# Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
# This script converts an existing audio dataset with a manifest to
# a tarred and sharded audio dataset that can be read by the
# TarredAudioToTextDataLayer.

# Please make sure your audio_filepath DOES NOT CONTAIN '-sub'!
# Because we will use it to handle files which have duplicate filenames but with different offsets
# (see function create_shard for details)


# Bucketing can help to improve the training speed. You may use --buckets_num to specify the number of buckets.
# It creates multiple tarred datasets, one per bucket, based on the audio durations.
# The range of [min_duration, max_duration) is split into equal sized buckets.
# Recommend to use --sort_in_shards to speedup the training by reducing the paddings in the batches
# More info on how to use bucketing feature: https://docs.nvidia.com/deeplearning/nemo/user-guide/docs/en/main/asr/datasets.html

# If valid NVIDIA DALI version is installed, will also generate the corresponding DALI index files that need to be
# supplied to the config in order to utilize webdataset for efficient large dataset handling.
# NOTE: DALI + Webdataset is NOT compatible with Bucketing support !

# Usage:
1) Creating a new tarfile dataset

python convert_to_tarred_audio_dataset.py \
    --manifest_path=<path to the manifest file> \
    --target_dir=<path to output directory> \
    --num_shards=<number of tarfiles that will contain the audio> \
    --max_duration=<float representing maximum duration of audio samples> \
    --min_duration=<float representing minimum duration of audio samples> \
    --shuffle --shuffle_seed=1 \
    --sort_in_shards \
    --force_codec=flac \
    --workers=-1


2) Concatenating more tarfiles to a pre-existing tarred dataset

python convert_to_tarred_audio_dataset.py \
    --manifest_path=<path to the tarred manifest file> \
    --metadata_path=<path to the metadata.yaml (or metadata_version_{X}.yaml) file> \
    --target_dir=<path to output directory where the original tarfiles are contained> \
    --max_duration=<float representing maximum duration of audio samples> \
    --min_duration=<float representing minimum duration of audio samples> \
    --shuffle --shuffle_seed=1 \
    --sort_in_shards \
    --workers=-1 \
    --concat_manifest_paths
    <space separated paths to 1 or more manifest files to concatenate into the original tarred dataset>

3) Writing an empty metadata file

python convert_to_tarred_audio_dataset.py \
    --target_dir=<path to output directory> \
    # any other optional argument
    --num_shards=8 \
    --max_duration=16.7 \
    --min_duration=0.01 \
    --shuffle \
    --workers=-1 \
    --sort_in_shards \
    --shuffle_seed=1 \
    --write_metadata

"""
import argparse
import copy
import json
import os
import random
import tarfile
from collections import defaultdict
from dataclasses import dataclass, field
from datetime import datetime
from io import BytesIO
from typing import Any, List, Optional, Union

import numpy as np
import soundfile
from joblib import Parallel, delayed
from omegaconf import DictConfig, OmegaConf, open_dict
from tabulate import tabulate
from tqdm import tqdm

try:
    import create_dali_tarred_dataset_index as dali_index

    DALI_INDEX_SCRIPT_AVAILABLE = True
except (ImportError, ModuleNotFoundError, FileNotFoundError):
    DALI_INDEX_SCRIPT_AVAILABLE = False


@dataclass
class ASRTarredDatasetConfig:
    num_shards: int = -1
    shuffle: bool = False
    max_duration: Optional[float] = None
    min_duration: Optional[float] = None
    shuffle_seed: Optional[int] = None
    sort_in_shards: bool = True
    slice_with_offset: bool = True
    shard_manifests: bool = True
    keep_files_together: bool = False
    force_codec: Optional[str] = None
    use_lhotse: bool = False
    use_bucketing: bool = False
    num_buckets: Optional[int] = None
    bucket_duration_bins: Optional[list[float]] = None


@dataclass
class ASRTarredDatasetMetadata:
    created_datetime: Optional[str] = None
    version: int = 0
    num_samples_per_shard: Optional[int] = None
    is_concatenated_manifest: bool = False

    dataset_config: Optional[ASRTarredDatasetConfig] = field(default_factory=lambda: ASRTarredDatasetConfig())
    history: Optional[List[Any]] = field(default_factory=lambda: [])

    def __post_init__(self):
        self.created_datetime = self.get_current_datetime()

    def get_current_datetime(self):
        return datetime.now().strftime("%m-%d-%Y %H-%M-%S")

    @classmethod
    def from_config(cls, config: DictConfig):
        obj = cls()
        obj.__dict__.update(**config)
        return obj

    @classmethod
    def from_file(cls, filepath: str):
        config = OmegaConf.load(filepath)
        return ASRTarredDatasetMetadata.from_config(config=config)


class ASRTarredDatasetBuilder:
    """
    Helper class that constructs a tarred dataset from scratch, or concatenates tarred datasets
    together and constructs manifests for them.
    """

    def __init__(self):
        self.config = None

    def configure(self, config: ASRTarredDatasetConfig):
        """
        Sets the config generated from command line overrides.

