"use client";

import { useRouter } from "next/navigation";
import { useState, useTransition } from "react";
import { Button } from "@/components/ui/button";
import { Modal } from "@/components/ui/modal";
import { Textarea } from "@/components/ui/textarea";
import {
  cancelStaffAppointmentAction,
  checkInAppointmentAction,
  completeAppointmentAction,
  confirmAppointmentAction,
  markNoShowAction,
  startAppointmentAction,
} from "../actions/appointment-actions";
import type { StaffAppointmentActionResult } from "../actions/appointment-actions";

type RawStatus =
  "PENDING" | "CONFIRMED" | "CHECKED_IN" | "IN_PROGRESS" | "COMPLETED" | "CANCELLED" | "NO_SHOW";
type ConfirmKind = "complete" | "no_show" | "cancel";

/** Same shape the owner variant (src/features/owner/actions/appointments.ts) implements — see AppointmentStatusActions' `actions` prop. */
export interface AppointmentActionSet {
  confirm: (appointmentId: string) => Promise<StaffAppointmentActionResult>;
  checkIn: (appointmentId: string) => Promise<StaffAppointmentActionResult>;
  start: (appointmentId: string) => Promise<StaffAppointmentActionResult>;
  complete: (appointmentId: string) => Promise<StaffAppointmentActionResult>;
  markNoShow: (appointmentId: string) => Promise<StaffAppointmentActionResult>;
  cancel: (params: { appointmentId: string; reason?: string }) => Promise<StaffAppointmentActionResult>;
}

const DEFAULT_ACTIONS: AppointmentActionSet = {
  confirm: confirmAppointmentAction,
  checkIn: checkInAppointmentAction,
  start: startAppointmentAction,
  complete: completeAppointmentAction,
  markNoShow: markNoShowAction,
  cancel: cancelStaffAppointmentAction,
};

/**
 * The status-appropriate action set — shared by Current Appointment and
 * Appointment Details, since both need exactly the same buttons for the
 * same status. Every button calls a Server Action that delegates to
 * AppointmentService's own state machine; this component never decides
 * whether a transition is legal, only which buttons to *offer* for a given
 * status (offering an illegal one would just get rejected server-side —
 * see appointment-actions.ts). `actions` defaults to the staff (own-only)
 * Server Actions; the owner appointment details page passes the owner
 * variant instead, so this one component serves both contexts without
 * forking — see docs/phase-6-summary.md, "Owner appointment access".
 */
export function AppointmentStatusActions({
  appointmentId,
  status,
  actions = DEFAULT_ACTIONS,
  layout = "wrap",
}: {
  appointmentId: string;
  status: RawStatus;
  actions?: AppointmentActionSet;
  /** "stack" renders one full-width button per row (Current Appointment); "wrap" (default, used by Appointment Details) keeps the original inline small buttons. */
  layout?: "wrap" | "stack";
}) {
  const router = useRouter();
  const [isPending, startTransition] = useTransition();
  const [error, setError] = useState<string | null>(null);
  const [confirmKind, setConfirmKind] = useState<ConfirmKind | null>(null);
  const [reason, setReason] = useState("");
  const [done, setDone] = useState<{ loyaltyStampAwarded?: boolean } | null>(null);

  const runQuiet = (action: () => Promise<{ success: boolean; error?: string }>) => {
    setError(null);
    startTransition(async () => {
      const result = await action();
      if (!result.success) {
        setError(result.error ?? "Something went wrong.");
        return;
      }
      router.refresh();
    });
  };

  const runConfirmed = () => {
    if (!confirmKind) return;
    setError(null);
    startTransition(async () => {
      const result =
        confirmKind === "complete"
          ? await actions.complete(appointmentId)
          : confirmKind === "no_show"
            ? await actions.markNoShow(appointmentId)
            : await actions.cancel({ appointmentId, reason: reason || undefined });
      if (!result.success) {
        setError(result.error ?? "Something went wrong.");
        return;
      }
      setDone(
        confirmKind === "complete" ? { loyaltyStampAwarded: result.loyaltyStampAwarded } : {},
      );
    });
  };

  const closeConfirm = () => {
    const shouldRefresh = !!done;
    setConfirmKind(null);
    setDone(null);
    setReason("");
    setError(null);
    if (shouldRefresh) router.refresh();
  };

  const modalTitle =
    confirmKind === "complete"
      ? "Complete Appointment?"
      : confirmKind === "no_show"
        ? "Mark as No-Show?"
        : "Cancel Appointment?";

