"use client";

import React, { useEffect, useState } from "react";
import { useAuth } from "@/hooks/useAuth";
import { useRouter } from "next/navigation";
import { apiFetch } from "@/lib/api";
import { useDismissingState } from "@/hooks/useDismissingState";
import { UserPlus } from "lucide-react";

type FormField = { id: string; type: 'yes_no'|'text'|'date'|'numeric'|'statement'|'paragraph'; label: string; isRequired?: boolean; helpText?: string|null };

export default function ManualRegistrationPage() {
  const { user, token, loading } = useAuth();
  const router = useRouter();
  const [eventId, setEventId] = useState("");
  const [optionId, setOptionId] = useState("");
  const [quantity, setQuantity] = useState(1);
  const [name, setName] = useState("");
  const [email, setEmail] = useState("");
  const [phoneNumber, setPhoneNumber] = useState("");
  const [registerAsGuest, setRegisterAsGuest] = useState(false);
  const [busy, setBusy] = useState(false);
  const [error, setError] = useDismissingState<string | null>(null);
  const [createdReg, setCreatedReg] = useState<any | null>(null);
  const [form, setForm] = useState<{ isRequired: boolean; fields: FormField[] } | null>(null);
  const [formsData, setFormsData] = useState<Record<number, Record<string, string>>>({});

  useEffect(() => {
    if (loading) return;
    if (!user) router.replace("/login");
  }, [user, loading, router]);

  async function submit(e: React.FormEvent) {
    e.preventDefault();
    if (!token) return;
    setBusy(true);
    setError(null);
    try {
      const res = await apiFetch<any>("/api/registrations/manual", {
        method: "POST",
        authToken: token,
        body: {
          eventId,
          options: [{ eventOptionId: optionId, quantity }],
          user: { name, ...(email ? { email } : {}), ...(phoneNumber ? { phoneNumber } : {}) },
          guestOnly: registerAsGuest,
        },
      });
      setCreatedReg(res);
      // Load form definition for this event (if any)
      try {
        const ev = await apiFetch<any>(`/api/events/${encodeURIComponent(eventId)}`);
        if (ev?.form) setForm(ev.form);
      } catch {}
      alert("Manual registration created");
    } catch (e: any) {
      setError(e?.message || "Failed to create manual registration");
    } finally {
      setBusy(false);
    }
  }

  return (
    <div className="max-w-xl">
      <div className="flex items-center gap-3 mb-4">
        <div className="w-10 h-10 rounded-xl bg-brand-50 flex items-center justify-center shrink-0">
          <UserPlus className="w-5 h-5 text-brand-600" />
        </div>
        <h1 className="text-xl font-semibold text-gray-900">Manual Registration</h1>
      </div>
      <form onSubmit={submit} className="space-y-3">
        <div>
          <label className="block text-sm font-medium">Event ID</label>
          <input className="w-full border rounded px-3 py-2" value={eventId} onChange={(e) => setEventId(e.target.value)} required />
        </div>
        <div className="grid grid-cols-2 gap-3">
          <div>
            <label className="block text-sm font-medium">Option ID</label>
            <input className="w-full border rounded px-3 py-2" value={optionId} onChange={(e) => setOptionId(e.target.value)} required />
          </div>
          <div>
            <label className="block text-sm font-medium">Quantity</label>
            <input type="number" min={1} className="w-full border rounded px-3 py-2" value={quantity} onChange={(e) => setQuantity(parseInt(e.target.value || "1", 10))} required />
          </div>
        </div>
        <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
          <div>
            <label className="block text-sm font-medium">Name</label>
            <input className="w-full border rounded px-3 py-2" value={name} onChange={(e) => setName(e.target.value)} required />
          </div>
          <div>
            <div className="flex items-center justify-between">
              <label className="block text-sm font-medium">Email</label>
              <label className="text-xs flex items-center gap-2"><input type="checkbox" checked={registerAsGuest} onChange={e=>setRegisterAsGuest(e.target.checked)} /> Guest (no account)</label>
            </div>
            <input type="email" className="w-full border rounded px-3 py-2" value={email} onChange={(e) => setEmail(e.target.value)} placeholder="email@example.com" />
          </div>
        </div>
        <div>
          <label className="block text-sm font-medium">Cell Number</label>
          <input type="tel" className="w-full border rounded px-3 py-2" value={phoneNumber} onChange={(e) => setPhoneNumber(e.target.value)} placeholder="+27…" />
        </div>
        <p className="text-xs text-gray-500">At least one of email or cell number is required. If no email is provided, a guest account is created automatically.</p>
        {error && <p className="text-sm text-red-600">{error}</p>}
        <button type="submit" disabled={busy} className="bg-brand-600 hover:bg-brand-700 text-white rounded px-4 py-2 disabled:opacity-60">
          {busy ? "Submitting..." : "Create"}
        </button>
      </form>