        Args:
            config: ASRTarredDatasetConfig dataclass object.
        """
        self.config = config  # type: ASRTarredDatasetConfig

        if self.config.num_shards < 0:
            raise ValueError("`num_shards` must be > 0. Please fill in the metadata information correctly.")

    def create_new_dataset(
        self,
        manifest_path: str,
        target_dir: str = "./tarred/",
        num_workers: int = 0,
        buckets_num: int = 1,
        dynamic_buckets_num: int = 30,
        only_manifests: bool = False,
        dry_run: bool = False,
    ):
        """
        Creates a new tarred dataset from a given manifest file.

        Args:
            manifest_path (str): Path to the original ASR manifest file.
            target_dir (str, optional): Output directory where tarred files and manifests will be saved. Defaults to "./tarred/".
            num_workers (int, optional): Number of parallel worker processes for writing tar files. Defaults to 0 (sequential processing).
            buckets_num (int, optional): Number of buckets for static bucketing. Defaults to 1 (no bucketing).
            dynamic_buckets_num (int, optional): Number of buckets to estimate for dynamic bucketing. Defaults to 30.
            only_manifests (bool, optional): If True, performs a dry run without creating actual tar files. Defaults to False.

        Raises:
            ValueError: If the configuration has not been set.
            FileNotFoundError: If the manifest file does not exist.

        Output:
            - Creates tar files and a tarred dataset compatible manifest file in the specified `target_dir`.
            - Preserves a record of the metadata used to construct the tarred dataset in `metadata.yaml`.
            - Optionally creates shard manifests if `config.shard_manifests` is enabled.

        Notes:
            - The function reads the manifest, applies filtering and shuffling if specified, and creates shards of tar files.
            - It generates shard manifests and the main tarred dataset manifest.
            - Metadata is updated and saved based on the tarred dataset configuration.
        """
        if self.config is None:
            raise ValueError("Config has not been set. Please call `configure(config: ASRTarredDatasetConfig)`")

        if manifest_path is None:
            raise FileNotFoundError("Manifest filepath cannot be None !")

        config = self.config  # type: ASRTarredDatasetConfig

        if not os.path.exists(target_dir):
            os.makedirs(target_dir)

        # Read the existing manifest
        entries, total_duration, filtered_entries, filtered_duration = self._read_manifest(manifest_path, config)

        header = [
            "Min.\nduration",
            "Max.\nduration",
            "Entries amount\nafter filtration",
            "Total duration\nafter filtration",
            "Shards\namount",
            "Entries\nper shard",
            "Remainded\nentries",
        ]

        entires_amount = f'{len(entries)} / {len(entries) + len(filtered_entries)}'
        entries_duration = f'{total_duration:.2f} / {total_duration + filtered_duration:.2f} s'
        entries_per_shard = len(entries) // config.num_shards
        remainder = len(entries) % config.num_shards

        data = [
            [
                f"{config.min_duration} s",
                f"{config.max_duration} s",
                f"{entires_amount}",
                f"{entries_duration}",
                f"{config.num_shards}",
                f"{entries_per_shard}",
                f"{remainder}",
            ]
        ]

        print('\n' + tabulate(data, headers=header, tablefmt="grid", colalign=["center"] * len(header)))
        if dry_run:
            return

        if len(entries) == 0:
            print("No tarred dataset was created as there were 0 valid samples after filtering!")
            return
        if config.shuffle:
            random.seed(config.shuffle_seed)
            print(f"Shuffling (seed: {config.shuffle_seed})...")
            if config.keep_files_together:
                filename_entries = defaultdict(list)
                for ent in entries:
                    filename_entries[ent["audio_filepath"]].append(ent)
                filenames = list(filename_entries.keys())
                random.shuffle(filenames)
                shuffled_entries = []
                for filename in filenames:
                    shuffled_entries += filename_entries[filename]
                entries = shuffled_entries
            else:
                random.shuffle(entries)

        start_indices = []
        end_indices = []
        # Build indices
        for i in range(config.num_shards):
            start_idx = (len(entries) // config.num_shards) * i
            end_idx = start_idx + (len(entries) // config.num_shards)
            print(f"Shard {i} has entries {start_idx} ~ {end_idx}")
            files = set()
            for ent_id in range(start_idx, end_idx):
                files.add(entries[ent_id]["audio_filepath"])
            print(f"Shard {i} contains {len(files)} files")
            if i == config.num_shards - 1:
                # We discard in order to have the same number of entries per shard.
                print(f"Have {len(entries) - end_idx} entries left over that will be discarded.")

