# app/src/molecules/generated_variations.py

import sys
import subprocess
from pathlib import Path
import os

import pandas as pd
from rdkit import Chem
from rdkit.Chem import Draw


def _ensure_attachment_point(smiles: str) -> str:
    """
    Ensure the scaffold contains the required [*] wildcard.
    If missing, add [*] to the front.
    """
    smiles = (smiles or "").strip()
    if not smiles:
        return ""
    if "[*]" in smiles:
        return smiles
    return "[*]" + smiles


def generate_variations_from_partial_smiles(user_smiles: str, n_to_gen: int = 12):
    """
    Use Gen_PartialSMILES2.py to generate molecules from a scaffold SMILES,
    then turn them into RDKit images for the UI grid.

    Returns a list of dicts:
        [
          {"smiles": str, "image": PIL.Image, "style": "partial_smiles_gen"},
          ...
        ]
    """

    if not user_smiles or not user_smiles.strip():
        return []

    scaffold = _ensure_attachment_point(user_smiles)
    print(f"[generate_variations_from_partial_smiles] Using scaffold: {scaffold}")

    # Resolve /app as project root
    # This file is app/src/molecules/generated_variations.py
    # parents[0] = .../molecules, [1] = .../src, [2] = .../app
    project_root = Path(__file__).resolve().parents[2]
    script_path = project_root / "Gen_PartialSMILES2.py"
    csv_path = project_root / "generated_molecules.csv"
    icons_dir = project_root / "icons"

    # Clean up old CSV (optional)
    if csv_path.exists():
        try:
            csv_path.unlink()
        except Exception as e:
            print(f"Warning: could not delete old CSV: {e}")

    icons_dir.mkdir(exist_ok=True)

    # Build the command: python Gen_PartialSMILES2.py --scaffold ... --n_to_gen ...
    cmd = [
        sys.executable,
        str(script_path),
        "--scaffold", scaffold,
        "--n_to_gen", str(n_to_gen),
    ]

    print(f"[generate_variations_from_partial_smiles] Running command:")
    print(" ", " ".join(cmd))

    try:
        # Run from /app so relative paths in Gen_PartialSMILES2.py work
        subprocess.run(cmd, cwd=project_root, check=True)
    except subprocess.CalledProcessError as e:
        print(f"[generate_variations_from_partial_smiles] Error running generator: {e}")
        return []

    if not csv_path.exists():
        print("[generate_variations_from_partial_smiles] generated_molecules.csv not found.")
        return []

    # Load generated SMILES
    df = pd.read_csv(csv_path)
    smiles_list = df["smiles"].tolist()

    variations = []

    for idx, smi in enumerate(smiles_list[:n_to_gen]):
        mol = Chem.MolFromSmiles(smi)
        if mol is None:
            print(f"[generate_variations_from_partial_smiles] Skipping invalid SMILES: {smi}")
            continue

        # Make a 2D icon image for the grid
        img = Draw.MolToImage(mol, size=(200, 200), kekulize=True)

        # Optionally save icon to /app/icons/icon_N.png (nice for debugging)
        icon_path = icons_dir / f"icon_{idx+1}.png"
        try:
            img.save(icon_path)
        except Exception as e:
            print(f"[generate_variations_from_partial_smiles] Could not save icon {icon_path}: {e}")

        variations.append({
            "smiles": smi,
            "image": img,
            "style": "partial_smiles_gen",
        })

    print(f"[generate_variations_from_partial_smiles] Created {len(variations)} variations.")
    return variations