import logging
import math
import os
import shutil
import time

from datasets import load_dataset
import gradio as gr
import moviepy.editor as mp
import numpy as np
import pysrt
import torch
from transformers import pipeline
import yt_dlp


os.environ['HF_HUB_ENABLE_HF_TRANSFER'] = '1'

logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(name)s - %(levelname)s - %(message)s', force=True)

LOG = logging.getLogger(__name__)
CLIP_SECONDS = 20
SLICES = 4
SLICE_DURATION = CLIP_SECONDS / SLICES
# At most 6 mins
MAX_CHUNKS = 45
BASEDIR = '/tmp/processed'

os.makedirs(BASEDIR, exist_ok=True)

asr_kwargs = {
    "task": "automatic-speech-recognition",
    "model": "openai/whisper-medium.en"
}

translator_kwargs = {
    "task": "translation_en_to_fr",
    "model": "Helsinki-NLP/opus-mt-en-fr"
}

summarizer_kwargs = {
    "task": "summarization",
    "model": "facebook/bart-large-cnn"
}

if torch.cuda.is_available():
    LOG.info("GPU available")

    asr_kwargs['device'] = 'cuda:0'
    translator_kwargs['device'] = 'cuda:0'
    summarizer_kwargs['device'] = 'cuda:0'

# All three models should fit together on a single T4 GPU

LOG.info("Fetching ASR model from the Hub if not already there")
asr = pipeline(**asr_kwargs)

LOG.info("Fetching translation model from the Hub if not already there")
translator = pipeline(**translator_kwargs)

LOG.info("Fetching summarization model from the Hub if not already there")
summarizer = pipeline(**summarizer_kwargs)


def demo(url: str, translate: bool):
    basedir = BASEDIR
    video_path, video = download(url, os.path.join(basedir, 'video.mp4'))
    audio_clips(video, basedir)
    srt_file, summary = process_video(basedir, video.duration, translate)
    return summary, srt_file, [video_path, srt_file]


def download(url, dst):
    LOG.info("Downloading provided url %s", url)

    opts = {
        'skip_download': False,
        'overwrites': True,
        'format': 'mp4',
        'outtmpl': {'default': dst}
    }

    with yt_dlp.YoutubeDL(opts) as dl:
        dl.download([url])

    return dst, mp.VideoFileClip(dst)


def audiodir(basedir):
    return os.path.join(basedir, 'audio')


def audio_clips(video: mp.VideoFileClip, basedir: str):

    LOG.info("Building audio clips")

    clips_dir = audiodir(basedir)
    shutil.rmtree(clips_dir, ignore_errors=True)
    os.makedirs(clips_dir, exist_ok=True)

    audio = video.audio
    end = audio.duration

    digits = int(math.log(end / CLIP_SECONDS, 10)) + 1

    for idx, i in enumerate(range(0, int(end), CLIP_SECONDS)):
        sub_end = min(i+CLIP_SECONDS, end)
        # print(sub_end)
        sub_clip = audio.subclip(t_start=i, t_end=sub_end)
        audio_file = os.path.join(clips_dir, f"audio_{idx:0{digits}d}" + ".ogg")
        # audio_file = os.path.join(AUDIO_CLIPS, "audio_" + str(idx))
        sub_clip.write_audiofile(audio_file, fps=16000)


def process_video(basedir: str, duration, translate: bool):
    audio_dir = audiodir(basedir)
    transcriptions = transcription(audio_dir, duration)
    subs = translation(transcriptions, translate)
    srt_file = build_srt_clips(subs, basedir)
    summary = summarize(transcriptions, translate)
    return srt_file, summary


def transcription(audio_dir: str, duration):
    LOG.info("Audio transcription")
    # Not exact, nvm, doesn't need to be
    chunks = int(duration / CLIP_SECONDS + 1)
    chunks = min(chunks, MAX_CHUNKS)

