
from timm.optim import create_optimizer
from timm.utils import NativeScaler
from lib.datasets import build_dataset
from model.space_engine import train_one_epoch, evaluate
from lib.samplers import RASampler
from lib import utils
from lib.config import cfg, update_config_from_file
import timm
from model.pit_space import pit
from model.autoformer_space import Vision_TransformerSuper
from collections import OrderedDict


def get_args_parser():
    parser = argparse.ArgumentParser('Training and Evaluation Script', add_help=False)
    parser.add_argument('--batch-size', default=512, type=int)
    parser.add_argument('--epochs', default=300, type=int)
    # config file
    parser.add_argument('--cfg',help='experiment configure file name',required=True,type=str)

    # custom parameters
    parser.add_argument('--platform', default='pai', type=str, choices=['itp', 'pai', 'aml'],
                        help='Name of model to train')
    parser.add_argument('--teacher_model', default='', type=str,
                        help='Name of teacher model to train')
    parser.add_argument('--relative_position', action='store_true')
    parser.add_argument('--gp', action='store_true')
    parser.add_argument('--change_qkv', action='store_true')
    parser.add_argument('--max_relative_position', type=int, default=14, help='max distance in relative position embedding')

    # Model parameters
    parser.add_argument('--model', default='', type=str, metavar='MODEL',
                        help='Name of model to train')
    parser.add_argument('--model_type', default='AUTOFORMER', type=str,
                        help='Type of space to search')

    parser.add_argument('--mode', type=str, default='retrain', choices=['super', 'retrain'], help='mode of AutoFormer')
    parser.add_argument('--input-size', default=224, type=int)
    parser.add_argument('--patch_size', default=16, type=int)

    parser.add_argument('--drop', type=float, default=0.0, metavar='PCT',
                        help='Dropout rate (default: 0.)')
    parser.add_argument('--drop-path', type=float, default=0.1, metavar='PCT',
                        help='Drop path rate (default: 0.1)')
    parser.add_argument('--drop-block', type=float, default=None, metavar='PCT',
                        help='Drop block rate (default: None)')

    parser.add_argument('--model-ema', action='store_true')
    parser.add_argument('--no-model-ema', action='store_false', dest='model_ema')
    # parser.set_defaults(model_ema=True)
    parser.add_argument('--model-ema-decay', type=float, default=0.99996, help='')
    parser.add_argument('--model-ema-force-cpu', action='store_true', default=False, help='')
    parser.add_argument('--rpe_type', type=str, default='bias', choices=['bias', 'direct'])
    parser.add_argument('--post_norm', action='store_true')
    parser.add_argument('--no_abs_pos', action='store_true')

    # Optimizer parameters
    parser.add_argument('--opt', default='adamw', type=str, metavar='OPTIMIZER',
                        help='Optimizer (default: "adamw"')
    parser.add_argument('--opt-eps', default=1e-8, type=float, metavar='EPSILON',
                        help='Optimizer Epsilon (default: 1e-8)')
    parser.add_argument('--opt-betas', default=None, type=float, nargs='+', metavar='BETA',
                        help='Optimizer Betas (default: None, use opt default)')
    parser.add_argument('--clip-grad', type=float, default=None, metavar='NORM',
                        help='Clip gradient norm (default: None, no clipping)')
    parser.add_argument('--momentum', type=float, default=0.9, metavar='M',
                        help='SGD momentum (default: 0.9)')
    parser.add_argument('--weight-decay', type=float, default=0.05,
                        help='weight decay (default: 0.05)')

