#!/usr/bin/env python3
"""
Convert non-redistributable datasets to RAON-TTS-Pool WebDataset format.

GigaSpeech and SPGISpeech cannot be included directly in RAON-TTS-Pool due to
license restrictions. Users who have agreed to the license on HuggingFace can
run this script to automatically download and convert them into the same
WebDataset tar + metadata parquet format.

Prerequisites
-------------
  1. Accept the dataset license on HuggingFace:
     - GigaSpeech:  https://huggingface.co/datasets/speechcolab/gigaspeech
     - SPGISpeech:  https://huggingface.co/datasets/kensho/spgispeech
  2. Set your HuggingFace token:
       export HF_TOKEN=hf_your_token_here

Supported datasets
------------------
  gigaspeech  : GigaSpeech (HuggingFace: speechcolab/gigaspeech)
                License: requires signing a license agreement
                Subsets: xs (10h), s (250h), m (1000h), l (2500h), xl (10000h)
  spgispeech  : SPGISpeech (HuggingFace: kensho/spgispeech)
                License: non-commercial use only

Output layout (per dataset)
----------------------------
  <output_dir>/
    {prefix}-000000.tar    # WebDataset shard (~10 GB each)
    {prefix}-000001.tar
    ...
    metadata_pool.parquet  # all samples (sample_key, text, duration, shard_name)
    metadata_core.parquet  # quality-filtered subset (requires --core_json)

Each tar contains pairs:
  {sample_key}.opus   16 kHz mono Opus 64 kbps
  {sample_key}.json   {"text": "...", "duration": 4.2, "source": "..."}

Usage
-----
  # GigaSpeech xl subset (requires HF_TOKEN with license agreement)
  python prepare_nonredist_datasets.py gigaspeech \\
      --output_dir ./GigaSpeech \\
      --gigaspeech_subset xl

  # GigaSpeech from local HF snapshot
  python prepare_nonredist_datasets.py gigaspeech \\
      --source_dir /path/to/gigaspeech_local \\
      --output_dir ./GigaSpeech \\
      --gigaspeech_subset xl

  # SPGISpeech (requires HF_TOKEN with license agreement)
  python prepare_nonredist_datasets.py spgispeech \\
      --output_dir ./SPGISpeech

  # SPGISpeech from local HF snapshot
  python prepare_nonredist_datasets.py spgispeech \\
      --source_dir /path/to/spgispeech_local \\
      --output_dir ./SPGISpeech

  # With core parquet (requires pool_indices JSON from RAON-TTS-Pool maintainers)
  python prepare_nonredist_datasets.py gigaspeech \\
      --output_dir ./GigaSpeech \\
      --core_json /path/to/pool_indices_filter_remove_15pct_combined.json \\
      --pool_offset <offset>

  # Parquet-only (tars already built)
  python prepare_nonredist_datasets.py gigaspeech \\
      --output_dir ./GigaSpeech \\
      --parquet_only

Notes
-----
  - Audio is always re-encoded to 16 kHz mono Opus 64 kbps via ffmpeg.
  - Samples longer than --max_duration (default 30s) are skipped.
  - Parallel ffmpeg encoding uses --num_workers (default 16) threads.
  - Resume: existing complete shards (>= 10 GB) are skipped automatically.
  - Requires: pip install "datasets<4.0" soundfile pyarrow numpy tqdm
  - datasets>=4.0 dropped soundfile audio decoding; use datasets<4.0 (e.g. 3.5.0).
"""

import os
import io
import sys
import json
import tarfile
import argparse
import subprocess
import collections
from concurrent.futures import ThreadPoolExecutor
from tqdm import tqdm

try:
    import soundfile as sf
    import numpy as np
    import pyarrow as pa
    import pyarrow.parquet as pq
    from datasets import load_from_disk, load_dataset
except ImportError as e:
    print(f"Missing dependency: {e}")
    print('Install: pip install "datasets<4.0" soundfile pyarrow numpy tqdm')
    sys.exit(1)

