from yacs.config import CfgNode as CN
_CN = CN()

##############  ↓  LoFTR Pipeline  ↓  ##############
_CN.LOFTR = CN()
_CN.LOFTR.BACKBONE_TYPE = 'ResNetFPN'
_CN.LOFTR.RESOLUTION = (8, 2)  # options: [(8, 2), (16, 4)]
_CN.LOFTR.FINE_WINDOW_SIZE = 5  # window_size in fine_level, must be odd
_CN.LOFTR.FINE_CONCAT_COARSE_FEAT = True

# 1. LoFTR-backbone (local feature CNN) config
_CN.LOFTR.RESNETFPN = CN()
_CN.LOFTR.RESNETFPN.INITIAL_DIM = 128
_CN.LOFTR.RESNETFPN.BLOCK_DIMS = [128, 196, 256]  # s1, s2, s3

# 2. LoFTR-coarse module config
_CN.LOFTR.COARSE = CN()
_CN.LOFTR.COARSE.D_MODEL = 256
_CN.LOFTR.COARSE.D_FFN = 256
_CN.LOFTR.COARSE.NHEAD = 8
_CN.LOFTR.COARSE.LAYER_NAMES = ['self', 'cross'] * 4
_CN.LOFTR.COARSE.ATTENTION = 'linear'  # options: ['linear', 'full']

# 3. Coarse-Matching config
_CN.LOFTR.MATCH_COARSE = CN()
_CN.LOFTR.MATCH_COARSE.THR = 0.2
_CN.LOFTR.MATCH_COARSE.BORDER_RM = 2
_CN.LOFTR.MATCH_COARSE.MATCH_TYPE = 'dual_softmax'  # options: ['dual_softmax, 'sinkhorn']
_CN.LOFTR.MATCH_COARSE.DSMAX_TEMPERATURE = 0.1
_CN.LOFTR.MATCH_COARSE.SKH_ITERS = 3
_CN.LOFTR.MATCH_COARSE.SKH_INIT_BIN_SCORE = 1.0
_CN.LOFTR.MATCH_COARSE.SKH_PREFILTER = False
_CN.LOFTR.MATCH_COARSE.TRAIN_COARSE_PERCENT = 0.4  # training tricks: save GPU memory
_CN.LOFTR.MATCH_COARSE.TRAIN_PAD_NUM_GT_MIN = 200  # training tricks: avoid DDP deadlock

# 4. LoFTR-fine module config
_CN.LOFTR.FINE = CN()
_CN.LOFTR.FINE.D_MODEL = 128
_CN.LOFTR.FINE.D_FFN = 128
_CN.LOFTR.FINE.NHEAD = 8
_CN.LOFTR.FINE.LAYER_NAMES = ['self', 'cross'] * 1
_CN.LOFTR.FINE.ATTENTION = 'linear'


##############  Dataset  ##############
_CN.DATASET = CN()
# 1. data config
# training and validating
_CN.DATASET.TRAINVAL_DATA_SOURCE = None  # options: ['ScanNet', 'MegaDepth']
_CN.DATASET.TRAIN_DATA_ROOT = None
_CN.DATASET.TRAIN_NPZ_ROOT = None
_CN.DATASET.TRAIN_LIST_PATH = None
_CN.DATASET.TRAIN_INTRINSIC_PATH = None
_CN.DATASET.VAL_DATA_ROOT = None
_CN.DATASET.VAL_NPZ_ROOT = None
_CN.DATASET.VAL_LIST_PATH = None    # None if val data from all scenes are bundled into a single npz file
_CN.DATASET.VAL_INTRINSIC_PATH = None
# testing
_CN.DATASET.TEST_DATA_SOURCE = None
_CN.DATASET.TEST_DATA_ROOT = None
_CN.DATASET.TEST_NPZ_ROOT = None
_CN.DATASET.TEST_LIST_PATH = None   # None if test data from all scenes are bundled into a single npz file
_CN.DATASET.TEST_INTRINSIC_PATH = None

# 2. dataset config
# general options
_CN.DATASET.MIN_OVERLAP_SCORE = 0.4  # discard data with overlap_score < min_overlap_score
_CN.DATASET.AUGMENTATION_TYPE = None  # options: [None, 'dark', 'mobile']

# MegaDepth options
_CN.DATASET.MGDPT_IMG_RESIZE = 640  # resize the longer side, zero-pad bottom-right to square.
_CN.DATASET.MGDPT_IMG_PAD = True  # pad img to square with size = MGDPT_IMG_RESIZE
_CN.DATASET.MGDPT_DEPTH_PAD = True  # pad depthmap to square with size = 2000
_CN.DATASET.MGDPT_DF = 8

##############  Trainer  ##############
_CN.TRAINER = CN()

# plotting related
_CN.TRAINER.ENABLE_PLOTTING = True
_CN.TRAINER.N_VAL_PAIRS_TO_PLOT = 32     # number of val/test paris for plotting

# geometric metrics and pose solver
_CN.TRAINER.EPI_ERR_THR = 5e-4  # recommendation: 5e-4 for ScanNet, 1e-4 for MegaDepth (from SuperGlue)
_CN.TRAINER.POSE_GEO_MODEL = 'E'  # ['E', 'F', 'H']
_CN.TRAINER.POSE_ESTIMATION_METHOD = 'RANSAC'  # [RANSAC, DEGENSAC, MAGSAC]
_CN.TRAINER.RANSAC_PIXEL_THR = 0.5
_CN.TRAINER.RANSAC_CONF = 0.99999
_CN.TRAINER.RANSAC_MAX_ITERS = 10000
_CN.TRAINER.USE_MAGSACPP = False

# data sampler for train_dataloader
_CN.TRAINER.DATA_SAMPLER = 'scene_balance'  # options: ['scene_balance', 'random', 'normal']
# 'scene_balance' config
_CN.TRAINER.N_SAMPLES_PER_SUBSET = 200
_CN.TRAINER.SB_SUBSET_SAMPLE_REPLACEMENT = True  # whether sample each scene with replacement or not
_CN.TRAINER.SB_SUBSET_SHUFFLE = True  # after sampling from scenes, whether shuffle within the epoch or not
_CN.TRAINER.SB_REPEAT = 1  # repeat N times for training the sampled data
# 'random' config
_CN.TRAINER.RDM_REPLACEMENT = True
_CN.TRAINER.RDM_NUM_SAMPLES = None

# gradient clipping
_CN.TRAINER.GRADIENT_CLIPPING = 0.5

# reproducibility
# This seed affects the data sampling. With the same seed, the data sampling is promised
# to be the same. When resume training from a checkpoint, it's better to use a different
# seed, otherwise the sampled data will be exactly the same as before resuming, which will
# cause less unique data items sampled during the entire training.
# Use of different seed value might affect the final training result, since not all data items
# are used during training on ScanNet. (60M pairs of images sampled during traing from 230M pairs in total.)
_CN.TRAINER.SEED = 66


def get_cfg_defaults():
    """Get a yacs CfgNode object with default values for my_project."""
    # Return a clone so that the defaults will not be altered
    # This is for the "local variable" use pattern
    return _CN.clone()