            start_indices.append(start_idx)
            end_indices.append(end_idx)

        manifest_folder, _ = os.path.split(manifest_path)

        with Parallel(n_jobs=num_workers, verbose=config.num_shards) as parallel:
            # Call parallel tarfile construction
            new_entries_list = parallel(
                delayed(self._create_shard)(entries[start_idx:end_idx], target_dir, i, manifest_folder, only_manifests)
                for i, (start_idx, end_idx) in enumerate(zip(start_indices, end_indices))
            )

        if config.shard_manifests:
            sharded_manifests_dir = target_dir + '/sharded_manifests'
            if not os.path.exists(sharded_manifests_dir):
                os.makedirs(sharded_manifests_dir)

            for manifest in new_entries_list:
                shard_id = manifest[0]['shard_id']
                new_manifest_shard_path = os.path.join(sharded_manifests_dir, f'manifest_{shard_id}.json')
                with open(new_manifest_shard_path, 'w', encoding='utf-8') as m2:
                    for entry in manifest:
                        json.dump(entry, m2, ensure_ascii=False)
                        m2.write('\n')

        # Flatten the list of list of entries to a list of entries
        new_entries = [sample for manifest in new_entries_list for sample in manifest]
        del new_entries_list

        print("Total number of entries in manifest :", len(new_entries))

        # Write manifest
        new_manifest_path = os.path.join(target_dir, 'tarred_audio_manifest.json')
        with open(new_manifest_path, 'w', encoding='utf-8') as m2:
            for entry in new_entries:
                json.dump(entry, m2, ensure_ascii=False)
                m2.write('\n')

        # Write metadata (default metadata for new datasets)
        new_metadata_path = os.path.join(target_dir, 'metadata.yaml')
        metadata = ASRTarredDatasetMetadata()

        # Update metadata
        metadata.dataset_config = config
        metadata.num_samples_per_shard = len(new_entries) // config.num_shards

        if buckets_num <= 1:
            # Estimate and update dynamic bucketing args
            bucketing_kwargs = self.estimate_dynamic_bucketing_duration_bins(
                new_manifest_path, num_buckets=dynamic_buckets_num
            )
            for k, v in bucketing_kwargs.items():
                setattr(metadata.dataset_config, k, v)

        # Write metadata
        metadata_yaml = OmegaConf.structured(metadata)
        OmegaConf.save(metadata_yaml, new_metadata_path, resolve=True)

    def estimate_dynamic_bucketing_duration_bins(self, manifest_path: str, num_buckets: int = 30) -> dict:
        from lhotse import CutSet
        from lhotse.dataset.sampling.dynamic_bucketing import estimate_duration_buckets

        from nemo.collections.common.data.lhotse.nemo_adapters import LazyNeMoIterator

        cuts = CutSet(LazyNeMoIterator(manifest_path, metadata_only=True))
        bins = estimate_duration_buckets(cuts, num_buckets=num_buckets)
        print(
            f"Note: we estimated the optimal bucketing duration bins for {num_buckets} buckets. "
            "You can enable dynamic bucketing by setting the following options in your training script:\n"
            "  use_lhotse=true\n"
            "  use_bucketing=true\n"
            f"  num_buckets={num_buckets}\n"
            f"  bucket_duration_bins=[{','.join(map(str, bins))}]\n"
            "  batch_duration=<tune-this-value>\n"
            "If you'd like to use a different number of buckets, re-estimate this option manually using "
            "scripts/speech_recognition/estimate_duration_bins.py"
        )
        return dict(
            use_lhotse=True,
            use_bucketing=True,
            num_buckets=num_buckets,
            bucket_duration_bins=list(map(float, bins)),  # np.float -> float for YAML serialization
        )

    def create_concatenated_dataset(
        self,
        base_manifest_path: str,
        manifest_paths: List[str],
        metadata: ASRTarredDatasetMetadata,
        target_dir: str = "./tarred_concatenated/",
        num_workers: int = 1,
        only_manifests: bool = False,
        dry_run: bool = False,
    ):
        """
        Creates a concatenated tarred dataset from the base manifest and additional manifest files.

        Args:
            base_manifest_path (str): Path to the base manifest file that contains information for the original
                tarred dataset (with flattened paths).
            manifest_paths (List[str]): List of paths to additional manifest files that will be concatenated with
                the base tarred dataset.
            metadata (ASRTarredDatasetMetadata): Metadata instance containing configuration and overrides.
            target_dir (str, optional): Output directory where tarred files and manifests will be saved. Defaults to "./tarred_concatenated/".
            num_workers (int, optional): Number of parallel worker processes for creating tar files. Defaults to 1.
            only_manifests (bool, optional): If True, performs a dry run without creating actual tar files. Defaults to False.

