import librosa

# Monkeypatch for pyloudnorm which uses the deprecated scipy.signal.hann
import scipy.signal
import scipy.signal.windows
if not hasattr(scipy.signal, 'hann'):
    scipy.signal.hann = scipy.signal.windows.hann

import pyloudnorm as pyln
import numpy as np

def analyze_audio(file_path: str) -> dict:
    """Analyzes an audio file and returns metadata."""
    try:
        # Load audio (mono, original sample rate to preserve frequency content)
        y, sr = librosa.load(file_path, sr=None, mono=True)
        
        # BPM
        tempo, _ = librosa.beat.beat_track(y=y, sr=sr)
        if isinstance(tempo, np.ndarray):
            bpm = float(tempo[0])
        else:
            bpm = float(tempo)
            
        # Key extraction using chroma (simplified root note extraction)
        chroma = librosa.feature.chroma_cqt(y=y, sr=sr)
        key_idx = np.argmax(np.sum(chroma, axis=1))
        keys = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#', 'A', 'A#', 'B']
        key = keys[key_idx]
        
        # Energy (RMS)
        rms = librosa.feature.rms(y=y)
        energy = float(np.mean(rms))
        
        # Spectral Centroid (Brightness)
        cent = librosa.feature.spectral_centroid(y=y, sr=sr)
        spectral_centroid = float(np.mean(cent))
        
        # Onset Density (Danceability/Rhythm)
        onset_env = librosa.onset.onset_strength(y=y, sr=sr)
        onsets = librosa.onset.onset_detect(onset_envelope=onset_env, sr=sr)
        duration_sec = len(y) / sr
        onset_density = len(onsets) / duration_sec if duration_sec > 0 else 0
        
        # LUFS
        meter = pyln.Meter(sr) # create BS.1770 meter
        lufs = meter.integrated_loudness(y)
        
        return {
            "bpm": bpm,
            "key": key,
            "energy": energy,
            "spectral_centroid": spectral_centroid,
            "onset_density": float(onset_density),
            "lufs": float(lufs)
        }
    except Exception as e:
        print(f"Error analyzing {file_path}: {e}")
        return None