from pathlib import Path
import random
from statistics import mean

import numpy as np
import torch
from torch import nn
from tqdm import tqdm
from torch.utils.data import DataLoader
from easyfsl.utils import evaluate

import argparse
import os
import re
import time
from torch.optim import SGD, Optimizer
from torch.optim.lr_scheduler import MultiStepLR
from glob import glob
from itertools import chain, combinations, permutations

def powerset(iterable):
    "powerset([1,2,3]) --> () (1,) (2,) (3,) (1,2) (1,3) (2,3) (1,2,3)"
    s = list(iterable)
    return chain.from_iterable(combinations(s, r) for r in range(len(s)+1))

torch.autograd.set_detect_anomaly(True)
device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
print(device)
parser = argparse.ArgumentParser()
parser.add_argument('--run_num', help='Number for Identifying train folder', required=True)
parser.add_argument('--timestamps', help='Frequency for saving Weights and Validation', required=False, default=5)
parser.add_argument('--epochs', help='Number of epochs', required=False, default=5)
parser.add_argument('--norm', help='0: No norm, 1: Subtract minimum to get positive values', required=False, default="1")
parser.add_argument('--multi', help='If 1, use multiclass training else use binary', required=False, default="1")
parser.add_argument('--addlayer', help='layer(s) to add after resnet', required=False, default="dense")

args = parser.parse_args()
train_num = int(args.run_num)
timestamps = int(args.timestamps)
epochs = int(args.epochs)
norm_type = int(args.norm)
use_multi = int(args.multi)
additional_layer = args.addlayer

# Params
# The assumption is, that the dataset is stored in base_path + "GNSS_dataset"
base_path_data = "../../Spectrum_Highway1/"
base_path = "./"
train_file = base_path_data + "GNSS_dataset/train.txt"
adap_file = base_path_data + "GNSS_dataset/adap.txt"
if norm_type == 0:
    norm_data = None
elif norm_type == 1:
    norm_data = [-135.99690198, 0.]
time_size = 243
# ----------- #

# Create Folders
# The post training weights and logs will be saved in the already existing path base_path + "results_episodic + x" + "post"
train_output_folder = "results_episodic"
if additional_layer != "None":
    train_output_folder += "_" + additional_layer
if not use_multi:
    train_output_folder += "_binary"
cur_folders = glob(base_path + train_output_folder + "/%06d_202*-*" % train_num)
if len(cur_folders) == 0:
    print("No Training with number %d found for: " % train_num, additional_layer, " Multi: " + str(use_multi))
    exit()
base_path_train = cur_folders[0]
print("Running: ", train_num, timestamps, epochs, norm_type, use_multi, additional_layer)
if not os.path.exists(base_path_train + "/post"):
    os.mkdir(base_path_train + "/post")
    os.mkdir(base_path_train + "/post/weights")
else:
    print("Already proccessing on another node")
    #exit()
outputWeightspath = base_path_train + "/post/weights/"
log_loss = open(base_path_train + "/post/loss.txt", "w")
log = open(base_path_train + "/post/log.txt", "w")
random_seed = int(base_path_train.split("/")[-1].split("_")[-6])
# ------------ #

# Make deterministic #
np.random.seed(random_seed)
torch.manual_seed(random_seed)
random.seed(random_seed)
torch.backends.cudnn.deterministic = True
torch.backends.cudnn.benchmark = False
# ------------------ #

