"""Compare Goldenset gold labels against inference output.

Reads each country's goldenset_<cc>.jsonl (the human-labelled truth, produced
by ``convert_goldenset_to_jsonl.py``) and the matching ``inference_<system>.csv``
file from one of the evaluated systems (``harvey``, ``gemini``, ``gpt``), then
reports per-field agreement.
"""

import argparse
import csv
import json
import logging
import re
import sys
from datetime import date, datetime
from pathlib import Path
from typing import get_args

from legex.config import settings
from legex.models.classification import Classification
from legex.utils import (
    EXCLUDED_FOR_EVAL,
    countries_with_goldenset_jsonl,
    evaluable_countries,
    goldenset_jsonl_path,
    inference_csv_path,
)

# Systems whose inference outputs are evaluated.
SYSTEMS: tuple[str, ...] = ("harvey", "gemini", "gpt")

log = logging.getLogger(__name__)

# Columns that don't carry a label to evaluate against (matched case-insensitively).
_NON_LABEL_COLUMNS = {"case_id", "link", "full_text"}

# Goldenset / inference sentinels for “no value” (non_empty as empty).
_EMPTY_LITERALS = frozenset({"", "none", "null", "nan"})

# CSV columns whose Classification field is numeric (int / float). Loose
# parsing (apostrophe thousand separators, leading number + trailing prose)
# applies only to these.
_NUMERIC_COLUMNS = frozenset(
    (info.alias or name)
    for name, info in Classification.model_fields.items()
    if any(a is int or a is float for a in (get_args(info.annotation) or (info.annotation,)))
)

_NUM_TOKEN_RE = re.compile(r"-?\d[\d',. ]*")

# CSV columns whose Classification field is a date. Separator normalisation
# (treat `_`, `/`, `.` as `-`) plus a small format fallback applies only here.
_DATE_COLUMNS = frozenset(
    (info.alias or name)
    for name, info in Classification.model_fields.items()
    if any(a is date for a in (get_args(info.annotation) or (info.annotation,)))
)

_DATE_SEP_RE = re.compile(r"[_/.\s]+")
_DATE_FALLBACK_FORMATS = ("%d-%m-%Y", "%m-%d-%Y", "%Y%m%d")


def _is_label_column(name: str) -> bool:
    if not name or name.lower() in _NON_LABEL_COLUMNS:
        return False
    if name.startswith("Currency_"):
        return False
    return True

def _normalise(value: object) -> str:
    """Make gold and prediction cells comparable as strings."""
    if value is None:
        return ""
    if isinstance(value, float):
        if value != value:  # NaN
            return ""
        if value.is_integer():
            return str(int(value))
    s = str(value).strip()
    if s.lower() in _EMPTY_LITERALS:
        return ""
    return s


def _try_float(s: str) -> float | None:
    if not s:
        return None
    try:
        return float(s)
    except ValueError:
        return None


def _parse_loose_number(s: str) -> float | None:
    """Extract the first numeric token from `s`, tolerating apostrophe/space
    thousand separators (`20'000`, `20 000`), EU decimal commas (`1.000,50`),
    and trailing prose (`150 GEL state fee awarded …`, `0%, motion satisfied`).
    Returns None when no digit appears.
    """
    if not s:
        return None
    m = _NUM_TOKEN_RE.search(s)
    if not m:
        return None
    tok = m.group(0).strip().rstrip(",.' ")
    if not tok:
        return None
    cleaned = tok.replace("'", "").replace(" ", "")
    if "," in cleaned and "." in cleaned:
        # Whichever appears last is the decimal mark.
        if cleaned.rfind(",") > cleaned.rfind("."):
            cleaned = cleaned.replace(".", "").replace(",", ".")
        else:
            cleaned = cleaned.replace(",", "")
    elif "," in cleaned:
        parts = cleaned.split(",")
        # Single trailing group of 1-2 digits → decimal comma; else thousands.
        if len(parts) == 2 and 1 <= len(parts[1]) <= 2:
            cleaned = parts[0] + "." + parts[1]
        else:
            cleaned = cleaned.replace(",", "")
    try:
        return float(cleaned)
    except ValueError:
        return None


def _numeric_value(s: str, column: str | None) -> float | None:
    """Strict float for any column, plus loose parse for numeric columns."""
    n = _try_float(s)
    if n is not None:
        return n
    if column in _NUMERIC_COLUMNS:
        return _parse_loose_number(s)
    return None


def _parse_loose_date(s: str) -> date | None:
    """Parse a date string, treating `_`, `/`, `.`, whitespace as `-`.

