import itertools
from typing import Optional
from datasets import load_dataset
from model import ModelArguments
import segment
from tqdm import tqdm
from dataclasses import dataclass, field
from transformers import HfArgumentParser
from shared import GeneralArguments, CustomTokens
import csv
import re
import random
import logging
from youtube_transcript_api import YouTubeTranscriptApi
from youtube_transcript_api._errors import CouldNotRetrieveTranscript, YouTubeRequestFailed
import os
import json
import time
import requests
from utils import InterruptibleThreadPool, Job


def find(s, ch):
    return [i for i, ltr in enumerate(s) if ltr == ch]


def wordify(transcript):
    """Try to replicate format for automatically generated transcripts"""
    words = []

    for line_index, line in enumerate(transcript):
        text = line['text'].replace('\n', ' ').strip()
        if not text:
            continue

        start = line['start']
        next_start = transcript[line_index +
                                1]['start'] if line_index < len(transcript) - 1 else float('inf')
        end = min(start + line['duration'], next_start)
        duration = end - start

        indices = find(text, ' ') + [len(text)]
        start_index = 0
        for i in range(len(indices)):
            word = text[start_index:indices[i]].strip()
            if not word:
                continue  # Skip empty words (e.g., \n)
            percentage = start_index/indices[-1]

            w_duration = len(word)/indices[-1] * duration

            w_start = start + percentage * duration

            words.append({
                'start': round(w_start, 5),
                'duration': round(w_duration, 5),
                'end': round(w_start + w_duration, 5),
                'text': word,
            })

            start_index = indices[i] + 1

    return words


def get_manual_words(transcript_list):
    transcript = transcript_list.find_manually_created_transcript(
        ['en-GB', 'en-US', 'en']).fetch()
    return wordify(transcript)


def get_auto_words(transcript_list):
    words = []
    transcript = transcript_list.find_generated_transcript(['en'])
    url = transcript._url + '&fmt=json3'
    info = transcript._http_client.get(url)

    for event in info.json()['events']:
        start_ms = event.get('tStartMs', 0)

        for word in event.get('segs') or []:
            offset_ms = word.get('tOffsetMs', 0)

            texts = word['utf8'].replace(
                CustomTokens.PROFANITY_RAW.value, CustomTokens.PROFANITY_CONVERTED.value
            ).strip().split()

            for text in texts:
                words.append({
                    'start': (start_ms + offset_ms)/1000,
                    'text': text
                })

    return words


def get_words(video_id, process=True, fallback=False, transcript_type='auto'):
    """Get parsed video transcript with caching system
    returns None if not processed yet and process is False
    """
    get_manual_if_fail = fallback and transcript_type == 'auto'
    transcript_path = os.path.join(
        'transcripts', transcript_type, f'{video_id}.json')
    words = []
    try:
        if os.path.exists(transcript_path):
            with open(transcript_path) as fp:
                wds = json.load(fp)

            if not wds and get_manual_if_fail:
                return get_words(video_id, process, fallback, 'manual')
            return wds

        elif not process:
            return None

        transcript_list = YouTubeTranscriptApi.list_transcripts(video_id)

        if transcript_type == 'manual':
            words = get_manual_words(transcript_list)
        else:
            words = get_auto_words(transcript_list)

    except YouTubeRequestFailed as e:
        print(e)
        time.sleep(30)  # Timeout
        return get_words(video_id, process, fallback, transcript_type)

    except CouldNotRetrieveTranscript:
        if get_manual_if_fail:
            print('fallback')
            return get_words(video_id, process, fallback, 'manual')

    except json.decoder.JSONDecodeError:
        # Warning, unable to parse JSON
        pass

    with open(transcript_path, 'w') as fp:
        json.dump(words, fp)

    return words


# TODO make min_sponsor_segment_length param
def extract_sponsors(words, min_sponsor_segment_length=5):
    if len(words) < min_sponsor_segment_length:
        return []  # Force short phrases to not be sponsors

    paragraphs = []
    current = []
    for word in words:
        if not word.get('sponsor') and not current:
            continue

        if word['sponsor']:
            current.append(word['text'])
        else:
            paragraphs.append(current)
            current = []
    if current:
        paragraphs.append(current)

