#!/usr/bin/env python3
"""
Lädt das Qwen2.5-0.5B-Instruct Modell (GGUF) herunter.
Klein, schnell, gut für Deutsch geeignet.

Aufruf:
    python download_model.py
"""

import urllib.request
import sys
from pathlib import Path

SCRIPT_DIR = Path(__file__).parent
MODELS_DIR = SCRIPT_DIR / "models"

MODEL_URL  = "https://huggingface.co/Qwen/Qwen2.5-0.5B-Instruct-GGUF/resolve/main/qwen2.5-0.5b-instruct-q4_k_m.gguf"
MODEL_FILE = MODELS_DIR / "qwen2.5-0.5b-instruct-q4_k_m.gguf"
MODEL_SIZE = "~400 MB"

def download_with_progress(url: str, dest: Path):
    """Lädt eine Datei herunter mit Fortschrittsanzeige."""
    dest.parent.mkdir(parents=True, exist_ok=True)

    def progress(block_num, block_size, total_size):
        downloaded = block_num * block_size
        if total_size > 0:
            pct = min(downloaded / total_size * 100, 100)
            mb_done  = downloaded / 1024 / 1024
            mb_total = total_size / 1024 / 1024
            bar = "█" * int(pct // 2) + "░" * (50 - int(pct // 2))
            print(f"\r  [{bar}] {pct:5.1f}%  {mb_done:.1f}/{mb_total:.1f} MB", end="", flush=True)

    print(f"Lade herunter: {url}")
    print(f"Ziel: {dest}")
    print(f"Größe: ca. {MODEL_SIZE}\n")

    urllib.request.urlretrieve(url, dest, reporthook=progress)
    print(f"\n\n✅ Modell erfolgreich gespeichert: {dest}")

def main():
    if MODEL_FILE.exists():
        size_mb = MODEL_FILE.stat().st_size / 1024 / 1024
        print(f"✅ Modell bereits vorhanden: {MODEL_FILE} ({size_mb:.1f} MB)")
        return

    print("=" * 60)
    print("  Qwen2.5-0.5B-Instruct Download")
    print("=" * 60)
    print(f"  Modell: Qwen2.5-0.5B-Instruct Q4_K_M (quantisiert)")
    print(f"  Größe:  {MODEL_SIZE}")
    print(f"  Quelle: Hugging Face")
    print("=" * 60)

    try:
        download_with_progress(MODEL_URL, MODEL_FILE)
    except KeyboardInterrupt:
        print("\n\n[Abgebrochen] Download unterbrochen.")
        if MODEL_FILE.exists():
            MODEL_FILE.unlink()  # Unvollständige Datei löschen
        sys.exit(1)
    except Exception as e:
        print(f"\n\n❌ Fehler beim Download: {e}", file=sys.stderr)
        sys.exit(1)

if __name__ == "__main__":
    main()