# Create Train Test data lists
new_classes = np.array([3, 6, 8, 9])
old_classes = list(set(np.arange(11)) - set(new_classes))
print("New classes: ", new_classes, " Old classes: ", old_classes)
class_permutations = list(permutations(new_classes))  # Post train on every combination and order of new classes

print("Train File: ", train_file)
with open(train_file, "r") as f:
    train_info = f.readlines()
train_info = [x.split("\n")[0].split("\t") for x in train_info]
print("Adaptation File: ", adap_file)
with open(adap_file, "r") as f:
    adap_info = f.readlines()
adap_info = [x.split("\n")[0].split("\t") for x in adap_info]
data_info = train_info
data_info.extend(adap_info)

import utilities
if use_multi:
    train_list_raw, valid_list_raw, train_y_raw, valid_y_raw, num_classes = utilities.get_training_data(data_info)
else:
    train_list_raw, valid_list_raw, train_y_raw, valid_y_raw, num_classes = utilities.get_training_data(data_info, reduce_to_binary=True)
train_list = []
valid_list = []
train_y = []
valid_y = []
for ti, tlr in enumerate(train_list_raw):
    # add_folder = ("data/%02d" % (int(tlr.split("/")[-1].split(".npy")[0]) // 15000)) + "/" + tlr.split("/")[-1]
    add_folder = ("data/" + tlr.split("/")[-1]
    for i in range(4):
        train_list.append([base_path_data + "GNSS_dataset/" + add_folder, i])
        train_y.append(train_y_raw[ti])
for vi, vlr in enumerate(valid_list_raw):
    # add_folder = ("data/%02d" % (int(vlr.split("/")[-1].split(".npy")[0]) // 15000)) + "/" + vlr.split("/")[-1]
    add_folder = ("data/" + vlr.split("/")[-1]
    for i in range(4):
        valid_list.append([base_path_data + "GNSS_dataset/" + add_folder, i])
        valid_y.append(valid_y_raw[vi])
# -------------------------- #

# ------------------------------ Select Base starting weights ---------------------------------------- #
wm = re.compile(r'.*/weights/(?P<num>\d{1,6}).h5')
weights = glob(base_path_train + "/weights/*")
weights.sort(key=lambda x: int(wm.match(x).group(1)))
if len(weights) == 0:
    print("Skipped %d: Training not finished." % training_num)
    exit()
# For getting best weights --- #
log_train_file = glob(base_path_train + "/log.txt")[0]
with open(log_train_file, "r") as f:
    log_train_info = f.readlines()
log_accs = np.array([float(x.split("\n")[0].split(" ")[-1]) for x in log_train_info])
weights_ind_best = np.argmax(log_accs)
# ---------------------------- #
base_startweight = weights[weights_ind_best]
# ---------------------------------------------------------------------------------------------------- #

class extract_tensor(nn.Module):
    # For extracting the tensor from an lstm output
    def forward(self,x):
        # Output shape (batch, features, hidden)
        tensor, _ = x
        return tensor

class TransposeB(torch.nn.Module):
    def forward(self, x):
        x = torch.transpose(x, 1, 0)
        return x

class TransposeT(torch.nn.Module):
    def forward(self, x):
        x = torch.transpose(x, 2, 1)
        return x

class multihead_Attention(nn.Module):
    def __init__(self, embeded_dim, num_heads):
        super().__init__()
        self.attention = nn.MultiheadAttention(embeded_dim, num_heads, batch_first=True)