        Raises:
            FileNotFoundError: If the base manifest file or any of the additional manifest files does not exist.

        Output:
            - Creates tar files and a concatenated tarred dataset compatible manifest file in the specified `target_dir`.
            - Updates metadata to reflect the concatenated dataset, including the version and historical data.

        Notes:
            - The function reads the base manifest and additional manifests, filters and shuffles entries as needed,
            and creates new shards of tar files.
            - It generates a new concatenated dataset manifest and updates metadata with versioning and historical context.
            - If `metadata` is provided, the function updates its version and includes historical data in the new metadata.
        """
        if not os.path.exists(target_dir):
            os.makedirs(target_dir)

        if base_manifest_path is None:
            raise FileNotFoundError("Base manifest filepath cannot be None !")

        if manifest_paths is None or len(manifest_paths) == 0:
            raise FileNotFoundError("List of additional manifest filepaths cannot be None !")

        config = ASRTarredDatasetConfig(**(metadata.dataset_config))

        # Read the existing manifest (no filtering here)
        base_entries, _, _, _ = self._read_manifest(base_manifest_path, config)
        print(f"Read base manifest containing {len(base_entries)} samples.")

        # Precompute number of samples per shard
        if metadata.num_samples_per_shard is None:
            num_samples_per_shard = len(base_entries) // config.num_shards
        else:
            num_samples_per_shard = metadata.num_samples_per_shard

        print("Number of samples per shard :", num_samples_per_shard)

        # Compute min and max duration and update config (if no metadata passed)
        print(f"Selected max duration : {config.max_duration}")
        print(f"Selected min duration : {config.min_duration}")

        entries = []
        for new_manifest_idx in range(len(manifest_paths)):
            new_entries, total_duration, filtered_new_entries, filtered_duration = self._read_manifest(
                manifest_paths[new_manifest_idx], config
            )

            if len(filtered_new_entries) > 0:
                print(
                    f"Filtered {len(filtered_new_entries)} files which amounts to {filtered_duration:0.2f}"
                    f" seconds of audio from manifest {manifest_paths[new_manifest_idx]}."
                )
            print(
                f"After filtering, manifest has {len(entries)} files which amounts to {total_duration} seconds of audio."
            )

            entries.extend(new_entries)

        if len(entries) == 0:
            print("No tarred dataset was created as there were 0 valid samples after filtering!")
            return

        if config.shuffle:
            random.seed(config.shuffle_seed)
            print(f"Shuffling (seed: {config.shuffle_seed})...")
            random.shuffle(entries)

        # Drop last section of samples that cannot be added onto a chunk
        drop_count = len(entries) % num_samples_per_shard
        total_new_entries = len(entries)
        entries = entries[:-drop_count]

        print(
            f"Dropping {drop_count} samples from total new samples {total_new_entries} since they cannot "
            f"be added into a uniformly sized chunk."
        )

        # Create shards and updated manifest entries
        num_added_shards = len(entries) // num_samples_per_shard

        print(f"Number of samples in base dataset : {len(base_entries)}")
        print(f"Number of samples in additional datasets : {len(entries)}")
        print(f"Number of added shards : {num_added_shards}")
        print(f"Remainder: {len(entries) % num_samples_per_shard}")

        if dry_run:
            return

        start_indices = []
        end_indices = []
        shard_indices = []
        for i in range(num_added_shards):
            start_idx = (len(entries) // num_added_shards) * i
            end_idx = start_idx + (len(entries) // num_added_shards)
            shard_idx = i + config.num_shards
            print(f"Shard {shard_idx} has entries {start_idx + len(base_entries)} ~ {end_idx + len(base_entries)}")

            start_indices.append(start_idx)
            end_indices.append(end_idx)
            shard_indices.append(shard_idx)

        manifest_folder, _ = os.path.split(base_manifest_path)

        with Parallel(n_jobs=num_workers, verbose=num_added_shards) as parallel:
            # Call parallel tarfile construction
            new_entries_list = parallel(
                delayed(self._create_shard)(
                    entries[start_idx:end_idx], target_dir, shard_idx, manifest_folder, only_manifests
                )
                for i, (start_idx, end_idx, shard_idx) in enumerate(zip(start_indices, end_indices, shard_indices))
            )

        if config.shard_manifests:
            sharded_manifests_dir = target_dir + '/sharded_manifests'
            if not os.path.exists(sharded_manifests_dir):
                os.makedirs(sharded_manifests_dir)

            for manifest in new_entries_list:
                shard_id = manifest[0]['shard_id']
                new_manifest_shard_path = os.path.join(sharded_manifests_dir, f'manifest_{shard_id}.json')
                with open(new_manifest_shard_path, 'w', encoding='utf-8') as m2:
                    for entry in manifest:
                        json.dump(entry, m2, ensure_ascii=False)
                        m2.write('\n')