# ── Dataset configuration ─────────────────────────────────────────────────────

DATASET_CONFIGS = {
    "gigaspeech": {
        "hf_repo": "speechcolab/gigaspeech",
        "prefix": "gs",
        "source_label": "gigaspeech",
        "pool_offset": None,       # set via --pool_offset if needed
        "text_col": "text",
        "audio_col": "audio",
        "key_col": "segment_id",   # use as sample_key if available
        "splits": ["train"],
        "description": "GigaSpeech (speechcolab/gigaspeech)",
    },
    "spgispeech": {
        "hf_repo": "kensho/spgispeech",
        "prefix": "sp",
        "source_label": "spgispeech",
        "pool_offset": None,       # set via --pool_offset if needed
        "text_col": "transcript",  # fallback: "text"
        "audio_col": "audio",
        "key_col": None,
        "splits": ["train"],
        "description": "SPGISpeech (kensho/spgispeech, non-commercial)",
    },
}

SHARD_SIZE_DEFAULT = 10.0        # GB
MAX_DURATION_DEFAULT = 30.0      # seconds
NUM_WORKERS_DEFAULT = 16


# ── Audio conversion ──────────────────────────────────────────────────────────

def audio_feature_to_opus_16k_bytes(audio_feature):
    """
    Convert a HuggingFace Audio feature dict to 16 kHz mono Opus bytes.
    audio_feature: {"array": np.ndarray, "sampling_rate": int, "path": str|None}
    """
    array = audio_feature["array"]
    sr = audio_feature["sampling_rate"]
    buf = io.BytesIO()
    sf.write(buf, array, sr, format="WAV", subtype="PCM_16")
    wav_bytes = buf.getvalue()

    result = subprocess.run(
        ["ffmpeg", "-y",
         "-f", "wav", "-i", "pipe:0",
         "-ar", "16000", "-ac", "1",
         "-c:a", "libopus", "-b:a", "64k",
         "-f", "ogg", "pipe:1",
         "-loglevel", "error"],
        input=wav_bytes,
        capture_output=True,
    )
    if result.returncode != 0:
        raise RuntimeError(result.stderr.decode()[:300])
    return result.stdout


def file_path_to_opus_16k_bytes(audio_path):
    """Convert any audio file to 16 kHz mono Opus bytes via ffmpeg."""
    # Fast path: already 16 kHz opus
    if audio_path.endswith(".opus"):
        try:
            if sf.info(audio_path).samplerate == 16000:
                with open(audio_path, "rb") as f:
                    return f.read()
        except Exception:
            pass
    result = subprocess.run(
        ["ffmpeg", "-y", "-i", audio_path,
         "-ar", "16000", "-ac", "1",
         "-c:a", "libopus", "-b:a", "64k",
         "-f", "ogg", "pipe:1",
         "-loglevel", "error"],
        capture_output=True,
    )
    if result.returncode != 0:
        raise RuntimeError(result.stderr.decode()[:300])
    return result.stdout


# ── Sample key ────────────────────────────────────────────────────────────────

def make_sample_key(row, cfg, idx):
    """Generate a stable sample key from row data."""
    # Prefer dataset-specific ID column
    key_col = cfg.get("key_col")
    if key_col and key_col in row and row[key_col]:
        return str(row[key_col])
    # Fall back to audio path basename
    audio = row.get(cfg["audio_col"]) or row.get("audio_path")
    if isinstance(audio, dict):
        path = audio.get("path")
        if path:
            return os.path.splitext(os.path.basename(path))[0]
    elif isinstance(audio, str) and audio:
        return os.path.splitext(os.path.basename(audio))[0]
    return f"{cfg['source_label']}-{idx:08d}"


