import { and, eq, inArray } from 'drizzle-orm';

import { db } from '@/lib/db';
import { interests } from '@/lib/db/schema/interests';
import { user } from '@/lib/db/schema/users';
import { searchAuditLogs, type AuditSearchOptions } from '@/lib/services/audit-search.service';

/**
 * Shared loader for the per-entity Activity tab. Wraps `searchAuditLogs`
 * with actor-email resolution so each row can render `who did what`.
 *
 * Tenant gate happens at the API route - this service trusts the caller
 * to pass an entityId that belongs to `portId`.
 */
export async function loadEntityActivity(args: {
  portId: string;
  entityType: string;
  entityId: string;
  limit?: number;
}) {
  const { rows } = await searchAuditLogs({
    portId: args.portId,
    entityType: args.entityType,
    entityId: args.entityId,
    limit: args.limit ?? 50,
  });

  const userIds = Array.from(
    new Set(rows.map((r) => r.userId).filter((u): u is string => Boolean(u))),
  );
  const userRows = userIds.length
    ? await db
        .select({ id: user.id, email: user.email, name: user.name })
        .from(user)
        .where(inArray(user.id, userIds))
    : [];
  const userMap = new Map(userRows.map((u) => [u.id, u]));

  return rows.map((r) => ({
    ...r,
    actor: r.userId ? (userMap.get(r.userId) ?? null) : null,
  }));
}

/**
 * Aggregated activity for a client - includes audit logs for the
 * client itself + every interest belonging to that client. Used by
 * the Client overview's Activity tab so the rep sees the whole
 * timeline without clicking into each interest individually.
 *
 * Two queries (one per entityType) merged + sorted in JS rather than
 * a UNION because the auditLogs.entityType field would need to match
 * different values in the same SELECT - cleaner to keep the search
 * helper's per-entity-type semantics intact and merge here.
 */
export async function loadClientActivityAggregated(args: {
  portId: string;
  clientId: string;
  limit?: number;
}) {
  const limit = args.limit ?? 50;

  // Resolve interest ids upfront so we know what to fetch in parallel.
  const interestRows = await db
    .select({ id: interests.id })
    .from(interests)
    .where(and(eq(interests.clientId, args.clientId), eq(interests.portId, args.portId)));
  const interestIds = interestRows.map((r) => r.id);

  const baseOpts = (entityType: string, entityId?: string, entityIds?: string[]) =>
    ({
      portId: args.portId,
      entityType,
      entityId,
      entityIds,
      // Fetch up to `limit` per slice; we'll resort + slice to limit
      // after merging. Slight over-fetch keeps the merged window honest
      // when the activity is unbalanced (e.g. mostly interest events).
      limit,
    }) satisfies AuditSearchOptions;

  const [clientPage, interestPage] = await Promise.all([
    searchAuditLogs(baseOpts('client', args.clientId)),
    interestIds.length > 0
      ? searchAuditLogs(baseOpts('interest', undefined, interestIds))
      : Promise.resolve({ rows: [], nextCursor: null }),
  ]);

  const merged = [...clientPage.rows, ...interestPage.rows]
    .sort((a, b) => b.createdAt.getTime() - a.createdAt.getTime())
    .slice(0, limit);

  // Resolve actor names in one round-trip across the merged set.
  const userIds = Array.from(
    new Set(merged.map((r) => r.userId).filter((u): u is string => Boolean(u))),
  );
  const userRows = userIds.length
    ? await db
        .select({ id: user.id, email: user.email, name: user.name })
        .from(user)
        .where(inArray(user.id, userIds))
    : [];
  const userMap = new Map(userRows.map((u) => [u.id, u]));

  return merged.map((r) => ({
    ...r,
    actor: r.userId ? (userMap.get(r.userId) ?? null) : null,
  }));
}