    # Learning rate schedule parameters
    parser.add_argument('--sched', default='cosine', type=str, metavar='SCHEDULER',
                        help='LR scheduler (default: "cosine"')
    parser.add_argument('--lr', type=float, default=5e-4, metavar='LR',
                        help='learning rate (default: 5e-4)')
    parser.add_argument('--lr-noise', type=float, nargs='+', default=None, metavar='pct, pct',
                        help='learning rate noise on/off epoch percentages')
    parser.add_argument('--lr-noise-pct', type=float, default=0.67, metavar='PERCENT',
                        help='learning rate noise limit percent (default: 0.67)')
    parser.add_argument('--lr-noise-std', type=float, default=1.0, metavar='STDDEV',
                        help='learning rate noise std-dev (default: 1.0)')
    parser.add_argument('--warmup-lr', type=float, default=1e-6, metavar='LR',
                        help='warmup learning rate (default: 1e-6)')
    parser.add_argument('--min-lr', type=float, default=1e-5, metavar='LR',
                        help='lower lr bound for cyclic schedulers that hit 0 (1e-5)')
    parser.add_argument('--lr-power', type=float, default=1.0,
                        help='power of the polynomial lr scheduler')

    parser.add_argument('--decay-epochs', type=float, default=30, metavar='N',
                        help='epoch interval to decay LR')
    parser.add_argument('--warmup-epochs', type=int, default=5, metavar='N',
                        help='epochs to warmup LR, if scheduler supports')
    parser.add_argument('--cooldown-epochs', type=int, default=10, metavar='N',
                        help='epochs to cooldown LR at min_lr, after cyclic schedule ends')
    parser.add_argument('--patience-epochs', type=int, default=10, metavar='N',
                        help='patience epochs for Plateau LR scheduler (default: 10')
    parser.add_argument('--decay-rate', '--dr', type=float, default=0.1, metavar='RATE',
                        help='LR decay rate (default: 0.1)')

    # Augmentation parameters
    parser.add_argument('--color-jitter', type=float, default=0.4, metavar='PCT',
                        help='Color jitter factor (default: 0.4)')
    parser.add_argument('--aa', type=str, default='rand-m9-mstd0.5-inc1', metavar='NAME',
                        help='Use AutoAugment policy. "v0" or "original". " + \
                             "(default: rand-m9-mstd0.5-inc1)'),
    parser.add_argument('--smoothing', type=float, default=0.1, help='Label smoothing (default: 0.1)')
    parser.add_argument('--train-interpolation', type=str, default='bicubic',
                        help='Training interpolation (random, bilinear, bicubic default: "bicubic")')

    parser.add_argument('--repeated-aug', action='store_true')
    parser.add_argument('--no-repeated-aug', action='store_false', dest='repeated_aug')


    parser.set_defaults(repeated_aug=True)

    # * Random Erase params
    parser.add_argument('--reprob', type=float, default=0.25, metavar='PCT',
                        help='Random erase prob (default: 0.25)')
    parser.add_argument('--remode', type=str, default='pixel',
                        help='Random erase mode (default: "pixel")')
    parser.add_argument('--recount', type=int, default=1,
                        help='Random erase count (default: 1)')
    parser.add_argument('--resplit', action='store_true', default=False,
                        help='Do not random erase first (clean) augmentation split')

    # * Mixup params
    parser.add_argument('--mixup', type=float, default=0.8,
                        help='mixup alpha, mixup enabled if > 0. (default: 0.8)')
    parser.add_argument('--cutmix', type=float, default=1.0,
                        help='cutmix alpha, cutmix enabled if > 0. (default: 1.0)')
    parser.add_argument('--cutmix-minmax', type=float, nargs='+', default=None,
                        help='cutmix min/max ratio, overrides alpha and enables cutmix if set (default: None)')
    parser.add_argument('--mixup-prob', type=float, default=1.0,
                        help='Probability of performing mixup or cutmix when either/both is enabled')
    parser.add_argument('--mixup-switch-prob', type=float, default=0.5,
                        help='Probability of switching to cutmix when both mixup and cutmix enabled')
    parser.add_argument('--mixup-mode', type=str, default='batch',
                        help='How to apply mixup/cutmix params. Per "batch", "pair", or "elem"')