# ── Per-sample worker ─────────────────────────────────────────────────────────

def process_sample(args_tuple):
    """
    Returns (sample_key, audio_bytes, meta_json_bytes) or None if skip.
    """
    idx, row, cfg, pool_offset, max_duration = args_tuple

    audio_feature = row.get(cfg["audio_col"])
    # Fallback: local Arrow datasets may use "audio_path" instead of "audio"
    if audio_feature is None:
        audio_feature = row.get("audio_path")
    text_col = cfg["_resolved_text_col"]
    text = row.get(text_col, "") or ""
    duration = row.get("duration")

    try:
        if isinstance(audio_feature, dict) and "array" in audio_feature:
            if duration is None:
                array = audio_feature["array"]
                sr = audio_feature["sampling_rate"]
                duration = len(array) / sr
            if duration > max_duration:
                return None
            audio_bytes = audio_feature_to_opus_16k_bytes(audio_feature)
        elif isinstance(audio_feature, str):
            if not os.path.exists(audio_feature):
                return None
            if duration is None:
                duration = sf.info(audio_feature).duration
            if duration > max_duration:
                return None
            audio_bytes = file_path_to_opus_16k_bytes(audio_feature)
        else:
            return None
    except Exception as e:
        print(f"  skip idx={idx}: {e}", flush=True)
        return None

    sample_key = make_sample_key(row, cfg, idx)
    meta = {"text": text, "duration": round(float(duration), 4),
            "source": cfg["source_label"]}
    if pool_offset is not None:
        meta["pool_idx"] = pool_offset + idx
    return (sample_key, audio_bytes, json.dumps(meta).encode("utf-8"))


# ── Tar writer ────────────────────────────────────────────────────────────────

class TarWriter:
    def __init__(self, output_dir, prefix, shard_size_limit, shard_idx_start=0):
        self.output_dir = output_dir
        self.prefix = prefix
        self.shard_size_limit = shard_size_limit
        self.shard_idx = shard_idx_start
        self.shard_count = 0
        self.sample_count = 0
        self.tar = None
        self.current_size = 0

    def _open_new_shard(self):
        name = f"{self.prefix}-{self.shard_idx:06d}.tar"
        path = os.path.join(self.output_dir, name)
        self.tar = tarfile.open(path, "w")
        self.current_size = 0
        print(f"  → {name}", flush=True)

    def write(self, sample_key, audio_bytes, meta_bytes):
        opus_size = len(audio_bytes)
        if self.tar is None or self.current_size + opus_size > self.shard_size_limit:
            if self.tar is not None:
                self.tar.close()
                self.shard_count += 1
                self.shard_idx += 1
            self._open_new_shard()

        opus_info = tarfile.TarInfo(name=f"{sample_key}.opus")
        opus_info.size = opus_size
        self.tar.addfile(opus_info, io.BytesIO(audio_bytes))

        json_info = tarfile.TarInfo(name=f"{sample_key}.json")
        json_info.size = len(meta_bytes)
        self.tar.addfile(json_info, io.BytesIO(meta_bytes))

        self.current_size += opus_size + len(meta_bytes)
        self.sample_count += 1

    def close(self):
        if self.tar is not None:
            self.tar.close()
            self.shard_count += 1
            self.shard_idx += 1


# ── Existing shard detection (resume) ────────────────────────────────────────

def count_complete_shards(output_dir, prefix, shard_size_limit):
    """Return (n_complete, next_shard_idx)."""
    if not os.path.isdir(output_dir):
        return 0, 0
    pattern_prefix = f"{prefix}-"
    shard_indices = []
    for fname in os.listdir(output_dir):
        if fname.startswith(pattern_prefix) and fname.endswith(".tar"):
            try:
                idx = int(fname[len(pattern_prefix):-4])
                size = os.path.getsize(os.path.join(output_dir, fname))
                if size >= shard_size_limit:
                    shard_indices.append(idx)
            except (ValueError, OSError):
                pass
    if not shard_indices:
        return 0, 0
    return len(shard_indices), max(shard_indices) + 1