    Accepts ISO `YYYY-MM-DD` (after separator collapse), and as a fallback
    `DD-MM-YYYY`, `MM-DD-YYYY`, `YYYYMMDD`.
    """
    if not s:
        return None
    t = _DATE_SEP_RE.sub("-", s.strip()).strip("-")
    if not t:
        return None
    try:
        return date.fromisoformat(t)
    except ValueError:
        pass
    for fmt in _DATE_FALLBACK_FORMATS:
        try:
            return datetime.strptime(t, fmt).date()
        except ValueError:
            continue
    return None


def _values_agree(gv: str, pv: str, column: str | None = None) -> bool:
    """Compare normalised gold vs prediction cell values."""
    if gv == pv:
        return True
    if column in _DATE_COLUMNS:
        gd, pd_ = _parse_loose_date(gv), _parse_loose_date(pv)
        if gd is not None and pd_ is not None and gd == pd_:
            return True
    gn = _numeric_value(gv, column)
    if gn is not None and gn == 0:
        # Gold is zero: empty pred or any zero form (0, 0.0, …) counts as match.
        if not pv:
            return True
        pn = _numeric_value(pv, column)
        return pn is not None and pn == 0
    if gn is not None:
        pn = _numeric_value(pv, column)
        if pn is not None:
            return gn == pn
    return False


_BUCKETS = ("tp", "mismatch", "missed", "hallucinated", "tn")


def _classify_cell(gv: str, pv: str, column: str | None) -> str:
    """Bucket a (gold, pred) cell. `gv`/`pv` must already be `_normalise()`-d.

      tp           - gold filled, values agree
      mismatch     - gold filled, pred filled, values differ (FP_wrong)
      missed       - gold filled, pred empty (FN)
      hallucinated - gold empty,  pred filled (FP on a not-filled gold field)
      tn           - both empty
    """
    gold_filled = bool(gv)
    pred_filled = bool(pv)
    if _values_agree(gv, pv, column):
        return "tp" if gold_filled else "tn"
    if gold_filled and pred_filled:
        return "mismatch"
    if gold_filled:
        return "missed"
    return "hallucinated"


def _derived(c: dict[str, int]) -> tuple[float, float, float]:
    """Per-column precision, recall, F1 from a bucket counter."""
    tp, mism, miss, hallu = c["tp"], c["mismatch"], c["missed"], c["hallucinated"]
    p_denom = tp + mism + hallu
    r_denom = tp + mism + miss
    p = tp / p_denom if p_denom else 0.0
    r = tp / r_denom if r_denom else 0.0
    f1 = 2 * p * r / (p + r) if (p + r) else 0.0
    return p, r, f1


def _read_goldenset_rows(cc: str) -> tuple[list[str], dict[str, dict[str, str]]]:
    """Return (label_columns, rows_by_case_id) for a country's JSONL goldenset."""
    path = goldenset_jsonl_path(cc)
    if not path.exists():
        raise FileNotFoundError(f"{path} does not exist")

    label_columns: list[str] | None = None
    by_id: dict[str, dict[str, str]] = {}
    with path.open(encoding="utf-8") as f:
        for line in f:
            if not line.strip():
                continue
            record = json.loads(line)
            if label_columns is None:
                label_columns = [k for k in record.keys() if _is_label_column(k)]
            case_id = _normalise(record.get("case_id"))
            if not case_id:
                continue
            labels = {col: _normalise(record.get(col)) for col in label_columns}
            if not any(labels.values()):
                continue
            by_id[case_id] = labels
    return label_columns or [], by_id


def _read_predictions(cc: str, system: str) -> dict[str, dict[str, str]]:
    path = inference_csv_path(cc, system)
    by_id: dict[str, dict[str, str]] = {}
    with open(path, encoding="utf-8", newline="") as f:
        reader = csv.DictReader(f)
        for row in reader:
            case_id = _normalise(row.get("case_id"))
            if not case_id:
                continue
            by_id[case_id] = {k: _normalise(v) for k, v in row.items()}
    return by_id


def _coverage(
    gold: dict[str, dict[str, str]], preds: dict[str, dict[str, str]]
) -> dict[str, int]:
    gold_ids = set(gold)
    pred_ids = set(preds)
    overlap = len(gold_ids & pred_ids)
    return {
        "gold": len(gold_ids),
        "pred": len(pred_ids),
        "overlap": overlap,
        "missing": len(gold_ids - pred_ids),
        "extra": len(pred_ids - gold_ids),
    }


def score_country(
    cc: str, system: str, verbose: bool = True
) -> tuple[dict[str, dict[str, int]], dict[str, int]] | None:
    """Return (per-column counters, case coverage stats) for one (country, system)."""
    pred_path = inference_csv_path(cc, system)
    gs_path = goldenset_jsonl_path(cc)
    if not pred_path.exists():
        if verbose:
            log.warning(f"[{cc}/{system}] missing predictions {pred_path}, skipping")
        return None
    if not gs_path.exists():
        if verbose:
            log.warning(f"[{cc}] missing goldenset {gs_path}, skipping")
        return None