        # Flatten the list of list of entries to a list of entries
        new_entries = [sample for manifest in new_entries_list for sample in manifest]
        del new_entries_list

        # Write manifest
        if metadata is None:
            new_version = 1  # start with `1`, where `0` indicates the base manifest + dataset
        else:
            new_version = metadata.version + 1

        print("Total number of entries in manifest :", len(base_entries) + len(new_entries))

        new_manifest_path = os.path.join(target_dir, f'tarred_audio_manifest_version_{new_version}.json')
        with open(new_manifest_path, 'w', encoding='utf-8') as m2:
            # First write all the entries of base manifest
            for entry in base_entries:
                json.dump(entry, m2, ensure_ascii=False)
                m2.write('\n')

            # Finally write the new entries
            for entry in new_entries:
                json.dump(entry, m2, ensure_ascii=False)
                m2.write('\n')

        # Preserve historical metadata
        base_metadata = metadata

        # Write metadata (updated metadata for concatenated datasets)
        new_metadata_path = os.path.join(target_dir, f'metadata_version_{new_version}.yaml')
        metadata = ASRTarredDatasetMetadata()

        # Update config
        config.num_shards = config.num_shards + num_added_shards

        # Update metadata
        metadata.version = new_version
        metadata.dataset_config = config
        metadata.num_samples_per_shard = num_samples_per_shard
        metadata.is_concatenated_manifest = True
        metadata.created_datetime = metadata.get_current_datetime()

        # Attach history
        current_metadata = OmegaConf.structured(base_metadata.history)
        metadata.history = current_metadata

        # Write metadata
        metadata_yaml = OmegaConf.structured(metadata)
        OmegaConf.save(metadata_yaml, new_metadata_path, resolve=True)

    def _read_manifest(self, manifest_path: Union[str, List[str]], config: ASRTarredDatasetConfig):
        """Read and filters data from the manifest"""
        entries = []
        total_duration = 0.0
        filtered_entries = []
        filtered_duration = 0.0

        if isinstance(manifest_path, str):
            manifest_paths = manifest_path.split(",")
        else:
            manifest_paths = manifest_path

        print(f"Found {len(manifest_paths)} manifest files to be processed")
        for manifest_file in manifest_paths:
            entries_i, total_dur_i, filtered_ent_i, filtered_dur_i = self._read_single_manifest(
                str(manifest_file), config
            )
            entries.extend(entries_i)
            total_duration += total_dur_i
            filtered_entries.extend(filtered_ent_i)
            filtered_duration += filtered_dur_i

        return entries, total_duration, filtered_entries, filtered_duration

    def _read_single_manifest(self, manifest_path: str, config: ASRTarredDatasetConfig):
        # Read the existing manifest
        entries = []
        total_duration = 0.0
        filtered_entries = []
        filtered_duration = 0.0
        print(f"Reading manifest: {manifest_path}")
        with open(manifest_path, 'r', encoding='utf-8') as m:
            for line in m:
                line = line.strip()
                if not line:
                    continue
                entry = json.loads(line)
                audio_key = "audio_filepath" if "audio_filepath" in entry else "audio_file"
                if config.slice_with_offset and "offset" not in entry:
                    raise KeyError(
                        f"Manifest entry does not contain 'offset' field, but '--slice_with_offset' is enabled: {entry}"
                    )
                if audio_key not in entry:
                    raise KeyError(f"Manifest entry does not contain 'audio_filepath' or  'audio_file' key: {entry}")
                audio_filepath = entry[audio_key]
                if not os.path.isfile(audio_filepath) and not os.path.isabs(audio_filepath):
                    audio_filepath_abs = os.path.join(os.path.dirname(manifest_path), audio_filepath)
                    if not os.path.isfile(audio_filepath_abs):
                        raise FileNotFoundError(f"Could not find {audio_filepath} or {audio_filepath_abs}!")
                    entry[audio_key] = audio_filepath_abs
                if (config.max_duration is None or entry['duration'] < config.max_duration) and (
                    config.min_duration is None or entry['duration'] >= config.min_duration
                ):
                    entries.append(entry)
                    total_duration += entry["duration"]
                else:
                    filtered_entries.append(entry)
                    filtered_duration += entry['duration']

        return entries, total_duration, filtered_entries, filtered_duration

    def _write_to_tar(
        self, tar, audio_filepath: str, squashed_filename: str, duration: float = None, offset: float = 0
    ) -> None:
        codec = self.config.force_codec
        to_transcode = not (codec is None or audio_filepath.endswith(f".{codec}"))
        to_crop = not (duration is None and offset == 0)

        if not to_crop and not to_transcode:
            # Add existing file without transcoding, trimming, or re-encoding.
            tar.add(audio_filepath, arcname=squashed_filename)
            return

