/// <reference types="google-apps-script" />
// The CHECKING project. A different Apps Script project, installed by a different
// account, with read-only access to the hiring workbook and the journal. It never
// sends a welcome letter; it emails the people named in its alerts.
import { composeMorningSummary, emptyCheckState, markNotified, renderAlertNote, runCheck, type CheckResult, type CheckState } from "../core/monitor";
import { planTriggers } from "../core/triggers";
import type { CheckConfig } from "../core/types";
import { authorizationStatus, formatter, installExactly, prop, readGrid, readJournal, tab, TABS } from "./common";

const MANAGED = ["runCheck", "morningSummary"];

function config(): CheckConfig {
  return {
    staleAfterMinutes: Number(prop("STALE_AFTER_MINUTES", "40")),
    pendingAfterMinutes: Number(prop("PENDING_AFTER_MINUTES", "60")),
    contacts: { technicalOwner: prop("TECHNICAL_OWNER"), hiringCoordinator: prop("HIRING_COORDINATOR") },
  };
}

function loadState(): CheckState {
  const raw = PropertiesService.getScriptProperties().getProperty("CHECK_STATE");
  return raw ? (JSON.parse(raw) as CheckState) : emptyCheckState();
}
function saveState(st: CheckState) {
  PropertiesService.getScriptProperties().setProperty("CHECK_STATE", JSON.stringify(st));
}

function check(state: CheckState): CheckResult {
  const r = runCheck(
    {
      readHiring: () => readGrid(tab(prop("HIRING_BOOK_ID"), TABS.hiring)),
      readJournal: () => readJournal(prop("OPS_BOOK_ID")),
    },
    config(),
    new Date(),
    state,
    formatter(Session.getScriptTimeZone()),
  );
  PropertiesService.getScriptProperties().setProperty(
    "LAST_CHECK",
    JSON.stringify({ at: r.checkedAt, status: r.status, alerts: r.alerts.length }),
  );
  return r;
}

function withLock<T>(f: () => T): T | { skipped: string } {
  const lock = LockService.getScriptLock();
  if (!lock.tryLock(20000)) return { skipped: "another check is running" };
  try {
    return f();
  } finally {
    lock.releaseLock();
  }
}

/**
 * Every 15 minutes: send each open alert whose note has not been accepted yet.
 * An alert counts as notified only after MailApp accepted its note; a failed send is retried next time.
 */
export function periodicCheck() {
  return withLock(() => {
    const r = check(loadState());
    let state: CheckState = { firstSeen: r.firstSeen, notified: r.notified };
    const fmt = formatter(Session.getScriptTimeZone());
    const emailed: string[] = [];
    const failed: string[] = [];
    for (const a of r.toNotify) {
      const note = renderAlertNote(a, r.checkedAt, fmt);
      try {
        MailApp.sendEmail({ to: prop("ALERT_TO"), subject: note.subject, body: note.body });
        state = markNotified(state, [a.key], new Date().toISOString());
        emailed.push(a.kind);
      } catch (e) {
        failed.push(`${a.kind}: ${(e as Error).message}`);
      }
      saveState(state);
    }
    saveState(state);
    return { status: r.status, alerts: r.alerts.map((a) => a.kind), emailed, failed };
  });
}

/** Once a day: the summary. It never marks an alert as notified. */
export function dailySummary() {
  return withLock(() => {
    const r = check(loadState());
    saveState({ firstSeen: r.firstSeen, notified: r.notified });
    const s = composeMorningSummary(r, formatter(Session.getScriptTimeZone()));
    MailApp.sendEmail({ to: prop("SUMMARY_TO", prop("ALERT_TO")), subject: s.subject, body: s.body });
    return { status: r.status };
  });
}

export function install() {
  const desired = [
    { handler: "runCheck", kind: "every-minutes" as const, value: Number(prop("CHECK_EVERY_MINUTES", "15")) },
    { handler: "morningSummary", kind: "daily-at-hour" as const, value: Number(prop("SUMMARY_HOUR", "7")) },
  ];
  return installExactly(desired, (existing, installed) => planTriggers(existing, desired, MANAGED, undefined, installed));
}

export function verify() {
  return {
    authorization: authorizationStatus(),
    triggers: ScriptApp.getProjectTriggers().map((t) => t.getHandlerFunction()).join(", ") || "none",
    lastCheck: PropertiesService.getScriptProperties().getProperty("LAST_CHECK") ?? "never",
  };
}