import { auth } from "@/auth";
import { db } from "@/lib/db";
import { hasPermission, submitterCanViewAll } from "@/lib/permissions";
import { redirect } from "next/navigation";
import Link from "next/link";
import { formatCurrency, formatDate } from "@/lib/utils";
import { PoStatusBadge } from "@/components/po/po-status-badge";
import { HistoryFilters } from "./history-filters";
import { buildAccountGroups } from "@/lib/cost-centre-groups";
import { buildPoHistoryWhere } from "@/lib/history-filter";
import { resolvePagination } from "@/lib/pagination";
import { Suspense } from "react";
import type { Metadata } from "next";

export const metadata: Metadata = { title: "History" };

const PER_PAGE_OPTIONS = [25, 50, 100];
const DEFAULT_PER_PAGE = 25;

interface Props {
  searchParams: Promise<{
    dateFrom?: string;
    dateTo?: string;
    approvedFrom?: string;
    approvedTo?: string;
    vesselId?: string;
    accountId?: string;
    status?: string | string[];
    page?: string;
    perPage?: string;
  }>;
}

export default async function HistoryPage({ searchParams }: Props) {
  const session = await auth();
  if (!session?.user) redirect("/login");

  // Report-export holders see History; submitters get read+export access when the
  // submitter-view-all feature flag is on.
  if (
    !hasPermission(session.user.role, "export_reports") &&
    !submitterCanViewAll(session.user.role)
  ) {
    redirect("/dashboard");
  }

  const { dateFrom, dateTo, approvedFrom, approvedTo, vesselId, accountId, status, page: pageParam, perPage: perPageParam } =
    await searchParams;

  const statuses = (Array.isArray(status) ? status : status ? [status] : []).filter(Boolean);
  const where = await buildPoHistoryWhere({
    dateFrom, dateTo, approvedFrom, approvedTo, vesselId, accountId, statuses,
  });

  const total = await db.purchaseOrder.count({ where });
  const { perPage, page, totalPages, skip, take } = resolvePagination({
    perPageParam,
    pageParam,
    total,
    options: PER_PAGE_OPTIONS,
    defaultPerPage: DEFAULT_PER_PAGE,
  });

  const [orders, vessels, leafAccounts] = await Promise.all([
    db.purchaseOrder.findMany({
      where,
      include: { submitter: true, vessel: true, account: true },
      orderBy: { createdAt: "desc" },
      skip,
      take,
    }),
    db.vessel.findMany({ orderBy: { name: "asc" }, select: { id: true, name: true } }),
    db.account.findMany({
      where: { isActive: true, children: { none: {} } },
      orderBy: { code: "asc" },
      select: { id: true, code: true, name: true, parent: { select: { name: true, code: true, parent: { select: { name: true, code: true } } } } },
    }),
  ]);

  const accounts = buildAccountGroups(leafAccounts);

  // Shared filter params for the pagination footer links (everything except `page`).
  const pageParams = new URLSearchParams();
  if (dateFrom) pageParams.set("dateFrom", dateFrom);
  if (dateTo) pageParams.set("dateTo", dateTo);
  if (approvedFrom) pageParams.set("approvedFrom", approvedFrom);
  if (approvedTo) pageParams.set("approvedTo", approvedTo);
  if (vesselId) pageParams.set("vesselId", vesselId);
  if (accountId) pageParams.set("accountId", accountId);
  for (const s of statuses) pageParams.append("status", s);
  pageParams.set("perPage", String(perPage));

  const pageHref = (p: number) => {
    const params = new URLSearchParams(pageParams);
    params.set("page", String(p));
    return `/history?${params.toString()}`;
  };

  const firstRow = total === 0 ? 0 : skip + 1;
  const lastRow = skip + orders.length;

  const exportParams = new URLSearchParams({ format: "csv" });
  if (dateFrom) exportParams.set("dateFrom", dateFrom);
  if (dateTo) exportParams.set("dateTo", dateTo);
  if (approvedFrom) exportParams.set("approvedFrom", approvedFrom);
  if (approvedTo) exportParams.set("approvedTo", approvedTo);
  if (vesselId) exportParams.set("vesselId", vesselId);
  if (accountId) exportParams.set("accountId", accountId);
  for (const s of statuses) exportParams.append("status", s);

  return (
    <div>
      <div className="mb-4 flex items-center justify-between">
        <h1 className="text-2xl font-semibold text-neutral-900">PO History</h1>
        <div className="flex items-center gap-2">
          <a
            href={`/api/reports/export?${exportParams.toString()}&format=pdf`}
            target="_blank"
            rel="noopener noreferrer"
            className="rounded-lg border border-neutral-300 bg-white px-3 py-2 text-sm font-medium text-neutral-700 hover:bg-neutral-50 transition-colors"
          >
            Export PDF
          </a>
          <a
            href={`/api/reports/export?${exportParams.toString()}`}
            className="rounded-lg border border-neutral-300 bg-white px-3 py-2 text-sm font-medium text-neutral-700 hover:bg-neutral-50 transition-colors"
          >
            Export CSV
          </a>
        </div>
      </div>

