"""Applies the 1st training stage of our approach on the low-shot Imagenet dataset[*].

Example of usage - train a cosine-similarity based recognition model with a ResNet10 feature extractor:
CUDA_VISIBLE_DEVICES=0 python lowshot_train_stage1.py --config=imagenet_ResNet10CosineClassifier

The configuration file imagenet_ResNet10CosineClassifier.py used on the above experiment is placed on
the directory ./config .

[*] B. Hariharan and R. Girshick. Low-shot visual recognition by shrinking and hallucinating features.
"""


from __future__ import print_function
import argparse
import os
import imp
import algorithms as alg
from dataloader import ImageNetLowShot, FewShotDataloader

parser = argparse.ArgumentParser()
parser.add_argument('--config', type=str, required=True, default='',
    help='config file with parameters of the experiment.')
parser.add_argument('--checkpoint', type=int, default=0,
    help='checkpoint (epoch id) that will be loaded. If a negative value is '
         'given then the latest existing checkpoint is loaded.')
parser.add_argument('--num_workers', type=int, default=4,
    help='number of data loading workers')
parser.add_argument('--cuda', type=bool, default=True, help='enables cuda')
parser.add_argument('--disp_step', type=int, default=200,
    help='display step during training')
args_opt = parser.parse_args()

exp_config_file = os.path.join('.', 'config', args_opt.config + '.py')
exp_directory = os.path.join('.', 'experiments', args_opt.config)

# Load the configuration params of the experiment
print('Launching experiment: %s' % exp_config_file)
config = imp.load_source("",exp_config_file).config
config['exp_dir'] = exp_directory # the place where logs, models, and other stuff will be stored
print("Loading experiment %s from file: %s" % (args_opt.config, exp_config_file))
print("Generated logs, snapshots, and model files will be stored on %s" % (config['exp_dir']))

# Set the train dataset and the corresponding data loader.
data_train_opt = config['data_train_opt']
dataset_train = ImageNetLowShot(phase='train')
dloader_train = FewShotDataloader(
    dataset=dataset_train,
    nKnovel=data_train_opt['nKnovel'],
    nKbase=data_train_opt['nKbase'],
    nExemplars=data_train_opt['nExemplars'], # num training examples per novel category
    nTestNovel=data_train_opt['nTestNovel'], # num test examples for all the novel categories
    nTestBase=data_train_opt['nTestBase'], # num test examples for all the base categories
    batch_size=data_train_opt['batch_size'],
    num_workers=args_opt.num_workers,
    epoch_size=data_train_opt['epoch_size'], # num of batches per epoch
)

config['disp_step'] = args_opt.disp_step
algorithm = alg.FewShot(config)
if args_opt.cuda: # enable cuda
    algorithm.load_to_gpu()

if args_opt.checkpoint != 0: # load checkpoint
    algorithm.load_checkpoint(
        epoch=args_opt.checkpoint if  (args_opt.checkpoint > 0) else '*',
        train=True)

algorithm.solve(dloader_train)
