from __future__ import annotations

import json
import sqlite3
from dataclasses import dataclass
from datetime import datetime, timezone, timedelta
from pathlib import Path
from typing import Any


@dataclass
class ClusterRow:
    cluster_id: str
    topic: str
    payload: dict
    updated_at: datetime


class SQLiteClusterStore:
    def __init__(self, db_path: str | Path):
        self.db_path = str(db_path)
        self._init_db()

    def _conn(self) -> sqlite3.Connection:
        return sqlite3.connect(self.db_path)

    def _init_db(self) -> None:
        Path(self.db_path).parent.mkdir(parents=True, exist_ok=True)
        with self._conn() as conn:
            conn.execute(
                """
                CREATE TABLE IF NOT EXISTS clusters (
                  cluster_id TEXT PRIMARY KEY,
                  topic TEXT NOT NULL,
                  payload TEXT NOT NULL,
                  updated_at TEXT NOT NULL
                )
                """
            )
            conn.execute(
                "CREATE INDEX IF NOT EXISTS idx_clusters_topic ON clusters(topic)"
            )

    def upsert_clusters(self, clusters: list[dict], topic: str) -> None:
        now = datetime.now(timezone.utc)
        with self._conn() as conn:
            for c in clusters:
                cluster_id = c["cluster_id"]
                payload = json.dumps(c, ensure_ascii=False)
                conn.execute(
                    "INSERT INTO clusters(cluster_id, topic, payload, updated_at) VALUES(?,?,?,?) "
                    "ON CONFLICT(cluster_id) DO UPDATE SET topic=excluded.topic, payload=excluded.payload, updated_at=excluded.updated_at",
                    (cluster_id, topic, payload, now.isoformat()),
                )

    def get_latest_clusters(self, topic: str, ttl_hours: float, limit: int) -> list[dict]:
        cutoff = datetime.now(timezone.utc) - timedelta(hours=ttl_hours)
        cutoff_iso = cutoff.isoformat()
        with self._conn() as conn:
            cur = conn.execute(
                "SELECT payload FROM clusters WHERE topic=? AND updated_at >= ? ORDER BY updated_at DESC LIMIT ?",
                (topic, cutoff_iso, int(limit)),
            )
            rows = [json.loads(r[0]) for r in cur.fetchall()]
        return rows