#!/usr/bin/env python
"""
Evaluate retrieval on MassSpecGym. Plan §5.
Metrics: Recall@1/10/50, optional Tanimoto@1. Unfiltered and formula-filtered.
"""
from __future__ import annotations

import argparse
import json
import sys
from functools import lru_cache
from pathlib import Path

ROOT = Path(__file__).resolve().parents[1]
if str(ROOT) not in sys.path:
    sys.path.insert(0, str(ROOT))


def parse_args():
    p = argparse.ArgumentParser(description="Evaluate retrieval JSONL (from retrieve_generate.py)")
    p.add_argument("--pred-jsonl", required=True, help="JSONL: each line has smiles_gt, candidates list")
    p.add_argument("--report", default=None, help="Write metrics JSON here")
    p.add_argument("--tanimoto", action="store_true", help="Compute Tanimoto@1 (requires RDKit)")
    return p.parse_args()


@lru_cache(maxsize=200000)
def canonicalize_smiles(smiles: str) -> str:
    text = str(smiles or "").strip()
    if not text:
        return ""
    try:
        from rdkit import Chem
    except ImportError:
        return text
    mol = Chem.MolFromSmiles(text)
    if mol is None:
        return text
    return Chem.MolToSmiles(mol, canonical=True)


def recall_at_k(candidates: list, gt_smiles: str, k: int) -> bool:
    """True if gt_smiles is in the first k candidates (by order)."""
    if not gt_smiles or not candidates:
        return False
    gt_canon = canonicalize_smiles(gt_smiles)
    smiles_list = [
        canonicalize_smiles(c.get("smiles", c) if isinstance(c, dict) else c)
        for c in candidates[:k]
    ]
    return gt_canon in smiles_list


def recall_at_k_rank(candidates: list, gt_smiles: str, k: int) -> int | None:
    """Rank (1-based) of gt_smiles in candidates, or None if not in top k."""
    if not gt_smiles or not candidates:
        return None
    gt_canon = canonicalize_smiles(gt_smiles)
    for i, c in enumerate(candidates[:k]):
        smi = canonicalize_smiles(c.get("smiles", c) if isinstance(c, dict) else c)
        if smi == gt_canon:
            return i + 1
    return None


def tanimoto_at_1(candidates: list, gt_smiles: str) -> float | None:
    """Tanimoto similarity of top-1 candidate to gt_smiles. None if no RDKit or no candidates."""
    try:
        from rdkit import Chem
        from rdkit.Chem import DataStructs
        from rdkit.Chem.AllChem import GetMorganFingerprintAsBitVect
    except ImportError:
        return None
    if not candidates or not gt_smiles:
        return None
    top = candidates[0]
    smi_pred = top.get("smiles", top) if isinstance(top, dict) else top
    mol_gt = Chem.MolFromSmiles(gt_smiles)
    mol_pred = Chem.MolFromSmiles(smi_pred)
    if mol_gt is None or mol_pred is None:
        return None
    fp_gt = GetMorganFingerprintAsBitVect(mol_gt, 2, nBits=2048)
    fp_pred = GetMorganFingerprintAsBitVect(mol_pred, 2, nBits=2048)
    return DataStructs.TanimotoSimilarity(fp_gt, fp_pred)


def compute_metrics(rows: list, include_tanimoto: bool = False) -> dict:
    n = len(rows)
    if n == 0:
        return {"n": 0, "Recall@1": 0.0, "Recall@10": 0.0, "Recall@50": 0.0}

    metrics = {
        "n": n,
        "Recall@1": sum(1 for r in rows if recall_at_k(r.get("candidates", []), r.get("smiles_gt", ""), 1)) / n,
        "Recall@10": sum(1 for r in rows if recall_at_k(r.get("candidates", []), r.get("smiles_gt", ""), 10)) / n,
        "Recall@50": sum(1 for r in rows if recall_at_k(r.get("candidates", []), r.get("smiles_gt", ""), 50)) / n,
    }

    if include_tanimoto:
        tan_list = []
        for r in rows:
            t = tanimoto_at_1(r.get("candidates", []), r.get("smiles_gt", ""))
            if t is not None:
                tan_list.append(t)
        if tan_list:
            metrics["Tanimoto@1_mean"] = sum(tan_list) / len(tan_list)
            metrics["Tanimoto@1_count"] = len(tan_list)

    return metrics


def main():
    args = parse_args()
    path = Path(args.pred_jsonl)
    if not path.exists():
        raise SystemExit(f"Not found: {path}")

    rows = []
    with open(path) as f:
        for line in f:
            line = line.strip()
            if not line:
                continue
            rows.append(json.loads(line))

    if not rows:
        raise SystemExit("Empty JSONL")
    metrics = compute_metrics(rows, include_tanimoto=args.tanimoto)

    mode_groups = {}
    for row in rows:
        mode = row.get("retrieval_mode")
        if not mode:
            continue
        mode_groups.setdefault(str(mode), []).append(row)
    if mode_groups:
        metrics["by_retrieval_mode"] = {
            mode: compute_metrics(group_rows, include_tanimoto=args.tanimoto)
            for mode, group_rows in sorted(mode_groups.items())
        }

    print("Metrics:", json.dumps(metrics, indent=2))
    if args.report:
        with open(args.report, "w") as f:
            json.dump(metrics, f, indent=2)
        print(f"Wrote {args.report}")


if __name__ == "__main__":
    main()