    # Remove all too short:
    paragraphs = list(filter(lambda x: len(
        x) >= min_sponsor_segment_length, paragraphs))

    return paragraphs


def clean_text(text):

    # Replace impossibly long words with a special token
    # Usually the result of incorrect labelling
    text = re.sub(r'\w{64,}', CustomTokens.LONG_WORD.value, text)

    SHORT_HYPHENATED_REGEX = r'\w{1,2}(?:-\w{1,2}){3,}(?:-?\w*)'

    # Replace hyphenated URLs with special token
    # For some reason, youtube sometimes transcribes urls in this form:
    # 'b-a-b-b-e-l-dot-com', 'g-e-t-r-o-m-a-n-com'
    # not 'e-commerce'
    text = re.sub(f'{SHORT_HYPHENATED_REGEX}(?:com|org|net)',
                  CustomTokens.HYPHENATED_URL.value, text)

    # Replace short+hyphenated text with a special token. Of the form:
    # 'i-i-i-i-i-i-i-i-i-i-i-i', 'b-u-m-f-u-z-z-l-e', 'v-e-r-i-t-a-s-i-u-m', 'do-do-do-do-do'
    text = re.sub(SHORT_HYPHENATED_REGEX,
                  CustomTokens.SHORT_HYPHENATED.value, text)

    # Replace URLs with URL_TOKEN
    URL_REGEX = r'(?:(?:http|https)\:\/\/)?[a-zA-Z0-9\.\/\?\:@\-_=#]+\.(?:[a-zA-Z]){2,6}(?:[a-zA-Z0-9\.\&\/\?\:@\-_=#%])*'
    text = re.sub(URL_REGEX, CustomTokens.URL.value, text)

    NUM_REGEX = r'(?:\d+,)*(?:\d*[.])?\d+'

    # Encode specific numeric words
    # Of the form: 12%, 12.34%
    # Usually included in sponsorships
    text = re.sub(f'{NUM_REGEX}%',
                  CustomTokens.NUMBER_PERCENTAGE.value, text)

    # Normal numbers, should not have an effect on sponsorship
    text = re.sub(NUM_REGEX, CustomTokens.NUMBER.value, text)

    # Replace profanity with special token
    text = text.replace(CustomTokens.PROFANITY_RAW.value,
                        CustomTokens.PROFANITY.value)
    text = text.replace(CustomTokens.PROFANITY_CONVERTED.value,
                        CustomTokens.PROFANITY.value)

    return text.strip()


def remove_duplicate_sponsor_segments(sponsor_segments):
    """Choose the best sponsor segment if overlapping with others"""

    # Algorithm based on SponsorBlock algorithm
    # Find sponsors that are overlapping
    similar = []
    for i in sponsor_segments:
        for j in sponsor_segments:
            # Since we do pairwise, we only check one direction
            if (j['start'] >= i['start'] and j['start'] <= i['end']):
                similar.append([i, j])

    # Within each group, choose the segment with the most votes.
    processed = []
    best = []
    for i in similar:
        if i in processed:
            continue
        group = i
        for j in similar:
            if j[0] in group or j[1] in group:  # If either in, append both
                group.append(j[0])
                group.append(j[1])
                processed.append(j)

        best.append(max(group, key=lambda item: (
            item['votes'], item['reputation'], item['views'])))

    return best


@dataclass
class PreprocessArguments:
    """
    Arguments pertaining to what data we are going to preprocess.
    """
    update_database: bool = field(
        default=False, metadata={'help': 'Download the raw database.'}
    )

    do_create: bool = field(
        default=False, metadata={'help': 'Merge sponsor segments into single file'}
    )
    min_votes: int = field(
        default=0, metadata={'help': 'Minimum number of votes'})
    # Downvotes will make this negative.
    # 1 = At least one positive vote

