import React, { useState } from 'react';
import { useParams, useNavigate } from 'react-router-dom';
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import { ArrowRightIcon } from '@heroicons/react/24/outline';
import { toast } from 'sonner';
import { api } from '../lib/api';
import type { ApiResponse } from '../lib/api';
import type { Appointment, AppointmentStatus, AppointmentEvent } from '../types';
import { formatDate, formatDateTime, toDate } from '../lib/utils';
import PageHeader from '../components/ui/PageHeader';
import AppointmentInvoiceCard from '../components/AppointmentInvoiceCard';
import StatusBadge from '../components/ui/StatusBadge';
import ConfirmDialog from '../components/ui/ConfirmDialog';
import SearchableSelect from '../components/ui/SearchableSelect';
import ConfirmAppointmentModal from '../components/appointments/ConfirmAppointmentModal';

const ALL_STATUSES: { value: AppointmentStatus; label: string }[] = [
  { value: 'pending',             label: 'رزرو شده' },
  { value: 'confirmed',           label: 'تأیید شده' },
  { value: 'completed',           label: 'تکمیل شده' },
  { value: 'cancelled_by_doctor', label: 'لغو پزشک' },
  { value: 'cancelled_by_user',   label: 'لغو بیمار' },
  { value: 'no_show',             label: 'غیبت' },
  { value: 'expired',             label: 'منقضی' },
];

// روزِ محلیِ نوبت (YYYY-MM-DD) برای بازگشت به همان تاریخ در لیست.
const isoDay = (ts?: number | null) => {
  if (!ts) return '';
  const d = new Date(ts * 1000);
  return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}-${String(d.getDate()).padStart(2, '0')}`;
};

const timeOf = (ts?: number | null) => {
  const d = toDate(ts ?? null);
  return d
    ? new Intl.DateTimeFormat('fa-IR-u-nu-latn', { hour: '2-digit', minute: '2-digit', hour12: false }).format(d)
    : '—';
};

function InfoRow({ label, value }: { label: string; value: React.ReactNode }) {
  return (
    <div className="cp-info-row">
      <span className="cp-info-label text-sm">{label}</span>
      <span className="cp-info-value">{value ?? '—'}</span>
    </div>
  );
}

export default function AppointmentDetailPage() {
  const { uuid } = useParams<{ uuid: string }>();
  const navigate = useNavigate();
  const qc = useQueryClient();
  const [cancelOpen, setCancelOpen] = useState(false);
  const [confirmOpen, setConfirmOpen] = useState(false);
  const [cancelReason, setCancelReason] = useState('');
  const [newStatus, setNewStatus] = useState('');

  const { data, isLoading } = useQuery({
    queryKey: ['appointment', uuid],
    queryFn: () => api.get<ApiResponse<Appointment>>(`/api/v1/appointment/${uuid}`),
    enabled: !!uuid,
  });

  const eventsQuery = useQuery({
    queryKey: ['appointment-events', uuid],
    queryFn: () => api.get<ApiResponse<AppointmentEvent[]>>(`/api/v1/appointment/${uuid}/events`),
    enabled: !!uuid,
  });
  const events: AppointmentEvent[] = (eventsQuery.data?.data as any) ?? [];

  const statusMutation = useMutation({
    mutationFn: (status: string) =>
      api.patch<ApiResponse<null>>(`/api/v1/appointment/${uuid}/status`, { status, version: appt?.version }),
    onSuccess: () => {
      toast.success('وضعیت نوبت بروزرسانی شد');
      qc.invalidateQueries({ queryKey: ['appointment', uuid] });
      qc.invalidateQueries({ queryKey: ['appointment-events', uuid] });
    },
    onError: (err: Error) => toast.error(err.message),
  });

  const cancelMutation = useMutation({
    mutationFn: () => api.patch<ApiResponse<null>>(`/api/v1/appointment/${uuid}/status`, {
      status: 'cancelled_by_doctor',
      version: appt?.version,
      ...(cancelReason.trim() ? { cancel_reason: cancelReason.trim() } : {}),
    }),
    onSuccess: () => {
      toast.success('نوبت لغو شد');
      setCancelOpen(false);
      setCancelReason('');
      qc.invalidateQueries({ queryKey: ['appointment', uuid] });
      qc.invalidateQueries({ queryKey: ['appointment-events', uuid] });
    },
    onError: (err: Error) => toast.error(err.message),
  });

  // پاسخ single تودرتو است: { data: { data: {...} } }
  const appt: any = (data?.data as any)?.data ?? data?.data;

  // قطعی‌کردن هزینه و پرداخت دارد؛ از مسیر مودال می‌رود، نه PATCH وضعیت.
  function applyStatus() {
    if (!newStatus) return;
    if (newStatus === 'confirmed') {
      setConfirmOpen(true);
      return;
    }
    statusMutation.mutate(newStatus);
  }

  // بازگشت به همان روزِ نوبت (نه امروز).
  const day = isoDay(appt?.slot_start);
  const backTo = day ? `/admin/appointments?date=${day}` : '/admin/appointments';

  return (
    <div>
      <PageHeader
        backTo="/admin/appointments"
        title="جزئیات نوبت"
        breadcrumbs={[
          { label: 'داشبورد', to: '/admin/dashboard' },
          { label: 'نوبت‌ها', to: backTo },
          { label: 'جزئیات' },
        ]}
      />

