import os
from os import path
from argparse import ArgumentParser
import shutil

import torch
import torch.nn.functional as F
from torch.utils.data import DataLoader
import numpy as np
from PIL import Image

from inference.data.test_datasets import LongTestDataset, DAVISTestDataset, YouTubeVOSTestDataset
from inference.data.mask_mapper import MaskMapper
from model.network import XMem
from inference.inference_core import InferenceCore

from progressbar import progressbar

try:
    import hickle as hkl
except ImportError:
    print('Failed to import hickle. Fine if not using multi-scale testing.')


"""
Arguments loading
"""
parser = ArgumentParser()
parser.add_argument('--model', default='/ssd1/gaomingqi/checkpoints/XMem-s012.pth')

# Data options
parser.add_argument('--d16_path', default='../DAVIS/2016')
parser.add_argument('--d17_path', default='../DAVIS/2017')
parser.add_argument('--y18_path', default='/ssd1/gaomingqi/datasets/youtube-vos/2018')
parser.add_argument('--y19_path', default='../YouTube')
parser.add_argument('--lv_path', default='../long_video_set')
# For generic (G) evaluation, point to a folder that contains "JPEGImages" and "Annotations"
parser.add_argument('--generic_path')

parser.add_argument('--dataset', help='D16/D17/Y18/Y19/LV1/LV3/G', default='D17')
parser.add_argument('--split', help='val/test', default='val')
parser.add_argument('--output', default=None)
parser.add_argument('--save_all', action='store_true', 
            help='Save all frames. Useful only in YouTubeVOS/long-time video', )

parser.add_argument('--benchmark', action='store_true', help='enable to disable amp for FPS benchmarking')
        
# Long-term memory options
parser.add_argument('--disable_long_term', action='store_true')
parser.add_argument('--max_mid_term_frames', help='T_max in paper, decrease to save memory', type=int, default=10)
parser.add_argument('--min_mid_term_frames', help='T_min in paper, decrease to save memory', type=int, default=5)
parser.add_argument('--max_long_term_elements', help='LT_max in paper, increase if objects disappear for a long time', 
                                                type=int, default=10000)
parser.add_argument('--num_prototypes', help='P in paper', type=int, default=128)

parser.add_argument('--top_k', type=int, default=30)
parser.add_argument('--mem_every', help='r in paper. Increase to improve running speed.', type=int, default=5)
parser.add_argument('--deep_update_every', help='Leave -1 normally to synchronize with mem_every', type=int, default=-1)

# Multi-scale options
parser.add_argument('--save_scores', action='store_true')
parser.add_argument('--flip', action='store_true')
parser.add_argument('--size', default=480, type=int, 
            help='Resize the shorter side to this size. -1 to use original resolution. ')

args = parser.parse_args()
config = vars(args)
config['enable_long_term'] = not config['disable_long_term']

if args.output is None:
    args.output = f'../output/{args.dataset}_{args.split}'
    print(f'Output path not provided. Defaulting to {args.output}')

"""
Data preparation
"""
is_youtube = args.dataset.startswith('Y')
is_davis = args.dataset.startswith('D')
is_lv = args.dataset.startswith('LV')

if is_youtube or args.save_scores:
    out_path = path.join(args.output, 'Annotations')
else:
    out_path = args.output

if is_youtube:
    if args.dataset == 'Y18':
        yv_path = args.y18_path
    elif args.dataset == 'Y19':
        yv_path = args.y19_path

    if args.split == 'val':
        args.split = 'valid'
        meta_dataset = YouTubeVOSTestDataset(data_root=yv_path, split='valid', size=args.size)
    elif args.split == 'test':
        meta_dataset = YouTubeVOSTestDataset(data_root=yv_path, split='test', size=args.size)
    else:
        raise NotImplementedError

elif is_davis:
    if args.dataset == 'D16':
        if args.split == 'val':
            # Set up Dataset, a small hack to use the image set in the 2017 folder because the 2016 one is of a different format
            meta_dataset = DAVISTestDataset(args.d16_path, imset='../../2017/trainval/ImageSets/2016/val.txt', size=args.size)
        else:
            raise NotImplementedError
        palette = None
    elif args.dataset == 'D17':
        if args.split == 'val':
            meta_dataset = DAVISTestDataset(path.join(args.d17_path, 'trainval'), imset='2017/val.txt', size=args.size)
        elif args.split == 'test':
            meta_dataset = DAVISTestDataset(path.join(args.d17_path, 'test-dev'), imset='2017/test-dev.txt', size=args.size)
        else:
            raise NotImplementedError

elif is_lv:
    if args.dataset == 'LV1':
        meta_dataset = LongTestDataset(path.join(args.lv_path, 'long_video'))
    elif args.dataset == 'LV3':
        meta_dataset = LongTestDataset(path.join(args.lv_path, 'long_video_x3'))
    else:
        raise NotImplementedError
elif args.dataset == 'G':
    meta_dataset = LongTestDataset(path.join(args.generic_path), size=args.size)
    if not args.save_all:
        args.save_all = True
        print('save_all is forced to be true in generic evaluation mode.')
else:
    raise NotImplementedError

torch.autograd.set_grad_enabled(False)