    do_transcribe: bool = field(
        default=False, metadata={'help': 'Get transcripts for videos'}
    )
    num_jobs: int = field(
        default=4, metadata={'help': 'Number of transcripts to download in parallel'})

    overwrite: bool = field(
        default=False, metadata={'help': 'Overwrite training, testing and validation data, if present.'}
    )

    do_generate: bool = field(
        default=False, metadata={'help': 'Generate labelled data.'}
    )

    do_split: bool = field(
        default=False, metadata={'help': 'Generate training, testing and validation data.'}
    )
    percentage_positive: float = field(
        default=0.5, metadata={'help': 'Ratio of positive (sponsor) segments to include in final output'})

    train_split: float = field(
        default=0.9, metadata={'help': 'Ratio of training data. Value between 0 and 1.'})

    # TODO play around with ratios? lower test/validation split?
    test_split: float = field(
        default=0.05, metadata={'help': 'Ratio of testing data. Value between 0 and 1.'})
    valid_split: float = field(
        default=0.05, metadata={'help': 'Ratio of validation data. Value between 0 and 1.'})

    skip_videos: int = field(default=None, metadata={
        'help': 'Number of videos to skip. Set this to the latest video index to append to the current file'})

    max_videos: int = field(default=None, metadata={
        'help': 'Maximum number of videos to preprocess.'})

    max_segments: int = field(default=None, metadata={
        'help': 'Maximum number of segments to produce to preprocess.'})

    raw_data_dir: Optional[str] = field(
        default='raw',
        metadata={
            'help': 'Raw data directory'
        },
    )
    raw_data_file: Optional[str] = field(
        default='sponsorTimes.csv',
        metadata={
            'help': 'Raw data file'
        },
    )

    min_wps: float = field(
        default=0.4, metadata={'help': 'Ignore videos with not enough words spoken per second. This is usually indicitive of video whose captions aren\'t English.'})
    # 0.1 ~ 1%
    # 0.4 ~ 2.5%
    # 0.9 ~ 5%


# Mirrors for database
MIRRORS = [
    'https://sponsor.ajay.app/database/sponsorTimes.csv',  # Latest
    'https://sb-mirror.mchang.xyz/sponsorTimes.csv',  # 5 minute delay
    'https://sb.ltn.fi/database/sponsorTimes.csv',  # 5 minute delay
]
# TODO only download latest (updates/changes)


def download_file(url, filename):
    """
    Helper method handling downloading large files from `url` to `filename`.

    Adapted from https://stackoverflow.com/a/42071418
    """
    chunk_size = 1024
    r = requests.get(url, stream=True)
    total_bytes = int(r.headers['Content-Length'])
    with open(filename, 'wb') as f, tqdm(unit='B', total=total_bytes) as progress:
        for chunk in r.iter_content(chunk_size=chunk_size):
            if chunk:  # filter out keep-alive new chunks
                progress.update(len(chunk))
                f.write(chunk)

    return total_bytes == os.path.getsize(filename)


@dataclass
class ProcessedArguments:
    processed_dir: Optional[str] = field(
        default='processed',
        metadata={
            'help': 'Processed data directory'
        },
    )
    processed_file: Optional[str] = field(
        default='final.json',
        metadata={
            'help': 'Processed data file'
        },
    )


def load_datasets(dataset_args):
    print('Reading datasets')
    data_files = {}

    if dataset_args.train_file is not None:
        data_files['train'] = os.path.join(
            dataset_args.data_dir, dataset_args.train_file)
    if dataset_args.validation_file is not None:
        data_files['validation'] = os.path.join(
            dataset_args.data_dir, dataset_args.validation_file)
    if dataset_args.test_file is not None:
        data_files['test'] = os.path.join(
            dataset_args.data_dir, dataset_args.test_file)

    return load_dataset('json', data_files=data_files)