      <Suspense>
        <HistoryFilters vessels={vessels} accounts={accounts} perPageOptions={PER_PAGE_OPTIONS} defaultPerPage={DEFAULT_PER_PAGE} />
      </Suspense>

      <div className="rounded-lg border border-neutral-200 bg-white overflow-hidden">
        <table className="w-full text-sm">
          <thead className="bg-neutral-50 border-b border-neutral-200">
            <tr>
              <th className="px-4 py-3 text-left font-medium text-neutral-600">PO Number</th>
              <th className="px-4 py-3 text-left font-medium text-neutral-600">Title</th>
              <th className="px-4 py-3 text-left font-medium text-neutral-600">Cost Centre</th>
              <th className="px-4 py-3 text-left font-medium text-neutral-600">Accounting Code</th>
              <th className="px-4 py-3 text-left font-medium text-neutral-600">Submitter</th>
              <th className="px-4 py-3 text-left font-medium text-neutral-600">Status</th>
              <th className="px-4 py-3 text-right font-medium text-neutral-600">Amount</th>
              <th className="px-4 py-3 text-left font-medium text-neutral-600">Created</th>
            </tr>
          </thead>
          <tbody className="divide-y divide-neutral-100">
            {orders.map((po) => (
              <tr
                key={po.id}
                className={`hover:bg-neutral-50 ${po.status === "CANCELLED" ? "bg-neutral-50/60 text-neutral-400 [&_td]:text-neutral-400" : ""}`}
              >
                <td className="px-4 py-3">
                  <Link href={`/po/${po.id}`} className="font-mono text-xs text-primary-600 hover:text-primary-700">
                    {po.poNumber}
                  </Link>
                </td>
                <td className="px-4 py-3 font-medium text-neutral-900 max-w-xs truncate">{po.title}</td>
                <td className="px-4 py-3 text-neutral-600">{po.vessel.name}</td>
                <td className="px-4 py-3 text-neutral-600">
                  <span className="font-mono text-xs text-neutral-400">{po.account.code}</span> {po.account.name}
                </td>
                <td className="px-4 py-3 text-neutral-600">{po.submitter.name}</td>
                <td className="px-4 py-3">
                  <PoStatusBadge status={po.status} />
                </td>
                <td className="px-4 py-3 text-right font-mono text-xs">
                  {formatCurrency(Number(po.totalAmount), po.currency)}
                </td>
                <td className="px-4 py-3 text-neutral-500">{formatDate(po.createdAt)}</td>
              </tr>
            ))}
          </tbody>
        </table>
        {orders.length === 0 && (
          <div className="p-12 text-center text-neutral-500">No purchase orders found.</div>
        )}
      </div>
      {total > 0 && (
        <div className="mt-3 flex items-center justify-between text-sm text-neutral-600">
          <span>
            Showing {firstRow}–{lastRow} of {total}
          </span>
          <div className="flex items-center gap-2">
            {page > 1 ? (
              <Link
                href={pageHref(page - 1)}
                className="rounded-lg border border-neutral-300 bg-white px-3 py-1.5 font-medium text-neutral-700 hover:bg-neutral-50 transition-colors"
              >
                Previous
              </Link>
            ) : (
              <span className="rounded-lg border border-neutral-200 bg-neutral-50 px-3 py-1.5 font-medium text-neutral-300">
                Previous
              </span>
            )}
            <span className="text-neutral-500">
              Page {page} of {totalPages}
            </span>
            {page < totalPages ? (
              <Link
                href={pageHref(page + 1)}
                className="rounded-lg border border-neutral-300 bg-white px-3 py-1.5 font-medium text-neutral-700 hover:bg-neutral-50 transition-colors"
              >
                Next
              </Link>
            ) : (
              <span className="rounded-lg border border-neutral-200 bg-neutral-50 px-3 py-1.5 font-medium text-neutral-300">
                Next
              </span>
            )}
          </div>
        </div>
      )}
    </div>
  );
}