"""
Bundled VOX engine for ttstoy.
Based on VOXGen by wphillips (https://github.com/wphillips/VOXGen)
Black Mesa / Half-Life VOX announcer text-to-speech via word-level WAV concatenation.
"""
import os
import wave
import struct
from pathlib import Path
from typing import List, Optional

_BASE_DIR = Path(__file__).resolve().parent

VOX_PACKS = {
    "vox": _BASE_DIR / "vox_words",
    "vox2": _BASE_DIR / "vox2_words",
}


def get_available_packs() -> List[str]:
    """Return list of installed VOX packs."""
    return [name for name, p in VOX_PACKS.items() if p.exists()]


def get_available_words(pack: str = "vox") -> List[str]:
    """Return sorted list of available words for a VOX pack."""
    pack_dir = VOX_PACKS.get(pack)
    if not pack_dir or not pack_dir.exists():
        return []
    return sorted(
        p.stem for p in pack_dir.glob("*.wav")
        if not p.stem.startswith("00_") and not p.stem.startswith("_")
    )


def generate_vox(text: str, output_path: str, pack: str = "vox") -> List[str]:
    """
    Generate VOX audio from text by concatenating word WAV files.

    Args:
        text: Input sentence (words separated by spaces).
        output_path: Path to write the output WAV/MP3 file.
        pack: Which VOX pack to use ("vox" or "vox2").

    Returns:
        List of words that were actually found and used.

    Raises:
        RuntimeError: If no words matched or pack not found.
    """
    pack_dir = VOX_PACKS.get(pack)
    if not pack_dir or not pack_dir.exists():
        raise RuntimeError(f"VOX pack '{pack}' not found at {pack_dir}")

    words = text.lower().split()
    accepted = []
    splice = bytes()

    sample_rate = 11025
    sample_width = 1
    channels = 1

    for word in words:
        wav_path = pack_dir / f"{word}.wav"
        if not wav_path.exists():
            continue

        with wave.open(str(wav_path), 'rb') as snd:
            sample_rate = snd.getframerate()
            sample_width = snd.getsampwidth()
            channels = snd.getnchannels()
            splice += snd.readframes(snd.getnframes())
            accepted.append(word)

    if not accepted:
        raise RuntimeError(
            f"No matching VOX words found. Available words include: "
            f"{', '.join(get_available_words(pack)[:20])}..."
        )

    # Write intermediate WAV
    wav_out = output_path.rsplit('.', 1)[0] + '_tmp.wav'
    with wave.open(wav_out, 'wb') as out:
        out.setnchannels(channels)
        out.setsampwidth(sample_width)
        out.setframerate(sample_rate)
        out.writeframes(splice)

    # Convert to MP3 using ffmpeg for consistency with the rest of ttstoy
    import subprocess
    cmd = [
        "ffmpeg", "-y", "-i", wav_out,
        "-ac", "1", "-ar", "32000", "-b:a", "128k",
        output_path,
    ]
    subprocess.run(cmd, check=True, capture_output=True, text=True)

    # Clean up temp WAV
    try:
        os.remove(wav_out)
    except OSError:
        pass

    return accepted