  // "wrap" buttons are `flex-1` (not intrinsically sized) so a row of
  // two or three ends up as an even, aligned segmented row instead of
  // packing left at whatever width each label's text happens to need —
  // that's what made "Check In"/"Mark No-Show"/"Cancel" (very different
  // label lengths) look lopsided together. `min-w` keeps a button from
  // getting squeezed illegibly thin before the row wraps.
  const buttonSize = layout === "stack" ? undefined : "sm";
  const buttonClassName = layout === "stack" ? "w-full" : "min-w-[110px] flex-1";

  return (
    <div className="space-y-3">
      {error && !confirmKind && (
        <p role="alert" className="text-danger text-sm font-medium">
          {error}
        </p>
      )}
      <div className={layout === "stack" ? "flex flex-col gap-2" : "flex flex-wrap gap-2"}>
        {status === "PENDING" && (
          <Button
            size={buttonSize}
            className={buttonClassName}
            isLoading={isPending}
            onClick={() => runQuiet(() => actions.confirm(appointmentId))}
          >
            Confirm Booking
          </Button>
        )}
        {status === "CONFIRMED" && (
          <Button
            size={buttonSize}
            className={buttonClassName}
            isLoading={isPending}
            onClick={() => runQuiet(() => actions.checkIn(appointmentId))}
          >
            Check In
          </Button>
        )}
        {status === "CHECKED_IN" && (
          <Button
            size={buttonSize}
            className={buttonClassName}
            isLoading={isPending}
            onClick={() => runQuiet(() => actions.start(appointmentId))}
          >
            Start Appointment
          </Button>
        )}
        {status === "IN_PROGRESS" && (
          <Button size={buttonSize} className={buttonClassName} onClick={() => setConfirmKind("complete")}>
            Complete Appointment
          </Button>
        )}
        {status === "CONFIRMED" && (
          <Button size={buttonSize} className={buttonClassName} variant="secondary" onClick={() => setConfirmKind("no_show")}>
            Mark No-Show
          </Button>
        )}
        {(status === "PENDING" || status === "CONFIRMED" || status === "CHECKED_IN") && (
          <Button size={buttonSize} className={buttonClassName} variant="destructive" onClick={() => setConfirmKind("cancel")}>
            Cancel
          </Button>
        )}
      </div>

      <Modal open={!!confirmKind} onClose={closeConfirm} title={done ? "Done" : modalTitle}>
        {done ? (
          <div className="space-y-4">
            <p role="status" className="text-muted text-sm">
              {confirmKind === "complete" && "This appointment is marked complete."}
              {confirmKind === "no_show" && "This appointment is marked as a no-show."}
              {confirmKind === "cancel" &&
                "This appointment has been cancelled. It won't be deleted from history."}
            </p>
            {done.loyaltyStampAwarded && (
              <p className="border-accent-loyalty/30 bg-accent-loyalty/10 rounded-lg border p-3 text-xs font-medium">
                A loyalty stamp was added for this visit.
              </p>
            )}
            <Button className="w-full" onClick={closeConfirm}>
              Done
            </Button>
          </div>
        ) : (
          <div className="space-y-4">
            <p className="text-muted text-sm">
              {confirmKind === "complete" &&
                "This marks the visit as finished and (if eligible) adds a loyalty stamp."}
              {confirmKind === "no_show" &&
                "The customer didn't arrive for this appointment. This can't be undone."}
              {confirmKind === "cancel" &&
                "This can't be undone. You can add an optional reason below."}
            </p>
            {confirmKind === "cancel" && (
              <Textarea
                placeholder="Reason (optional)"
                value={reason}
                onChange={(e) => setReason(e.target.value)}
              />
            )}
            {error && (
              <p role="alert" className="text-danger text-sm font-medium">
                {error}
              </p>
            )}
            <div className="flex gap-3">
              <Button variant="secondary" className="flex-1" onClick={closeConfirm}>
                Keep As Is
              </Button>
              <Button
                variant={confirmKind === "complete" ? "primary" : "destructive"}
                className="flex-1"
                isLoading={isPending}
                onClick={runConfirmed}
              >
                {confirmKind === "complete"
                  ? "Complete"
                  : confirmKind === "no_show"
                    ? "Mark No-Show"
                    : "Cancel It"}
              </Button>
            </div>
          </div>
        )}
      </Modal>
    </div>
  );
}