"""SQLite-backed NetDB cache for persistent RouterInfo storage.

Stores RouterInfo entries in ~/.i2p-python/netdb.sqlite3. Survives
restarts so the router doesn't need to reseed every time. Uses WAL
mode for concurrent read/write from maintenance tasks.

Schema designed to support future reputation system columns.
"""

from __future__ import annotations

import sqlite3
import time
from pathlib import Path


class SqliteNetDB:
    """SQLite-backed persistent NetDB cache."""

    def __init__(self, data_dir: str) -> None:
        db_path = Path(data_dir).expanduser() / "netdb.sqlite3"
        db_path.parent.mkdir(parents=True, exist_ok=True)
        self._conn = sqlite3.connect(str(db_path))
        self._conn.execute("PRAGMA journal_mode=WAL")
        self._conn.execute("""
            CREATE TABLE IF NOT EXISTS router_info (
                key BLOB PRIMARY KEY,
                data BLOB NOT NULL,
                received_at INTEGER NOT NULL,
                expires_at INTEGER NOT NULL
            )
        """)
        self._conn.commit()

    def store(self, key: bytes, data: bytes, ttl_ms: int = 86_400_000) -> None:
        """Store or replace a RouterInfo entry.

        Parameters
        ----------
        key:
            32-byte router identity hash.
        data:
            Raw RouterInfo bytes.
        ttl_ms:
            Time-to-live in milliseconds (default 24h).
        """
        now = int(time.time() * 1000)
        self._conn.execute(
            "INSERT OR REPLACE INTO router_info (key, data, received_at, expires_at) "
            "VALUES (?, ?, ?, ?)",
            (key, data, now, now + ttl_ms),
        )
        self._conn.commit()

    def load_all(self) -> list[tuple[bytes, bytes]]:
        """Load all non-expired entries.

        Returns
        -------
        list[tuple[bytes, bytes]]
            List of (key, data) tuples.
        """
        now = int(time.time() * 1000)
        rows = self._conn.execute(
            "SELECT key, data FROM router_info WHERE expires_at > ?", (now,)
        ).fetchall()
        return rows

    def evict_expired(self) -> int:
        """Delete expired entries.

        Returns
        -------
        int
            Number of entries deleted.
        """
        now = int(time.time() * 1000)
        cur = self._conn.execute(
            "DELETE FROM router_info WHERE expires_at <= ?", (now,)
        )
        self._conn.commit()
        return cur.rowcount

    def count(self) -> int:
        """Return total entry count (including expired)."""
        return self._conn.execute(
            "SELECT COUNT(*) FROM router_info"
        ).fetchone()[0]

    def close(self) -> None:
        """Close the database connection."""
        self._conn.close()