        # Standard processing: read, trim, and transcode the audio file
        with soundfile.SoundFile(audio_filepath) as f:
            sampling_rate = f.samplerate

        # Trim audio based on offset and duration.
        start_sample = int(offset * sampling_rate)
        num_frames = int(duration * sampling_rate) if duration else -1
        audio, sampling_rate = soundfile.read(file_path, start=start_sample, frames=num_frames)

        # Determine codec parameters.
        if codec is not None:
            if codec == "opus":
                kwargs = {"format": "ogg", "subtype": "opus"}
            else:
                kwargs = {"format": codec}
        else:
            codec = soundfile.info(audio_filepath).format.lower()
            kwargs = {"format": codec}

        # Transcode and write audio to tar.
        encoded_audio = BytesIO()
        soundfile.write(encoded_audio, audio, sampling_rate, closefd=False, **kwargs)

        # Generate filename with the appropriate extension.
        encoded_squashed_filename = f"{squashed_filename.split('.')[0]}.{codec}"

        # Add the in-memory audio file to the tar archive.
        ti = tarfile.TarInfo(encoded_squashed_filename)
        encoded_audio.seek(0)
        ti.size = len(encoded_audio.getvalue())
        tar.addfile(ti, encoded_audio)

    def _create_shard(self, entries, target_dir, shard_id, manifest_folder: str = None, only_manifests: bool = False):
        """Creates a tarball containing the audio files from `entries`."""
        if self.config.sort_in_shards:
            entries.sort(key=lambda x: x["duration"], reverse=False)

        new_entries = []

        tar_filepath = os.path.join(target_dir, f'audio_{shard_id}.tar')
        if not only_manifests:
            tar = tarfile.open(tar_filepath, mode='w', dereference=True)

        count = dict()
        for entry in tqdm(entries, desc="Creating shard.."):
            # We squash the filename since we do not preserve directory structure of audio files in the tarball.
            if os.path.exists(entry["audio_filepath"]) or only_manifests:
                audio_filepath = entry["audio_filepath"]
            else:
                if not manifest_folder:
                    raise FileNotFoundError(f"Could not find {entry['audio_filepath']}!")

                audio_filepath = os.path.join(manifest_folder, entry["audio_filepath"])
                if not os.path.exists(audio_filepath):
                    raise FileNotFoundError(f"Could not find {entry['audio_filepath']}!")

            base, ext = os.path.splitext(audio_filepath)
            base = base.replace('/', '_')
            # Need the following replacement as long as WebDataset splits on first period
            base = base.replace('.', '_')
            squashed_filename = f'{base}{ext}'

            if self.config.slice_with_offset:
                if squashed_filename not in count:
                    count[squashed_filename] = 1

                entry_offset = str(entry['offset']).split('.')
                if len(entry_offset) == 1:
                    # Example: offset = 12 -> becomes 12_0
                    entry_offset.append('0')
                elif len(entry_offset) == 2:
                    # Example: offset = 12.34 -> becomes 12_34
                    pass
                else:
                    raise ValueError(
                        f"The offset for the entry with audio_filepath '{entry['audio_filepath']}' is incorrectly provided ({entry['offset']}). "
                        "Expected a float-like value (e.g., 12 or 12.34)."
                    )
                entry_offset = "_".join(entry_offset)

                entry_duration = str(entry['duration']).split('.')
                if len(entry_duration) == 1:
                    entry_duration.append('0')
                elif len(entry_duration) > 2:
                    raise ValueError(
                        f"The duration for the entry with audio_filepath '{entry['audio_filepath']}' is incorrectly provided ({entry['duration']})."
                    )
                entry_duration = "_".join(entry_duration)

                to_write = base + "_" + entry_offset + "_" + entry_duration + ext
                if not only_manifests:
                    self._write_to_tar(
                        tar, audio_filepath, to_write, duration=entry['duration'], offset=entry['offset']
                    )
                count[squashed_filename] += 1

                entry['source_audio_offset'] = entry['offset']
                del entry['offset']
            else:
                if squashed_filename not in count:
                    if not only_manifests:
                        self._write_to_tar(tar, audio_filepath, squashed_filename)
                    to_write = squashed_filename
                    count[squashed_filename] = 1
                else:
                    to_write = base + "-sub" + str(count[squashed_filename]) + ext
                    count[squashed_filename] += 1

            if only_manifests:
                entry['abs_audio_filepath'] = audio_filepath

            # Carry over every key in the entry, override audio_filepath and shard_id
            new_entry = {
                **entry,
                'audio_filepath': to_write,
                'shard_id': shard_id,  # Keep shard ID for recordkeeping
            }
            new_entries.append(new_entry)

