#!/usr/bin/env python3
"""AcuBench evaluation harness (self-contained).

Ports the metric definitions from the research repo's `acubench/src/metrics.py`
with NO external import beyond numpy/scikit-learn. Scores a predictions file
against a gold file over the fixed 361-point WHO label space.

METRIC SUITE
------------
  * jaccard_mean          -- mean per-sample Jaccard(pred_set, gold_set)
  * f1_macro              -- mean per-sample (example-based) F1
  * f1_micro              -- pooled TP/FP/FN across all samples, one global F1
  * precision_at_k / recall_at_k / ndcg_at_k  for k in --ks (default 5,10,20)
  * prauc_mean            -- mean per-sample average precision (needs scores)
  * invalid_combination_rate  -- structural meridian-scatter PROXY (needs --who)

INPUT FORMATS
-------------
predictions file (JSONL, one object per line). Each object needs an "id" and
at least one of:
    {"id": 12, "acupoints": ["LU1","LU7"]}                 # a predicted set
    {"id": 12, "scores": {"LU1": 0.9, "LU7": 0.8, ...}}    # per-point scores
    {"id": 12, "acupoints": [...], "scores": {...}}        # both (recommended)

  - "acupoints" drives the SET metrics (Jaccard / F1-micro / F1-macro) and the
    meridian-validity proxy.
  - "scores" drives the RANKING metrics (P@k / R@k / NDCG@k / PRAUC). If a
    row has no "scores", ranking falls back to its "acupoints" ranked
    alphabetically (a weak but deterministic proxy -- provide real scores for
    meaningful ranking metrics). PRAUC is only reported when at least one row
    supplies "scores".
  - If a row has "scores" but no "acupoints", the predicted set is taken as
    every point with score > --score-threshold (default 0.5).

gold file (JSONL). Each object needs "id" and "acupoints". The AcuBench
`acubench.jsonl` produced by build_acubench.py works directly as the gold
file (it also carries "split", so pass --split test to score only the test
rows). The shipped sample_labels.jsonl uses "symptoms" instead of an "id";
pass --gold-key symptoms to key rows by their symptom string, and key your
predictions the same way (use the symptom string as "id").

USAGE
-----
    python3 eval.py --pred preds.jsonl --gold acubench.jsonl --who who_acupoints.csv
    python3 eval.py --pred preds.jsonl --gold acubench.jsonl --split test --who who_acupoints.csv
    python3 eval.py --pred preds.jsonl --gold sample_labels.jsonl --gold-key symptoms

Prints a JSON metric dict to stdout (use --out to also write it to a file).

TINY EXAMPLE (predictions JSONL)
    {"id": 0, "acupoints": ["CV15"], "scores": {"CV15": 0.9, "LU1": 0.1}}
    {"id": 1, "acupoints": ["LU1", "LU2"], "scores": {"LU1": 0.8, "LU2": 0.7}}
"""
import argparse
import csv
import json
import math
from collections import defaultdict
from typing import Dict, Iterable, List, Optional, Sequence, Tuple

import numpy as np
from sklearn.metrics import average_precision_score


# --------------------------------------------------------------------------
# Set metrics (ported verbatim from src/metrics.py).
# --------------------------------------------------------------------------
def jaccard(pred: Iterable[str], gold: Iterable[str]) -> float:
    pred, gold = set(pred), set(gold)
    if not pred and not gold:
        return 1.0
    union = pred | gold
    if not union:
        return 1.0
    return len(pred & gold) / len(union)


def precision_recall_f1(pred: Iterable[str], gold: Iterable[str]) -> Tuple[float, float, float]:
    pred, gold = set(pred), set(gold)
    tp = len(pred & gold)
    precision = tp / len(pred) if pred else (1.0 if not gold else 0.0)
    recall = tp / len(gold) if gold else (1.0 if not pred else 0.0)
    f1 = 2 * precision * recall / (precision + recall) if (precision + recall) > 0 else 0.0
    return precision, recall, f1


def f1_macro(pred_sets: Sequence[Iterable[str]], gold_sets: Sequence[Iterable[str]]) -> float:
    if not pred_sets:
        return 0.0
    scores = [precision_recall_f1(p, g)[2] for p, g in zip(pred_sets, gold_sets)]
    return sum(scores) / len(scores)


def f1_micro(pred_sets: Sequence[Iterable[str]], gold_sets: Sequence[Iterable[str]]) -> float:
    tp = fp = fn = 0
    for pred, gold in zip(pred_sets, gold_sets):
        pred, gold = set(pred), set(gold)
        tp += len(pred & gold)
        fp += len(pred - gold)
        fn += len(gold - pred)
    precision = tp / (tp + fp) if (tp + fp) > 0 else 0.0
    recall = tp / (tp + fn) if (tp + fn) > 0 else 0.0
    return 2 * precision * recall / (precision + recall) if (precision + recall) > 0 else 0.0