# ── Parquet generation ────────────────────────────────────────────────────────

def build_parquets(output_dir, prefix, core_json=None):
    """Scan tars in output_dir and write metadata_pool.parquet + metadata_core.parquet."""
    tar_files = sorted(f for f in os.listdir(output_dir) if f.endswith(".tar"))
    if not tar_files:
        print("No tar files found — skipping parquet generation.", flush=True)
        return

    print(f"\nBuilding parquets from {len(tar_files)} tars ...", flush=True)

    core_set = None
    if core_json:
        print(f"Loading core indices: {core_json}", flush=True)
        with open(core_json) as f:
            core_set = set(json.load(f))
        print(f"  Core set: {len(core_set):,} indices", flush=True)

    schema = pa.schema([
        pa.field("sample_key", pa.string()),
        pa.field("text", pa.string()),
        pa.field("duration", pa.float64()),
        pa.field("shard_name", pa.string()),
    ])

    pool_rows = {k: [] for k in ["sample_key", "text", "duration", "shard_name"]}
    core_rows = {k: [] for k in ["sample_key", "text", "duration", "shard_name"]}

    for tar_name in tqdm(tar_files, desc="Scanning tars"):
        tar_path = os.path.join(output_dir, tar_name)
        try:
            with tarfile.open(tar_path, "r") as tf:
                members = {m.name: m for m in tf.getmembers()}
                opus_keys = [
                    os.path.splitext(n)[0] for n in members if n.endswith(".opus")
                ]
                for key in opus_keys:
                    json_name = f"{key}.json"
                    if json_name not in members:
                        continue
                    meta = json.loads(tf.extractfile(members[json_name]).read())
                    text = meta.get("text", "")
                    duration = float(meta.get("duration", 0.0))
                    pool_idx = meta.get("pool_idx")

                    row = {"sample_key": key, "text": text,
                           "duration": duration, "shard_name": tar_name}
                    for k in pool_rows:
                        pool_rows[k].append(row[k])

                    is_core = True
                    if core_set is not None and pool_idx is not None:
                        is_core = pool_idx in core_set
                    if is_core:
                        for k in core_rows:
                            core_rows[k].append(row[k])
        except Exception as e:
            print(f"  skip {tar_name}: {e}")

    pool_path = os.path.join(output_dir, "metadata_pool.parquet")
    core_path = os.path.join(output_dir, "metadata_core.parquet")
    pq.write_table(pa.table(pool_rows, schema=schema), pool_path)
    pq.write_table(pa.table(core_rows, schema=schema), core_path)

    pool_n = len(pool_rows["sample_key"])
    core_n = len(core_rows["sample_key"])
    pool_h = sum(pool_rows["duration"]) / 3600
    core_h = sum(core_rows["duration"]) / 3600
    print(f"  pool: {pool_n:,} samples, {pool_h:.0f}h  → {pool_path}")
    print(f"  core: {core_n:,} samples, {core_h:.0f}h  → {core_path}")
    if core_set is None:
        print("  (core = pool; no --core_json provided)")


# ── Main build ────────────────────────────────────────────────────────────────

def build_tars(ds, cfg, args):
    """Iterate dataset ds and write WebDataset tars."""
    shard_size_limit = int(args.shard_size_gb * 1024 ** 3)
    pool_offset = args.pool_offset if args.pool_offset is not None else cfg.get("pool_offset")

    os.makedirs(args.output_dir, exist_ok=True)

    # Detect text column
    col_names = ds.column_names
    text_col = cfg["text_col"]
    if text_col not in col_names:
        fallbacks = ["text", "transcript", "sentence", "normalized_text", "transcription"]
        for fb in fallbacks:
            if fb in col_names:
                text_col = fb
                break
        else:
            raise ValueError(f"No text column found. Available: {col_names}")
    cfg = dict(cfg, _resolved_text_col=text_col)
    print(f"Columns: audio={cfg['audio_col']!r}  text={text_col!r}", flush=True)

    # Resume
    n_complete, shard_idx_start = count_complete_shards(
        args.output_dir, cfg["prefix"], shard_size_limit
    )
    # Rough skip estimate (samples already in complete shards)
    # Use 0 to be safe — duplicate sample_keys in tar would just overwrite
    skip_samples = 0
    if n_complete > 0:
        # Estimate from parquet if it exists (more accurate)
        pool_parquet = os.path.join(args.output_dir, "metadata_pool.parquet")
        if os.path.exists(pool_parquet):
            skip_samples = len(pq.read_table(pool_parquet))
        print(f"Resume: {n_complete} complete shards, shard_idx_start={shard_idx_start}, "
              f"skipping {skip_samples:,} samples", flush=True)

