import tensorflow as tf
from util.setup import logdir, modeldir, cachepath
import subprocess

import os, datetime
import numpy as np
import pickle
import h5py

from icing.pirep_goes import split_data, normalize

LOG_DEVICE_PLACEMENT = False

CACHE_DATA_IN_MEM = True
CACHE_GFS = True

PROC_BATCH_SIZE = 60
PROC_BATCH_BUFFER_SIZE = 50000
NumLabels = 1
BATCH_SIZE = 256
NUM_EPOCHS = 200


TRACK_MOVING_AVERAGE = False

DAY_NIGHT = 'ANY'

TRIPLET = False
CONV3D = False

img_width = 16

mean_std_file = '/Users/tomrink/data/icing/fovs_mean_std_day.pkl'
f = open(mean_std_file, 'rb')
mean_std_dct = pickle.load(f)
f.close()

train_params = ['cld_height_acha', 'cld_geo_thick', 'supercooled_cloud_fraction', 'cld_temp_acha', 'cld_press_acha',
                'cld_reff_dcomp', 'cld_opd_dcomp', 'cld_cwp_dcomp', 'iwc_dcomp', 'lwc_dcomp']
                    #'cloud_phase']


def build_residual_block(input, drop_rate, num_neurons, activation, block_name, doDropout=True, doBatchNorm=True):
    with tf.name_scope(block_name):
        if doDropout:
            fc = tf.keras.layers.Dropout(drop_rate)(input)
            fc = tf.keras.layers.Dense(num_neurons, activation=activation)(fc)
        else:
            fc = tf.keras.layers.Dense(num_neurons, activation=activation)(input)
        if doBatchNorm:
            fc = tf.keras.layers.BatchNormalization()(fc)
        print(fc.shape)
        fc_skip = fc

        if doDropout:
            fc = tf.keras.layers.Dropout(drop_rate)(fc)
        fc = tf.keras.layers.Dense(num_neurons, activation=activation)(fc)
        if doBatchNorm:
            fc = tf.keras.layers.BatchNormalization()(fc)
        print(fc.shape)

        if doDropout:
            fc = tf.keras.layers.Dropout(drop_rate)(fc)
        fc = tf.keras.layers.Dense(num_neurons, activation=activation)(fc)
        if doBatchNorm:
            fc = tf.keras.layers.BatchNormalization()(fc)
        print(fc.shape)

        if doDropout:
            fc = tf.keras.layers.Dropout(drop_rate)(fc)
        fc = tf.keras.layers.Dense(num_neurons, activation=None)(fc)
        if doBatchNorm:
            fc = tf.keras.layers.BatchNormalization()(fc)

        fc = fc + fc_skip
        fc = tf.keras.layers.LeakyReLU()(fc)
        print(fc.shape)

    return fc


class IcingIntensityNN:
    
    def __init__(self, gpu_device=0, datapath=None):
        self.train_data = None
        self.train_label = None
        self.test_data = None
        self.test_label = None
        self.test_data_denorm = None
        
        self.train_dataset = None
        self.inner_train_dataset = None
        self.test_dataset = None
        self.X_img = None
        self.X_prof = None
        self.X_u = None
        self.X_v = None
        self.X_sfc = None
        self.inputs = []
        self.y = None
        self.handle = None
        self.inner_handle = None
        self.in_mem_batch = None
        self.filename = None
        self.h5f = None
        self.h5f_l1b = None

        self.logits = None

        self.predict_data = None
        self.predict_dataset = None
        self.mean_list = None
        self.std_list = None
        
        self.training_op = None
        self.correct = None
        self.accuracy = None
        self.loss = None
        self.pred_class = None
        self.gpu_device = gpu_device
        self.variable_averages = None

        self.global_step = None

        self.writer_train = None
        self.writer_valid = None

        self.OUT_OF_RANGE = False

        self.abi = None
        self.temp = None
        self.wv = None
        self.lbfp = None
        self.sfc = None

        self.in_mem_data_cache = {}

        self.model = None
        self.optimizer = None
        self.train_loss = None
        self.train_accuracy = None
        self.test_loss = None
        self.test_accuracy = None

        self.learningRateSchedule = None
        self.num_data_samples = None
        self.initial_learning_rate = None

