main.py

import os
import json

import uvicorn
from fastapi import FastAPI, Request
from fastapi.middleware.cors import CORSMiddleware
from contextlib import asynccontextmanager

from helperfunctions import *
from models import load_models
from languages import CODE2LANG
from s3_handler import S3Handler

from media_download import YoutubeDownloader
from transcription import StableWhisper
from translation import Translation
from summarizer import Extract_Summary, AudioBookNarration
from audiobook import AudioBook



### API Configurations

# Context Manager for FastAPI Start/Shutdown
@asynccontextmanager
async def lifespan(app: FastAPI):

    ## FastAPI Startup Code
    
    # Loading ML models
    print('Loading ML Models..')

    # For Storing Models
    global MODELS
    MODELS = load_models()
    
    print('ML Models Loaded!')
    
    yield

    ## FastAPI Shutdown Code
    
    # Cleaning ML Models & Releasing the Resources
    MODELS.clear()

# Initializing FastAPI App
app = FastAPI(lifespan=lifespan)

# Output Directory for Files Storage
output_folder = 'Output'

# S3 Handler
s3 = S3Handler()

# Create a context variable to store the contexts for each user
users_context = dict()

# CORS (Cross-Origin Resource Sharing)
origins = [
    "http://localhost",
    "http://localhost:4200",
]

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # origins,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


### APIs

@app.get("/get_media_metadata")
async def get_media_metadata(request: Request, url: str):

    # Getting User's IP & Generating UUID
    user_ip = request.client.host
    user_id = generate_uuid(user_ip, url)

    # User Folder Path
    user_folder_path = os.path.join(output_folder, user_id)

    # Getting User's Youtube Downloader
    youtube_downloader = YoutubeDownloader(url, user_folder_path)

    # Getting Youtube Media Info
    media_metadata = youtube_downloader.get_media_metadata()

    # Storing User's Media Metadata to Directory
    media_metadata_path = os.path.join(user_folder_path, 'media_metadata.json')
    with open(media_metadata_path, "w") as outfile: 
        json.dump(media_metadata, outfile)
    
    # Storing User's Media Metadata to S3
    s3_path = s3.upload_file(user_id, 'media_metadata.json', media_metadata_path)

    # Getting Status
    status = 1 if media_metadata else 0
    
    if status:
        # Storing Info in the context for this user's session
        users_context[user_id] = dict()
        users_context[user_id]['downloader'] = youtube_downloader
        # users_context[user_id]['media_metadata'] = media_metadata
        users_context[user_id]['url'] = url
    
    return {'status': status, 
            'user_id': user_id, 
            'media_metadata': media_metadata, 
            'media_metadata_path': s3_path}


@app.get("/get_media_formats")
async def get_media_formats(user_id: str):
    
    # Getting Media Formats for User
    media_formats = users_context[user_id]['downloader'].get_media_formats()

    # User Folder Path
    user_folder_path = os.path.join(output_folder, user_id)

    # Storing User's Media Formats to Directory
    media_formats_path = os.path.join(user_folder_path, 'media_formats.json')
    with open(media_formats_path, "w") as outfile: 
        json.dump(media_formats, outfile)
    
    # Storing User's Media Formats to S3
    s3_path = s3.upload_file(user_id, 'media_formats.json', media_formats_path)
    
    # Getting Status
    status = 1 if media_formats else 0

    if status:
        # Storing Media Info in the context for this user's session
        users_context[user_id]['media_formats'] = media_formats
    
    return {'status': status, 
            'media_formats': media_formats, 
            'media_formats_path': s3_path}


@app.get("/download_media")
async def download_media(user_id: str, media_type: str, media_format: str, media_quality: str):
    
    # Downloading Media for User
    media_path = users_context[user_id]['downloader'].download(media_type, media_format, media_quality)

    # Storing User's Downloaded Media to S3
    media_file = f"{media_type.lower()}_{media_quality.lower()}.{media_format.lower()}"
    s3_path = s3.upload_file(user_id, media_file, media_path)
    
    # Getting Status
    status = 1 if media_path else 0

    if status:
        # Storing Media Info in the context for this user's session
        users_context[user_id]['media_path'] = media_path
        users_context[user_id]['media_type'] = media_type
    
    return {'status': status, 'media_path': s3_path}


@app.get("/get_transcript")
async def get_transcript(user_id: str, subtitle_format: str = 'srt', word_level: bool = False):
    