# Set up loader
meta_loader = meta_dataset.get_datasets()

# Load our checkpoint
network = XMem(config, args.model).cuda().eval()
if args.model is not None:
    model_weights = torch.load(args.model)
    network.load_weights(model_weights, init_as_zero_if_needed=True)
else:
    print('No model loaded.')

total_process_time = 0
total_frames = 0

# Start eval
for vid_reader in progressbar(meta_loader, max_value=len(meta_dataset), redirect_stdout=True):

    loader = DataLoader(vid_reader, batch_size=1, shuffle=False, num_workers=2)
    vid_name = vid_reader.vid_name
    vid_length = len(loader)
    # no need to count usage for LT if the video is not that long anyway
    config['enable_long_term_count_usage'] = (
        config['enable_long_term'] and
        (vid_length
            / (config['max_mid_term_frames']-config['min_mid_term_frames'])
            * config['num_prototypes'])
        >= config['max_long_term_elements']
    )

    mapper = MaskMapper()
    processor = InferenceCore(network, config=config)
    first_mask_loaded = False

    for ti, data in enumerate(loader):
        with torch.cuda.amp.autocast(enabled=not args.benchmark):
            rgb = data['rgb'].cuda()[0]
            msk = data.get('mask')
            info = data['info']
            frame = info['frame'][0]
            shape = info['shape']
            need_resize = info['need_resize'][0]

            """
            For timing see https://discuss.pytorch.org/t/how-to-measure-time-in-pytorch/26964
            Seems to be very similar in testing as my previous timing method 
            with two cuda sync + time.time() in STCN though 
            """
            start = torch.cuda.Event(enable_timing=True)
            end = torch.cuda.Event(enable_timing=True)
            start.record()

            if not first_mask_loaded:
                if msk is not None:
                    first_mask_loaded = True
                else:
                    # no point to do anything without a mask
                    continue

            if args.flip:
                rgb = torch.flip(rgb, dims=[-1])
                msk = torch.flip(msk, dims=[-1]) if msk is not None else None

            # Map possibly non-continuous labels to continuous ones
            if msk is not None:
                msk, labels = mapper.convert_mask(msk[0].numpy())
                msk = torch.Tensor(msk).cuda()
                if need_resize:
                    msk = vid_reader.resize_mask(msk.unsqueeze(0))[0]
                processor.set_all_labels(list(mapper.remappings.values()))
            else:
                labels = None

            # Run the model on this frame
            prob = processor.step(rgb, msk, labels, end=(ti==vid_length-1)) # 0, background, >0, objects

            # Upsample to original size if needed
            if need_resize:
                prob = F.interpolate(prob.unsqueeze(1), shape, mode='bilinear', align_corners=False)[:,0]

            end.record()
            torch.cuda.synchronize()
            total_process_time += (start.elapsed_time(end)/1000)
            total_frames += 1

            if args.flip:
                prob = torch.flip(prob, dims=[-1])

            # Probability mask -> index mask
            out_mask = torch.argmax(prob, dim=0)
            out_mask = (out_mask.detach().cpu().numpy()).astype(np.uint8)

            if args.save_scores:
                prob = (prob.detach().cpu().numpy()*255).astype(np.uint8)

            # Save the mask
            if args.save_all or info['save'][0]:
                this_out_path = path.join(out_path, vid_name)
                os.makedirs(this_out_path, exist_ok=True)
                out_mask = mapper.remap_index_mask(out_mask)
                out_img = Image.fromarray(out_mask)
                if vid_reader.get_palette() is not None:
                    out_img.putpalette(vid_reader.get_palette())
                out_img.save(os.path.join(this_out_path, frame[:-4]+'.png'))

            if args.save_scores:
                np_path = path.join(args.output, 'Scores', vid_name)
                os.makedirs(np_path, exist_ok=True)
                if ti==len(loader)-1:
                    hkl.dump(mapper.remappings, path.join(np_path, f'backward.hkl'), mode='w')
                if args.save_all or info['save'][0]:
                    hkl.dump(prob, path.join(np_path, f'{frame[:-4]}.hkl'), mode='w', compression='lzf')


print(f'Total processing time: {total_process_time}')
print(f'Total processed frames: {total_frames}')
print(f'FPS: {total_frames / total_process_time}')
print(f'Max allocated memory (MB): {torch.cuda.max_memory_allocated() / (2**20)}')

if not args.save_scores:
    if is_youtube:
        print('Making zip for YouTubeVOS...')
        shutil.make_archive(path.join(args.output, path.basename(args.output)), 'zip', args.output, 'Annotations')
    elif is_davis and args.split == 'test':
        print('Making zip for DAVIS test-dev...')
        shutil.make_archive(args.output, 'zip', args.output)