        n_chans = len(train_params)
        NUM_PARAMS = 1
        if TRIPLET:
            n_chans *= 3
        #self.X_img = tf.keras.Input(shape=(img_width, img_width, n_chans))
        self.X_img = tf.keras.Input(shape=n_chans)
        #self.X_prof = tf.keras.Input(shape=(NUM_VERT_LEVELS, NUM_VERT_PARAMS))
        #self.X_sfc = tf.keras.Input(shape=2)

        self.inputs.append(self.X_img)
        #self.inputs.append(self.X_prof)

        self.DISK_CACHE = True

        if datapath is not None:
            self.DISK_CACHE = False
            f = open(datapath, 'rb')
            self.in_mem_data_cache = pickle.load(f)
            f.close()

        tf.debugging.set_log_device_placement(LOG_DEVICE_PLACEMENT)

        gpus = tf.config.experimental.list_physical_devices('GPU')
        if gpus:
            try:
                # Currently, memory growth needs to be the same across GPUs
                for gpu in gpus:
                    tf.config.experimental.set_memory_growth(gpu, True)
                logical_gpus = tf.config.experimental.list_logical_devices('GPU')
                print(len(gpus), "Physical GPUs,", len(logical_gpus), "Logical GPUs")
            except RuntimeError as e:
                # Memory growth must be set before GPUs have been initialized
                print(e)

    def get_in_mem_data_batch(self, keys):

        # sort these to use as numpy indexing arrays
        nd_keys = np.array(keys)
        nd_keys = np.sort(nd_keys)

        data = []
        for param in train_params:
            nda = self.h5f[param][nd_keys, ]
            nda = normalize(nda, param, mean_std_dct)
            data.append(nda)
        data = np.stack(data)
        data = data.astype(np.float32)
        data = np.transpose(data, axes=(1, 0))

        label = self.h5f['icing_intensity'][nd_keys]
        label = label.astype(np.int32)
        label = np.where(label == -1, 0, label)

        # binary, two class
        label = np.where(label != 0, 1, label)
        label = label.reshape((label.shape[0], 1))

        # TODO: Implement in memory cache
        # for key in keys:
        #     if CACHE_DATA_IN_MEM:
        #         tup = self.in_mem_data_cache.get(key)
        #         if tup is not None:
        #             images.append(tup[0])
        #             vprof.append(tup[1])
        #             label.append(tup[2])
        #             continue
        #
        #     if CACHE_DATA_IN_MEM:
        #         self.in_mem_data_cache[key] = (nda, ndb, ndc)

        return data, label

    @tf.function(input_signature=[tf.TensorSpec(None, tf.int32)])
    def data_function(self, indexes):
        out = tf.numpy_function(self.get_in_mem_data_batch, [indexes], [tf.float32, tf.int32])
        return out

    def get_train_dataset(self, indexes):
        indexes = list(indexes)

        dataset = tf.data.Dataset.from_tensor_slices(indexes)
        dataset = dataset.batch(PROC_BATCH_SIZE)
        dataset = dataset.map(self.data_function, num_parallel_calls=8)
        dataset = dataset.shuffle(PROC_BATCH_BUFFER_SIZE)
        dataset = dataset.prefetch(buffer_size=1)
        self.train_dataset = dataset

    def get_test_dataset(self, indexes):
        indexes = list(indexes)

        dataset = tf.data.Dataset.from_tensor_slices(indexes)
        dataset = dataset.batch(PROC_BATCH_SIZE)
        dataset = dataset.map(self.data_function, num_parallel_calls=8)
        self.test_dataset = dataset

    def setup_pipeline(self, filename, train_idxs=None, test_idxs=None):
        self.filename = filename
        self.h5f = h5py.File(filename, 'r')
        time = self.h5f['time']
        num_obs = time.shape[0]
        trn_idxs, tst_idxs = split_data(num_obs, skip=8)
        self.num_data_samples = trn_idxs.shape[0]

        self.get_train_dataset(trn_idxs)
        self.get_test_dataset(tst_idxs)

        print('num train samples: ', self.num_data_samples)
        print('BATCH SIZE: ', BATCH_SIZE)
        print('num test samples: ', tst_idxs.shape[0])
        print('setup_pipeline: Done')

    def build_1d_cnn(self):
        print('build_1d_cnn')
        # padding = 'VALID'
        padding = 'SAME'

