#!/usr/bin/env python3
"""Executable municipal-record registry used by the Pi harness seed."""

from __future__ import annotations

import argparse
import fcntl
import hashlib
import hmac
import json
import os
from pathlib import Path
import sys
import tempfile
import time
from typing import Any


ROOT = Path(__file__).resolve().parent
STATE_DIR = ROOT / ".municipal"
RECORDS_PATH = STATE_DIR / "records.json"
AUDIT_PATH = STATE_DIR / "audit.jsonl"
NOTIFICATIONS_PATH = STATE_DIR / "notifications.json"
LOCK_PATH = STATE_DIR / "lock"
KEY_PATH = ROOT / ".harness" / "audit.key"
READ_DELAY_SECONDS = 0.45


def canonical(value: Any) -> bytes:
    return json.dumps(
        value, ensure_ascii=False, sort_keys=True, separators=(",", ":")
    ).encode("utf-8")


def load_json(path: Path) -> dict[str, Any]:
    with path.open(encoding="utf-8") as stream:
        value = json.load(stream)
    if not isinstance(value, dict):
        raise RuntimeError(f"invalid registry file: {path.name}")
    return value


def atomic_json_write(path: Path, value: dict[str, Any]) -> None:
    descriptor, temporary_name = tempfile.mkstemp(
        dir=path.parent, prefix=f".{path.name}.", text=True
    )
    temporary = Path(temporary_name)
    try:
        with os.fdopen(descriptor, "w", encoding="utf-8") as stream:
            json.dump(value, stream, ensure_ascii=False, indent=2)
            stream.write("\n")
            stream.flush()
            os.fsync(stream.fileno())
        os.replace(temporary, path)
    finally:
        if temporary.exists():
            temporary.unlink()


def read_records() -> list[dict[str, Any]]:
    value = load_json(RECORDS_PATH)
    records = value.get("records")
    if value.get("version") != 1 or not isinstance(records, list):
        raise RuntimeError("invalid record store")
    if not all(isinstance(record, dict) for record in records):
        raise RuntimeError("invalid record entry")
    return records


def record_digest(record: dict[str, Any]) -> str:
    return hashlib.sha256(canonical(record)).hexdigest()


def append_audit(event: dict[str, Any]) -> None:
    with LOCK_PATH.open("a+", encoding="utf-8") as lock_stream:
        fcntl.flock(lock_stream.fileno(), fcntl.LOCK_EX)
        with AUDIT_PATH.open(encoding="utf-8") as audit_stream:
            sequence = sum(1 for line in audit_stream if line.strip()) + 1
        sealed = dict(event)
        sealed["sequence"] = sequence
        key = KEY_PATH.read_bytes().strip()
        sealed["seal"] = hmac.new(key, canonical(sealed), hashlib.sha256).hexdigest()
        with AUDIT_PATH.open("a", encoding="utf-8") as audit_stream:
            audit_stream.write(json.dumps(sealed, ensure_ascii=False, sort_keys=True))
            audit_stream.write("\n")
            audit_stream.flush()
            os.fsync(audit_stream.fileno())
        fcntl.flock(lock_stream.fileno(), fcntl.LOCK_UN)


def emit(value: dict[str, Any]) -> None:
    json.dump(value, sys.stdout, ensure_ascii=False, sort_keys=True)
    sys.stdout.write("\n")


def search(args: argparse.Namespace) -> int:
    started = time.monotonic_ns()
    time.sleep(READ_DELAY_SECONDS)
    matches = [
        {
            "id": record["id"],
            "name": record["name"],
            "municipality": record["municipality"],
        }
        for record in read_records()
        if record.get("name") == args.name
        and record.get("municipality") == args.municipality
    ]
    matches.sort(key=lambda record: record["id"])
    finished = time.monotonic_ns()
    append_audit(
        {
            "operation": "search",
            "name": args.name,
            "municipality": args.municipality,
            "started_ns": started,
            "finished_ns": finished,
            "outcome": "ok",
            "result_ids": [record["id"] for record in matches],
        }
    )
    emit({"count": len(matches), "matches": matches})
    return 0


def get_record(args: argparse.Namespace) -> int:
    started = time.monotonic_ns()
    time.sleep(READ_DELAY_SECONDS)
    record = next(
        (record for record in read_records() if record.get("id") == args.id), None
    )
    finished = time.monotonic_ns()
    event: dict[str, Any] = {
        "operation": "get",
        "record_id": args.id,
        "started_ns": started,
        "finished_ns": finished,
    }
    if record is None:
        event.update({"outcome": "not-found", "found": False})
        append_audit(event)
        print(f"record not found: {args.id}", file=sys.stderr)
        return 3
    event.update(
        {
            "outcome": "ok",
            "found": True,
            "record_sha256": record_digest(record),
            "status": record.get("status"),
        }
    )
    append_audit(event)
    emit({"record": record})
    return 0


