import argparse
import os, sys
import os.path as osp
import torchvision
import numpy as np
import torch
import torch.nn as nn
import torch.optim as optim
from torchvision import transforms
import network, loss
from torch.utils.data import DataLoader
from data_list import ImageList, ImageList_idx
import random, pdb, math, copy
from tqdm import tqdm
from scipy.spatial.distance import cdist
from sklearn.metrics import confusion_matrix
import rotation

def op_copy(optimizer):
    for param_group in optimizer.param_groups:
        param_group['lr0'] = param_group['lr']
    return optimizer

def lr_scheduler(optimizer, iter_num, max_iter, gamma=10, power=0.75):
    decay = (1 + gamma * iter_num / max_iter) ** (-power)
    for param_group in optimizer.param_groups:
        param_group['lr'] = param_group['lr0'] * decay
        param_group['weight_decay'] = 1e-3
        param_group['momentum'] = 0.9
        param_group['nesterov'] = True
    return optimizer

def image_train(resize_size=256, crop_size=224, alexnet=False):
  if not alexnet:
    normalize = transforms.Normalize(mean=[0.485, 0.456, 0.406],
                                   std=[0.229, 0.224, 0.225])
  else:
    normalize = Normalize(meanfile='./ilsvrc_2012_mean.npy')
  return  transforms.Compose([
        transforms.Resize((resize_size, resize_size)),
        transforms.RandomCrop(crop_size),
        transforms.RandomHorizontalFlip(),
        transforms.ToTensor(),
        normalize
    ])

def image_test(resize_size=256, crop_size=224, alexnet=False):
  if not alexnet:
    normalize = transforms.Normalize(mean=[0.485, 0.456, 0.406],
                                   std=[0.229, 0.224, 0.225])
  else:
    normalize = Normalize(meanfile='./ilsvrc_2012_mean.npy')
  return  transforms.Compose([
        transforms.Resize((resize_size, resize_size)),
        transforms.CenterCrop(crop_size),
        transforms.ToTensor(),
        normalize
    ])

def data_load(args): 
    ## prepare data
    dsets = {}
    dset_loaders = {}
    train_bs = args.batch_size
    txt_src = open(args.s_dset_path).readlines()

    txt_tar = []
    for i in range(len(args.t_dset_path)):
        tmp = open(args.t_dset_path[i]).readlines()
        txt_tar.extend(tmp)
    txt_test = txt_tar.copy()

    dsets["target"] = ImageList_idx(txt_tar, transform=image_train())
    dset_loaders["target"] = DataLoader(dsets["target"], batch_size=train_bs, shuffle=True, num_workers=args.worker, drop_last=False)
    dsets["test"] = ImageList(txt_test, transform=image_test())
    dset_loaders["test"] = DataLoader(dsets["test"], batch_size=train_bs*2, shuffle=False, num_workers=args.worker, drop_last=False)

    return dset_loaders

def cal_acc(loader, netF, netB, netC, flag=False):
    start_test = True
    with torch.no_grad():
        iter_test = iter(loader)
        for i in range(len(loader)):
            data = iter_test.next()
            inputs = data[0]
            labels = data[1]
            inputs = inputs.cuda()
            outputs = netC(netB(netF(inputs)))
            if start_test:
                all_output = outputs.float().cpu()
                all_label = labels.float()
                start_test = False
            else:
                all_output = torch.cat((all_output, outputs.float().cpu()), 0)
                all_label = torch.cat((all_label, labels.float()), 0)
    _, predict = torch.max(all_output, 1)
    accuracy = torch.sum(torch.squeeze(predict).float() == all_label).item() / float(all_label.size()[0])
    mean_ent = torch.mean(loss.Entropy(nn.Softmax(dim=1)(all_output))).cpu().data.item()

    if flag:
        matrix = confusion_matrix(all_label, torch.squeeze(predict).float())
        acc = matrix.diagonal()/matrix.sum(axis=1) * 100
        aacc = acc.mean()
        aa = [str(np.round(i, 2)) for i in acc]
        acc = ' '.join(aa)
        return aacc, acc
    else:
        return accuracy*100, mean_ent

def print_args(args):
    s = "==========================================\n"
    for arg, content in args.__dict__.items():
        s += "{}:{}\n".format(arg, content)
    return s

def train_target(args):
    dset_loaders = data_load(args)
    ## set base network
    if args.net[0:3] == 'res':
        netF = network.ResBase(res_name=args.net).cuda()
    elif args.net[0:3] == 'vgg':
        netF = network.VGGBase(vgg_name=args.net).cuda()  

    netB = network.feat_bootleneck(type=args.classifier, feature_dim=netF.in_features, bottleneck_dim=args.bottleneck).cuda()
    netC = network.feat_classifier(type=args.layer, class_num = args.class_num, bottleneck_dim=args.bottleneck).cuda()