    def forward(self,x):
        x, _ = self.attention(x, x, x)
        return x

# Create Model
from torchvision.models import resnet18
model = resnet18()
if additional_layer == "dense":
    model.fc = nn.Linear(512, 512)
elif additional_layer == "lstm":
    model.avgpool = nn.AdaptiveAvgPool2d((8, 1))
    model.use_flatten = False
    model.fc = nn.Sequential(nn.Flatten(start_dim=-2),
                             nn.LSTM(8, 8, batch_first=True),
                             extract_tensor(),
                             nn.AdaptiveAvgPool1d(1),
                             nn.Flatten())
elif additional_layer == "multiheadattention":
    model.avgpool = nn.AdaptiveAvgPool2d((8, 1))
    model.use_flatten = False
    model.fc = nn.Sequential(nn.Flatten(start_dim=-2),
                             multihead_Attention(8, 8),
                             nn.AdaptiveAvgPool2d(1),
                             nn.Flatten())
elif additional_layer == "conv":
    model.avgpool = nn.AdaptiveAvgPool2d((16, 1))  # Shape: (BS, 512, 16, 1)
    model.use_flatten = False
    model.fc = nn.Sequential(nn.Flatten(start_dim=-2),
                             nn.Conv1d(512, 512, 4),
                             nn.AdaptiveAvgPool1d(1),
                             nn.Flatten())
elif additional_layer == "TSiT":
    from tsai.models.TSiTPlus import TSiTPlus
    model.avgpool = nn.AdaptiveAvgPool2d((16, 1))  # -> (BS, 512, 16, 1)
    model.use_flatten = False
    model.fc = nn.Sequential(nn.Flatten(start_dim=-2),  # -> (BS, 512, 16)
                             TransposeT(),  # -> (BS, 16, 512)
                             TSiTPlus(16, 16, seq_len=512, d_model=32, depth=3))  # -> (BS, 16)
elif additional_layer == "gMLP":
    from tsai.models.gMLP import gMLP
    model.avgpool = nn.AdaptiveAvgPool2d((16, 1))  # -> (BS, 512, 16, 1)
    model.use_flatten = False
    model.fc = nn.Sequential(nn.Flatten(start_dim=-2),  # -> (BS, 512, 16)
                             TransposeT(),  # -> (BS, 16, 512)
                             gMLP(16, 16, seq_len=512, d_model=32, depth=3))  # -> (BS, 16)
elif additional_layer == "autoencoder":
    model.fc = nn.Sequential(nn.Linear(512, 128),
                             nn.ReLU(),
                             nn.Linear(128, 32),
                             nn.ReLU(),
                             nn.Linear(32, 8),
                             nn.Linear(8, 32),
                             nn.ReLU(),
                             nn.Linear(32, 128),
                             nn.ReLU(),
                             nn.Linear(128, 512))
else:
    model.use_fc = False
for ci, child in enumerate(model.children()):  # freezes all layers up to and including the averaging layer -> (BS, 512, 1, 1)
    if ci < 9:
        for param in child.parameters():
            param.requires_grad = False
model.train()
model = model.to(device)
from easyfsl.methods import FewShotClassifier
from easyfsl.methods import PrototypicalNetworks
few_shot_classifier = PrototypicalNetworks(model).to(device)
from easyfsl.samplers import TaskSampler
# ---------- #

for cpi, classes in enumerate(class_permutations):  # Iterate over all class permutations
    print("Dealing with class permutation: ", classes)
    prev_classes = []
    for cpj, cclass in enumerate(classes):  # Add each class in the current permutation one by one
        print("Dealing with current class: ", cclass)
        if len(prev_classes) == 0:
            prev_weights = base_startweight
            new_weights = outputWeightspath + str(cclass) + ".h5"
        else:
            prev_weights = outputWeightspath + "_".join(prev_classes) + ".h5"
            new_weights = outputWeightspath + "_".join(prev_classes) + "_" + str(cclass) + ".h5"
        prev_classes.append(str(cclass))
        if os.path.exists(new_weights):  # Skip if previous permutations already covered the current order
            print("Skipped new class: ", cclass, " It already exists.")
            continue
        num_classes = len(old_classes) + len(prev_classes)
        cur_classes = old_classes + [int(c) for c in prev_classes]
        if len(prev_classes) == 1:
            few_shot_classifier.backbone.load_state_dict(torch.load(prev_weights, map_location=device))
        else:
            few_shot_classifier.backbone.fc.load_state_dict(torch.load(prev_weights, map_location=device))
        train_optimizer = SGD(few_shot_classifier.parameters(), lr=1e-2, momentum=0.9, weight_decay=5e-4)
        train_scheduler = MultiStepLR(train_optimizer, milestones=[120, 160], gamma=0.1)
        criterion = torch.nn.CrossEntropyLoss().to(device)
        print("Current classes: ", cur_classes)
        cur_train_list = [tl for ti, tl in enumerate(train_list) if train_y[ti] in cur_classes]
        cur_train_y = [ty for ty in train_y if ty in cur_classes]
        cur_valid_list = [vl for vi, vl in enumerate(valid_list) if valid_y[vi] in cur_classes]
        cur_valid_y = [vy for vy in valid_y if vy in cur_classes]