        # activation = tf.nn.relu
        # activation = tf.nn.elu
        activation = tf.nn.leaky_relu

        num_filters = 6

        conv = tf.keras.layers.Conv1D(num_filters, 5, strides=1, padding=padding)(self.inputs[1])
        conv = tf.keras.layers.MaxPool1D(padding=padding)(conv)
        print(conv)

        num_filters *= 2
        conv = tf.keras.layers.Conv1D(num_filters, 3, strides=1, padding=padding)(conv)
        conv = tf.keras.layers.MaxPool1D(padding=padding)(conv)
        print(conv)

        num_filters *= 2
        conv = tf.keras.layers.Conv1D(num_filters, 3, strides=1, padding=padding)(conv)
        conv = tf.keras.layers.MaxPool1D(padding=padding)(conv)
        print(conv)

        num_filters *= 2
        conv = tf.keras.layers.Conv1D(num_filters, 3, strides=1, padding=padding)(conv)
        conv = tf.keras.layers.MaxPool1D(padding=padding)(conv)
        print(conv)

        flat = tf.keras.layers.Flatten()(conv)
        print(flat)

        return flat

    def build_cnn(self):
        print('build_cnn')
        # padding = "VALID"
        padding = "SAME"

        # activation = tf.nn.relu
        # activation = tf.nn.elu
        activation = tf.nn.leaky_relu
        momentum = 0.99

        num_filters = 8

        conv = tf.keras.layers.Conv2D(num_filters, 5, strides=[1, 1], padding=padding, activation=activation)(self.inputs[0])
        conv = tf.keras.layers.MaxPool2D(padding=padding)(conv)
        conv = tf.keras.layers.BatchNormalization()(conv)
        print(conv.shape)

        num_filters *= 2
        conv = tf.keras.layers.Conv2D(num_filters, 3, strides=[1, 1], padding=padding, activation=activation)(conv)
        conv = tf.keras.layers.MaxPool2D(padding=padding)(conv)
        conv = tf.keras.layers.BatchNormalization()(conv)
        print(conv.shape)

        num_filters *= 2
        conv = tf.keras.layers.Conv2D(num_filters, 3, strides=[1, 1], padding=padding, activation=activation)(conv)
        conv = tf.keras.layers.MaxPool2D(padding=padding)(conv)
        conv = tf.keras.layers.BatchNormalization()(conv)
        print(conv.shape)

        num_filters *= 2
        conv = tf.keras.layers.Conv2D(num_filters, 3, strides=[1, 1], padding=padding, activation=activation)(conv)
        conv = tf.keras.layers.MaxPool2D(padding=padding)(conv)
        conv = tf.keras.layers.BatchNormalization()(conv)
        print(conv.shape)

        num_filters *= 2
        conv = tf.keras.layers.Conv2D(num_filters, 3, strides=[1, 1], padding=padding, activation=activation)(conv)
        conv = tf.keras.layers.MaxPool2D(padding=padding)(conv)
        conv = tf.keras.layers.BatchNormalization()(conv)
        print(conv.shape)

        flat = tf.keras.layers.Flatten()(conv)

        return flat

    def build_dnn(self, input_layer=None):
        print('build fully connected layer')
        drop_rate = 0.5

        # activation = tf.nn.relu
        # activation = tf.nn.elu
        activation = tf.nn.leaky_relu
        momentum = 0.99
        
        if input_layer is not None:
            flat = input_layer
            n_hidden = input_layer.shape[1]
        else:
            flat = self.X_img
            n_hidden = self.X_img.shape[1]
            n_hidden = 100

        fac = 1

        fc = build_residual_block(flat, drop_rate, fac*n_hidden, activation, 'Residual_Block_1')

        fc = build_residual_block(fc, drop_rate, fac*n_hidden, activation, 'Residual_Block_2')

        fc = build_residual_block(fc, drop_rate, fac*n_hidden, activation, 'Residual_Block_3')

        fc = build_residual_block(fc, drop_rate, fac*n_hidden, activation, 'Residual_Block_4')

        fc = build_residual_block(fc, drop_rate, fac*n_hidden, activation, 'Residual_Block_5')

        fc = tf.keras.layers.Dense(n_hidden, activation=activation)(fc)
        fc = tf.keras.layers.BatchNormalization()(fc)
        print(fc.shape)