    # If Video Already Downloaded
    if 'media_path' in users_context[user_id].keys():

        # Retrieving the media_path from the context for this user's session
        media_path = users_context[user_id]['media_path']

        # Checking if the media_type is Video, then extract it's audio
        media_type = users_context[user_id]['media_type']
        if media_type == 'video':
            media_path = extract_audio(media_path)
    
    else:

        # Downloading Audio for Transcription
        media_path = users_context[user_id]['downloader'].download('audio', 'mp3', '128kbps')

    # Whisper based transcription
    user_folder_path = os.path.join(output_folder, user_id)
    stable_whisper_transcript = StableWhisper(model=MODELS['transcription'], 
                                              media_path=media_path, 
                                              output_path=user_folder_path, 
                                              subtitle_format=subtitle_format, 
                                              word_level=word_level)
    transcript = stable_whisper_transcript.generate_transcript()
    transcript_path = stable_whisper_transcript.save_transcript()
    subtitles_path = stable_whisper_transcript.save_subtitles()

    # Storing User's Transcripts to S3
    s3_transcript_path = s3.upload_file(user_id, 'transcript.txt', transcript_path)
    s3_subtitles_path = s3.upload_file(user_id, f'subtitles.{subtitle_format}', subtitles_path)
    
    # Getting Status
    status = 1 if transcript and s3_transcript_path and s3_subtitles_path else 0

    if status:
        # Storing Transcript Info in the context for this user's session
        users_context[user_id]['transcript'] = transcript
        users_context[user_id]['transcript_path'] = transcript_path
        users_context[user_id]['subtitles_path'] = subtitles_path
    
    return {'status': status, 
            'transcript': transcript, 
            'transcript_path': s3_transcript_path, 
            'subtitles_path': s3_subtitles_path}


@app.get("/get_languages")
async def get_translation(user_id: str):
    return CODE2LANG


@app.get("/get_translation")
async def get_translation(user_id: str, target_language: str = 'en'):

    # If Transcript Available
    if 'transcript' in users_context[user_id].keys():
    
        # Retrieving the transcript from the context for this user's session
        transcript = users_context[user_id]['transcript']
    
    else:
        return {'status': 0, 'message': 'Transcript not generated yet'}

    # NLLB based Translation
    user_folder_path = os.path.join(output_folder, user_id)
    nllb_translator = Translation(model=MODELS['translation'], 
                                  transcript_dict=transcript, 
                                  source_lang=transcript['language'], 
                                  target_lang=target_language, 
                                  output_path=user_folder_path)
    translated_transcript = nllb_translator.get_translated_transcript()
    translated_subtitles = nllb_translator.get_translated_subtitles()

    # Storing Translated Transcript as TXT file in UTF-8 format
    translated_transcript_path = os.path.join(user_folder_path, 'translated_transcript.txt')
    with open(translated_transcript_path, 'w', encoding='utf-8') as file:
        file.write(translated_transcript)
    
    # Storing Translated Transcript to S3
    s3_transcript_path = s3.upload_file(user_id, 'translated_transcript.txt', translated_transcript_path)

    # TODO: Write Translated Transcript as SRT, VTT, ASS files
    # Storing Translated Subtitles as JSON file (For Now)
    translated_subtitles_path = os.path.join(user_folder_path, 'translated_subtitles.json')
    with open(translated_subtitles_path, "w", encoding='utf-8') as file:
        json.dump(media_formats, file)
    
    # Storing Translated Subtitles to S3
    s3_subtitles_path = s3.upload_file(user_id, 'translated_subtitles.json', translated_subtitles_path)
    
    # Getting Status
    status = 1 if translated_transcript and translated_subtitles else 0

    if status:
        # Storing Translated Transcript Info in the context for this user's session
        users_context[user_id]['translated_transcript'] = translated_transcript
        users_context[user_id]['translated_transcript_path'] = translated_transcript_path
        users_context[user_id]['translated_subtitles'] = translated_subtitles
        users_context[user_id]['translated_subtitles_path'] = translated_subtitles_path
    
    return {'status': status, 
            'transcript': translated_transcript, 
            'subtitles': translated_subtitles, 
            'transcript_path': s3_transcript_path, 
            'subtitles_path': s3_subtitles_path}


@app.get("/get_summary")
async def get_summary(user_id: str, Summary_type: str, Summary_strategy: str, Target_Person_type: str,
                      Response_length: str, Writing_style: str):

