import { useMemo, useState } from 'react';
import { useParams, useNavigate } from 'react-router-dom';
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import { useForm } from 'react-hook-form';
import { zodResolver } from '@hookform/resolvers/zod';
import { z } from 'zod';
import { toast } from 'sonner';
import { ChevronRightIcon, PlusIcon, XMarkIcon } from '@heroicons/react/24/outline';
import { api } from '../lib/api';
import type { ApiResponse } from '../lib/api';
import type { PatientRecord, ServiceSection, ServiceItem } from '../types';
import { formatRial } from '../lib/utils';
import SearchableSelect from '../components/ui/SearchableSelect';

const schema = z.object({
  visit_price_rials: z.coerce.number().min(0),
  base_insurance_discount_percent: z.coerce.number().min(0).max(100),
  supplementary_discount_percent: z.coerce.number().min(0).max(100),
  insurance_base_id: z.coerce.number().optional(),
  insurance_supplementary_id: z.coerce.number().optional(),
  payment_method: z.enum(['cash', 'card', 'insurance', 'online', 'pending']),
  notes: z.string().optional(),
});
type FormData = z.infer<typeof schema>;

interface PricingInsurance { insurance_id: number; insurance_name: string; type: string; patient_share_rials: number | null }
interface InsurancePricing { free_visit_price_rials: number; insurances: PricingInsurance[] }

const PAYMENT_LABELS: Record<string, string> = {
  cash: 'نقدی', card: 'کارت', insurance: 'بیمه', online: 'آنلاین', pending: 'در انتظار',
};

function calcFinal(visit: number, base: number, supp: number, services: number) {
  const afterBase = visit * (1 - base / 100);
  const afterSupp = afterBase * (1 - supp / 100);
  return Math.round(afterSupp) + services;
}

const sectionTitle: React.CSSProperties = { fontWeight: 700, fontSize: 13.5, color: 'var(--text-2)', margin: '0 0 12px' };
const fieldLabel: React.CSSProperties = { fontSize: 12.5, fontWeight: 600, marginBottom: 5, display: 'block' };

export default function NewSessionPage() {
  const { recordUuid = '' } = useParams();
  const nav = useNavigate();
  const qc = useQueryClient();

  const [selectedServices, setSelectedServices] = useState<{ uuid: string; name: string; price: number }[]>([]);
  const [sectionUuid, setSectionUuid] = useState('');
  const [itemUuid, setItemUuid] = useState('');
  const [baseId, setBaseId] = useState('');
  const [suppId, setSuppId] = useState('');

  const form = useForm<FormData>({
    resolver: zodResolver(schema),
    defaultValues: { visit_price_rials: 0, base_insurance_discount_percent: 0, supplementary_discount_percent: 0, payment_method: 'cash' },
  });

  const recordQ = useQuery<ApiResponse<PatientRecord>>({
    queryKey: ['patient-detail', recordUuid],
    queryFn: () => api.get(`/api/v1/patient/${recordUuid}`),
    enabled: !!recordUuid,
  });
  const record = (recordQ.data?.data as PatientRecord | undefined) ?? undefined;
  const patientName = record?.user_name || record?.profile?.full_name || '—';

  const { data: sectionsData } = useQuery<ApiResponse<ServiceSection[]>>({
    queryKey: ['service-sections'], queryFn: () => api.get('/api/v1/service-sections'),
  });
  const { data: itemsData } = useQuery<ApiResponse<ServiceItem[]>>({
    queryKey: ['service-items-for-session', sectionUuid],
    queryFn: () => api.get(`/api/v1/service-items/${sectionUuid}`),
    enabled: !!sectionUuid,
  });
  const { data: pricingData } = useQuery<ApiResponse<InsurancePricing>>({
    queryKey: ['insurance-pricing'], queryFn: () => api.get('/api/v1/insurance-pricing'),
  });

  const pricing = (pricingData?.data as InsurancePricing | undefined) ?? undefined;
  const freeVisit = pricing?.free_visit_price_rials ?? 0;
  const baseOpts = (pricing?.insurances ?? []).filter(i => i.type === 'basic').map(i => ({ value: String(i.insurance_id), label: i.insurance_name }));
  const suppOpts = (pricing?.insurances ?? []).filter(i => i.type === 'supplementary').map(i => ({ value: String(i.insurance_id), label: i.insurance_name }));

  const sectionOptions = (sectionsData?.data ?? []).map(s => ({ value: s.uuid, label: s.name }));
  const itemOptions = (itemsData?.data ?? []).filter(i => i.active).map(i => ({ value: i.uuid, label: `${i.name} — ${formatRial(i.price_rials)}` }));