        def training_epoch(model: FewShotClassifier, data_loader: DataLoader, optimizer: Optimizer, method : str = "prototypical"):
            all_loss = []
            model.train()
            with tqdm(
                enumerate(data_loader), total=len(data_loader), desc="Training"
            ) as tqdm_train:
                for episode_index, (
                    support_images,
                    support_labels,
                    query_images,
                    query_labels,
                    _,
                ) in tqdm_train:
                    optimizer.zero_grad()
                    model.process_support_set(
                        support_images.to(device), support_labels.to(device)
                    )
                    classification_scores = model(query_images.to(device))
                    # Added to deal with different losses for different fewshot methods ------------------------------------- #
                    if method == "simpleshot" or method == "bdcspn":
                        classification_scores = (torch.clamp(classification_scores, min=-0.1) + 0.1) / 1.1
                    if method == "simpleshot" or method == "bdcspn" or method == "relation" or method == "laplacianshot":
                        query_labels = torch.nn.functional.one_hot(query_labels, num_classes=num_classes).float()
                    # ------------------------------------------------------------------------------------------------------- #
                    loss = criterion(classification_scores, query_labels.to(device))
                    loss.backward()
                    optimizer.step()

                    all_loss.append(loss.item())

                    tqdm_train.set_postfix(loss=mean(all_loss))

            return mean(all_loss)

        # For validation -------------------------------------------------------------------- #
        n_way = num_classes
        n_shot = 1
        if use_multi:
            n_query = 1
        else:
            n_query = 9
        n_validation_tasks = 250

        val_set = utilities.val_set(cur_valid_list, cur_valid_y, time_size, norm=norm_data, norm_type=norm_type)
        val_sampler = TaskSampler(
            val_set, n_way=n_way, n_shot=n_shot, n_query=n_query, n_tasks=n_validation_tasks
        )
        val_loader = DataLoader(
            val_set,
            batch_sampler=val_sampler,
            num_workers=1,
            pin_memory=True,
            collate_fn=val_sampler.episodic_collate_fn,
        )
        # ----------------------------------------------------------------------------------- #

        # For training -------------------------------------------------------------------- #
        n_shot_tr = 2
        if use_multi:
            n_query_tr = 3
        else:
            n_query_tr = 20
        n_tasks_per_epoch = 250
        train_set = utilities.val_set(cur_train_list, cur_train_y, time_size, norm=norm_data, norm_type=norm_type)
        train_sampler = TaskSampler(
            train_set, n_way=n_way, n_shot=n_shot_tr, n_query=n_query_tr, n_tasks=n_tasks_per_epoch
        )
        train_loader = DataLoader(
            train_set,
            batch_sampler=train_sampler,
            num_workers=1,
            pin_memory=True,
            collate_fn=train_sampler.episodic_collate_fn,
        )
        # --------------------------------------------------------------------------------- #

        for e in range(epochs):
            print("Epoch: %d/%d" % (e, epochs))
            average_loss = training_epoch(few_shot_classifier, train_loader, train_optimizer)
            log_loss.write("%f\n" % average_loss)
            log_loss.flush()
            if (e + 1) % int(timestamps) == 0:
                few_shot_classifier.eval()
                validation_accuracy = evaluate(
                    few_shot_classifier, val_loader, device=device, tqdm_prefix="Validation"
                )
                print('Valid Acc: %.5f' % validation_accuracy)
                log.write("Valid Acc: %.5f" % validation_accuracy + "\t" + "_".join(prev_classes) + "\n")
                log.flush()
                torch.save(few_shot_classifier.backbone.fc.state_dict(), new_weights)
                few_shot_classifier.train()
log.close()
log_loss.close()
print("Done")