@dataclass
class DatasetArguments:
    data_dir: Optional[str] = field(
        default='data',
        metadata={
            'help': 'The directory which stores train, test and/or validation data.'
        },
    )

    train_file: Optional[str] = field(
        default='train.json', metadata={'help': 'The input training data file (a jsonlines file).'}
    )
    validation_file: Optional[str] = field(
        default='valid.json',
        metadata={
            'help': 'An optional input evaluation data file to evaluate the metrics (rouge) on (a jsonlines file).'
        },
    )
    test_file: Optional[str] = field(
        default='test.json',
        metadata={
            'help': 'An optional input test data file to evaluate the metrics (rouge) on (a jsonlines file).'
        },
    )
    excess_file: Optional[str] = field(
        default='excess.json',
        metadata={
            'help': 'The excess segments left after the split'
        },
    )

    overwrite_cache: bool = field(
        default=False, metadata={'help': 'Overwrite the cached training and evaluation sets'}
    )

    positive_file: Optional[str] = field(
        default='sponsor_segments.json', metadata={'help': 'File to output sponsored segments to (a jsonlines file).'}
    )
    negative_file: Optional[str] = field(
        default='normal_segments.json', metadata={'help': 'File to output normal segments to (a jsonlines file).'}
    )

    def __post_init__(self):
        # TODO check if train/validation datasets exist
        if self.train_file is None and self.validation_file is None:
            raise ValueError(
                'Need either a dataset name or a training/validation file.')


def main():
    # Responsible for getting transcrips using youtube_transcript_api,
    # then labelling it according to SponsorBlock's API

    logging.getLogger().setLevel(logging.INFO)  # TODO make param

    # Generate final.json from sponsorTimes.csv
    hf_parser = HfArgumentParser((
        PreprocessArguments,
        ProcessedArguments,
        DatasetArguments,
        segment.SegmentationArguments,
        ModelArguments,
        GeneralArguments
    ))
    preprocess_args, processed_args, dataset_args, segmentation_args, model_args, _ = hf_parser.parse_args_into_dataclasses()

    raw_dataset_path = os.path.join(
        preprocess_args.raw_data_dir, preprocess_args.raw_data_file)

    def get_rows():
        with open(raw_dataset_path, newline='') as csvfile:
            reader = csv.DictReader(csvfile)
            for line in reader:
                if line['service'] != 'YouTube':
                    continue

                # TODO add support for other categories and action types?
                if line['category'] != 'sponsor':
                    continue
                if line['actionType'] != 'skip':
                    continue

                # Ignore hidden items
                if line['hidden'] == '1' or line['shadowHidden'] == '1':
                    continue

                if len(line['videoID']) != 11:
                    continue  # Invalid youtube video ID

                # Skip those that aren't highly voted
                line['votes'] = int(line['votes'])
                # incorrect_votes = int(line['incorrectVotes'])

                if line['votes'] < preprocess_args.min_votes:
                    continue

                yield line

    if preprocess_args.update_database:
        print('Updating database')
        for mirror in MIRRORS:
            print('Downloading from', mirror)
            if download_file(mirror, raw_dataset_path):
                break
            print('Failed, trying next')

    # 'videoID', 'startTime', 'endTime', 'votes', 'locked', 'incorrectVotes', 'UUID',
    # 'userID', 'timeSubmitted', 'views', 'category', 'actionType', 'service', 'videoDuration',
    # 'hidden', 'reputation', 'shadowHidden', 'hashedVideoID', 'userAgent', 'description'
    data_rows = None
    if preprocess_args.do_transcribe:
        print('Collecting videos')
        video_ids = set()
        data_rows = get_rows()
        for row in data_rows:
            video_ids.add(row['videoID'])

        print('Start transcribing')
        with tqdm(total=len(video_ids)) as progress:
            def on_job_complete(job):
                progress.set_description(f'Processed {job.video_id}')
                progress.update()

            pool = InterruptibleThreadPool(
                preprocess_args.num_jobs, on_job_complete=on_job_complete)

            print('Adding jobs to pool')
            for video_id in video_ids:
                job = Job(get_words, video_id)
                job.video_id = video_id
                pool.add_job(job)

            print('Start processing')
            pool.run()

        print('Finished transcribing')

    final_path = os.path.join(
        processed_args.processed_dir, processed_args.processed_file)

    if os.path.exists(final_path) and not preprocess_args.do_create:
        logging.info(f'{final_path} exists, opening file')
        with open(final_path) as fp:
            final_data = json.load(fp)
    else:
        print('Create final data')

        final_data = {}

        if data_rows is None:
            data_rows = get_rows()