    # Dataset parameters
    parser.add_argument('--data-path', default='./data/imagenet/', type=str,
                        help='dataset path')
    parser.add_argument('--data-set', default='IMNET', choices=['CIFAR10', 'CIFAR100', 'IMNET'],
                        type=str, help='Image Net dataset path')
    parser.add_argument('--inat-category', default='name',
                        choices=['kingdom', 'phylum', 'class', 'order', 'supercategory', 'family', 'genus', 'name'],
                        type=str, help='semantic granularity')

    parser.add_argument('--output_dir', default='',
                        help='path where to save, empty for no saving')
    parser.add_argument('--device', default='cuda',
                        help='device to use for training / testing')
    parser.add_argument('--seed', default=0, type=int)
    parser.add_argument('--resume', default='', help='resume from checkpoint')
    parser.add_argument('--start_epoch', default=0, type=int, metavar='N',
                        help='start epoch')
    parser.add_argument('--eval', action='store_true', help='Perform evaluation only')
    parser.add_argument('--num_workers', default=6, type=int)
    parser.add_argument('--dist-eval', action='store_true', default=False, help='Enabling distributed evaluation')
    parser.add_argument('--pin-mem', action='store_true',
                        help='Pin CPU memory in DataLoader for more efficient (sometimes) transfer to GPU.')
    parser.add_argument('--no-pin-mem', action='store_false', dest='pin_mem',
                        help='')
    parser.set_defaults(pin_mem=True)

    # distributed training parameters
    parser.add_argument('--world_size', default=1, type=int,
                        help='number of distributed processes')
    parser.add_argument('--dist_url', default='env://', help='url used to set up distributed training')

    parser.add_argument('--amp', action='store_true')
    parser.add_argument('--no-amp', action='store_false', dest='amp')
    parser.set_defaults(amp=True)


    return parser

def main(args):

    utils.init_distributed_mode(args)
    update_config_from_file(args.cfg)

    print(args)
    args_text = yaml.safe_dump(args.__dict__, default_flow_style=False)

    device = torch.device(args.device)

    seed = args.seed + utils.get_rank()
    torch.manual_seed(seed)
    np.random.seed(seed)
    cudnn.benchmark = True

    dataset_train, args.nb_classes = build_dataset(is_train=True, args=args)
    dataset_val, _ = build_dataset(is_train=False, args=args)

    if args.distributed:
        num_tasks = utils.get_world_size()
        global_rank = utils.get_rank()
        if args.repeated_aug:
            sampler_train = RASampler(
                dataset_train, num_replicas=num_tasks, rank=global_rank, shuffle=True
            )
        else:
            sampler_train = torch.utils.data.DistributedSampler(
                dataset_train, num_replicas=num_tasks, rank=global_rank, shuffle=True
            )
        if args.dist_eval:
            if len(dataset_val) % num_tasks != 0:
                print(
                    'Warning: Enabling distributed evaluation with an eval dataset not divisible by process number. '
                    'This will slightly alter validation results as extra duplicate entries are added to achieve '
                    'equal num of samples per-process.')
            sampler_val = torch.utils.data.DistributedSampler(
                dataset_val, num_replicas=num_tasks, rank=global_rank, shuffle=False)
        else:
            sampler_val = torch.utils.data.SequentialSampler(dataset_val)
    else:
        sampler_val = torch.utils.data.SequentialSampler(dataset_val)
        sampler_train = torch.utils.data.RandomSampler(dataset_train)

    data_loader_train = torch.utils.data.DataLoader(
        dataset_train, sampler=sampler_train,
        batch_size=args.batch_size,
        num_workers=args.num_workers,
        pin_memory=args.pin_mem,
        drop_last=True,
    )

    data_loader_val = torch.utils.data.DataLoader(
        dataset_val, batch_size=int(2 * args.batch_size),
        sampler=sampler_val, num_workers=args.num_workers,
        pin_memory=args.pin_mem, drop_last=False
    )

    mixup_fn = None
    mixup_active = args.mixup > 0 or args.cutmix > 0. or args.cutmix_minmax is not None
    if mixup_active:
        mixup_fn = Mixup(
            mixup_alpha=args.mixup, cutmix_alpha=args.cutmix, cutmix_minmax=args.cutmix_minmax,
            prob=args.mixup_prob, switch_prob=args.mixup_switch_prob, mode=args.mixup_mode,
            label_smoothing=args.smoothing, num_classes=args.nb_classes)