# --------------------------------------------------------------------------
# Ranking metrics.
# --------------------------------------------------------------------------
def precision_at_k(ranked_points: Sequence[str], gold: Iterable[str], k: int) -> float:
    gold = set(gold)
    top_k = ranked_points[:k]
    if not top_k:
        return 0.0
    hits = sum(1 for p in top_k if p in gold)
    return hits / len(top_k)


def recall_at_k(ranked_points: Sequence[str], gold: Iterable[str], k: int) -> float:
    gold = set(gold)
    if not gold:
        return 1.0
    top_k = ranked_points[:k]
    hits = sum(1 for p in top_k if p in gold)
    return hits / len(gold)


def ndcg_at_k(ranked_points: Sequence[str], gold: Iterable[str], k: int) -> float:
    gold = set(gold)
    top_k = ranked_points[:k]
    dcg = sum((1.0 if p in gold else 0.0) / math.log2(i + 2) for i, p in enumerate(top_k))
    ideal_hits = min(len(gold), k)
    idcg = sum(1.0 / math.log2(i + 2) for i in range(ideal_hits))
    return dcg / idcg if idcg > 0 else 0.0


def average_precision(scores: Dict[str, float], gold: Iterable[str]) -> float:
    gold = set(gold)
    if not scores:
        return 0.0
    points = list(scores.keys())
    y_true = [1 if p in gold else 0 for p in points]
    if sum(y_true) == 0:
        return 0.0
    y_score = [scores[p] for p in points]
    return float(average_precision_score(y_true, y_score))


def _ranked_from_scores(scores: Dict[str, float]) -> List[str]:
    """Rank points by score descending; deterministic alphabetical tie-break."""
    return [p for p, _ in sorted(scores.items(), key=lambda kv: (-kv[1], kv[0]))]


# --------------------------------------------------------------------------
# Meridian-validity heuristic (structural PROXY, NOT a clinical judgment).
# --------------------------------------------------------------------------
def is_valid_combination(
    pred: Iterable[str],
    point_meridian_map: Dict[str, str],
    max_distinct_meridian_ratio: float = 0.8,
    min_size_for_check: int = 3,
) -> bool:
    """Documented, rule-based PROXY for prescription plausibility -- NOT a
    clinical validity check. Flags a set of size >= min_size_for_check as
    'implausible' (structurally scattered) when distinct_meridians / n_points
    exceeds max_distinct_meridian_ratio. See src/metrics.py for full rationale.
    """
    pred = list(pred)
    n = len(pred)
    if n < min_size_for_check:
        return True
    meridians = [point_meridian_map[p] for p in pred if p in point_meridian_map]
    if not meridians:
        return True
    distinct = len(set(meridians))
    ratio = distinct / n
    return ratio <= max_distinct_meridian_ratio


def invalid_combination_rate(
    pred_sets: Sequence[Iterable[str]],
    point_meridian_map: Dict[str, str],
    max_distinct_meridian_ratio: float = 0.8,
    min_size_for_check: int = 3,
) -> float:
    if not pred_sets:
        return 0.0
    flags = [
        not is_valid_combination(p, point_meridian_map, max_distinct_meridian_ratio, min_size_for_check)
        for p in pred_sets
    ]
    return sum(flags) / len(flags)


# --------------------------------------------------------------------------
# Batch summary.
# --------------------------------------------------------------------------
def summarize(
    pred_sets: Sequence[Iterable[str]],
    gold_sets: Sequence[Iterable[str]],
    scores: Optional[Sequence[Optional[Dict[str, float]]]] = None,
    point_meridian_map: Optional[Dict[str, str]] = None,
    ks: Sequence[int] = (5, 10, 20),
) -> Dict[str, float]:
    pred_sets = [set(p) for p in pred_sets]
    gold_sets = [set(g) for g in gold_sets]
    n = len(pred_sets)

    result: Dict[str, float] = {"n_samples": n}
    if n == 0:
        return result

    result["jaccard_mean"] = sum(jaccard(p, g) for p, g in zip(pred_sets, gold_sets)) / n
    result["f1_macro"] = f1_macro(pred_sets, gold_sets)
    result["f1_micro"] = f1_micro(pred_sets, gold_sets)

