import numpy as np

import torch

import torch.nn as nn

import torch.nn.functional as F

from models.model_mil import MIL_fc, MIL_fc_mc

from models.model_clam import CLAM, CLAM_Simple

from models.model_attention_mil import MIL_Attention_fc

from models.model_histogram import MIL_fc_Histogram

import pdb

import os

import pandas as pd

from utils.utils import *

from utils.core_utils import EarlyStopping,  Accuracy_Logger

from utils.file_utils import save_pkl, load_pkl

from sklearn.metrics import roc_auc_score, roc_curve, auc

import h5py

from models.resnet_custom import resnet50_baseline

import math

from sklearn.preprocessing import label_binarize

def initiate_model(args, ckpt_path=None):

    print('Init Model')    

    model_dict = {"dropout": args.drop_out, 'n_classes': args.n_classes}

    if args.model_size is not None and args.model_type in ['clam', 'attention_mil', 'clam_simple']:

        model_dict.update({"size_arg": args.model_size})

    if args.model_type =='clam':

        model = CLAM(**model_dict)

    elif args.model_type =='clam_simple':

        model = CLAM_Simple(**model_dict)

    elif args.model_type == 'attention_mil':

        model = MIL_Attention_fc(**model_dict) 

    elif args.model_type == 'histogram_mil':

        model = MIL_fc_Histogram(**model_dict)

    else: # args.model_type == 'mil'

        if args.n_classes > 2:

            model = MIL_fc_mc(**model_dict)

        else:

            model = MIL_fc(**model_dict)

    #model.relocate()

    print_network(model)

    if ckpt_path is not None:

        ckpt = torch.load(ckpt_path)

        ckpt_clean = {}

        for key in ckpt.keys():

            if 'instance_loss_fn' in key:

                continue

            ckpt_clean.update({key.replace('.module', ''):ckpt[key]})

        model.load_state_dict(ckpt_clean, strict=True)

    model.relocate()

    model.eval()

    return model

#%------------

#    if ckpt_path is not None:

#        ckpt = torch.load(ckpt_path)

#        ckpt_clean = {}

#        for key in ckpt.keys():

#            if 'instance_loss_fn' in key:

#                continue

#            ckpt_clean.update({key.replace('.module', ''):ckpt[key]})

#        model.load_state_dict(ckpt_clean, strict=True)

#    model.relocate()

#    model.eval()

#    return model

#

#%----------

def eval(dataset, args, ckpt_path):

    model = initiate_model(args, ckpt_path)

    print('Init Loaders')

    loader = get_simple_loader(dataset)

    patient_results, test_error, auc, aucs, df, _ = summary(model, loader, args)

    print('test_error: ', test_error)

    print('auc: ', auc)

    for cls_idx in range(len(aucs)):

        print('class {} auc: {}'.format(cls_idx, aucs[cls_idx]))

    return model, patient_results, test_error, auc, aucs, df

def infer(dataset, args, ckpt_path, class_labels):

    model = initiate_model(args, ckpt_path)

    df = infer_dataset(model, dataset, args, class_labels)

    return model, df

# Code taken from pytorch/examples for evaluating topk classification on on ImageNet

def accuracy(output, target, topk=(1,)):

    """Computes the accuracy over the k top predictions for the specified values of k"""

    with torch.no_grad():

        maxk = max(topk)

        batch_size = target.size(0)

        _, pred = output.topk(maxk, 1, True, True)

        pred = pred.t()

        correct = pred.eq(target.view(1, -1).expand_as(pred))

        res = []

        for k in topk:

            correct_k = correct[:k].view(-1).float().sum(0, keepdim=True)

            res.append(correct_k.mul_(1.0 / batch_size))

        return res

def summary(model, loader, args):

    acc_logger = Accuracy_Logger(n_classes=args.n_classes)

    model.eval()

    test_loss = 0.

    test_error = 0.