    args.modelpath = args.output_dir_src + '/source_F.pt'   
    netF.load_state_dict(torch.load(args.modelpath))
    args.modelpath = args.output_dir_src + '/source_B.pt'   
    netB.load_state_dict(torch.load(args.modelpath))
    args.modelpath = args.output_dir_src + '/source_C.pt'    
    netC.load_state_dict(torch.load(args.modelpath))
    netC.eval()
    for k, v in netC.named_parameters():
        v.requires_grad = False

    param_group = []
    for k, v in netF.named_parameters():
        if args.lr_decay1 > 0:
            param_group += [{'params': v, 'lr': args.lr * args.lr_decay1}]
        else:
            v.requires_grad = False
    for k, v in netB.named_parameters():
        if args.lr_decay2 > 0:
            param_group += [{'params': v, 'lr': args.lr * args.lr_decay2}]
        else:
            v.requires_grad = False
    optimizer = optim.SGD(param_group)
    optimizer = op_copy(optimizer)

    max_iter = args.max_epoch * len(dset_loaders["target"])
    interval_iter = max_iter // args.interval
    iter_num = 0

    while iter_num < max_iter:
        try:
            inputs_test, _, tar_idx = iter_test.next()
        except:
            iter_test = iter(dset_loaders["target"])
            inputs_test, _, tar_idx = iter_test.next()

        if inputs_test.size(0) == 1:
            continue

        if iter_num % interval_iter == 0 and args.cls_par > 0:
            netF.eval()
            netB.eval()
            mem_label = obtain_label(dset_loaders['test'], netF, netB, netC, args)
            mem_label = torch.from_numpy(mem_label).cuda()
            netF.train()
            netB.train()

        inputs_test = inputs_test.cuda()

        iter_num += 1
        lr_scheduler(optimizer, iter_num=iter_num, max_iter=max_iter)

        features_test = netB(netF(inputs_test))
        outputs_test = netC(features_test)

        if args.cls_par > 0:
            pred = mem_label[tar_idx]
            classifier_loss = nn.CrossEntropyLoss()(outputs_test, pred)
            classifier_loss *= args.cls_par
        else:
            classifier_loss = torch.tensor(0.0).cuda()

        if args.ent:
            softmax_out = nn.Softmax(dim=1)(outputs_test)
            entropy_loss = torch.mean(loss.Entropy(softmax_out))
            if args.gent:
                msoftmax = softmax_out.mean(dim=0)
                gentropy_loss = torch.sum(-msoftmax * torch.log(msoftmax + args.epsilon))
                entropy_loss -= gentropy_loss
            classifier_loss += entropy_loss * args.ent_par

        optimizer.zero_grad()
        classifier_loss.backward()
        optimizer.step()

        if iter_num % interval_iter == 0 or iter_num == max_iter:
            netF.eval()
            netB.eval()
            acc, _ = cal_acc(dset_loaders['test'], netF, netB, netC, False)
            log_str = 'Task: {}, Iter:{}/{}; Accuracy = {:.2f}%'.format(args.name, iter_num, max_iter, acc)
            args.out_file.write(log_str + '\n')
            args.out_file.flush()
            print(log_str+'\n')
            netF.train()
            netB.train()
    
    if args.issave:   
        torch.save(netF.state_dict(), osp.join(args.output_dir, "target_F_" + args.savename + ".pt"))
        torch.save(netB.state_dict(), osp.join(args.output_dir, "target_B_" + args.savename + ".pt"))
        torch.save(netC.state_dict(), osp.join(args.output_dir, "target_C_" + args.savename + ".pt"))

    return netF, netB, netC

def obtain_label(loader, netF, netB, netC, args):
    start_test = True
    with torch.no_grad():
        iter_test = iter(loader)
        for _ in range(len(loader)):
            data = iter_test.next()
            inputs = data[0]
            labels = data[1]
            inputs = inputs.cuda()
            feas = netB(netF(inputs))
            outputs = netC(feas)
            if start_test:
                all_fea = feas.float().cpu()
                all_output = outputs.float().cpu()
                all_label = labels.float()
                start_test = False
            else:
                all_fea = torch.cat((all_fea, feas.float().cpu()), 0)
                all_output = torch.cat((all_output, outputs.float().cpu()), 0)
                all_label = torch.cat((all_label, labels.float()), 0)

    all_output = nn.Softmax(dim=1)(all_output)
    ent = torch.sum(-all_output * torch.log(all_output + args.epsilon), dim=1)
    unknown_weight = 1 - ent / np.log(args.class_num)
    _, predict = torch.max(all_output, 1)

    accuracy = torch.sum(torch.squeeze(predict).float() == all_label).item() / float(all_label.size()[0])
    if args.distance == 'cosine':
        all_fea = torch.cat((all_fea, torch.ones(all_fea.size(0), 1)), 1)
        all_fea = (all_fea.t() / torch.norm(all_fea, p=2, dim=1)).t()

