import Link from "next/link";
import { CreditCard, Receipt } from "lucide-react";
import { requireAdmin } from "@/lib/session";
import { getBillingOverview } from "@/lib/queries/admin";
import { formatNumber, formatUsd } from "@/lib/format";
import { PageHeader } from "@/components/ui/page-header";
import { Alert } from "@/components/ui/alert";
import { Badge, StatusBadge } from "@/components/ui/badge";
import { EmptyState } from "@/components/ui/empty-state";
import { Stat, StatGrid } from "@/components/ui/stat";
import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "@/components/ui/table";
import { DateCell, MarginText, Mono, Panel, PlanBadge, numCell } from "@/components/admin/primitives";

export const dynamic = "force-dynamic";

export default async function AdminBillingPage() {
  await requireAdmin();
  const b = await getBillingOverview();
  const paying = b.distribution.filter((d) => d.price > 0).reduce((s, d) => s + d.orgs, 0);

  return (
    <>
      <PageHeader eyebrow="Revenue" title="Billing" description="Private platform: a single Unlimited plan with no list price, so MRR is always zero. Usage revenue reflects metered price_usd only. Stripe checkout and invoicing are not connected." />

      {!b.stripeConfigured ? (
        <Alert variant="info" title="Stripe is not connected" className="mb-4">
          `STRIPE_SECRET_KEY` is not set and there is nothing to bill: every organization is on the Unlimited plan (private platform, no billing). Subscriptions and billing events below stay empty unless a Stripe integration is added later.
        </Alert>
      ) : null}

      <StatGrid cols={4} className="mb-6">
        <Stat label="MRR estimate" value={formatUsd(b.mrr)} hint="orgs × plan list price" />
        <Stat label="Paying organizations" value={formatNumber(paying)} hint={`${b.stripeCustomers} with a Stripe customer id`} />
        <Stat label="Usage revenue 30d" value={formatUsd(b.usageRevenue30d)} hint="metered price_usd" />
        <Stat label="Usage margin 30d" value={<MarginText value={b.usageRevenue30d - b.usageCost30d} pct={b.usageRevenue30d > 0 ? ((b.usageRevenue30d - b.usageCost30d) / b.usageRevenue30d) * 100 : null} />} hint="vs upstream cost" />
      </StatGrid>

      <Panel title="Plan distribution" flush>
        <Table>
          <TableHeader>
            <TableRow>
              <TableHead>Plan</TableHead>
              <TableHead className="text-right">Organizations</TableHead>
              <TableHead className="text-right">List price / mo</TableHead>
              <TableHead className="text-right">MRR</TableHead>
              <TableHead></TableHead>
            </TableRow>
          </TableHeader>
          <TableBody>
            {b.distribution.map((d) => (
              <TableRow key={d.plan}>
                <TableCell>
                  <PlanBadge plan={d.plan} />
                </TableCell>
                <TableCell className={numCell}>{formatNumber(d.orgs)}</TableCell>
                <TableCell className={numCell}>{formatUsd(d.price)}</TableCell>
                <TableCell className={numCell}>{formatUsd(d.mrr)}</TableCell>
                <TableCell className="text-right">
                  <Link href={`/admin/organizations?plan=${d.plan}`} className="text-[12.5px] text-accent hover:underline">
                    view →
                  </Link>
                </TableCell>
              </TableRow>
            ))}
            {b.unknown.map((u) => (
              <TableRow key={u.plan}>
                <TableCell>
                  <Badge variant="danger">{u.plan}</Badge> <span className="text-[12px] text-fg-muted">legacy plan value — treated as Unlimited; run `pnpm db:seed` to normalize</span>
                </TableCell>
                <TableCell className={numCell}>{u.n}</TableCell>
                <TableCell className={numCell}>—</TableCell>
                <TableCell className={numCell}>—</TableCell>
                <TableCell />
              </TableRow>
            ))}
          </TableBody>
        </Table>
      </Panel>

      <div className="mt-6 grid gap-6 xl:grid-cols-2">
        <Panel title="Subscriptions" flush>
          {b.subs.length === 0 ? (
            <div className="p-4">
              <EmptyState icon={CreditCard} title="No subscriptions" description="Stripe is not connected yet. Rows appear here when checkout goes live and webhooks create subscriptions." compact />
            </div>
          ) : (
            <Table>
              <TableHeader>
                <TableRow>
                  <TableHead>Organization</TableHead>
                  <TableHead>Plan</TableHead>
                  <TableHead>Status</TableHead>
                  <TableHead>Period</TableHead>
                  <TableHead>Stripe</TableHead>
                </TableRow>
              </TableHeader>
              <TableBody>
                {b.subs.map((s) => (
                  <TableRow key={s.id}>
                    <TableCell>
                      <Link href={`/admin/organizations/${s.organizationId}`} className="hover:underline">
                        {s.orgName ?? s.organizationId}
                      </Link>
                    </TableCell>
                    <TableCell>
                      <PlanBadge plan={s.plan} />
                    </TableCell>
                    <TableCell>
                      <StatusBadge status={s.status} />
                      {s.cancelAtPeriodEnd ? <Badge variant="warning" className="ml-1">cancels</Badge> : null}
                    </TableCell>
                    <TableCell className="text-[12.5px] text-fg-muted">
                      <DateCell value={s.currentPeriodStart} relative={false} /> → <DateCell value={s.currentPeriodEnd} relative={false} />
                    </TableCell>
                    <TableCell>
                      <Mono>{s.stripeSubscriptionId ?? "—"}</Mono>
                    </TableCell>
                  </TableRow>
                ))}
              </TableBody>
            </Table>
          )}
        </Panel>
        <Panel title="Billing events" flush>
          {b.events.length === 0 ? (
            <div className="p-4">
              <EmptyState icon={Receipt} title="No billing events" description="Stripe webhook events (invoices, payment failures, plan changes) will be listed here once the integration is live." compact />
            </div>
          ) : (
            <Table>
              <TableHeader>
                <TableRow>
                  <TableHead>When</TableHead>
                  <TableHead>Type</TableHead>
                  <TableHead>Organization</TableHead>
                  <TableHead>Stripe event</TableHead>
                </TableRow>
              </TableHeader>
              <TableBody>
                {b.events.map((e) => (
                  <TableRow key={e.id}>
                    <TableCell>
                      <DateCell value={e.createdAt} relative={false} />
                    </TableCell>
                    <TableCell>
                      <Mono>{e.type}</Mono>
                    </TableCell>
                    <TableCell>{e.orgName ?? e.organizationId ?? "—"}</TableCell>
                    <TableCell>
                      <Mono>{e.stripeEventId ?? "—"}</Mono>
                    </TableCell>
                  </TableRow>
                ))}
              </TableBody>
            </Table>
          )}
        </Panel>
      </div>
    </>
  );
}