import Link from "next/link";
import { Suspense } from "react";
import { EmployeeFilters } from "@/components/employees/EmployeeFilters";
import { Avatar } from "@/components/ui/Avatar";
import { StatusChip } from "@/components/ui/StatusChip";
import { fmtDate } from "@/lib/format";
import { breadcrumbFor, loadOrgMaps } from "@/lib/org";
import { createClient } from "@/lib/supabase/server";
import type { EmploymentStatus } from "@/lib/supabase/types";

const PAGE_SIZE = 15;

type SearchParams = { q?: string; division?: string; status?: string; location?: string; page?: string };

type EmployeesPageProps = {
  searchParams: Promise<SearchParams>;
};

function pageHref(params: SearchParams, page: number): string {
  const sp = new URLSearchParams();
  if (params.q) sp.set("q", params.q);
  if (params.division) sp.set("division", params.division);
  if (params.status) sp.set("status", params.status);
  if (params.location) sp.set("location", params.location);
  sp.set("page", String(page));
  return `/employees?${sp.toString()}`;
}

export default async function EmployeesPage({ searchParams }: EmployeesPageProps) {
  const params = await searchParams;
  const supabase = await createClient();
  const orgMaps = await loadOrgMaps(supabase);

  const page = Math.max(1, Number(params.page ?? "1") || 1);
  const from = (page - 1) * PAGE_SIZE;
  const to = from + PAGE_SIZE - 1;

  let query = supabase
    .from("employees")
    .select(
      "id, first_name, last_name, personnel_number, job_title, team_id, division_id, location_id, entry_date, employment_type, weekly_hours, status",
      { count: "exact" }
    )
    .order("last_name", { ascending: true })
    .range(from, to);

  if (params.q) {
    const q = params.q.trim();
    if (/^\d+$/.test(q)) {
      query = query.eq("personnel_number", Number(q));
    } else {
      query = query.or(`first_name.ilike.%${q}%,last_name.ilike.%${q}%,job_title.ilike.%${q}%`);
    }
  }
  if (params.division) query = query.eq("division_id", params.division);
  if (params.status) query = query.eq("status", params.status as EmploymentStatus);
  if (params.location) query = query.eq("location_id", params.location);

  const { data: employeesData, count } = await query;
  const employees = employeesData ?? [];
  const totalPages = Math.max(1, Math.ceil((count ?? 0) / PAGE_SIZE));

  return (
    <div className="flex flex-col gap-4">
      <Suspense>
        <EmployeeFilters divisions={orgMaps.divisionList} locations={orgMaps.locationList} />
      </Suspense>
      <p className="text-sm text-ink-muted">{count ?? 0} Mitarbeiter:innen gefunden</p>

      <div className="overflow-x-auto rounded border border-border bg-white">
        <table className="w-full min-w-[800px] text-sm">
          <thead>
            <tr className="border-b border-border bg-surface text-left text-xs font-semibold uppercase tracking-wide text-ink-muted">
              <th className="px-4 py-3">Mitarbeiter:in</th>
              <th className="px-4 py-3">Pers.-Nr.</th>
              <th className="px-4 py-3">Bereich/Team</th>
              <th className="px-4 py-3">Standort</th>
              <th className="px-4 py-3">Eintritt</th>
              <th className="px-4 py-3">Beschäftigung</th>
              <th className="px-4 py-3">Status</th>
            </tr>
          </thead>
          <tbody>
            {employees.map((e) => {
              const { division, team } = breadcrumbFor(orgMaps, e.division_id, e.team_id);
              const location = e.location_id ? orgMaps.locations.get(e.location_id) : undefined;
              return (
                <tr key={e.id} className="border-b border-border last:border-0 hover:bg-surface">
                  <td className="px-4 py-3">
                    <Link href={`/employees/${e.id}`} className="flex items-center gap-3">
                      <Avatar firstName={e.first_name} lastName={e.last_name} />
                      <div>
                        <div className="font-semibold text-ink">
                          {e.first_name} {e.last_name}
                        </div>
                        <div className="text-xs text-ink-muted">{e.job_title}</div>
                      </div>
                    </Link>
                  </td>
                  <td className="px-4 py-3 text-ink-body">{e.personnel_number}</td>
                  <td className="px-4 py-3 text-ink-body">
                    <div>{division?.name ?? "–"}</div>
                    <div className="text-xs text-ink-muted">{team?.name ?? "–"}</div>
                  </td>
                  <td className="px-4 py-3 text-ink-body">{location?.name ?? "–"}</td>
                  <td className="px-4 py-3 text-ink-body">{fmtDate(e.entry_date)}</td>
                  <td className="px-4 py-3 text-ink-body">
                    {e.employment_type} · {e.weekly_hours}h
                  </td>
                  <td className="px-4 py-3">
                    <StatusChip status={e.status} entryDate={e.entry_date} />
                  </td>
                </tr>
              );
            })}
            {employees.length === 0 && (
              <tr>
                <td colSpan={7} className="px-4 py-8 text-center text-sm text-ink-muted">
                  Keine Mitarbeiter:innen gefunden.
                </td>
              </tr>
            )}
          </tbody>
        </table>
      </div>

      {totalPages > 1 && (
        <div className="flex items-center justify-center gap-2 text-sm">
          {Array.from({ length: totalPages }, (_, i) => i + 1).map((p) => (
            <Link
              key={p}
              href={pageHref(params, p)}
              className={`rounded px-3 py-1 ${p === page ? "bg-brand-500 text-white" : "text-ink-body hover:bg-surface"}`}
            >
              {p}
            </Link>
          ))}
        </div>
      )}
    </div>
  );
}