        # activation = tf.nn.softmax
        activation = tf.nn.sigmoid  # For binary

        logits = tf.keras.layers.Dense(NumLabels, activation=activation)(fc)
        print(logits.shape)
        
        self.logits = logits

    def build_training(self):
        self.loss = tf.keras.losses.BinaryCrossentropy(from_logits=True)  # for two-class only
        #self.loss = tf.keras.losses.SparseCategoricalCrossentropy()  # For multi-class

        # decayed_learning_rate = learning_rate * decay_rate ^ (global_step / decay_steps)
        initial_learning_rate = 0.0016
        decay_rate = 0.95
        steps_per_epoch = int(self.num_data_samples/BATCH_SIZE)  # one epoch
        # decay_steps = int(steps_per_epoch / 2)
        decay_steps = 2 * steps_per_epoch
        print('initial rate, decay rate, steps/epoch, decay steps: ', initial_learning_rate, decay_rate, steps_per_epoch, decay_steps)

        self.learningRateSchedule = tf.keras.optimizers.schedules.ExponentialDecay(initial_learning_rate, decay_steps, decay_rate)

        optimizer = tf.keras.optimizers.Adam(learning_rate=self.learningRateSchedule)

        if TRACK_MOVING_AVERAGE:
            ema = tf.train.ExponentialMovingAverage(decay=0.999)

            with tf.control_dependencies([optimizer]):
                optimizer = ema.apply(self.model.trainable_variables)

        self.optimizer = optimizer
        self.initial_learning_rate = initial_learning_rate

    def build_evaluation(self):
        self.train_accuracy = tf.keras.metrics.MeanAbsoluteError(name='train_accuracy')
        self.test_accuracy = tf.keras.metrics.MeanAbsoluteError(name='test_accuracy')
        self.train_loss = tf.keras.metrics.Mean(name='train_loss')
        self.test_loss = tf.keras.metrics.Mean(name='test_loss')

    def build_predict(self):
        _, pred = tf.nn.top_k(self.logits)
        self.pred_class = pred

        if TRACK_MOVING_AVERAGE:
            self.variable_averages = tf.train.ExponentialMovingAverage(0.999, self.global_step)
            self.variable_averages.apply(self.model.trainable_variables)

    @tf.function
    def train_step(self, mini_batch):
        inputs = [mini_batch[0]]
        labels = mini_batch[1]
        with tf.GradientTape() as tape:
            pred = self.model(inputs, training=True)
            loss = self.loss(labels, pred)
            total_loss = loss
            if len(self.model.losses) > 0:
                reg_loss = tf.math.add_n(self.model.losses)
                total_loss = loss + reg_loss
        gradients = tape.gradient(total_loss, self.model.trainable_variables)
        self.optimizer.apply_gradients(zip(gradients, self.model.trainable_variables))

        self.train_loss(loss)
        self.train_accuracy(labels, pred)

        return loss

    @tf.function
    def test_step(self, mini_batch):
        inputs = [mini_batch[0]]
        labels = mini_batch[1]
        pred = self.model(inputs, training=False)
        t_loss = self.loss(labels, pred)

        self.test_loss(t_loss)
        self.test_accuracy(labels, pred)

    def predict(self, mini_batch):
        inputs = [mini_batch[0]]
        labels = mini_batch[1]
        pred = self.model(inputs, training=False)
        t_loss = self.loss(labels, pred)

    def do_training(self, ckpt_dir=None):

        if ckpt_dir is None:
            if not os.path.exists(modeldir):
                os.mkdir(modeldir)
            ckpt = tf.train.Checkpoint(step=tf.Variable(1), model=self.model)
            ckpt_manager = tf.train.CheckpointManager(ckpt, modeldir, max_to_keep=3)
        else:
            ckpt = tf.train.Checkpoint(step=tf.Variable(1), model=self.model)
            ckpt_manager = tf.train.CheckpointManager(ckpt, ckpt_dir, max_to_keep=3)

        self.writer_train = tf.summary.create_file_writer(os.path.join(logdir, 'plot_train'))
        self.writer_valid = tf.summary.create_file_writer(os.path.join(logdir, 'plot_valid'))

        step = 0
        total_time = 0

        for epoch in range(NUM_EPOCHS):
            self.train_loss.reset_states()
            self.train_accuracy.reset_states()

            t0 = datetime.datetime.now().timestamp()

            proc_batch_cnt = 0
            n_samples = 0

            for data0, label in self.train_dataset:
                trn_ds = tf.data.Dataset.from_tensor_slices((data0, label))
                trn_ds = trn_ds.batch(BATCH_SIZE)
                for mini_batch in trn_ds:
                    if self.learningRateSchedule is not None:
                        loss = self.train_step(mini_batch)

                    if (step % 100) == 0:

