import gradio as gr
from pydub import AudioSegment
import uuid
import os

UPLOAD_DIR = "uploads"
OUTPUT_DIR = "outputs"
CROSSFADE_MS = 20_000  # 20 segundos reales

os.makedirs(UPLOAD_DIR, exist_ok=True)
os.makedirs(OUTPUT_DIR, exist_ok=True)

# -------------------------
# MOTOR DE MEZCLA REAL
# -------------------------

def create_mix(files, progress=gr.Progress()):
    if not files or len(files) < 2 or len(files) > 4:
        raise gr.Error("Sube entre 2 y 4 canciones")

    progress(0, desc="Validando archivos…")

    paths = []
    for f in files:
        ext = f.name.split(".")[-1].lower()
        if ext not in ["mp3", "wav", "flac", "m4a"]:
            raise gr.Error("Formato no soportado")

        name = f"{uuid.uuid4().hex}.{ext}"
        path = os.path.join(UPLOAD_DIR, name)

        # Copia segura (NO rename, esto arregla bugs en HF)
        with open(f.name, "rb") as src, open(path, "wb") as dst:
            dst.write(src.read())

        paths.append(path)

    progress(10, desc="Cargando primera canción…")

    current = AudioSegment.from_file(paths[0])
    step = 80 // (len(paths) - 1)

    for i, p in enumerate(paths[1:], start=1):
        progress(10 + step * (i - 1), desc=f"Mezclando canción {i + 1}")
        next_track = AudioSegment.from_file(p)
        current = current.append(next_track, crossfade=CROSSFADE_MS)

    progress(95, desc="Exportando mix…")

    out_name = f"monx_ai_mix_{uuid.uuid4().hex}.wav"
    out_path = os.path.join(OUTPUT_DIR, out_name)
    current.export(out_path, format="wav")

    progress(100, desc="Mix listo 🎶")

    return out_path

# -------------------------
# INTERFAZ GRADIO
# -------------------------

with gr.Blocks(title="MONX AI") as demo:
    gr.Markdown(
        """
        <div style="text-align:center">
          <h1>🎵 MONX AI</h1>
          <p>Fusión de audio inteligente con crossfade</p>
        </div>
        """
    )

    with gr.Column():
        files = gr.File(
            label="Sube de 2 a 4 canciones",
            file_count="multiple",
            file_types=[".mp3", ".wav", ".flac", ".m4a"]
        )

        btn = gr.Button("✨ Crear Mix", variant="primary")

        output = gr.Audio(
            label="Resultado",
            type="filepath"
        )

    btn.click(
        fn=create_mix,
        inputs=files,
        outputs=output
    )

# -------------------------
# HF ENTRYPOINT
# -------------------------

if __name__ == "__main__":
    demo.launch()