  const shareToPercent = (id: string): number => {
    if (!id || freeVisit <= 0) return 0;
    const ins = pricing?.insurances.find(i => String(i.insurance_id) === id);
    if (!ins || ins.patient_share_rials == null) return 0;
    return Math.round((Math.max(0, freeVisit - ins.patient_share_rials) / freeVisit) * 1000) / 10;
  };
  const applyBase = (id: string) => {
    setBaseId(id);
    form.setValue('insurance_base_id', id ? Number(id) : undefined);
    if (id && freeVisit > 0) {
      form.setValue('visit_price_rials', freeVisit);
      form.setValue('base_insurance_discount_percent', shareToPercent(id));
    }
  };
  const applySupp = (id: string) => {
    setSuppId(id);
    form.setValue('insurance_supplementary_id', id ? Number(id) : undefined);
    if (id) form.setValue('supplementary_discount_percent', shareToPercent(id));
  };

  const addService = () => {
    if (!itemUuid) return;
    const found = itemsData?.data?.find(i => i.uuid === itemUuid);
    if (!found || selectedServices.some(s => s.uuid === found.uuid)) return;
    setSelectedServices(p => [...p, { uuid: found.uuid, name: found.name, price: found.price_rials }]);
    setItemUuid('');
  };

  const visit = Number(form.watch('visit_price_rials')) || 0;
  const base = Number(form.watch('base_insurance_discount_percent')) || 0;
  const supp = Number(form.watch('supplementary_discount_percent')) || 0;
  const servicesTotal = useMemo(() => selectedServices.reduce((s, x) => s + x.price, 0), [selectedServices]);
  const afterBase = Math.round(visit * (1 - base / 100));
  const afterSupp = Math.round(afterBase * (1 - supp / 100));
  const finalPrice = calcFinal(visit, base, supp, servicesTotal);

  const createMut = useMutation({
    mutationFn: (body: object) => api.post(`/api/v1/patient/${recordUuid}/session`, body),
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ['patient-sessions', recordUuid] });
      toast.success('مراجعه ثبت شد');
      nav(-1);
    },
    onError: (e: Error) => toast.error(e.message),
  });

  const submit = form.handleSubmit((d) => {
    createMut.mutate({ ...d, services: selectedServices.map(s => ({ service_item_uuid: s.uuid })) });
  });

  const summaryRow = (label: string, val: number, strong = false) => (
    <div style={{ display: 'flex', justifyContent: 'space-between', fontSize: strong ? 15 : 13, fontWeight: strong ? 700 : 400, color: strong ? 'var(--text)' : 'var(--text-3)' }}>
      <span>{label}</span>
      <span style={strong ? { color: 'var(--primary)' } : undefined}>{formatRial(val)}</span>
    </div>
  );

  return (
    <div className="fade-in" style={{ maxWidth: 1100, margin: '0 auto' }}>
      <div style={{ display: 'flex', alignItems: 'center', gap: 10, marginBottom: 16 }}>
        <button className="btn ghost sm" onClick={() => nav(-1)}>
          <ChevronRightIcon style={{ width: 15 }} /> بازگشت
        </button>
        <div>
          <h1 className="section-title" style={{ margin: 0 }}>ثبت مراجعه جدید</h1>
          <div className="muted" style={{ fontSize: 13, marginTop: 2 }}>بیمار: {patientName}</div>
        </div>
      </div>

      <form onSubmit={submit} style={{ display: 'grid', gridTemplateColumns: 'minmax(0,1fr) 320px', gap: 16, alignItems: 'start' }}>
        <div style={{ display: 'flex', flexDirection: 'column', gap: 16 }}>
          <div className="card" style={{ padding: 20 }}>
            <h3 style={sectionTitle}>بیمه و مبلغ ویزیت</h3>
            <div style={{ display: 'grid', gridTemplateColumns: '1fr 1fr', gap: 12, marginBottom: 12 }}>
              <div>
                <label style={fieldLabel}>بیمه پایه</label>
                <SearchableSelect options={baseOpts} value={baseId} onChange={v => applyBase(v ? String(v) : '')} placeholder="بدون بیمه پایه" isClearable />
              </div>
              <div>
                <label style={fieldLabel}>بیمه تکمیلی</label>
                <SearchableSelect options={suppOpts} value={suppId} onChange={v => applySupp(v ? String(v) : '')} placeholder="بدون بیمه تکمیلی" isClearable />
              </div>
            </div>
            <div style={{ display: 'grid', gridTemplateColumns: '1fr 1fr 1fr', gap: 12 }}>
              <div>
                <label style={fieldLabel}>قیمت ویزیت (تومان)</label>
                <input className="input" type="number" min={0} dir="ltr" {...form.register('visit_price_rials')} />
              </div>
              <div>
                <label style={fieldLabel}>تخفیف بیمه پایه (%)</label>
                <input className="input" type="number" min={0} max={100} dir="ltr" {...form.register('base_insurance_discount_percent')} />
              </div>
              <div>
                <label style={fieldLabel}>تخفیف تکمیلی (%)</label>
                <input className="input" type="number" min={0} max={100} dir="ltr" {...form.register('supplementary_discount_percent')} />
              </div>
            </div>
          </div>

