const fs = require("fs");
const path = require("path");

function createSqliteStorage(options) {
  const sqlitePath = options.sqlitePath;
  let db = null;

  function requireDriver() {
    try {
      return require("node:sqlite").DatabaseSync;
    } catch {
      throw new Error("SQLite storage requires Node.js with built-in 'node:sqlite' (Node 22+)");
    }
  }

  return {
    id: "sqlite",
    async init() {
      const Database = requireDriver();
      fs.mkdirSync(path.dirname(sqlitePath), { recursive: true });
      db = new Database(sqlitePath);
      db.exec("PRAGMA journal_mode = WAL");
      db.exec("CREATE TABLE IF NOT EXISTS kv (k TEXT PRIMARY KEY, v TEXT NOT NULL)");
      db.exec("CREATE TABLE IF NOT EXISTS logs (k TEXT NOT NULL, ts INTEGER NOT NULL, line TEXT NOT NULL)");
    },
    async exists(key) {
      const row = db.prepare("SELECT 1 AS ok FROM kv WHERE k = ? LIMIT 1").get(key);
      return Boolean(row);
    },
    async readJson(key, fallback = null) {
      const row = db.prepare("SELECT v FROM kv WHERE k = ? LIMIT 1").get(key);
      if (!row) {
        return fallback;
      }
      try {
        return JSON.parse(row.v);
      } catch {
        return fallback;
      }
    },
    async writeJson(key, value) {
      const raw = JSON.stringify(value);
      db.prepare("INSERT INTO kv(k, v) VALUES(?, ?) ON CONFLICT(k) DO UPDATE SET v = excluded.v").run(key, raw);
    },
    async appendText(key, text) {
      db.prepare("INSERT INTO logs(k, ts, line) VALUES(?, ?, ?)").run(key, Date.now(), text);
    },
    async readText(key, fallback = "") {
      const rows = db.prepare("SELECT line FROM logs WHERE k = ? ORDER BY ts ASC").all(key);
      if (!rows.length) {
        return fallback;
      }
      return rows.map((row) => row.line).join("");
    },
    async writeText(key, text) {
      db.prepare("DELETE FROM logs WHERE k = ?").run(key);
      if (text) {
        db.prepare("INSERT INTO logs(k, ts, line) VALUES(?, ?, ?)").run(key, Date.now(), text);
      }
    }
  };
}

module.exports = {
  createSqliteStorage
};