      {isLoading ? (
        <div className="cp-card p-6 space-y-3">
          {Array.from({ length: 6 }).map((_, i) => (
            <div key={i} className="h-8 rounded-lg skeleton" />
          ))}
        </div>
      ) : appt ? (
        <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
          <div className="bg-[var(--surface)] rounded-2xl border border-[var(--border)] shadow-sm p-6">
            <h3 className="font-semibold text-[var(--text)] mb-4">اطلاعات بیمار</h3>
            <InfoRow label="نام بیمار" value={appt.patient_name} />
            <InfoRow label="موبایل" value={<span dir="ltr">{appt.patient_mobile}</span>} />
            <InfoRow label="پزشک" value={appt.doctor?.name ?? null} />
            <InfoRow label="تاریخ نوبت" value={formatDate(appt.slot_start)} />
            <InfoRow label="ساعت شروع" value={timeOf(appt.slot_start)} />
            <InfoRow label="ساعت پایان" value={timeOf(appt.slot_end)} />
            {appt.patient_reason && <InfoRow label="علت مراجعه" value={appt.patient_reason} />}
            {appt.note && <InfoRow label="توضیحات" value={appt.note} />}
            <InfoRow label="تاریخ ثبت" value={formatDateTime(appt.created_at)} />
          </div>

          <AppointmentInvoiceCard appointmentUuid={appt.uuid} />

          <div className="bg-[var(--surface)] rounded-2xl border border-[var(--border)] shadow-sm p-6">
            <h3 className="font-semibold text-[var(--text)] mb-4">وضعیت و اقدامات</h3>
            <div className="mb-4">
              <p className="text-sm text-[var(--text-2)] mb-2">وضعیت فعلی:</p>
              <StatusBadge type="appointment" value={appt.status} />
            </div>

            {appt.status === 'pending' && (
              <button
                onClick={() => setConfirmOpen(true)}
                className="btn primary w-full"
              >
                قطعی کردن نوبت
              </button>
            )}

            <div className="mt-6">
              <label className="cp-label mb-2">تغییر وضعیت:</label>
              <div className="flex gap-2">
                <div style={{ flex: 1 }}>
                  <SearchableSelect
                    options={ALL_STATUSES.map(s => ({ value: s.value, label: s.label }))}
                    value={newStatus || null}
                    onChange={(v) => setNewStatus(v ? String(v) : '')}
                    placeholder="انتخاب وضعیت..."
                    isClearable
                  />
                </div>
                <button
                  onClick={() => applyStatus()}
                  disabled={!newStatus || statusMutation.isPending}
                  className="btn primary sm"
                >
                  اعمال
                </button>
              </div>
            </div>

            <div className="mt-4 pt-4 border-t border-[var(--border)]">
              <button
                onClick={() => setCancelOpen(true)}
                className="w-full py-2 border border-[var(--danger)] text-[var(--danger)] text-sm rounded-[10px] hover:bg-[var(--danger-bg)] transition-colors"
              >
                لغو نوبت
              </button>
            </div>
          </div>

          <div className="bg-[var(--surface)] rounded-2xl border border-[var(--border)] shadow-sm p-6 lg:col-span-2">
            <h3 className="font-semibold text-[var(--text)] mb-4">تاریخچه رویدادها</h3>
            {eventsQuery.isLoading ? (
              <div className="h-6 w-40 rounded skeleton" />
            ) : events.length === 0 ? (
              <p className="text-sm text-[var(--text-3)]">رویدادی برای این نوبت ثبت نشده است.</p>
            ) : (
              <ol className="space-y-4">
                {events.map((ev, i) => (
                  <li key={i} className="flex gap-3">
                    <span className="mt-1.5 w-2.5 h-2.5 rounded-full bg-[var(--danger)] shrink-0" />
                    <div className="flex-1">
                      <div className="flex items-center justify-between gap-2">
                        <span className="text-sm font-medium text-[var(--text)]">{ev.title}</span>
                        <span className="text-xs text-[var(--text-3)]">{formatDateTime(ev.created_at)}</span>
                      </div>
                      {ev.actor_name && (
                        <div className="text-xs text-[var(--text-2)] mt-0.5">توسط: {ev.actor_name}</div>
                      )}
                      {ev.reason && (
                        <div className="text-xs text-[var(--text-2)] mt-0.5">دلیل: {ev.reason}</div>
                      )}
                    </div>
                  </li>
                ))}
              </ol>
            )}
          </div>
        </div>
      ) : (
        <div className="bg-[var(--surface)] rounded-2xl border border-[var(--border)] p-16 text-center text-[var(--text-3)]">
          نوبتی یافت نشد
        </div>
      )}

      <ConfirmDialog
        open={cancelOpen}
        title="لغو نوبت"
        message="آیا از لغو این نوبت اطمینان دارید؟"
        confirmLabel="لغو نوبت"
        danger
        loading={cancelMutation.isPending}
        onConfirm={() => cancelMutation.mutate()}
        onCancel={() => { setCancelOpen(false); setCancelReason(''); }}
      >
        <div style={{ marginTop: 14 }}>
          <label className="cp-label mb-2">دلیل لغو (اختیاری)</label>
          <textarea
            className="cp-input"
            rows={2}
            value={cancelReason}
            onChange={(e) => setCancelReason(e.target.value)}
            placeholder="دلیل لغو نوبت را وارد کنید..."
            style={{ width: '100%', resize: 'vertical' }}
          />
        </div>
      </ConfirmDialog>

      <ConfirmAppointmentModal
        open={confirmOpen}
        appointmentUuid={uuid!}
        appointment={appt}
        onClose={() => setConfirmOpen(false)}
        queryKey={['appointment', uuid]}
      />
    </div>
  );
}