        if not only_manifests:
            tar.close()
        return new_entries

    @classmethod
    def setup_history(cls, base_metadata: ASRTarredDatasetMetadata, history: List[Any]):
        if 'history' in base_metadata.keys():
            for history_val in base_metadata.history:
                cls.setup_history(history_val, history)

        if base_metadata is not None:
            metadata_copy = copy.deepcopy(base_metadata)
            with open_dict(metadata_copy):
                metadata_copy.pop('history', None)
            history.append(metadata_copy)


def main(args):
    if args.buckets_num > 1:
        bucket_length = (args.max_duration - args.min_duration) / float(args.buckets_num)
        for i_bucket in range(args.buckets_num):
            bucket_config = copy.deepcopy(args)
            bucket_config.min_duration = args.min_duration + i_bucket * bucket_length
            bucket_config.max_duration = bucket_config.min_duration + bucket_length
            if i_bucket == args.buckets_num - 1:
                # add a small number to cover the samples with exactly duration of max_duration in the last bucket.
                bucket_config.max_duration += 1e-5
            bucket_config.target_dir = os.path.join(args.target_dir, f"bucket{i_bucket+1}")
            print(
                f"Creating bucket {i_bucket+1} with min_duration={bucket_config.min_duration} and max_duration={bucket_config.max_duration} ..."
            )
            print(f"Results are being saved at: {bucket_config.target_dir}.")
            create_tar_datasets(**vars(bucket_config))
            if not args.dry_run:
                print(f"Bucket {i_bucket+1} is created.")
    else:
        create_tar_datasets(**vars(args))


def create_tar_datasets(
    manifest_path: str = None,
    concat_manifest_paths: str = None,
    target_dir: str = None,
    metadata_path: str = None,
    num_shards: int = -1,
    max_duration: float = None,
    min_duration: float = None,
    shuffle: bool = False,
    keep_files_together: bool = False,
    sort_in_shards: bool = False,
    buckets_num: int = 1,
    dynamic_buckets_num: int = 30,
    shuffle_seed: int = None,
    write_metadata: bool = False,
    no_shard_manifests: bool = False,
    force_codec: str = None,
    workers: int = 1,
    slice_with_offset: bool = False,
    only_manifests: bool = False,
    dry_run: bool = False,
):
    builder = ASRTarredDatasetBuilder()

    shard_manifests = False if no_shard_manifests else True

    if write_metadata:
        metadata = ASRTarredDatasetMetadata()
        dataset_cfg = ASRTarredDatasetConfig(
            num_shards=num_shards,
            shuffle=shuffle,
            max_duration=max_duration,
            min_duration=min_duration,
            shuffle_seed=shuffle_seed,
            sort_in_shards=sort_in_shards,
            shard_manifests=shard_manifests,
            keep_files_together=keep_files_together,
            force_codec=force_codec,
            slice_with_offset=slice_with_offset,
        )
        metadata.dataset_config = dataset_cfg

        output_path = os.path.join(target_dir, 'default_metadata.yaml')
        OmegaConf.save(metadata, output_path, resolve=True)
        print(f"Default metadata written to {output_path}")
        exit(0)

    if concat_manifest_paths is None or len(concat_manifest_paths) == 0:
        # Create a tarred dataset from scratch
        config = ASRTarredDatasetConfig(
            num_shards=num_shards,
            shuffle=shuffle,
            max_duration=max_duration,
            min_duration=min_duration,
            shuffle_seed=shuffle_seed,
            sort_in_shards=sort_in_shards,
            shard_manifests=shard_manifests,
            keep_files_together=keep_files_together,
            force_codec=force_codec,
            slice_with_offset=slice_with_offset,
        )
        builder.configure(config)
        builder.create_new_dataset(
            manifest_path=manifest_path,
            target_dir=target_dir,
            num_workers=workers,
            buckets_num=buckets_num,
            dynamic_buckets_num=dynamic_buckets_num,
            only_manifests=only_manifests,
            dry_run=dry_run,
        )

    else:
        if buckets_num > 1:
            raise ValueError("Concatenation feature does not support buckets_num > 1.")
        print("Concatenating multiple tarred datasets ...")

        # Implicitly update config from base details
        if metadata_path is not None:
            metadata = ASRTarredDatasetMetadata.from_file(metadata_path)
        else:
            raise ValueError("`metadata` yaml file path must be provided!")