    print(cfg)
    if args.model_type == 'AUTOFORMER':
        model_type = args.model_type
        model = Vision_TransformerSuper(img_size=args.input_size,
                                        patch_size=args.patch_size,
                                        embed_dim=cfg.SUPERNET.EMBED_DIM, depth=cfg.SUPERNET.DEPTH,
                                        num_heads=cfg.SUPERNET.NUM_HEADS,mlp_ratio=cfg.SUPERNET.MLP_RATIO,
                                        qkv_bias=True, drop_rate=args.drop,
                                        drop_path_rate=args.drop_path,
                                        gp=args.gp,
                                        num_classes=args.nb_classes,
                                        max_relative_position=args.max_relative_position,
                                        relative_position=args.relative_position,
                                        change_qkv=args.change_qkv, abs_pos=not args.no_abs_pos)
        choices = {'num_heads': cfg.SEARCH_SPACE.NUM_HEADS, 'mlp_ratio': cfg.SEARCH_SPACE.MLP_RATIO,
                   'embed_dim': cfg.SEARCH_SPACE.EMBED_DIM, 'depth': cfg.SEARCH_SPACE.DEPTH}
    elif args.model_type == 'PIT':
        model_type = args.model_type
        retrain_config = None
        retrain_config = {'layer_num': cfg.RETRAIN.DEPTH, 'base_dim': cfg.RETRAIN.BASE_DIM,
                          'num_heads': cfg.RETRAIN.NUM_HEADS, 'mlp_ratio': cfg.RETRAIN.MLP_RATIO, 'patch_size': cfg.RETRAIN.PATCH_SIZE}
        model = pit(retrain_config, pretrain = False)
        choices = {'num_heads': cfg.SEARCH_SPACE.NUM_HEADS, 'mlp_ratio': cfg.SEARCH_SPACE.MLP_RATIO,
                   'base_dim': cfg.SEARCH_SPACE.BASE_DIM, 'depth': cfg.SEARCH_SPACE.DEPTH,
                   'patch_size': cfg.SEARCH_SPACE.PATCH_SIZE}

    model.to(device)
    if args.teacher_model:
        teacher_model = create_model(
            args.teacher_model,
            pretrained=True,
            num_classes=args.nb_classes,
        )
        teacher_model.to(device)
        teacher_loss = LabelSmoothingCrossEntropy(smoothing=args.smoothing)
    else:
        teacher_model = None
        teacher_loss = None

    model_ema = None

    model_without_ddp = model

    if args.distributed:

        model = torch.nn.parallel.DistributedDataParallel(model, device_ids=[args.gpu], find_unused_parameters=True)
        model_without_ddp = model.module

    n_parameters = sum(p.numel() for p in model.parameters() if p.requires_grad)
    print('number of params:', n_parameters)

    linear_scaled_lr = args.lr * args.batch_size * utils.get_world_size() / 512.0
    args.lr = linear_scaled_lr
    optimizer = create_optimizer(args, model_without_ddp)
    loss_scaler = NativeScaler()
    lr_scheduler, _ = create_scheduler(args, optimizer)

    if args.mixup > 0.:
        # smoothing is handled with mixup label transform
        criterion = SoftTargetCrossEntropy()
    elif args.smoothing:
        criterion = LabelSmoothingCrossEntropy(smoothing=args.smoothing)
    else:
        criterion = torch.nn.CrossEntropyLoss()

    output_dir = Path(args.output_dir)

