#pip install gradio nltk youtube-transcript-api pytube gtts --quiet

from __future__ import division
import nltk
import string
import re
import io, os, time
import numpy as np
import gradio as gr
from tempfile import TemporaryFile
from gtts import gTTS
from pytube import YouTube
from youtube_transcript_api import YouTubeTranscriptApi
from nltk import word_tokenize
from nltk.stem import WordNetLemmatizer
from collections import defaultdict

nltk.download('punkt')
nltk.download('averaged_perceptron_tagger')
nltk.download('wordnet')

"""## Transcript Summary Module"""

def summarize_text(url, percent):

  # Check if the URL is valid
  try:
      youtube = YouTube(url)
  except Exception as e:
      raise gr.Error(f"Invalid YouTube URL")

  # Get transcript using youtube-transcript-api
  try:
      transcript = YouTubeTranscriptApi.get_transcript(youtube.video_id)
      Text = ' '.join([entry['text'] for entry in transcript])
  except Exception as e:
      raise gr.Error(f"Could not retrieve the video's transcript. Please try another video")

  # Clean text

  Cleaned_text = re.sub(r'[^a-zA-Z0-9\._-]', ' ', Text)
  text = word_tokenize(Cleaned_text)
  case_insensitive_text = word_tokenize(Cleaned_text.lower())

  # Sentence Segmentation

  sentences = []
  tokenized_sentences = []
  sentence = " "
  for word in text:
      if word != '.':
          sentence+=str(word)+" "
      else:
          sentences.append(sentence.strip())
          tokenized_sentences.append(word_tokenize(sentence.lower().strip()))
          sentence = " "

  def lemmatize(POS_tagged_text):

      wordnet_lemmatizer = WordNetLemmatizer()
      adjective_tags = ['JJ','JJR','JJS']
      lemmatized_text = []

      for word in POS_tagged_text:
          if word[1] in adjective_tags:
              lemmatized_text.append(str(wordnet_lemmatizer.lemmatize(word[0],pos="a")))
          else:
              lemmatized_text.append(str(wordnet_lemmatizer.lemmatize(word[0]))) #default POS = noun

      return lemmatized_text


  #Pre_processing:

  POS_tagged_text = nltk.pos_tag(case_insensitive_text)
  lemmatized_text = lemmatize(POS_tagged_text)
  Processed_text = nltk.pos_tag(lemmatized_text)

  def generate_stopwords(POS_tagged_text):
    stopwords = []

    wanted_POS = ['NN','NNS','NNP','NNPS','JJ','JJR','JJS','FW'] #may be add VBG too

    for word in POS_tagged_text:
        if word[1] not in wanted_POS:
            stopwords.append(word[0])

    punctuations = list(str(string.punctuation))
    stopwords = stopwords + punctuations

    stopword_file = open("long_stopwords.txt", "r")
    #Source = https://www.ranks.nl/stopwords

    for line in stopword_file.readlines():
        stopwords.append(str(line.strip()))

    return set(stopwords)

  stopwords = generate_stopwords(Processed_text)

  def partition_phrases(text,delimeters):
    phrases = []
    phrase = " "
    for word in text:
        if word in delimeters:
            if phrase!= " ":
                phrases.append(str(phrase).split())
            phrase = " "
        elif word not in delimeters:
            phrase+=str(word)
            phrase+=" "
    return phrases

  phrase_list = partition_phrases(lemmatized_text,stopwords)

  phrase_partitioned_sentences = []

  for sentence in tokenized_sentences:
      POS_tagged_sentence = nltk.pos_tag(sentence)
      lemmatized_sentence = lemmatize(POS_tagged_sentence)
      phrase_partitioned_sentence = partition_phrases(lemmatized_sentence,stopwords)
      phrase_partitioned_sentences.append(phrase_partitioned_sentence)

   # keyword scoring

  frequency = defaultdict(int)
  degree = defaultdict(int)
  word_score = defaultdict(float)

  vocabulary = []

  for phrase in phrase_list:
      for word in phrase:
          frequency[word]+=1
          degree[word]+=len(phrase)
          if word not in vocabulary:
              vocabulary.append(word)

  for word in vocabulary:
      word_score[word] = degree[word]/frequency[word]

  phrase_scores = []
  keywords = []
  phrase_vocabulary = []

  for phrase in phrase_list:
      if phrase not in phrase_vocabulary:
          phrase_score = 0
          for word in phrase:
              phrase_score += word_score[word]
          phrase_scores.append(phrase_score)
          phrase_vocabulary.append(phrase)


  phrase_vocabulary = []

  for phrase in phrase_list:
      if phrase not in phrase_vocabulary:
          keyword=''
          for word in phrase:
              keyword += str(word)+" "
          phrase_vocabulary.append(phrase)
          keyword = keyword.strip()
          keywords.append(keyword)

  sorted_index = np.flip(np.argsort(phrase_scores),0)

  tokenized_keywords = []
  sorted_keywords = []

  keywords_num = 0
  threshold = 50
  if len(keywords)<threshold:
      keywords_num = len(keywords)
  else:
      keywords_num = threshold

  for i in range(0,keywords_num):
      sorted_keywords.append(keywords[sorted_index[i]])
      tokenized_keywords.append(sorted_keywords[i].split())

  sentence_scores = np.zeros((len(sentences)),np.float32)
  i=0
  for sentence in phrase_partitioned_sentences:
      for phrase in sentence:
          if phrase in tokenized_keywords:

              matched_tokenized_keyword_index = tokenized_keywords.index(phrase)

              corresponding_sorted_keyword = sorted_keywords[matched_tokenized_keyword_index]

              keyword_index_where_the_sorted_keyword_is_present = keywords.index(corresponding_sorted_keyword)

              sentence_scores[i]+=phrase_scores[keyword_index_where_the_sorted_keyword_is_present]
      i+=1