    # Ranked list per sample: real scores where given, else alphabetical
    # fallback over the predicted set (documented weak proxy).
    any_scores = scores is not None and any(s for s in scores)
    if scores is not None:
        ranked_lists = [
            _ranked_from_scores(s) if s else sorted(pred_sets[i])
            for i, s in enumerate(scores)
        ]
    else:
        ranked_lists = [sorted(p) for p in pred_sets]

    for k in ks:
        result[f"precision_at_{k}"] = sum(
            precision_at_k(r, g, k) for r, g in zip(ranked_lists, gold_sets)
        ) / n
        result[f"recall_at_{k}"] = sum(
            recall_at_k(r, g, k) for r, g in zip(ranked_lists, gold_sets)
        ) / n
        result[f"ndcg_at_{k}"] = sum(
            ndcg_at_k(r, g, k) for r, g in zip(ranked_lists, gold_sets)
        ) / n

    if any_scores:
        result["prauc_mean"] = sum(
            average_precision(s, g) for s, g in zip(scores, gold_sets) if s
        ) / sum(1 for s in scores if s)

    if point_meridian_map is not None:
        result["invalid_combination_rate"] = invalid_combination_rate(pred_sets, point_meridian_map)

    return result


# --------------------------------------------------------------------------
# I/O helpers.
# --------------------------------------------------------------------------
def load_jsonl(path: str) -> List[dict]:
    rows = []
    with open(path, encoding="utf-8") as f:
        for line in f:
            line = line.strip()
            if line:
                rows.append(json.loads(line))
    return rows


def load_point_meridian_map(who_csv: str) -> Dict[str, str]:
    mapping = {}
    with open(who_csv, newline="") as f:
        for row in csv.DictReader(f):
            mapping[row["point_code"]] = row["meridian"]
    return mapping


def _row_key(row: dict, key: str):
    """Key a row: by 'id' (default), or by the join column (e.g. 'symptoms').
    'symptoms' may be a list -> use its single element / joined string."""
    if key == "id":
        return row["id"]
    val = row.get(key)
    if isinstance(val, list):
        return val[0] if len(val) == 1 else "|".join(map(str, val))
    return val


def align(
    preds: List[dict],
    golds: List[dict],
    gold_key: str,
    score_threshold: float,
) -> Tuple[List[List[str]], List[List[str]], List[Optional[Dict[str, float]]]]:
    """Join predictions to gold rows on the key column. Returns aligned
    (pred_sets, gold_sets, scores_per_row) over the intersection of keys."""
    pred_by_key = {}
    for r in preds:
        # Predictions key on "id" by default; when gold is keyed by another
        # column, predictions should carry that value in "id".
        k = r.get("id")
        if k is None and gold_key != "id":
            k = _row_key(r, gold_key)
        pred_by_key[k] = r

    pred_sets: List[List[str]] = []
    gold_sets: List[List[str]] = []
    scores: List[Optional[Dict[str, float]]] = []

    matched = 0
    for g in golds:
        gk = _row_key(g, gold_key)
        if gk not in pred_by_key:
            # Missing prediction = empty predicted set (penalized, not skipped).
            pred_sets.append([])
            gold_sets.append(list(g["acupoints"]))
            scores.append(None)
            continue
        matched += 1
        pr = pred_by_key[gk]
        sc = pr.get("scores")
        if pr.get("acupoints") is not None:
            pset = list(pr["acupoints"])
        elif sc:
            pset = [p for p, v in sc.items() if v > score_threshold]
        else:
            pset = []
        pred_sets.append(pset)
        gold_sets.append(list(g["acupoints"]))
        scores.append(sc if sc else None)

    print(f"Matched {matched}/{len(golds)} gold rows to predictions "
          f"({len(golds) - matched} gold rows had no prediction -> scored as empty set).")
    return pred_sets, gold_sets, scores


def main() -> None:
    ap = argparse.ArgumentParser(description="Evaluate AcuBench predictions against gold labels.")
    ap.add_argument("--pred", required=True, help="Predictions JSONL file.")
    ap.add_argument("--gold", required=True, help="Gold JSONL file (e.g. acubench.jsonl).")
    ap.add_argument("--who", default=None, help="who_acupoints.csv (enables invalid_combination_rate).")
    ap.add_argument("--split", default=None, help="Only score gold rows whose 'split' == this value.")
    ap.add_argument("--gold-key", default="id", help="Join column (default 'id'; use 'symptoms' for sample_labels.jsonl).")
    ap.add_argument("--score-threshold", type=float, default=0.5, help="Threshold to derive a set from scores when 'acupoints' absent.")
    ap.add_argument("--ks", default="5,10,20", help="Comma-separated k values for @k metrics.")
    ap.add_argument("--out", default=None, help="Optional path to also write the metric dict as JSON.")
    args = ap.parse_args()

    preds = load_jsonl(args.pred)
    golds = load_jsonl(args.gold)
    if args.split is not None:
        golds = [g for g in golds if g.get("split") == args.split]
        print(f"Filtered gold to split={args.split!r}: {len(golds)} rows.")

    ks = tuple(int(x) for x in args.ks.split(",") if x.strip())
    pmm = load_point_meridian_map(args.who) if args.who else None

    pred_sets, gold_sets, scores = align(preds, golds, args.gold_key, args.score_threshold)
    result = summarize(pred_sets, gold_sets, scores=scores, point_meridian_map=pmm, ks=ks)

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


if __name__ == "__main__":
    main()