    print(f"Dataset size: {len(ds):,} samples", flush=True)

    writer = TarWriter(args.output_dir, cfg["prefix"], shard_size_limit, shard_idx_start)
    prefetch = args.num_workers * 2

    with ThreadPoolExecutor(max_workers=args.num_workers) as executor:
        pending = collections.deque()
        pbar = tqdm(total=len(ds) - skip_samples, desc=cfg["source_label"])

        for i in range(len(ds)):
            if i < skip_samples:
                continue
            row = ds[i]
            task = (i, row, cfg, pool_offset, args.max_duration)
            pending.append(executor.submit(process_sample, task))

            while len(pending) >= prefetch:
                result = pending.popleft().result()
                if result is not None:
                    writer.write(*result)
                pbar.update(1)

        while pending:
            result = pending.popleft().result()
            if result is not None:
                writer.write(*result)
            pbar.update(1)

        pbar.close()

    writer.close()
    print(f"\nTar build done: {writer.shard_count} shards, {writer.sample_count:,} samples",
          flush=True)


# ── Argument parsing ──────────────────────────────────────────────────────────

def get_args():
    p = argparse.ArgumentParser(
        description="Convert non-redistributable datasets to RAON-TTS-Pool format.",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog=__doc__,
    )
    p.add_argument("dataset", choices=list(DATASET_CONFIGS.keys()),
                   help="Dataset to convert")
    p.add_argument("--output_dir", required=True,
                   help="Output directory for tar shards and parquet files")
    p.add_argument("--source_dir", default=None,
                   help="Local HF dataset snapshot path (default: download from Hub)")
    p.add_argument("--gigaspeech_subset", default="xl",
                   choices=["xs", "s", "m", "l", "xl"],
                   help="GigaSpeech subset size (default: xl)")
    p.add_argument("--spgispeech_subset", default="L",
                   choices=["L", "M", "S", "dev", "test"],
                   help="SPGISpeech subset size (default: L)")
    p.add_argument("--split", default="train",
                   help="Dataset split (default: train)")
    p.add_argument("--shard_size_gb", type=float, default=SHARD_SIZE_DEFAULT)
    p.add_argument("--max_duration", type=float, default=MAX_DURATION_DEFAULT)
    p.add_argument("--num_workers", type=int, default=NUM_WORKERS_DEFAULT)
    p.add_argument("--pool_offset", type=int, default=None,
                   help="pool_idx base offset for this dataset (optional)")
    p.add_argument("--core_json", default=None,
                   help="pool_indices_filter_remove_15pct_combined.json for core split")
    p.add_argument("--parquet_only", action="store_true",
                   help="Skip tar build; only (re)generate parquet files")
    return p.parse_args()


# ── Entry point ───────────────────────────────────────────────────────────────

def main():
    args = get_args()
    cfg = DATASET_CONFIGS[args.dataset]

    print(f"=== RAON-TTS-Pool: {cfg['description']} ===", flush=True)
    print(f"Output: {args.output_dir}", flush=True)

    if not args.parquet_only:
        if args.source_dir:
            print(f"Loading from local path: {args.source_dir}", flush=True)
            ds = load_from_disk(args.source_dir)
        elif cfg["hf_repo"]:
            print(f"Downloading from HuggingFace Hub: {cfg['hf_repo']}", flush=True)
            load_kwargs = {"split": args.split}
            if args.dataset == "gigaspeech":
                load_kwargs["name"] = args.gigaspeech_subset
            elif args.dataset == "spgispeech":
                load_kwargs["name"] = args.spgispeech_subset
            ds = load_dataset(cfg["hf_repo"], **load_kwargs)
        else:
            print(f"ERROR: {args.dataset} has no public HF Hub repo. "
                  f"Please provide --source_dir.", file=sys.stderr)
            sys.exit(1)

        build_tars(ds, cfg, args)

    build_parquets(args.output_dir, cfg["prefix"], args.core_json)

    print("\n=== Done ===", flush=True)
    print(f"Output directory: {args.output_dir}")


if __name__ == "__main__":
    main()