#!/usr/bin/env python3
"""Atomically convert checker-confirmed bare branch decision/owner refs to wikilinks."""

from __future__ import annotations

import argparse
import importlib.util
import json
from pathlib import Path
import re
import sys
from typing import Any

from fs_transaction import replace_many


DEFAULT_ROOT = Path(__file__).resolve().parents[2]


def _load_checker(root: Path):
    path = root / ".claude/hooks/wiki_consistency_check.py"
    hooks = str(path.parent)
    if hooks not in sys.path:
        sys.path.insert(0, hooks)
    spec = importlib.util.spec_from_file_location("wiki_consistency_fix_source", path)
    if spec is None or spec.loader is None:
        raise OSError(f"cannot load checker: {path}")
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    return module


def _replace_slug(line: str, slug: str, branch_dir: str) -> tuple[str, bool]:
    pattern = re.compile(
        rf"(?<![\/\w-])`?{re.escape(slug)}`?(?![\w-])"
    )
    rendered, count = pattern.subn(f"[[{branch_dir}/{slug}]]", line, count=1)
    return rendered, bool(count)


def build_updates(root: Path) -> tuple[dict[Path, str], dict[str, Any]]:
    checker = _load_checker(root)
    updates: dict[Path, str] = {}
    decision_fixes = 0
    owner_fixes = 0
    for branch_path in sorted((root / checker.BRANCH_DIR).glob("*.md")):
        text = branch_path.read_text(encoding="utf-8")
        lines = text.splitlines(keepends=True)
        for line_number, slug, _ref_id, kind in checker.extract_refs(text, branch_path.stem):
            if kind != "bare":
                continue
            original = lines[line_number - 1]
            lines[line_number - 1], changed = _replace_slug(original, slug, checker.BRANCH_DIR)
            if changed:
                decision_fixes += 1
        current = "".join(lines)
        coverage = checker.coverage_rows(current)
        for line_number, _concern, status, owner in coverage:
            if "delegated" not in status or not owner:
                continue
            slugs = [match.group(1) for match in checker.BARE_SLUG_RE.finditer(owner)]
            for slug in slugs:
                original = lines[line_number - 1]
                lines[line_number - 1], changed = _replace_slug(original, slug, checker.BRANCH_DIR)
                if changed:
                    owner_fixes += 1
        rendered = "".join(lines)
        if rendered != text:
            updates[branch_path] = rendered
    return updates, {
        "decision_ref_fixes": decision_fixes,
        "owner_ref_fixes": owner_fixes,
        "changed_files": [path.relative_to(root).as_posix() for path in sorted(updates)],
    }


def main(argv: list[str] | None = None) -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    mode = parser.add_mutually_exclusive_group(required=True)
    mode.add_argument("--check", action="store_true")
    mode.add_argument("--write", action="store_true")
    parser.add_argument("--root", type=Path, default=DEFAULT_ROOT)
    args = parser.parse_args(argv)
    try:
        root = args.root.resolve(strict=True)
        updates, counts = build_updates(root)
        if args.write and updates:
            replace_many({path: text.encode("utf-8") for path, text in updates.items()})
        result = {
            "schema_version": "bare-ref-migration-result/v1",
            "status": "DRIFT" if args.check and updates else "UPDATED" if updates else "CURRENT",
            **counts,
        }
        json.dump(result, sys.stdout, ensure_ascii=False, indent=2, sort_keys=True)
        sys.stdout.write("\n")
        return 1 if args.check and updates else 0
    except (OSError, UnicodeError, ValueError) as exc:
        json.dump({"schema_version": "bare-ref-migration-result/v1", "status": "FAIL", "error": str(exc)}, sys.stdout, ensure_ascii=False, indent=2)
        sys.stdout.write("\n")
        return 2


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