import { getSettings, getInternalFlag, setInternalFlag } from "./settingsStore.js";
import { purgeOldLogs } from "./logRetention.js";
import { recordAudit } from "./audit.js";

const LAST_RUN_FLAG = "logRetentionLastRunAt";

async function runPurge(): Promise<void> {
  const { logRetention } = await getSettings();
  if (!logRetention.enabled) return;
  const result = await purgeOldLogs(logRetention.retentionDays);
  await setInternalFlag(LAST_RUN_FLAG, new Date().toISOString());
  if (result.diagDeleted || result.auditDeleted) {
    // Trimming the audit log is itself something to be able to look back on — attributed to the system, since no one asked for it.
    await recordAudit({
      category: "settings",
      action: "purge_logs",
      detail: { automatic: true, retentionDays: logRetention.retentionDays, ...result },
    });
    console.log(
      `[logRetention] purged ${result.diagDeleted} diagnostic log and ${result.auditDeleted} audit log entries older than ${logRetention.retentionDays} days`,
    );
  }
}

let currentTimer: ReturnType<typeof setInterval> | null = null;

/** (Re)arms the periodic purge timer per the current settings. Call again after settings change. */
export async function scheduleLogRetentionPurge(): Promise<void> {
  if (currentTimer) {
    clearInterval(currentTimer);
    currentTimer = null;
  }
  const { logRetention } = await getSettings();
  if (!logRetention.enabled) {
    console.log("[logRetention] automatic purge disabled");
    return;
  }
  const intervalMs = logRetention.intervalHours * 60 * 60 * 1000;
  currentTimer = setInterval(() => {
    runPurge().catch((err) => console.error("[logRetention] purge failed:", err));
  }, intervalMs);
  console.log(`[logRetention] automatic purge scheduled every ${logRetention.intervalHours}h, keeping ${logRetention.retentionDays} days`);
}

/** Runs immediately at startup if a purge is overdue (e.g. the server was down past the interval), then arms the periodic timer. */
export async function initLogRetentionScheduler(): Promise<void> {
  const { logRetention } = await getSettings();
  if (logRetention.enabled) {
    const lastRun = await getInternalFlag(LAST_RUN_FLAG);
    const dueAt = lastRun ? new Date(lastRun).getTime() + logRetention.intervalHours * 60 * 60 * 1000 : 0;
    if (Date.now() >= dueAt) {
      await runPurge().catch((err) => console.error("[logRetention] purge failed:", err));
    }
  }
  await scheduleLogRetentionPurge();
}