        # TODO add progress bar
        # TODO parallelise?
        for line in data_rows:
            video_id = line['videoID']

            if video_id not in final_data:
                final_data[video_id] = []

            segment_start = float(line['startTime'])
            segment_end = float(line['endTime'])

            video_words = get_words(video_id, process=True)
            segment_words = segment.extract_segment(
                video_words, segment_start, segment_end)

            if len(segment_words) <= 1:
                continue  # Useless to add segment since no words

            # duration = segment.word_end(segment_words[-1]) - segment.word_start(segment_words[0])
            duration = segment_end - segment_start
            wps = len(segment_words)/duration if duration > 0 else 0

            if wps < preprocess_args.min_wps:
                print('bad segment in', video_id, '| wps =', wps)
                continue

            final_data[video_id].append({
                'start': segment_start,
                'end': segment_end,
                'votes': line['votes'],
                'locked': line['locked'] == '1',
                'views': line['views'],
                'reputation': line['reputation'],
                'category': line['category'],
                'action': line['actionType'],
                'uuid': line['UUID'],
            })

        # Remove duplicate sponsor segments by choosing best (most votes)
        for key in final_data:
            final_data[key] = remove_duplicate_sponsor_segments(
                final_data[key])

        # Save data
        with open(final_path, 'w') as fp:
            json.dump(final_data, fp)

        # final_data = preprocess(
        #     raw_dataset_path, final_path, preprocess_args.min_votes)
        # # TODO save metadata in final.json?

    logging.info(f'Found {len(final_data)} videos')

    # TODO shuffle final_data

    # if not os.path.exists(excess_path) or preprocess_args.overwrite
    # TODO use overwrite param

    os.makedirs(dataset_args.data_dir, exist_ok=True)

    positive_file = os.path.join(
        dataset_args.data_dir, dataset_args.positive_file)
    negative_file = os.path.join(
        dataset_args.data_dir, dataset_args.negative_file)

    if preprocess_args.do_generate:
        print('Generating')
        from model import get_tokenizer

        # max_videos=preprocess_args.max_videos,
        # max_segments=preprocess_args.max_segments,
        # , max_videos, max_segments

        tokenizer = get_tokenizer(model_args)

        count_videos = 0
        count_segments = 0  # TODO

        write_mode = 'w' if preprocess_args.overwrite else 'a'

        get_all = preprocess_args.max_videos is None
        if get_all:
            total = len(final_data)
        else:
            total = preprocess_args.max_videos

        index = 0
        data = final_data.items()
        if preprocess_args.skip_videos is not None:
            print('Skipping first', preprocess_args.skip_videos, 'videos')
            data = itertools.islice(data, preprocess_args.skip_videos, None)
            index = preprocess_args.skip_videos

            if get_all:
                total = max(0, total - preprocess_args.skip_videos)
            else:
                total = min(len(final_data) -
                            preprocess_args.skip_videos, total)

        with open(positive_file, write_mode, encoding='utf-8') as positive, \
                open(negative_file, write_mode, encoding='utf-8') as negative, \
                tqdm(total=total) as progress:

            for video_id, sponsor_segments in data:
                index += 1  # TODO FIX index + incrementing
                progress.set_description(f'Processing {video_id}')

                if get_all:
                    progress.update()
                elif count_videos >= preprocess_args.max_videos:
                    break

                words = get_words(video_id, False)
                if not words:
                    continue

                num_words = len(words)
                if num_words <= 1:
                    continue

