import type { Metadata } from "next";
import { CalendarPlus, LogIn } from "lucide-react";
import Link from "next/link";
import { auth } from "@/auth";
import { AppointmentCard } from "@/components/ui/appointment-card";
import { Button } from "@/components/ui/button";
import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
import { EmptyState } from "@/components/feedback/empty-state";
import { TopNav } from "@/components/navigation/top-nav";
import { getPrimaryBusiness } from "@/lib/business/get-primary-business";
import { prisma } from "@/lib/db/prisma";
import { listAppointments } from "@/services/scheduling/appointment.service";
import { getUnreadNotificationCount } from "@/services/notifications/notification.service";
import { BookAgainButton } from "@/features/booking/components/book-again-button";
import { CancelAppointmentDialog } from "@/features/booking/components/cancel-appointment-dialog";
import { InlineNotificationBell } from "@/features/notifications/components/notification-bell";
import type { AppointmentStatus } from "@/types/domain";

export const metadata: Metadata = { title: "Appointments" };
export const dynamic = "force-dynamic";

const STATUS_MAP: Record<string, AppointmentStatus> = {
  PENDING: "pending_approval",
  CONFIRMED: "confirmed",
  CHECKED_IN: "arrived",
  IN_PROGRESS: "in_progress",
  COMPLETED: "completed",
  CANCELLED: "cancelled",
  NO_SHOW: "no_show",
};

const UPCOMING_STATUSES = ["PENDING", "CONFIRMED", "CHECKED_IN", "IN_PROGRESS"] as const;
const CANCELLED_STATUSES = ["CANCELLED", "NO_SHOW"] as const;
const RESCHEDULABLE_STATUSES = new Set(["PENDING", "CONFIRMED", "CHECKED_IN"]);
const CANCELLABLE_STATUSES = new Set(["PENDING", "CONFIRMED", "CHECKED_IN"]);

export default async function AppointmentsPage() {
  const session = await auth();

  if (!session?.user) {
    return (
      <div className="pb-12">
        <TopNav title="Appointments" sticky className="bg-stone" />
        <div className="mx-auto max-w-2xl px-6 pt-6">
          <EmptyState
            icon={LogIn}
            title="Sign in to see your appointments"
            description="Create an account or sign in to view, reschedule, and cancel your bookings."
            action={
              <Button asChild>
                <Link href="/sign-in?callbackUrl=/appointments">Sign In</Link>
              </Button>
            }
          />
        </div>
      </div>
    );
  }

  const [business, unreadNotificationCount] = await Promise.all([
    getPrimaryBusiness(),
    getUnreadNotificationCount(prisma, session.user.id),
  ]);
  const customerProfile = await prisma.customerProfile.findUnique({
    where: { userId: session.user.id },
  });
  const bell = <InlineNotificationBell href="/notifications" unreadCount={unreadNotificationCount} />;

  if (!customerProfile) {
    return (
      <div className="pb-12">
        <TopNav title="Appointments" sticky className="bg-stone" action={bell} />
        <div className="mx-auto max-w-2xl px-6 pt-6">
          <EmptyState
            icon={CalendarPlus}
            title="No appointments yet"
            description="Book your first appointment to see it here."
            action={
              <Button asChild>
                <Link href="/book">Book Now</Link>
              </Button>
            }
          />
        </div>
      </div>
    );
  }

  const [upcoming, past, cancelled] = await Promise.all([
    listAppointments(prisma, { customerId: customerProfile.id, statuses: [...UPCOMING_STATUSES] }),
    listAppointments(prisma, { customerId: customerProfile.id, statuses: ["COMPLETED"] }),
    listAppointments(prisma, { customerId: customerProfile.id, statuses: [...CANCELLED_STATUSES] }),
  ]);

  const renderList = (appointments: typeof upcoming, kind: "upcoming" | "past" | "cancelled") => {
    if (appointments.length === 0) {
      return (
        <EmptyState
          icon={CalendarPlus}
          title={
            kind === "upcoming"
              ? "No upcoming appointments"
              : kind === "past"
                ? "No past appointments"
                : "No cancelled appointments"
          }
          description={kind === "upcoming" ? "Book your next visit in a few taps." : undefined}
          action={
            kind === "upcoming" ? (
              <Button asChild>
                <Link href="/book">Book Now</Link>
              </Button>
            ) : undefined
          }
        />
      );
    }

    return (
      <div className="space-y-4">
        {appointments.map((appointment) => (
          <AppointmentCard
            key={appointment.id}
            status={STATUS_MAP[appointment.status] ?? "confirmed"}
            serviceName={appointment.services.map((s) => s.service.name).join(" + ")}
            person={{ id: appointment.staffId, name: appointment.staff.user.name ?? "Barber" }}
            formattedDate={appointment.startAt.toLocaleDateString("en-GB", {
              weekday: "short",
              day: "numeric",
              month: "short",
              timeZone: business.timezone,
            })}
            formattedTime={appointment.startAt.toLocaleTimeString("en-GB", {
              hour: "2-digit",
              minute: "2-digit",
              timeZone: business.timezone,
            })}
            actions={
              <div className="flex flex-1 flex-wrap gap-2">
                <Link
                  href={`/appointments/${appointment.id}`}
                  className="border-line rounded-lg border px-4 py-2 text-xs font-bold tracking-widest uppercase"
                >
                  View
                </Link>
                {kind === "upcoming" && RESCHEDULABLE_STATUSES.has(appointment.status) && (
                  <Link
                    href={`/appointments/${appointment.id}/reschedule`}
                    className="border-line rounded-lg border px-4 py-2 text-xs font-bold tracking-widest uppercase"
                  >
                    Reschedule
                  </Link>
                )}
                {kind === "upcoming" && CANCELLABLE_STATUSES.has(appointment.status) && (
                  <CancelAppointmentDialog appointmentId={appointment.id} />
                )}
                {kind !== "upcoming" && <BookAgainButton appointmentId={appointment.id} />}
              </div>
            }
          />
        ))}
      </div>
    );
  };

  return (
    <div className="pb-12">
      <TopNav title="Appointments" sticky className="bg-stone" action={bell} />
      <div className="mx-auto max-w-2xl px-6 pt-6">
        <Tabs defaultValue="upcoming">
          <TabsList>
            <TabsTrigger value="upcoming">Upcoming</TabsTrigger>
            <TabsTrigger value="past">Past</TabsTrigger>
            <TabsTrigger value="cancelled">Cancelled</TabsTrigger>
          </TabsList>
          <TabsContent value="upcoming">{renderList(upcoming, "upcoming")}</TabsContent>
          <TabsContent value="past">{renderList(past, "past")}</TabsContent>
          <TabsContent value="cancelled">{renderList(cancelled, "cancelled")}</TabsContent>
        </Tabs>
      </div>
    </div>
  );
}