        # Preserve history
        history = []
        builder.setup_history(OmegaConf.structured(metadata), history)
        metadata.history = history

        # Add command line overrides (everything other than num_shards)
        metadata.dataset_config.max_duration = max_duration
        metadata.dataset_config.min_duration = min_duration
        metadata.dataset_config.shuffle = shuffle
        metadata.dataset_config.shuffle_seed = shuffle_seed
        metadata.dataset_config.sort_in_shards = sort_in_shards
        metadata.dataset_config.shard_manifests = shard_manifests

        builder.configure(metadata.dataset_config)

        # Concatenate a tarred dataset onto a previous one
        builder.create_concatenated_dataset(
            base_manifest_path=manifest_path,
            manifest_paths=concat_manifest_paths,
            metadata=metadata,
            target_dir=target_dir,
            num_workers=workers,
            slice_with_offset=slice_with_offset,
            only_manifests=only_manifests,
            dry_run=dry_run,
        )

    if not dry_run and (DALI_INDEX_SCRIPT_AVAILABLE and dali_index.INDEX_CREATOR_AVAILABLE):
        print("Constructing DALI Tarfile Index - ", target_dir)
        index_config = dali_index.DALITarredIndexConfig(tar_dir=target_dir, workers=workers)
        dali_index.main(index_config)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="Convert an existing ASR dataset to tarballs compatible with TarredAudioToTextDataLayer."
    )
    parser.add_argument(
        "--manifest_path", default=None, type=str, required=False, help="Path to the existing dataset's manifest."
    )

    parser.add_argument(
        '--concat_manifest_paths',
        nargs='+',
        default=None,
        type=str,
        required=False,
        help="Path to the additional dataset's manifests that will be concatenated with base dataset.",
    )

    # Optional arguments
    parser.add_argument(
        "--target_dir",
        default='./tarred',
        type=str,
        help="Target directory for resulting tarballs and manifest. Defaults to `./tarred`. Creates the path if necessary.",
    )

    parser.add_argument(
        "--metadata_path",
        required=False,
        default=None,
        type=str,
        help="Path to metadata file for the dataset.",
    )

    parser.add_argument(
        "--num_shards",
        default=-1,
        type=int,
        help="Number of shards (tarballs) to create. Used for partitioning data among workers.",
    )
    parser.add_argument(
        '--max_duration',
        default=None,
        required=True,
        type=float,
        help='Maximum duration of audio clip in the dataset. By default, it is None and is required to be set.',
    )
    parser.add_argument(
        '--min_duration',
        default=None,
        type=float,
        help='Minimum duration of audio clip in the dataset. By default, it is None and will not filter files.',
    )
    parser.add_argument(
        "--shuffle",
        action='store_true',
        help="Whether or not to randomly shuffle the samples in the manifest before tarring/sharding.",
    )

    parser.add_argument(
        "--keep_files_together",
        action='store_true',
        help="Whether or not to keep entries from the same file (but different offsets) together when sorting before tarring/sharding.",
    )
    parser.add_argument(
        "--slice_with_offset",
        action='store_true',
        help=(
            "If set, the audio will be sliced based on `offset` and `duration` fields from the manifest. "
            "This is useful for creating datasets from audio segments instead of full files. "
            "When unset, the entire audio file is used without slicing, regardless of the offset/duration values in the manifest."
        ),
    )
    parser.add_argument(
        "--sort_in_shards",
        action='store_true',
        help="Whether or not to sort samples inside the shards based on their duration.",
    )

    parser.add_argument(
        "--buckets_num",
        type=int,
        default=1,
        help="Number of buckets to create based on duration.",
    )

    parser.add_argument(
        "--dynamic_buckets_num",
        type=int,
        default=30,
        help="Intended for dynamic (on-the-fly) bucketing; this option will not bucket your dataset during tar conversion. "
        "Estimates optimal bucket duration bins for a given number of buckets.",
    )

    parser.add_argument("--shuffle_seed", type=int, default=None, help="Random seed for use if shuffling is enabled.")
    parser.add_argument(
        '--write_metadata',
        action='store_true',
        help=(
            "Flag to write a blank metadata with the current call config. "
            "Note that the metadata will not contain the number of shards, "
            "and it must be filled out by the user."
        ),
    )
    parser.add_argument(
        "--no_shard_manifests",
        action='store_true',
        help="Do not write sharded manifests along with the aggregated manifest.",
    )
    parser.add_argument(
        "--force_codec",
        type=str,
        default=None,
        help=(
            "If specified, transcode the audio to the given format. "
            "Supports libnsndfile formats (example values: 'opus', 'flac')."
        ),
    )
    parser.add_argument(
        "--only_manifests",
        action='store_true',
        help=(
            "If set, only creates manifests for each shard without creating the actual tar files. "
            "This allows you to verify the output structure and content before committing to the full tarball creation process. "
            "Each manifest entry will also include the field `abs_audio_filepath`, which stores the absolute path to the original audio file."
        ),
    )
    parser.add_argument(
        "--dry_run",
        action='store_true',
        help=(
            "Run in simulation mode: calculate and display the number of shards and estimated data per shard without reading audio files or writing any output."
        ),
    )
    parser.add_argument('--workers', type=int, default=1, help='Number of worker processes')
    args = parser.parse_args()
    main(args)