import os
import re
import shutil
import subprocess


audio_extensions = ['wav', 'mp3']
video_extensions = ['webm', 'mp4', 'mkv']

def increment_filename_no_overwrite(proposed_path):
    output_dir, filename_ext = os.path.split(proposed_path)
    filename, file_format = os.splitext(filename_ext)
    files = os.listdir(output_dir)
    files = filter(lambda f: os.path.isfile(os.path.join(output_dir, f)), files)
    files = filter(lambda f: f.startswith(filename), files)
    files = filter(lambda f: f.endswith('.' + file_format), files)
    file_numbers = [re.search(r'_(\d+)\.', f) for f in files]
    file_numbers = [int(f.group(1)) for f in file_numbers if f]
    this_file_number = max(file_numbers) + 1 if file_numbers else 1
    output_path = os.path.join(output_dir, filename + f'_{this_file_number}.' + file_format)
    return output_path


def get_ffmpeg_path():
    system_ffmpeg = shutil.which("ffmpeg")
    if system_ffmpeg is not None:
        return system_ffmpeg
    raise FileNotFoundError("No valid ffmpeg found.")

def get_wav_bytes_from_file(filepath, start_time=0, duration=0):
    # ffmpeg -v error -i audio.(mp3|wav) -f wav -
    ffmpeg_path = get_ffmpeg_path()
    args = [ffmpeg_path, "-v", "error", "-i", filepath]
    if start_time > 0:
        args += ["-ss", str(start_time)]
    if duration > 0:
        args += ["-t", str(duration)]
    try:
        res = subprocess.run(
            args + ["-f", "wav", "-"],
            stdout=subprocess.PIPE,
            check=True
        ).stdout
    except subprocess.CalledProcessError as e:
        raise Exception(f"Failed to extract audio from: {filepath}")
    return res