# -*- coding: utf-8 -*-
"""
collatz_scission.py

Read CSV from collatz pipeline, extract covered classes (classe_mod_2^m and sœur),
output JSON certificate with clauses, covered set, and residual kernel info.

Usage: --input CSV_PATH --output JSON_PATH
"""

from __future__ import annotations
import argparse
import csv
import json
import re
from pathlib import Path


def _find_column(row: dict, *candidates: str) -> str | None:
    """Return first matching column name from row keys."""
    keys = set(row.keys())
    for c in candidates:
        for k in keys:
            if c in k or k.replace(" ", "").lower() == c.replace(" ", "").lower():
                return k
    return None


def _find_column_exact(row: dict, *candidates: str) -> str | None:
    """
    Return the first column whose normalized key equals one of the candidates.

    Use this for short keys like 'm' where substring matching is unsafe
    (e.g. 'classe_mod_2^m' contains 'm' but is not an exponent column).
    """
    keys = set(row.keys())
    normalized: dict[str, str] = {k.replace(" ", "").lower(): k for k in keys}
    for c in candidates:
        ck = c.replace(" ", "").lower()
        if ck in normalized:
            return normalized[ck]
    return None


def _try_parse_int(value: object) -> int | None:
    if value is None:
        return None
    if isinstance(value, int):
        return value
    if isinstance(value, str):
        s = value.strip()
        if not s:
            return None
        try:
            return int(s)
        except ValueError:
            return None
    return None


def infer_palier(rows: list[dict], classe_col: str | None, csv_path: Path | None = None) -> int:
    """
    Infer modulus power m.

    Priority order:
    - explicit numeric column 'palier' (or 'm' used as exponent in some CSVs)
    - class column name containing '2^<m>' (e.g. 'classe_mod_2^27')
    - filename containing 'palier2p<m>'
    - fallback heuristic from max class value (legacy; not reliable when values are sparse)
    """
    if rows:
        pal_col = _find_column_exact(rows[0], "palier")
        if pal_col:
            v = _try_parse_int(rows[0].get(pal_col))
            if v is not None and v > 0:
                return v
        m_col = _find_column_exact(rows[0], "m", "modulus_power")
        if m_col:
            v = _try_parse_int(rows[0].get(m_col))
            if v is not None and v > 0:
                return v

    if classe_col and ("2^" in classe_col or "2^" in str(classe_col)):
        m = re.search(r"2\^(\d+)", classe_col)
        if m:
            return int(m.group(1))

    if csv_path is not None:
        m2 = re.search(r"palier2p(\d+)", str(csv_path))
        if m2:
            return int(m2.group(1))

    if rows and classe_col:
        try:
            vals = [int(r.get(classe_col, 0) or 0) for r in rows if r.get(classe_col)]
            if vals:
                mx = max(vals)
                m = 0
                while (1 << m) <= mx:
                    m += 1
                return m
        except (ValueError, TypeError):
            pass
    return 0


def run_scission(csv_path: str, out_json_path: str) -> None:
    """Read CSV, extract clauses and covered set, write JSON certificate."""
    out_path = Path(out_json_path)
    out_path.parent.mkdir(parents=True, exist_ok=True)

    rows: list[dict] = []
    with Path(csv_path).open("r", encoding="utf-8") as f:
        reader = csv.DictReader(f)
        for row in reader:
            rows.append(dict(row))

    if not rows:
        cert = {"clauses": [], "covered": [], "palier": 0}
        out_path.write_text(json.dumps(cert, indent=2), encoding="utf-8")
        print(f"Wrote {out_json_path} (empty)")
        return

    classe_col = _find_column(rows[0], "classe_mod_2^m", "classe_mod_2^27", "classe_mod_2^28", "classe_mod_2")
    soeur_col = _find_column(rows[0], "sœur", "soeur")

    clauses: list[int] = []
    covered: set[int] = set()

    for r in rows:
        if classe_col:
            try:
                raw = r.get(classe_col)
                if raw is not None and str(raw).strip():
                    c = int(raw)
                    clauses.append(c)
                    covered.add(c)
            except (ValueError, TypeError):
                pass
        if soeur_col:
            try:
                raw = r.get(soeur_col)
                if raw is not None and str(raw).strip():
                    s = int(raw)
                    covered.add(s)
            except (ValueError, TypeError):
                pass

    clauses = sorted(set(clauses))
    covered_list = sorted(covered)
    palier = infer_palier(rows, classe_col, csv_path=Path(csv_path))

    cert = {
        "clauses": clauses,
        "covered": covered_list,
        "palier": palier,
    }
    out_path.write_text(json.dumps(cert, indent=2), encoding="utf-8")
    print(f"Wrote {out_json_path}: {len(clauses)} clauses, {len(covered_list)} covered, palier 2^{palier}")


def main() -> None:
    ap = argparse.ArgumentParser(description="Extract scission certificate from Collatz CSV")
    ap.add_argument("--input", "-i", required=True, help="Input CSV path")
    ap.add_argument("--output", "-o", required=True, help="Output JSON path")
    args = ap.parse_args()
    run_scission(args.input, args.output)


if __name__ == "__main__":
    main()