    all_fea = all_fea.float().cpu().numpy()
    K = all_output.size(1)
    aff = all_output.float().cpu().numpy()
    initc = aff.transpose().dot(all_fea)
    initc = initc / (1e-8 + aff.sum(axis=0)[:,None])
    cls_count = np.eye(K)[predict].sum(axis=0)
    labelset = np.where(cls_count>args.threshold)
    labelset = labelset[0]
    # print(labelset)

    dd = cdist(all_fea, initc[labelset], args.distance)
    pred_label = dd.argmin(axis=1)
    pred_label = labelset[pred_label]

    for round in range(1):
        aff = np.eye(K)[pred_label]
        initc = aff.transpose().dot(all_fea)
        initc = initc / (1e-8 + aff.sum(axis=0)[:,None])
        dd = cdist(all_fea, initc[labelset], args.distance)
        pred_label = dd.argmin(axis=1)
        pred_label = labelset[pred_label]

    acc = np.sum(pred_label == all_label.float().numpy()) / len(all_fea)
    log_str = 'Accuracy = {:.2f}% -> {:.2f}%'.format(accuracy*100, acc*100)

    args.out_file.write(log_str + '\n')
    args.out_file.flush()
    print(log_str+'\n')

    return pred_label.astype('int') #, labelset

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Conditional Domain Adversarial Network')
    parser.add_argument('--gpu_id', type=str, nargs='?', default='0', help="device id to run")
    parser.add_argument('--s', type=int, default=0, help="source")
    parser.add_argument('--t', type=int, default=1, help="target")
    parser.add_argument('--max_epoch', type=int, default=15, help="max iterations")
    parser.add_argument('--interval', type=int, default=15)
    parser.add_argument('--batch_size', type=int, default=64, help="batch_size")
    parser.add_argument('--worker', type=int, default=4, help="number of workers")
    parser.add_argument('--dset', type=str, default='office-caltech', choices=['office-caltech'])
    parser.add_argument('--lr', type=float, default=1e-2, help="learning rate")
    parser.add_argument('--net', type=str, default='resnet50', help="vgg16, resnet50, resnet101")
    parser.add_argument('--seed', type=int, default=2020, help="random seed")
 
    parser.add_argument('--gent', type=bool, default=True)
    parser.add_argument('--ent', type=bool, default=True)
    parser.add_argument('--threshold', type=int, default=-1)
    parser.add_argument('--cls_par', type=float, default=0.3)
    parser.add_argument('--ent_par', type=float, default=1.0)
    parser.add_argument('--lr_decay1', type=float, default=0.1)
    parser.add_argument('--lr_decay2', type=float, default=1.0)

    parser.add_argument('--bottleneck', type=int, default=256)
    parser.add_argument('--epsilon', type=float, default=1e-5)
    parser.add_argument('--layer', type=str, default="wn", choices=["linear", "wn"])
    parser.add_argument('--classifier', type=str, default="bn", choices=["ori", "bn"])
    parser.add_argument('--distance', type=str, default='cosine', choices=["euclidean", "cosine"])  
    parser.add_argument('--output', type=str, default='san')
    parser.add_argument('--output_src', type=str, default='ckps')
    parser.add_argument('--da', type=str, default='uda', choices=['uda'])
    parser.add_argument('--issave', type=bool, default=True)
    args = parser.parse_args()
       
    if args.dset == 'office-caltech':
        names = ['amazon', 'caltech', 'dslr', 'webcam']
        args.class_num = 10
        
    os.environ["CUDA_VISIBLE_DEVICES"] = args.gpu_id
    SEED = args.seed
    torch.manual_seed(SEED)
    torch.cuda.manual_seed(SEED)
    np.random.seed(SEED)
    random.seed(SEED)
    # torch.backends.cudnn.deterministic = True

    t_dset = []
    for i in range(len(names)):
        if i == args.s:
            continue
        args.t = i

        folder = './data/'
        args.s_dset_path = folder + args.dset + '/' + names[args.s] + '_list.txt'
        args.t_dset_path = folder + args.dset + '/' + names[args.t] + '_list.txt'
        t_dset.append(args.t_dset_path)

    args.t_dset_path = t_dset
    args.test_dset_path = args.t_dset_path

    args.output_dir_src = osp.join(args.output_src, args.da, args.dset, names[args.s][0].upper())
    args.output_dir = osp.join(args.output, args.da, args.dset, names[args.s][0].upper() + str(0))
    args.name = names[args.s][0].upper() + str(0)

    if not osp.exists(args.output_dir):
        os.system('mkdir -p ' + args.output_dir)
    if not osp.exists(args.output_dir):
        os.mkdir(args.output_dir)

    args.savename = 'par_' + str(args.cls_par)
    args.out_file = open(osp.join(args.output_dir, 'log_' + args.savename + '.txt'), 'w')
    args.out_file.write(print_args(args)+'\n')
    args.out_file.flush()
    train_target(args)