import tensorflow as tf
import random
import pandas as pd
from tensorflow import keras
from tensorflow.data import AUTOTUNE
from keras import layers, losses, optimizers
import requests

class NotifyServerCallback(tf.keras.callbacks.Callback):
    def on_epoch_end(self, epoch, log, *args, **kwargs):
        {{ if .HeadId }}
        requests.get(f'{{ .Host }}/api/model/head/epoch/update?epoch={epoch + 1}&accuracy={log["accuracy"]}&head_id={{.HeadId}}')
        {{ else }}
        requests.get(f'{{ .Host }}/api/model/epoch/update?model_id={{.Model.Id}}&epoch={epoch + 1}&accuracy={log["accuracy"]}&definition={{.DefId}}')
        {{end}}



DATA_DIR = "{{ .DataDir }}"
image_size = ({{ .Size }})

df = pd.read_csv("{{ .RunPath }}/train.csv", dtype=str)
keys = tf.constant(df['Id'].dropna())
values = tf.constant(list(map(int, df['Index'].dropna())))

depth = {{ .Depth }}
diff = {{ .StartPoint }}

table = tf.lookup.StaticHashTable(
    initializer=tf.lookup.KeyValueTensorInitializer(
        keys=keys,
        values=values,
    ),
    default_value=tf.constant(-1),
    name="Indexes"
)

DATA_DIR_PREPARE = DATA_DIR + "/"

#based on https://www.tensorflow.org/tutorials/load_data/images
def pathToLabel(path):
  path = tf.strings.regex_replace(path, DATA_DIR_PREPARE, "")
  {{ if eq .Model.Format "png" }}
  path = tf.strings.regex_replace(path, ".png", "")
  {{ else if eq .Model.Format "jpeg" }}
  path = tf.strings.regex_replace(path, ".jpeg", "")
  {{ else }}
  ERROR
  {{ end }}

  return tf.one_hot(table.lookup(tf.strings.as_string([path])) - diff, depth)[0]

def decode_image(img):
  {{ if eq .Model.Format "png" }}
  img = tf.io.decode_png(img, channels={{.ColorMode}})
  {{ else if eq .Model.Format "jpeg" }}
  img = tf.io.decode_jpeg(img, channels={{.ColorMode}})
  {{ else }}
  ERROR
  {{ end }}
  return tf.image.resize(img, image_size)

def process_path(path):
  label = pathToLabel(path)

  img = tf.io.read_file(path)
  img = decode_image(img)

  return img, label

def configure_for_performance(ds: tf.data.Dataset, size: int) -> tf.data.Dataset:
  #ds = ds.cache()
  ds = ds.shuffle(buffer_size=size)
  ds = ds.batch(batch_size)
  ds = ds.prefetch(AUTOTUNE)
  return ds

def prepare_dataset(ds: tf.data.Dataset, size: int) -> tf.data.Dataset:
  ds = ds.map(process_path, num_parallel_calls=AUTOTUNE)
  ds = configure_for_performance(ds, size)
  return ds

def filterDataset(path):
  path = tf.strings.regex_replace(path, DATA_DIR_PREPARE, "")
  
  {{ if eq .Model.Format "png" }}
  path = tf.strings.regex_replace(path, ".png", "")
  {{ else if eq .Model.Format "jpeg" }}
  path = tf.strings.regex_replace(path, ".jpeg", "")
  {{ else }}
  ERROR
  {{ end }}
  
  return tf.reshape(table.lookup(tf.strings.as_string([path])), []) != -1

seed = random.randint(0, 100000000)

batch_size = 64

# Read all the files from the direcotry
list_ds = tf.data.Dataset.list_files(str(f'{DATA_DIR}/*'), shuffle=False)
list_ds = list_ds.filter(filterDataset)

image_count = len(list(list_ds.as_numpy_iterator()))

list_ds = list_ds.shuffle(image_count, seed=seed)

val_size = int(image_count * 0.3)

train_ds = list_ds.skip(val_size)
val_ds = list_ds.take(val_size)

dataset = prepare_dataset(train_ds, image_count)
dataset_validation   = prepare_dataset(val_ds, val_size)

track = 0

def addBlock(
    b_size: int,
    filter_size: int,
    kernel_size: int = 3,
    top: bool = True,
    pooling_same: bool = False,
    pool_func=layers.MaxPool2D
):
    global track
    model = keras.Sequential(name=f"{track}-{b_size}-{filter_size}-{kernel_size}")
    track += 1
    for _ in range(b_size):
        model.add(layers.Conv2D(
            filter_size,
            kernel_size,
            padding="same"
        ))
        model.add(layers.ReLU())
    if top:
        if pooling_same:
            model.add(pool_func(padding="same", strides=(1, 1)))
        else:
            model.add(pool_func())
        model.add(layers.BatchNormalization())
        model.add(layers.LeakyReLU())
        model.add(layers.Dropout(0.4))
    return model


{{ if .LoadPrev }}
model = tf.keras.saving.load_model('{{.LastModelRunPath}}')
{{ else }}
model = keras.Sequential()

{{- range .Layers }}
{{- if eq .LayerType 1}}
model.add(layers.Rescaling(1./255))
{{- else if eq .LayerType 2 }}
model.add(layers.Dense({{ .Shape }}, activation="sigmoid"))
{{- else if eq .LayerType 3}}
model.add(layers.Flatten())
{{- else if eq .LayerType 4}}
model.add(addBlock(2, 128, 3, pool_func=layers.AveragePooling2D))
{{- else }}
ERROR
{{- end }}
{{- end }}
{{ end }}

model.compile(
    #loss=losses.SparseCategoricalCrossentropy(),
    loss=losses.BinaryCrossentropy(from_logits=False),
    optimizer=tf.keras.optimizers.Adam(),
    metrics=['accuracy'])

his = model.fit(dataset, validation_data= dataset_validation, epochs={{.EPOCH_PER_RUN}}, callbacks=[
                NotifyServerCallback(),
                tf.keras.callbacks.EarlyStopping("loss", mode="min", patience=5)], use_multiprocessing = True)

acc = his.history["accuracy"]

f = open("accuracy.val", "w")
f.write(str(acc[-1]))
f.close()


tf.saved_model.save(model, "{{ .SaveModelPath }}/model")
model.save("{{ .SaveModelPath }}/model.keras")