# utils.py - Utility Functions

import io
import re
import base64


def convert_to_mp3(audio_base64, source_format='wav'):
    """
    Convert audio from any format to MP3 base64.
    """
    try:
        from pydub import AudioSegment
        
        audio_bytes = base64.b64decode(audio_base64)
        audio_buffer = io.BytesIO(audio_bytes)
        audio = AudioSegment.from_file(audio_buffer, format=source_format)
        
        mp3_buffer = io.BytesIO()
        audio.export(mp3_buffer, format='mp3', bitrate='192k')
        mp3_buffer.seek(0)
        
        mp3_base64 = base64.b64encode(mp3_buffer.read()).decode('utf-8')
        return mp3_base64
    except ImportError:
        print("⚠️ pydub not installed, returning original format")
        return audio_base64
    except Exception as e:
        print(f"⚠️ MP3 conversion failed: {e}, returning original")
        return audio_base64


def sanitize_filename(name):
    """
    Sanitize a string for use as a filename.
    """
    if not name:
        return 'unnamed'
    return "".join(c for c in name if c.isalnum() or c in ('_', '-', ' '))


def strip_markdown(text):
    """
    Strip markdown formatting from text to get plain text for TTS.
    """
    if not text:
        return ""
    
    # Remove image references completely
    text = re.sub(r'!\[([^\]]*)\]\([^)]+\)', '', text)
    
    # Remove headings markers
    text = re.sub(r'^#{1,6}\s*', '', text, flags=re.MULTILINE)
    
    # Remove bold/italic
    text = re.sub(r'\*\*(.+?)\*\*', r'\1', text)
    text = re.sub(r'\*(.+?)\*', r'\1', text)
    text = re.sub(r'__(.+?)__', r'\1', text)
    text = re.sub(r'_(.+?)_', r'\1', text)
    
    # Remove strikethrough
    text = re.sub(r'~~(.+?)~~', r'\1', text)
    
    # Remove inline code
    text = re.sub(r'`([^`]+)`', r'\1', text)
    
    # Remove links but keep text
    text = re.sub(r'\[([^\]]+)\]\([^)]+\)', r'\1', text)
    
    # Remove blockquote markers
    text = re.sub(r'^>\s*', '', text, flags=re.MULTILINE)
    
    # Remove list markers
    text = re.sub(r'^\s*[-*+]\s+', '', text, flags=re.MULTILINE)
    text = re.sub(r'^\s*\d+\.\s+', '', text, flags=re.MULTILINE)
    
    # Remove horizontal rules
    text = re.sub(r'^(-{3,}|\*{3,}|_{3,})$', '', text, flags=re.MULTILINE)
    
    # Clean up whitespace
    text = re.sub(r'\n{3,}', '\n\n', text)
    
    return text.strip()