import os
import base64
import hashlib
from typing import List
from ..schema.blueprint import HelixBlueprint, Anchor, Metadata, Mesh

class AudioAnchorExtractor:
    """
    Extracts Spectral Anchors from Audio files.
    
    Logic:
    1. Identifies "Foreground Identity" (Voices, Key Sounds) -> High Bitrate Anchors
    2. Identifies "Background Aura" (Ambience, Noise) -> Low Bitrate Background Anchor
    3. Structural Reference -> Timestamps
    """
    
    def extract(self, audio_path: str) -> HelixBlueprint:
        if not os.path.exists(audio_path):
            raise FileNotFoundError(f"Audio file not found: {audio_path}")
            
        # simulating extraction without heavy dependencies (librosa/torch audio) for MVP.
        # In a real impl, we would use VAD (Voice Activity Detection).
        
        with open(audio_path, 'rb') as f:
            audio_data = f.read()
            
        total_size = len(audio_data)
        duration_approx = total_size / 32000  # distinct approximation
        
        # 1. Background Anchor (The whole track, but conceptually we'd downsample it)
        # For MVP, we effectively store the file as the background anchor.
        bg_b64 = base64.b64encode(audio_data).decode('utf-8')
        bg_hash = hashlib.sha256(bg_b64.encode()).hexdigest()
        
        bg_anchor = Anchor(
            id="background_audio",
            type="background_spectral",
            bbox=None,
            timestamp_start=0.0,
            timestamp_end=duration_approx,
            data=bg_b64,
            content_hash=bg_hash,
            semantic_label="background_ambience",
            confidence=1.0,
            resolution_hint="low"
        )
        
        # 2. Metadata
        meta = Metadata(
            modality="audio",
            asset_type="wav/mp3",
            original_dims=(0, 0), # Not applicable
            checksum=bg_hash,
            aura="Recorded Audio",
            scene_description="Audio recording"
        )
        
        return HelixBlueprint(
            metadata=meta,
            anchors=[bg_anchor],
            mesh=Mesh() # No spatial mesh for audio
        )