                        with self.writer_train.as_default():
                            tf.summary.scalar('loss_trn', loss.numpy(), step=step)
                            tf.summary.scalar('num_train_steps', step, step=step)
                            tf.summary.scalar('num_epochs', epoch, step=step)

                        self.test_loss.reset_states()
                        self.test_accuracy.reset_states()

                        for data0_tst, label_tst in self.test_dataset:
                            tst_ds = tf.data.Dataset.from_tensor_slices((data0_tst, label_tst))
                            tst_ds = tst_ds.batch(BATCH_SIZE)
                            for mini_batch_test in tst_ds:
                                self.test_step(mini_batch_test)

                        with self.writer_valid.as_default():
                            tf.summary.scalar('loss_val', self.test_loss.result(), step=step)
                            tf.summary.scalar('acc_val', self.test_accuracy.result(), step=step)
                            tf.summary.scalar('num_train_steps', step, step=step)
                            tf.summary.scalar('num_epochs', epoch, step=step)

                        print('****** test loss, acc: ', self.test_loss.result(), self.test_accuracy.result())

                    step += 1
                    print('train loss: ', loss.numpy())

                proc_batch_cnt += 1
                n_samples += data0.shape[0]
                print('proc_batch_cnt: ', proc_batch_cnt, n_samples)

            t1 = datetime.datetime.now().timestamp()
            print('End of Epoch: ', epoch+1, 'elapsed time: ', (t1-t0))
            total_time += (t1-t0)

            self.test_loss.reset_states()
            self.test_accuracy.reset_states()
            for data0, label in self.test_dataset:
                ds = tf.data.Dataset.from_tensor_slices((data0, label))
                ds = ds.batch(BATCH_SIZE)
                for mini_batch in ds:
                    self.test_step(mini_batch)

            print('loss, acc: ', self.test_loss.result(), self.test_accuracy.result())
            ckpt_manager.save()

            if self.DISK_CACHE and epoch == 0:
                f = open(cachepath, 'wb')
                pickle.dump(self.in_mem_data_cache, f)
                f.close()

        print('total time: ', total_time)
        self.writer_train.close()
        self.writer_valid.close()

    def build_model(self):
        # flat = self.build_cnn()
        # flat_1d = self.build_1d_cnn()
        # flat = tf.keras.layers.concatenate([flat, flat_1d, flat_anc])
        # flat = tf.keras.layers.concatenate([flat, flat_1d])
        # self.build_dnn(flat)
        self.build_dnn()
        self.model = tf.keras.Model(self.inputs, self.logits)

    def restore(self, ckpt_dir):

        ckpt = tf.train.Checkpoint(step=tf.Variable(1), model=self.model)
        ckpt_manager = tf.train.CheckpointManager(ckpt, ckpt_dir, max_to_keep=3)

        ckpt.restore(ckpt_manager.latest_checkpoint)

        self.test_loss.reset_states()
        self.test_accuracy.reset_states()

        for abi_tst, temp_tst, lbfp_tst in self.test_dataset:
            ds = tf.data.Dataset.from_tensor_slices((abi_tst, temp_tst, lbfp_tst))
            ds = ds.batch(BATCH_SIZE)
            for mini_batch_test in ds:
                self.predict(mini_batch_test)
        print('loss, acc: ', self.test_loss.result(), self.test_accuracy.result())

    def run(self, filename, filename_l1b=None, train_dict=None, valid_dict=None):
        #with tf.device('/device:GPU:'+str(self.gpu_device)):
            self.setup_pipeline(filename, train_idxs=train_dict, test_idxs=valid_dict)
            self.build_model()
            self.build_training()
            self.build_evaluation()
            self.do_training()

    def run_restore(self, matchup_dict, ckpt_dir):
        self.setup_pipeline(None, None, matchup_dict)
        self.build_model()
        self.build_training()
        self.build_evaluation()
        self.restore(ckpt_dir)


if __name__ == "__main__":
    nn = IcingIntensityNN()
    nn.run('matchup_filename')