/**
 * SQLite store for native FCM device tokens (staff chat push to the Android app).
 *
 * Frontend-owned operational data — same posture as chatDb.ts: lazy-opens inside try/catch on first
 * use and is only imported by the native-push code. If better-sqlite3 or the file fails, every export
 * logs and no-ops — native push degrades, the server never crashes at boot, and removing the feature
 * leaves nothing dangling. Lives at data/fcm-tokens.db.
 */

import Database from 'better-sqlite3'
import path from 'path'
import fs from 'fs'

let db: any = null
let initFailed = false

const getDb = () => {
  if (db) return db
  if (initFailed) return null
  try {
    const dbPath = path.join(process.cwd(), 'data', 'fcm-tokens.db')
    const dataDir = path.dirname(dbPath)
    if (!fs.existsSync(dataDir)) fs.mkdirSync(dataDir, { recursive: true })

    const _db = new Database(dbPath)
    _db.pragma('journal_mode = WAL')
    _db.exec(`
      CREATE TABLE IF NOT EXISTS fcm_tokens (
        id         INTEGER PRIMARY KEY AUTOINCREMENT,
        user_id    INTEGER NOT NULL,
        role_id    INTEGER,
        token      TEXT UNIQUE NOT NULL,
        platform   TEXT,
        created_at INTEGER NOT NULL,
        last_used  INTEGER NOT NULL
      );
      CREATE INDEX IF NOT EXISTS idx_fcm_user ON fcm_tokens(user_id);
    `)
    db = _db
    return db
  } catch (e: any) {
    initFailed = true
    console.warn('[fcmDb] open failed (native push disabled):', e?.message)
    return null
  }
}

export const saveFcmToken = (userId: number, roleId: number, token: string, platform = 'android') => {
  const d = getDb()
  if (!d || !token) return
  try {
    const now = Date.now()
    d.prepare(`
      INSERT INTO fcm_tokens (user_id, role_id, token, platform, created_at, last_used)
      VALUES (?, ?, ?, ?, ?, ?)
      ON CONFLICT(token) DO UPDATE SET
        user_id  = excluded.user_id,
        role_id  = excluded.role_id,
        platform = excluded.platform,
        last_used = excluded.last_used
    `).run(userId, roleId, token, platform, now, now)
  } catch (e: any) { console.warn('[fcmDb] save failed:', e?.message) }
}

export const getFcmTokensForUser = (userId: number): string[] => {
  const d = getDb()
  if (!d) return []
  try {
    return d.prepare('SELECT token FROM fcm_tokens WHERE user_id = ?').all(userId).map((r: any) => r.token)
  } catch { return [] }
}

export const deleteFcmToken = (token: string) => {
  const d = getDb()
  if (!d || !token) return
  try { d.prepare('DELETE FROM fcm_tokens WHERE token = ?').run(token) } catch { /* ignore */ }
}