    # If Transcript Available
    if 'transcript' in users_context[user_id].keys():
    
        # Retrieving the transcript from the context for this user's session
        text_input = users_context[user_id]['transcript']
    
    else:
        return {'status': 0, 'message': 'Transcript not generated yet'}
    
    # Extracting Summary
    summary_extractor = Extract_Summary(text_input=text_input)
    output = summary_extractor.define_chain(Summary_type=Summary_type,
                                            Summary_strategy=Summary_strategy,
                                            Target_Person_type=Target_Person_type,
                                            Response_length=Response_length,
                                            Writing_style=Writing_style,
                                            key_information=False)

    # Getting Status
    status = 1 if output else 0

    if status:
        # Storing Summary Info in the context for this user's session
        users_context[user_id]['summary'] = output
    
    return {'status': status, "summary": output}


@app.get("/get_key_info")
async def get_key_info(user_id: str, Summary_type: str, Summary_strategy: str, Target_Person_type: str, 
                       Response_length: str, Writing_style: str):

    # If Transcript Available
    if 'transcript' in users_context[user_id].keys():
    
        # Retrieving the transcript from the context for this user's session
        text_input = users_context[user_id]['transcript']
    
    else:
        return {'status': 0, 'message': 'Transcript not generated yet'}
    
    # Extracting Key Value Info
    summary_extractor = Extract_Summary(text_input=text_input)
    output = summary_extractor.define_chain(Summary_type=Summary_type,
                                            Summary_strategy=Summary_strategy,
                                            Target_Person_type=Target_Person_type,
                                            Response_length=Response_length,
                                            Writing_style=Writing_style,
                                            key_information=True)

    # Getting Status
    status = 1 if output else 0

    if status:
        # Storing Key Info in the context for this user's session
        users_context[user_id]['key_info'] = output
    
    return {'status': status, "key_info": output}


@app.get("/get_audiobook")
async def get_audiobook(user_id: str, narration_style: str, speaker: str = "male", 
                        audio_format: str = "mp3", audio_quality: str = "128kbps"):

    # If Transcript Available
    if 'transcript' in users_context[user_id].keys():
    
        # Retrieving the transcript from the context for this user's session
        text_input = users_context[user_id]['transcript']
    
    else:
        return {'status': 0, 'message': 'Transcript not generated yet'}
    
    # Extracting Narration

    narrator = AudioBookNarration(text_input=text_input)
    output = narrator.define_chain(narration_style=narration_style)

    # Generating Audiobook
    audiobook = AudioBook(output_folder=output_folder)
    audio_path = audiobook.generate_audio_from_text(output, speaker=speaker, filename="output_audio")
    
    # Converting the Audio to Required Audio Parameters
    audio_path = convert_audio(audio_path, audio_format, audio_quality)
    
    # Storing User's Audiobook to S3
    media_file = f"audiobook_{audio_quality.lower()}.{audio_format.lower()}"
    s3_path = s3.upload_file(user_id, media_file, audio_path)
    
    # Getting Status
    status = 1 if audio_path else 0

    if status:
        # Storing Audiobook path in the context for this user's session
        users_context[user_id]['audiobook_path'] = audio_path
    
    return {'status': status, "audiobook_path": s3_path}


@app.get("/get_rendered_video")
async def get_rendered_video(user_id: str, video_format: str, video_quality: str, subtitles_type: str = 'original'):

    # # Retrieving the media_path from the context for this user's session
    # media_path = users_context[user_id]['media_path']

    # Downloading Video with Required Video Parameters for User
    media_path = users_context[user_id]['downloader'].download('video', video_format, video_quality)
    
    # Getting Required Subtitles
    if 'original' in subtitles_type.lower():
        subtitles_path = users_context[user_id]['subtitles_path']

    elif 'translated' in subtitles_type.lower():

        # Getting Translated Subtitles from the context for this user's session
        translated_subtitles = users_context[user_id]['translated_subtitles_path']

        # Saving Translated Subtitles
        subtitles_path = save_translated_subtitles(translated_subtitles, media_path)
    
    # Burning Subtitles & Rendering Video
    rendered_video_path = burn_subtitles(media_path, subtitles_path)

    # Storing User's Rendered Video to S3
    media_file = f"subtitles_video_{video_quality.lower()}.{video_format.lower()}"
    s3_path = s3.upload_file(user_id, media_file, media_path)

    # Getting Status
    status = 1 if rendered_video_path else 0
    
    return {'status': status, "rendered_video_path": s3_path}



if __name__ == "__main__":
    uvicorn.run(app, host="127.0.0.1", port=8000)