                # TODO only count words that aren't [Music], [Applause], etc.

                segments = segment.generate_labelled_segments(
                    words, tokenizer, segmentation_args, sponsor_segments)

                if not segments:
                    continue

                count_videos += 1
                if not get_all:
                    progress.update()

                for seg in segments:

                    segment_text = ' '.join((x['text'] for x in seg))

                    extracted_text = ''
                    for p in extract_sponsors(seg):
                        p_text = ' '.join(p)
                        extracted_text += f'{CustomTokens.START_SPONSOR.value} {p_text} {CustomTokens.END_SPONSOR.value}. '

                    duration = segment.word_end(
                        seg[-1]) - segment.word_start(seg[0])
                    wps = len(seg)/duration if duration > 0 else 0
                    # Ignore segments with "not enough words" in the transcript
                    if wps < preprocess_args.min_wps:
                        continue

                    d = {
                        'video_index': index,
                        'video_id': video_id,
                        'text': clean_text(segment_text),
                        'words_per_second': wps,
                    }

                    d['sponsor'] = bool(extracted_text)
                    d['extracted'] = clean_text(
                        extracted_text) if d['sponsor'] else CustomTokens.NO_SPONSOR.value

                    print(json.dumps(d), file=(
                        positive if d['sponsor'] else negative))

    if preprocess_args.do_split:
        print('Splitting')
        print('Read files')

        with open(positive_file, encoding='utf-8') as positive:
            sponsors = positive.readlines()

        with open(negative_file, encoding='utf-8') as negative:
            non_sponsors = negative.readlines()

        print('Shuffle')
        random.shuffle(sponsors)
        random.shuffle(non_sponsors)

        print('Calculate ratios')
        # Ensure correct ratio of positive to negative segments
        percentage_negative = 1 - preprocess_args.percentage_positive

        if preprocess_args.percentage_positive * len(sponsors) > len(non_sponsors):
            # Negative is limiting
            z = int(preprocess_args.percentage_positive /
                    percentage_negative * len(non_sponsors))

            excess = sponsors[z:]
            sponsors = sponsors[:z]

        else:
            # Positive is limiting
            z = int(percentage_negative /
                    preprocess_args.percentage_positive * len(sponsors))

            excess = non_sponsors[z:]
            non_sponsors = non_sponsors[:z]

        print('Join')
        all_labelled_segments = sponsors + non_sponsors

        random.shuffle(all_labelled_segments)

        print('Split')
        ratios = [preprocess_args.train_split,
                  preprocess_args.test_split,
                  preprocess_args.valid_split]

        train_data, test_data, valid_data = split(
            all_labelled_segments, ratios)

        splits = {
            dataset_args.train_file: train_data,
            dataset_args.test_file: test_data,
            dataset_args.validation_file: valid_data
        }

        # Output training, testing and validation data
        for name, items in splits.items():
            outfile = os.path.join(dataset_args.data_dir, name)
            if not os.path.exists(outfile) or preprocess_args.overwrite:
                with open(outfile, 'w', encoding='utf-8') as fp:
                    fp.writelines(items)
            else:
                print('Skipping', name)

        print('Write')
        # Save excess items
        excess_path = os.path.join(
            dataset_args.data_dir, dataset_args.excess_file)
        if not os.path.exists(excess_path) or preprocess_args.overwrite:
            with open(excess_path, 'w', encoding='utf-8') as fp:
                fp.writelines(excess)
        else:
            print('Skipping', dataset_args.excess_file)

        print('Finished splitting:', len(sponsors),
              'sponsors,', len(non_sponsors), 'non sponsors')


def split(arr, ratios):
    """Split array according to ratios. Sum of ratios should be less than 1"""

    to_return = []

    cumulative_sum = 0
    for r in ratios:
        current = cumulative_sum

        cumulative_sum += r * len(arr)
        to_return.append(arr[int(current):int(cumulative_sum)])

    return to_return


if __name__ == '__main__':
    main()