"""
NovaAi – TTS-Engine-Hub
utils/audio.py
Version: v0.0.1

Description:
  Audio processing utilities: concat, merging chunks, etc.

Author: Abby (ChatGPT)
Date: 2025-07-23
Canvas: utils/audio.py
"""

import tempfile
import os
import ffmpeg
import shutil

def check_ffmpeg():
    """Check if ffmpeg is installed and available in the system's PATH."""
    return shutil.which("ffmpeg") is not None

def concat_audio(files, fmt):
    """
    Concatenate a list of audio files into a single file of the given format.
    Supports: wav, ogg, mp3
    """
    if len(files) == 1:
        # If there's only one file, just return it, no cleanup needed here.
        return files[0]

    # Securely create a temporary file for the output
    with tempfile.NamedTemporaryFile(suffix=f'.{fmt}', prefix="chunked_", delete=False) as temp_output_file:
        output_file_path = temp_output_file.name

    try:
        if fmt == "wav":
            import wave
            data = []
            params = None
            for f in files:
                with wave.open(f, 'rb') as wf:
                    if params is None:
                        params = wf.getparams()
                    data.append(wf.readframes(wf.getnframes()))
            with wave.open(output_file_path, 'wb') as wf:
                wf.setparams(params)
                for d in data:
                    wf.writeframes(d)
        else:
            if not check_ffmpeg():
                raise RuntimeError("ffmpeg not found. Please install ffmpeg and ensure it is in your PATH.")

            with tempfile.NamedTemporaryFile("w", delete=False) as tf:
                list_file_path = tf.name
                for f in files:
                    tf.write(f"file '{os.path.abspath(f)}'\\n")
                tf.flush()
            
            try:
                (
                    ffmpeg
                    .input(list_file_path, format='concat', safe=0)
                    .output(output_file_path, acodec='copy')
                    .run(overwrite_output=True, quiet=True)
                )
            finally:
                os.unlink(list_file_path)

    finally:
        # Clean up the input chunk files
        for f in files:
            if os.path.exists(f):
                os.remove(f)

    return output_file_path