#!/usr/bin/env python3
"""
Generate a deterministic summary of spec/coverage/*.json (sections + rule ids).
Outputs JSON and a short Markdown summary for status docs.
"""

from __future__ import annotations

import argparse
import json
from datetime import datetime, timezone
from pathlib import Path


def load_coverage_files(coverage_dir: Path) -> list[dict]:
    files = sorted(coverage_dir.glob("*.json"))
    payloads = []
    for path in files:
        payload = json.loads(path.read_text())
        payloads.append({"path": path, "data": payload})
    return payloads


def summarize(payloads: list[dict]) -> dict:
    books = {}
    all_rule_ids: set[str] = set()

    for item in payloads:
        data = item["data"]
        book = data.get("book", "UNKNOWN")
        sections = data.get("sections", [])

        status_counts: dict[str, int] = {}
        rule_ids: set[str] = set()

        for section in sections:
            status = section.get("status", "unknown")
            status_counts[status] = status_counts.get(status, 0) + 1
            for rid in section.get("rule_ids", []):
                rule_ids.add(rid)

        books[book] = {
            "sections": len(sections),
            "rules": len(rule_ids),
            "status_counts": dict(sorted(status_counts.items())),
        }
        all_rule_ids.update(rule_ids)

    return {
        "generated_utc": datetime.now(timezone.utc).replace(microsecond=0).isoformat().replace("+00:00", "Z"),
        "books": dict(sorted(books.items())),
        "total_rules": len(all_rule_ids),
    }


def write_json(out_path: Path, summary: dict) -> None:
    out_path.write_text(json.dumps(summary, indent=2) + "\n")


def write_md(out_path: Path, summary: dict) -> None:
    lines: list[str] = []
    lines.append("# Coverage Summary")
    lines.append("")
    lines.append(f"Generated (UTC): {summary['generated_utc']}")
    lines.append("")
    lines.append("## By Book")
    lines.append("")
    for book, stats in summary["books"].items():
        lines.append(f"- {book}: sections={stats['sections']}, rules={stats['rules']}, status_counts={stats['status_counts']}")
    lines.append("")
    lines.append(f"Total unique rule_ids: {summary['total_rules']}")
    lines.append("")
    out_path.write_text("\n".join(lines))


def main() -> int:
    parser = argparse.ArgumentParser(description="Summarize spec coverage files.")
    parser.add_argument("--coverage-dir", default="spec/coverage", help="Coverage directory (default: spec/coverage)")
    parser.add_argument("--out-json", default="out/coverage-summary.json", help="Output JSON path")
    parser.add_argument("--out-md", default="out/coverage-summary.md", help="Output Markdown path")
    args = parser.parse_args()

    coverage_dir = Path(args.coverage_dir)
    payloads = load_coverage_files(coverage_dir)
    summary = summarize(payloads)

    write_json(Path(args.out_json), summary)
    write_md(Path(args.out_md), summary)
    return 0


if __name__ == "__main__":
    raise SystemExit(main())