    all_probs = np.zeros((len(loader), args.n_classes))

    all_labels = np.zeros(len(loader))

    all_preds = np.zeros(len(loader))

    if not args.patient_level:

        slide_ids = loader.dataset.slide_data['slide_id']

        patient_results = {}

        for batch_idx, (data, label) in enumerate(loader):

            data, label = data.to(device), label.to(device)

            slide_id = slide_ids.iloc[batch_idx]

            with torch.no_grad():

                logits, Y_prob, Y_hat, _, results_dict = model(data)

            acc_logger.log(Y_hat, label)    

            probs = Y_prob.cpu().numpy()

            all_probs[batch_idx] = probs

            all_labels[batch_idx] = label.item()

            all_preds[batch_idx] = Y_hat.item()

            patient_results.update({slide_id: {'slide_id': np.array(slide_id), 'prob': probs, 'label': label.item()}})

            error = calculate_error(Y_hat, label)

            test_error += error

    else:

        case_ids = loader.dataset.slide_data['case_id']

        patient_results = {}

        for batch_idx, (data, label) in enumerate(loader):

            data, label = data.to(device), label.to(device)

            case_id = case_ids.iloc[batch_idx]

            with torch.no_grad():

                logits, Y_prob, Y_hat, _, results_dict = model(data)

            acc_logger.log(Y_hat, label)

            probs = Y_prob.cpu().numpy()

            all_probs[batch_idx] = probs

            all_labels[batch_idx] = label.item()

            all_preds[batch_idx] = Y_hat.item()

            patient_results.update({case_id: {'case_id': np.array(case_id), 'prob': probs, 'label': label.item()}})

            error = calculate_error(Y_hat, label)

            test_error += error

    del data

    test_error /= len(loader)

    if args.n_classes > 2:

        # pdb.set_trace()

        acc1, acc3 = accuracy(torch.from_numpy(all_probs), torch.from_numpy(all_labels), topk=(1, 3))

        print('top1 acc: {:.3f}, top3 acc: {:.3f}'.format(acc1.item(), acc3.item()))

    if len(np.unique(all_labels)) == 1:

        auc_score = -1

        aucs = []

    else:

        if args.n_classes == 2:

            auc_score = roc_auc_score(all_labels, all_probs[:, 1])

            aucs = []

        else:

            aucs = []

            binary_labels = label_binarize(all_labels, classes=[i for i in range(args.n_classes)])

            for class_idx in range(args.n_classes):

                if class_idx in all_labels:

                    fpr, tpr, _ = roc_curve(binary_labels[:, class_idx], all_probs[:, class_idx])

                    aucs.append(auc(fpr, tpr))

                else:

                    aucs.append(float('nan'))

            if args.micro_average:

                binary_labels = label_binarize(all_labels, classes=[i for i in range(args.n_classes)])

                fpr, tpr, _ = roc_curve(binary_labels.ravel(), all_probs.ravel())

                auc_score = auc(fpr, tpr)

            else:

                auc_score = np.nanmean(np.array(aucs))

    if not args.patient_level:  

        results_dict = {'slide_id': slide_ids, 'Y': all_labels, 'Y_hat': all_preds}

    else: 

        results_dict = {'case_id': case_ids, 'Y': all_labels, 'Y_hat': all_preds}

    for c in range(args.n_classes):

        results_dict.update({'p_{}'.format(c): all_probs[:,c]})

    df = pd.DataFrame(results_dict)

    if args.patient_level:  

        df = df.drop_duplicates(subset=['case_id'])     

    return patient_results, test_error, auc_score, aucs, df, acc_logger

def infer_dataset(model, dataset, args, class_labels, k=3):

    model.eval()

    all_probs = np.zeros((len(dataset), k))

    all_preds = np.zeros((len(dataset), k))

    all_preds_str = np.full((len(dataset), k), ' ', dtype=object)

    slide_ids = dataset.slide_data

    for batch_idx, data in enumerate(dataset):

        data = data.to(device)

        with torch.no_grad():

            logits, Y_prob, Y_hat, _, results_dict = model(data)

        probs, ids = torch.topk(Y_prob, k)

        probs = probs.cpu().numpy()

        ids = ids.cpu().numpy()