    label_columns, gold = _read_goldenset_rows(cc)
    preds = _read_predictions(cc, system)
    stats = _coverage(gold, preds)

    counters: dict[str, dict[str, int]] = {
        col: {b: 0 for b in _BUCKETS} for col in label_columns
    }
    overlap_ids = [cid for cid in gold if cid in preds]
    if verbose:
        print()
        log.info(
            f"[{cc}/{system}] gold={stats['gold']} pred={stats['pred']} "
            f"overlap={stats['overlap']} missing={stats['missing']} extra={stats['extra']}"
        )

    for case_id in overlap_ids:
        g = gold[case_id]
        p = preds[case_id]
        for col in label_columns:
            bucket = _classify_cell(g.get(col, ""), p.get(col, ""), col)
            counters[col][bucket] += 1
    return counters, stats


def _print_report(
    cc: str, counters: dict[str, dict[str, int]], coverage: dict[str, int] | None = None
) -> None:
    name_width = max((len(c) for c in counters), default=0)
    name_width = max(name_width, len("column"))
    print(f"=== {cc} ===")
    if coverage is not None:
        print(
            f"cases: gold={coverage['gold']} pred={coverage['pred']} "
            f"overlap={coverage['overlap']} missing={coverage['missing']} "
            f"extra={coverage['extra']}"
        )
    print(
        f"{'column'.ljust(name_width)}  "
        f"{'TP':>5}  {'Mism':>5}  {'Miss':>5}  {'Hallu':>5}  {'TN':>5}  "
        f"{'P':>7}  {'R':>7}  {'F1':>5}"
    )
    for col, c in counters.items():
        p, r, f1 = _derived(c)
        f1_s = f"{f1:.2f}" if (p + r) else "   - "
        print(
            f"{col.ljust(name_width)}  "
            f"{c['tp']:>5}  {c['mismatch']:>5}  {c['missed']:>5}  "
            f"{c['hallucinated']:>5}  {c['tn']:>5}  "
            f"{p:>7.2%}  {r:>7.2%}  {f1_s:>5}"
        )


def _schema_label_columns() -> list[str]:
    """The 14 label columns derived from the Classification pydantic model."""
    return [
        (info.alias or name)
        for name, info in Classification.model_fields.items()
        if _is_label_column(info.alias or name)
    ]


def evaluate(
    countries: list[str] | None,
    systems: list[str] | None,
) -> None:
    overall: dict[str, dict[str, int]] = {
        col: {b: 0 for b in _BUCKETS} for col in _schema_label_columns()
    }
    overall_coverage = {"gold": 0, "pred": 0, "overlap": 0, "missing": 0, "extra": 0}

    targets = countries or evaluable_countries()
    chosen_systems = systems or list(SYSTEMS)

    seen_any = False
    for system in chosen_systems:
        print(f"\n########## SYSTEM: {system} ##########")
        for cc in targets:
            result = score_country(cc, system)
            if result is None:
                continue
            counters, coverage = result
            seen_any = True
            _print_report(f"{cc} / {system}", counters, coverage)
            for key in overall_coverage:
                overall_coverage[key] += coverage[key]
            for col, c in counters.items():
                if col not in overall:
                    overall[col] = {b: 0 for b in _BUCKETS}
                for b in _BUCKETS:
                    overall[col][b] += c[b]

    if seen_any:
        _print_report("ALL", overall, overall_coverage)


def main() -> None:
    logging.basicConfig(
        level=logging.INFO,
        format="%(asctime)s [%(levelname)s] %(message)s",
        handlers=[logging.StreamHandler(sys.stderr)],
    )

    parser = argparse.ArgumentParser(
        prog="legex-evaluate",
        description="Compare Goldenset JSONL labels against system inference CSV outputs.",
    )
    parser.add_argument(
        "--country",
        action="extend",
        nargs="+",
        dest="countries",
        help=(
            "Country code(s). Repeatable and/or space-separated. "
            f"Defaults to the {len(SYSTEMS)}-system evaluation set "
            "(all jurisdictions with a goldenset JSONL minus "
            f"{sorted(EXCLUDED_FOR_EVAL)})."
        ),
    )
    parser.add_argument(
        "--system",
        action="extend",
        nargs="+",
        dest="systems",
        choices=list(SYSTEMS),
        help=f"Inference system(s). Repeatable. Default: all of {list(SYSTEMS)}.",
    )
    args = parser.parse_args()
    evaluate(
        countries=args.countries,
        systems=args.systems,
    )


if __name__ == "__main__":
    main()