          <div className="card" style={{ padding: 20 }}>
            <h3 style={sectionTitle}>خدمات</h3>
            <div style={{ display: 'flex', gap: 8, marginBottom: selectedServices.length ? 12 : 0 }}>
              <div style={{ flex: 1 }}>
                <SearchableSelect options={sectionOptions} value={sectionUuid} onChange={v => { setSectionUuid(v ? String(v) : ''); setItemUuid(''); }} placeholder="انتخاب بخش..." />
              </div>
              <div style={{ flex: 1 }}>
                <SearchableSelect options={itemOptions} value={itemUuid} onChange={v => setItemUuid(v ? String(v) : '')} placeholder="انتخاب سرویس..." isDisabled={!sectionUuid} />
              </div>
              <button type="button" className="btn primary sm" onClick={addService} disabled={!itemUuid}>
                <PlusIcon style={{ width: 14 }} />
              </button>
            </div>
            {selectedServices.length > 0 && (
              <div style={{ display: 'flex', flexWrap: 'wrap', gap: 6 }}>
                {selectedServices.map(svc => (
                  <span key={svc.uuid} style={{ display: 'inline-flex', alignItems: 'center', gap: 8, background: 'var(--primary-soft)', borderRadius: 20, padding: '4px 10px', fontSize: 12.5 }}>
                    <span style={{ fontWeight: 500 }}>{svc.name}</span>
                    <span style={{ color: 'var(--primary)', fontWeight: 600 }}>{formatRial(svc.price)}</span>
                    <button type="button" style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--danger)', padding: 0, display: 'flex' }}
                      onClick={() => setSelectedServices(p => p.filter(s => s.uuid !== svc.uuid))}>
                      <XMarkIcon style={{ width: 14 }} />
                    </button>
                  </span>
                ))}
              </div>
            )}
          </div>

          <div className="card" style={{ padding: 20 }}>
            <h3 style={sectionTitle}>پرداخت و یادداشت</h3>
            <div style={{ marginBottom: 12 }}>
              <label style={fieldLabel}>روش پرداخت</label>
              <SearchableSelect
                options={Object.entries(PAYMENT_LABELS).map(([v, l]) => ({ value: v, label: l }))}
                value={form.watch('payment_method')}
                onChange={v => form.setValue('payment_method', (v as FormData['payment_method']) || 'cash')}
                placeholder="روش پرداخت"
              />
            </div>
            <div>
              <label style={fieldLabel}>یادداشت</label>
              <textarea className="input" rows={3} dir="rtl" placeholder="یادداشت پزشک..." {...form.register('notes')} />
            </div>
          </div>
        </div>

        <div className="card" style={{ padding: 20, position: 'sticky', top: 16, display: 'flex', flexDirection: 'column', gap: 8 }}>
          <h3 style={sectionTitle}>خلاصه</h3>
          {summaryRow('ویزیت آزاد', visit)}
          {base > 0 && summaryRow('پس از بیمه پایه', afterBase)}
          {supp > 0 && summaryRow('پس از بیمه تکمیلی', afterSupp)}
          {servicesTotal > 0 && summaryRow('جمع خدمات', servicesTotal)}
          <div style={{ borderTop: '1px solid var(--border)', paddingTop: 8, marginTop: 2 }}>
            {summaryRow('مبلغ نهایی (سهم بیمار)', finalPrice, true)}
          </div>
          <button type="submit" className="btn primary block" style={{ marginTop: 8 }} disabled={createMut.isPending}>
            {createMut.isPending ? 'در حال ذخیره...' : 'ثبت مراجعه'}
          </button>
          <button type="button" className="btn ghost block" onClick={() => nav(-1)}>انصراف</button>
        </div>
      </form>
    </div>
  );
}