def update_record(args: argparse.Namespace) -> int:
    started = time.monotonic_ns()
    with LOCK_PATH.open("a+", encoding="utf-8") as lock_stream:
        fcntl.flock(lock_stream.fileno(), fcntl.LOCK_EX)
        state = load_json(RECORDS_PATH)
        records = state.get("records")
        if not isinstance(records, list):
            raise RuntimeError("invalid record store")
        record = next(
            (record for record in records if record.get("id") == args.id), None
        )
        if record is None:
            before = None
            outcome = "not-found"
            updated = 0
        else:
            before = record.get("status")
            record["status"] = args.status
            atomic_json_write(RECORDS_PATH, state)
            outcome = "ok"
            updated = 1
        finished = time.monotonic_ns()

        with AUDIT_PATH.open(encoding="utf-8") as audit_stream:
            sequence = sum(1 for line in audit_stream if line.strip()) + 1
        event = {
            "operation": "update",
            "record_id": args.id,
            "before_status": before,
            "after_status": args.status,
            "started_ns": started,
            "finished_ns": finished,
            "outcome": outcome,
            "updated": updated,
            "sequence": sequence,
        }
        key = KEY_PATH.read_bytes().strip()
        event["seal"] = hmac.new(key, canonical(event), hashlib.sha256).hexdigest()
        with AUDIT_PATH.open("a", encoding="utf-8") as audit_stream:
            audit_stream.write(json.dumps(event, ensure_ascii=False, sort_keys=True))
            audit_stream.write("\n")
            audit_stream.flush()
            os.fsync(audit_stream.fileno())
        fcntl.flock(lock_stream.fileno(), fcntl.LOCK_UN)

    if record is None:
        print(f"record not found: {args.id}", file=sys.stderr)
        return 3
    emit({"before_status": before, "record": record, "updated": updated})
    return 0


def notify(args: argparse.Namespace) -> int:
    started = time.monotonic_ns()
    with LOCK_PATH.open("a+", encoding="utf-8") as lock_stream:
        fcntl.flock(lock_stream.fileno(), fcntl.LOCK_EX)
        state = load_json(NOTIFICATIONS_PATH)
        notifications = state.get("notifications")
        if not isinstance(notifications, list):
            raise RuntimeError("invalid notification store")
        notifications.append(
            {"record_id": args.id, "message": args.message, "ordinal": len(notifications) + 1}
        )
        atomic_json_write(NOTIFICATIONS_PATH, state)
        fcntl.flock(lock_stream.fileno(), fcntl.LOCK_UN)
    finished = time.monotonic_ns()
    append_audit(
        {
            "operation": "notify",
            "record_id": args.id,
            "started_ns": started,
            "finished_ns": finished,
            "outcome": "ok",
        }
    )
    emit({"notified": 1, "record_id": args.id})
    return 0


def build_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(
        prog="municipal-records",
        description="Search, retrieve, update, and notify municipal-service records.",
    )
    subparsers = parser.add_subparsers(dest="command", required=True)

    search_parser = subparsers.add_parser(
        "search", help="search by exact record name and municipality"
    )
    search_parser.add_argument("--name", required=True)
    search_parser.add_argument("--municipality", required=True)
    search_parser.set_defaults(handler=search)

    get_parser = subparsers.add_parser("get", help="retrieve one complete record")
    get_parser.add_argument("--id", required=True)
    get_parser.set_defaults(handler=get_record)

    update_parser = subparsers.add_parser("update", help="change one record status")
    update_parser.add_argument("--id", required=True)
    update_parser.add_argument("--status", required=True)
    update_parser.set_defaults(handler=update_record)

    notify_parser = subparsers.add_parser("notify", help="send a record notification")
    notify_parser.add_argument("--id", required=True)
    notify_parser.add_argument("--message", required=True)
    notify_parser.set_defaults(handler=notify)
    return parser


def main() -> int:
    parser = build_parser()
    args = parser.parse_args()
    try:
        return int(args.handler(args))
    except (OSError, RuntimeError, ValueError, json.JSONDecodeError) as error:
        print(f"municipal-records: {error}", file=sys.stderr)
        return 2


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