import os
os.system('pip install tensorflow')
os.environ['TF_CPP_MIN_LOG_LEVEL'] = '2'

import json
import numpy as np
import gradio as gr
import tensorflow as tf
from tensorflow import keras
from huggingface_hub.keras_mixin import from_pretrained_keras

num_samples = 10000
data_path = 'fra.txt'

input_texts = []
target_texts = []
input_characters = set()
target_characters = set()

with open(data_path, "r", encoding="utf-8") as f:
    lines = f.read().split("\n")
for line in lines[: min(num_samples, len(lines) - 1)]:
    input_text, target_text, _ = line.split("\t")
    # We use "tab" as the "start sequence" character
    # for the targets, and "\n" as "end sequence" character.
    target_text = "\t" + target_text + "\n"
    input_texts.append(input_text)
    target_texts.append(target_text)
    for char in input_text:
        if char not in input_characters:
            input_characters.add(char)
    for char in target_text:
        if char not in target_characters:
            target_characters.add(char)

input_characters = sorted(list(input_characters))
target_characters = sorted(list(target_characters))

input_token_index = dict([(char, i) for i, char in enumerate(input_characters)])
target_token_index = dict([(char, i) for i, char in enumerate(target_characters)])

num_encoder_tokens = len(input_characters)
num_decoder_tokens = len(target_characters)
max_encoder_seq_length = max([len(txt) for txt in input_texts])
max_decoder_seq_length = max([len(txt) for txt in target_texts])

model = from_pretrained_keras("keras-io/cl_s2s")
print(model.summary())
latent_dim = 256

encoder_inputs = model.input[0]  # input_1
encoder_outputs, state_h_enc, state_c_enc = model.layers[2].output  # lstm_1
encoder_states = [state_h_enc, state_c_enc]
encoder_model = keras.Model(encoder_inputs, encoder_states)

decoder_inputs = tf.identity(model.input[1])  # input_2
decoder_state_input_h = keras.Input(shape=(latent_dim,))
decoder_state_input_c = keras.Input(shape=(latent_dim,))
decoder_states_inputs = [decoder_state_input_h, decoder_state_input_c]
decoder_lstm = model.layers[3]
decoder_outputs, state_h_dec, state_c_dec = decoder_lstm(
    decoder_inputs, initial_state=decoder_states_inputs
)
decoder_states = [state_h_dec, state_c_dec]
decoder_dense = model.layers[4]
decoder_outputs = decoder_dense(decoder_outputs)
decoder_model = keras.Model(
    [decoder_inputs] + decoder_states_inputs, [decoder_outputs] + decoder_states
)

# Reverse-lookup token index to decode sequences back to
# something readable.
reverse_input_char_index = dict((i, char) for char, i in input_token_index.items())
reverse_target_char_index = dict((i, char) for char, i in target_token_index.items())


def decode_sequence(input_seq):
    # Encode the input as state vectors.

    input_seq2 = list()
    input_seq2.append(input_seq)

    infer_input_data = np.zeros((len(input_seq2), max_encoder_seq_length, num_encoder_tokens), dtype="float32")

    for i, (input_text) in enumerate((input_seq2)):
        for t, char in enumerate(input_text):
            infer_input_data[i, t, input_token_index[char]] = 1.0
        infer_input_data[i, t + 1:, input_token_index[" "]] = 1.0

    states_value = encoder_model.predict(infer_input_data)

    # Generate empty target sequence of length 1.
    target_seq = np.zeros((1, 1, num_decoder_tokens))
    # Populate the first character of target sequence with the start character.
    target_seq[0, 0, target_token_index["\t"]] = 1.0

    # Sampling loop for a batch of sequences
    # (to simplify, here we assume a batch of size 1).
    stop_condition = False
    decoded_sentence = ""
    while not stop_condition:
        output_tokens, h, c = decoder_model.predict([target_seq] + states_value)

        # Sample a token
        sampled_token_index = np.argmax(output_tokens[0, -1, :])
        sampled_char = reverse_target_char_index[sampled_token_index]
        decoded_sentence += sampled_char

        # Exit condition: either hit max length
        # or find stop character.
        if sampled_char == "\n" or len(decoded_sentence) > max_decoder_seq_length:
            stop_condition = True

        # Update the target sequence (of length 1).
        target_seq = np.zeros((1, 1, num_decoder_tokens))
        target_seq[0, 0, sampled_token_index] = 1.0

        # Update states
        states_value = [h, c]

    return decoded_sentence


input_1 = gr.Textbox(lines=2)
output_1 = gr.Textbox()

iface = gr.Interface(decode_sequence,
                     inputs=input_1, outputs=output_1,
                     examples=[["Be kind."],
                               ["Hug me."]],
                     title="Character Level Recurrent Seq2Seq Model",
                     article="Author: <a href=\"https://huggingface.co/reichenbach\">Rishav Chandra Varma</a>")

iface.launch(debug=True)