  Reduce_to_percent = percent
  summary_size = int(((Reduce_to_percent)/100)*len(sentences))

  if summary_size == 0:
      summary_size = 1

  sorted_sentence_score_indices = np.flip(np.argsort(sentence_scores),0)

  indices_for_summary_results = sorted_sentence_score_indices[0:summary_size]

  summary = ""

  current_size = 0

  if 0 not in indices_for_summary_results and summary_size!=1:
      summary+=sentences[0]
      summary+=".\n\n"
      current_size+=1


  for i in range(0,len(sentences)):
      if i in indices_for_summary_results:
          summary+=sentences[i]
          summary+=".\n\n"
          current_size += 1
      if current_size == summary_size:
          break

  yt = YouTube(url)
  video_html = f'<div id="video-container" style="position: relative; width: 100%; padding-bottom: 56.25%;"><iframe id="video" style="position: absolute; width: 100%; height: 100%;" src="{yt.embed_url}" frameborder="0" allowfullscreen></iframe></div>'

  if summary == "":
      raise gr.Error(f"Could not retrieve the video's transcript. Please try another video")
  
  return summary, video_html

"""## Text-to-Speech Module"""

AUDIO_DIR = 'audio_files'
MAX_FILE_AGE = 60 * 60  # maximum age of audio files in seconds (1 hour)

def delete_old_audio_files():
    # delete audio files older than MAX_FILE_AGE
    now = time.time()
    for file_name in os.listdir(AUDIO_DIR):
        file_path = os.path.join(AUDIO_DIR, file_name)
        if now - os.path.getmtime(file_path) > MAX_FILE_AGE:
            os.remove(file_path)

def text_to_speech(input_text):
    # create the text-to-speech audio
    tts = gTTS(input_text, lang='en', slow=False)
    fp = io.BytesIO()
    tts.write_to_fp(fp)
    fp.seek(0)

    # create the audio directory if it does not exist
    os.makedirs(AUDIO_DIR, exist_ok=True)

    # generate a unique file name for the audio file
    file_name = str(time.time()) + '.wav'
    file_path = os.path.join(AUDIO_DIR, file_name)

    # save the audio stream to a file
    with open(file_path, 'wb') as f:
        f.write(fp.read())

    # delete old audio files
    delete_old_audio_files()

    # return the file path
    return file_path

theme = gr.themes.Soft(
    primary_hue="yellow",
    secondary_hue=gr.themes.Color(c100="#f8f8f8", c200="#d9d9d9", c300="#a5b4fc", c400="#818cf8", c50="#faf0e4", c500="#6366f1", c600="#4f46e5", c700="#4338ca", c800="#3730a3", c900="#312e81", c950="#2b2c5e"),
    neutral_hue="zinc",
).set(
    body_background_fill='*secondary_50',
    block_label_background_fill='*primary_50',
    block_label_background_fill_dark='*body_background_fill',
)


with gr.Blocks(theme=theme) as demo:

  gr.Markdown(
      '''
      <h1 align="center">Educational Video Transcript Summarizer</h1>

      <h6 align="center">Welcome to SnipSnap! Input a YouTube URL to get started.</h6>
      '''
  )

  with gr.Row():
    with gr.Column():
      fn = summarize_text
      url_input = gr.Textbox(label="URL", placeholder="Ex: https://youtu.be/JOiGEI9pQBs", info="Input YouTube URL")
      slider = gr.Slider(5, 100, value=20, step=5, label="Percent", info="Choose summary length (the lower the number, the shorter the summary)")

      with gr.Row():
        summarize_btn = gr.Button(variant="primary", value="Summarize")
        clear_btn = gr.ClearButton()

      video_preview = gr.HTML(label="Video Preview")
      examples = gr.Examples([['https://youtu.be/libKVRa01L8'], ['https://youtu.be/v6Agqm4K7Ok'], ['https://youtu.be/HpcTJW4ur54'], ['https://youtu.be/gjVX47dLlN8']], inputs=url_input)

    with gr.Column():
      summary_output = gr.Textbox(label="Summary", interactive=False, show_copy_button=True)
      tts_btn = gr.Button(variant="primary", value="Text-to-Speech")
      summary_tts = gr.Audio(label="Audio", interactive=False)

    # Buttons
    summarize_btn.click(summarize_text, inputs=[url_input, slider], outputs=[summary_output, video_preview])
    tts_btn.click(text_to_speech, inputs=summary_output, outputs=summary_tts)
    clear_btn.click(lambda:[None, None, None, None], outputs=[url_input, summary_output, video_preview, summary_tts])

demo.queue()
demo.launch()