    LOG.debug("Loading audio clips dataset")

    dataset = load_dataset("audiofolder", data_dir=audio_dir)
    dataset = dataset['train']
    dataset = dataset['audio'][0:chunks]

    start = time.time()
    transcriptions = []
    for i, d in enumerate(np.array_split(dataset, 5)):
        d = list(d)
        LOG.info("ASR batch %d / 5, samples %d", i, len(d))
        t = asr(d, max_new_tokens=10000)
        transcriptions.extend(t)

    transcriptions = [t['text'] for t in transcriptions]
    elapsed = time.time() - start
    LOG.info("Transcription done, elapsed %.2f seconds", elapsed)
    return transcriptions


def translation(transcriptions, translate):
    if translate:
        LOG.info("Performing translation")
        start = time.time()
        translations = translator(transcriptions)
        translations = [t['translation_text'] for t in translations]
        elapsed = time.time() - start
        LOG.info("Translation done, elapsed %.2f seconds", elapsed)
    else:
        translations = transcriptions
    return translations


def summarize(transcriptions, translate):
    LOG.info("Generating video summary")
    whole_text = ' '.join(transcriptions).strip()
    word_count = len(whole_text.split())
    summary = summarizer(whole_text)
    # min_length=word_count // 4 + 1,
    # max_length=word_count // 2 + 1)
    summary = translation([summary[0]['summary_text']], translate)[0]
    return summary


def subs_to_timed_segments(subtitles: list[str]):
    LOG.info("Building srt segments")
    all_chunks = []
    for sub in subtitles:
        chunks = np.array_split(sub.split(' '), SLICES)
        all_chunks.extend(chunks)

    subs = []
    for c in all_chunks:
        c = ' '.join(c)
        subs.append(c)

    segments = []
    for i, c in enumerate(subs):
        segments.append({
            'text': c.strip(),
            'start': i * SLICE_DURATION,
            'end': (i + 1) * SLICE_DURATION
        })

    return segments


def build_srt_clips(subs, basedir):

    LOG.info("Generating subtitles")
    segments = subs_to_timed_segments(subs)

    LOG.info("Building srt clips")
    max_text_len = 30
    subtitles = pysrt.SubRipFile()
    first = True
    for segment in segments:
        start = segment['start'] * 1000
        if first:
            start += 3000
            first = False
        end = segment['end'] * 1000
        text = segment['text']
        text = text.strip()
        if len(text) < max_text_len:
            o = pysrt.SubRipItem()
            o.start = pysrt.SubRipTime(0, 0, 0, start)
            o.end = pysrt.SubRipTime(0, 0, 0, end)
            o.text = text
            subtitles.append(o)
        else:
            # Just split in two, should be ok in most cases
            words = text.split()
            o = pysrt.SubRipItem()
            o.text = ' '.join(words[0:len(words)//2])
            o.start = pysrt.SubRipTime(0, 0, 0, start)
            chkpt = (start + end) / 2
            o.end = pysrt.SubRipTime(0, 0, 0, chkpt)
            subtitles.append(o)
            o = pysrt.SubRipItem()
            o.text = ' '.join(words[len(words)//2:])
            o.start = pysrt.SubRipTime(0, 0, 0, chkpt)
            o.end = pysrt.SubRipTime(0, 0, 0, end)
            subtitles.append(o)

    srt_path = os.path.join(basedir, 'video.srt')
    subtitles.save(srt_path, encoding='utf-8')
    LOG.info("Subtitles saved in srt file %s", srt_path)
    return srt_path


iface = gr.Interface(
    fn=demo,
    inputs=[
        gr.Text(value="https://youtu.be/tiZFewofSLM", label="English video url"),
        gr.Checkbox(value=True, label='Translate to French')],
    outputs=[
        gr.Text(label="Video summary"),
        gr.File(label="SRT file"),
        gr.Video(label="Video with subtitles"),
    ])

iface.launch()