import os
import subprocess
from pathlib import Path
import matchering as mg
import sys

def merge_stems_ffmpeg(stems_folder, output_file, ffmpeg_path):
    print(f"\n[STAGE 6] Mixing Stems using FFmpeg...")
    stems = [os.path.join(stems_folder, f) for f in os.listdir(stems_folder) if f.startswith("transformed_")]
    if not stems:
        print("[ERROR] No transformed stems found!")
        return False

    cmd = [ffmpeg_path, "-y"]
    for s in stems:
        cmd.extend(["-i", s])
    
    cmd.extend([
        "-filter_complex", f"amix=inputs={len(stems)}:duration=longest",
        "-ac", "2",
        output_file
    ])
    subprocess.run(cmd, capture_output=True)
    return True

def apply_mastering(input_file, output_file):
    print(f"\n[STAGE 5] Applying AI Mastering (Matchering)...")
    try:
        # Correct Matchering v2 usage: result is the target path string
        mg.process(
            target=input_file,
            reference=input_file, 
            save_to=output_file
        )
        print(f"[SUCCESS] Mastered file saved: {output_file}")
        return True
    except Exception as e:
        print(f"[ERROR] Mastering failed: {e}")
        # If matchering fails, we still have the final mix
        return False

if __name__ == "__main__":
    FFMPEG_BIN = "D:/CODE/Apps/devtools/ffmpeg/bin/ffmpeg.exe"
    FX_DIR = os.path.join(os.getcwd(), "Outputs", "Transformed")
    MIXED_WAV = os.path.join(os.getcwd(), "Outputs", "Final_Mix.wav")
    MASTERED_WAV = os.path.join(os.getcwd(), "Outputs", "Titan_Master_Final.wav")

    if merge_stems_ffmpeg(FX_DIR, MIXED_WAV, FFMPEG_BIN):
        apply_mastering(MIXED_WAV, MASTERED_WAV)