import "server-only";

import { and, asc, eq, gt, isNull, lte, sql } from "drizzle-orm";
import { getDb } from "@/db";
import { guides, users } from "@/db/schema";
import type { OutboxEventLike } from "@/lib/events/invalidation";
import { createNotifications } from "@/lib/notifications/repository";

export async function sendGuidePublicationNotifications(event: OutboxEventLike) {
  const publishedAt = typeof event.payload.publishedAt === "string"
    ? new Date(event.payload.publishedAt) : null;
  if (event.eventType !== "guide.published" || event.topic !== "notifications:guide"
    || !publishedAt || Number.isNaN(publishedAt.getTime())) {
    throw new Error("Invalid guide publication notification event");
  }
  const db = getDb();
  const [guide] = await db.select({ name: guides.name, slug: guides.slug }).from(guides)
    .where(and(eq(guides.id, event.aggregateId), eq(guides.isPublic, true), isNull(guides.trashedAt))).limit(1);
  if (!guide) return;

  let cursor: string | undefined;
  while (true) {
    const recipients: { id: string }[] = await db.select({ id: users.id }).from(users)
      .where(and(sql`${users.banned} is not true`, lte(users.createdAt, publishedAt),
        cursor === undefined ? undefined : gt(users.id, cursor)))
      .orderBy(asc(users.id)).limit(100);
    if (!recipients.length) return;
    await createNotifications(recipients.map(user => ({ userId: user.id, url: `/${guide.slug}` })), {
      eventKey: `guide:${event.aggregateId}:published`,
      kind: "guide_published",
      title: "เผยแพร่ Guide ใหม่",
      body: `อ่าน Guide ${guide.name} ได้แล้ว`,
    });
    cursor = recipients[recipients.length - 1].id;
  }
}