        all_probs[batch_idx] = probs

        all_preds[batch_idx] = ids

        all_preds_str[batch_idx] = np.array(class_labels)[ids]

    del data

    results_dict = {'slide_id': slide_ids}

    for c in range(k):

        results_dict.update({'Pred_{}'.format(c): all_preds_str[:, c]})

        results_dict.update({'p_{}'.format(c): all_probs[:, c]})

    df = pd.DataFrame(results_dict)

    return df

# def infer_dataset(model, dataset, args, class_labels, k=3):

#     model.eval()

#     all_probs = np.zeros((len(dataset), args.n_classes))

#     all_preds = np.zeros(len(dataset))

#     all_str_preds = np.full(len(dataset), ' ', dtype=object)

#     slide_ids = dataset.slide_data

#     for batch_idx, data in enumerate(dataset):

#         data = data.to(device)

#         with torch.no_grad():

#             logits, Y_prob, Y_hat, _, results_dict = model(data)

#         probs = Y_prob.cpu().numpy()

#         all_probs[batch_idx] = probs

#         all_preds[batch_idx] = Y_hat.item()

#         all_str_preds[batch_idx] = class_labels[Y_hat.item()]

#     del data

#     results_dict = {'slide_id': slide_ids, 'Prediction': all_str_preds, 'Y_hat': all_preds}

#     for c in range(args.n_classes):

#         results_dict.update({'p_{}_{}'.format(c, class_labels[c]): all_probs[:,c]})

#     df = pd.DataFrame(results_dict)

#     return df

def compute_features(dataset, args, ckpt_path, save_dir, model=None, feature_dim=512):

    if model is None:

        model = initiate_model(args, ckpt_path)

    names = dataset.get_list(np.arange(len(dataset))).values

    file_path = os.path.join(save_dir, 'features.h5')

    initialize_features_hdf5_file(file_path, len(dataset), feature_dim=feature_dim, names=names)

    for i in range(len(dataset)):

        print("Progress: {}/{}".format(i, len(dataset)))

        save_features(dataset, i, model, args, file_path)

def save_features(dataset, idx, model, args, save_file_path):

    name = dataset.get_list(idx)

    print(name)

    features, label = dataset[idx]

    features = features.to(device)

    with torch.no_grad():

        if type(model) == CLAM:

            _, Y_prob, Y_hat, _, results_dict = model(features, instance_eval=False, return_features=True)

            bag_feat = results_dict['features'][Y_hat.item()]

        else:

            _, Y_prob, Y_hat, _, results_dict = model(features, return_features=True)

            bag_feat = results_dict['features']

    del features

    Y_hat = Y_hat.item()

    Y_prob = Y_prob.view(-1).cpu().numpy()

    bag_feat = bag_feat.view(1, -1).cpu().numpy()

    with h5py.File(save_file_path, 'r+') as file:

        print('label', label)

        file['features'][idx, :] = bag_feat

        file['label'][idx] = label

        file['Y_hat'][idx] = Y_hat

        file['Y_prob'][idx] = Y_prob[Y_hat]

def initialize_features_hdf5_file(file_path, length, feature_dim=512, names = None):

    file = h5py.File(file_path, "w")

    dset = file.create_dataset('features', 

                                shape=(length, feature_dim), chunks=(1, feature_dim), dtype=np.float32)

    # if names is not None:

    #     names = np.array(names, dtype='S')

    #     dset.attrs['names'] = names

    if names is not None:

        dt = h5py.string_dtype()

        label_dset = file.create_dataset('names', 

                                        shape=(length, ), chunks=(1, ), dtype=dt)

        file['names'][:] = names

    label_dset = file.create_dataset('label', 

                                        shape=(length, ), chunks=(1, ), dtype=np.int32)

    pred_dset = file.create_dataset('Y_hat', 

                                        shape=(length, ), chunks=(1, ), dtype=np.int32)

    prob_dset = file.create_dataset('Y_prob', 

                                        shape=(length, ), chunks=(1, ), dtype=np.float32)

    file.close()

    return file_path