    if not output_dir.exists():
        output_dir.mkdir(parents=True)
    # save config for later experiments
    with open(output_dir / "config.yaml", 'w') as f:
        f.write(args_text)
    def copyStateDict(state_dict):
        if list(state_dict.keys())[0].startswith('module'):
            start_idx = 1
        else:
            start_idx = 0
        new_state_dict = OrderedDict()
        for k,v in state_dict.items():
            name = ','.join(k.split('.')[start_idx:])
            new_state_dict[name] = v
        return new_state_dict
    if args.resume:
        if args.resume.startswith('https'):
            checkpoint = torch.hub.load_state_dict_from_url(
                args.resume, map_location='cpu', check_hash=True)
        else:
            checkpoint = torch.load(args.resume, map_location='cpu')
        model_without_ddp.load_state_dict(checkpoint['model'])
        if not args.eval and 'optimizer' in checkpoint and 'lr_scheduler' in checkpoint and 'epoch' in checkpoint:
            optimizer.load_state_dict(checkpoint['optimizer'])
            lr_scheduler.load_state_dict(checkpoint['lr_scheduler'])
            args.start_epoch = checkpoint['epoch'] + 1
            if 'scaler' in checkpoint:
                loss_scaler.load_state_dict(checkpoint['scaler'])
            if args.model_ema:
                utils._load_checkpoint_for_ema(model_ema, checkpoint['model_ema'])
    if args.mode == 'retrain' and "RETRAIN" in cfg and model_type == 'AUTOFORMER':
        retrain_config = None
        retrain_config = {'layer_num': cfg.RETRAIN.DEPTH, 'embed_dim': [cfg.RETRAIN.EMBED_DIM]*cfg.RETRAIN.DEPTH,
                          'num_heads': cfg.RETRAIN.NUM_HEADS,'mlp_ratio': cfg.RETRAIN.MLP_RATIO}
    if args.eval:
        test_stats = evaluate(data_loader_val, model_type, model, device,  mode = args.mode, retrain_config=retrain_config)
        print(f"Accuracy of the network on the {len(dataset_val)} test images: {test_stats['acc1']:.1f}%")
        return

    print("Start training")
    start_time = time.time()
    max_accuracy = 0.0

    for epoch in range(args.start_epoch, args.epochs):
        if args.distributed:
            data_loader_train.sampler.set_epoch(epoch)

        train_stats = train_one_epoch(
            model, criterion, data_loader_train,
            optimizer, device, epoch, model_type, loss_scaler,
            args.clip_grad, model_ema, mixup_fn,
            amp=args.amp, teacher_model=teacher_model,
            teach_loss=teacher_loss,
            choices=choices, mode = args.mode, retrain_config=retrain_config,
        )

        lr_scheduler.step(epoch)
        if args.output_dir:
            checkpoint_paths = [output_dir / 'checkpoint.pth']
            for checkpoint_path in checkpoint_paths:
                utils.save_on_master({
                    'model': model_without_ddp.state_dict(),
                    'optimizer': optimizer.state_dict(),
                    'lr_scheduler': lr_scheduler.state_dict(),
                    'epoch': epoch,
                    # 'model_ema': get_state_dict(model_ema),
                    'scaler': loss_scaler.state_dict(),
                    'args': args,
                }, checkpoint_path)

        test_stats = evaluate(data_loader_val, model_type, model, device, amp=args.amp, choices=choices, mode = args.mode, retrain_config=retrain_config)
        print(f"Accuracy of the network on the {len(dataset_val)} test images: {test_stats['acc1']:.1f}%")
        max_accuracy = max(max_accuracy, test_stats["acc1"])
        print(f'Max accuracy: {max_accuracy:.2f}%')

        log_stats = {**{f'train_{k}': v for k, v in train_stats.items()},
                     **{f'test_{k}': v for k, v in test_stats.items()},
                     'epoch': epoch,
                     'n_parameters': n_parameters}

        if args.output_dir and utils.is_main_process():
            with (output_dir / "log.txt").open("a") as f:
                f.write(json.dumps(log_stats) + "\n")

    total_time = time.time() - start_time
    total_time_str = str(datetime.timedelta(seconds=int(total_time)))
    print('Training time {}'.format(total_time_str))


if __name__ == '__main__':
    parser = argparse.ArgumentParser('Training and Evaluation Script', parents=[get_args_parser()])
    args = parser.parse_args()
    if args.output_dir:
        Path(args.output_dir).mkdir(parents=True, exist_ok=True)
    main(args)