      {createdReg && form && Array.isArray(form.fields) && (
        <AttendeeFormsSection registration={createdReg} form={form} formsData={formsData} setFormsData={setFormsData} />
      )}
    </div>
  );
}

function AttendeeFormsSection({ registration, form, formsData, setFormsData }: { registration: any; form: { isRequired: boolean; fields: FormField[] }; formsData: Record<number, Record<string,string>>; setFormsData: any; }) {
  const { token } = useAuth();
  const [submitting, setSubmitting] = useState(false);
  const [error, setError] = useDismissingState<string | null>(null);
  const [info, setInfo] = useDismissingState<string | null>(null);
  const mainTickets = (registration?.registrationOptions || []).filter((o: any) => o?.eventOption?.isMainTicket).reduce((s: number, o: any) => s + (o.quantity || 0), 0);
  const count = Math.max(0, mainTickets);

  const canSubmit = React.useMemo(() => {
    if (!form || count <= 0) return false;
    const reqFields = (form.fields || [])
      .filter(f => !!f.isRequired && f.type !== 'statement' && f.type !== 'paragraph')
      .map(f => f.id);
    for (let i = 0; i < count; i++) {
      const data = formsData[i] || {};
      for (const fid of reqFields) {
        const v = data[fid];
        if (v === undefined || v === null || String(v).trim() === '') {
          return false;
        }
      }
    }
    return true;
  }, [form, formsData, count]);

  const update = (idx: number, fieldId: string, value: string) => {
    setFormsData((prev: any) => ({ ...prev, [idx]: { ...(prev[idx]||{}), [fieldId]: value } }));
  };

  const submit = async () => {
    if (!token) return;
    try {
      setSubmitting(true);
      setError(null); setInfo(null);
      const payload = [] as any[];
      for (let i = 0; i < count; i++) payload.push({ answers: formsData[i] || {} });
      await apiFetch(`/api/registrations/${encodeURIComponent(registration.id)}/forms/responses`, {
        method: 'POST', authToken: token, body: { responses: payload }
      });
      setInfo('Attendee forms submitted successfully.');
    } catch (e: any) {
      setError(e?.message || 'Failed to submit forms');
    } finally {
      setSubmitting(false);
    }
  };

  if (!form || !Array.isArray(form.fields) || count === 0) return null;
  return (
    <div className="mt-6 border rounded p-3 bg-gray-50">
      <div className="text-sm font-medium mb-2">Attendee forms for this registration</div>
      {error && <div className="text-xs text-red-600 mb-2">{error}</div>}
      {info && <div className="text-xs text-emerald-700 mb-2">{info}</div>}
      <div className="space-y-4">
        {Array.from({ length: count }, (_, idx) => (
          <div key={idx} className="bg-white border rounded p-3">
            <div className="font-medium mb-2">Attendee {idx + 1}</div>
            {form.fields.map((f) => (
              <div key={f.id} className="mb-2">
                {f.type === 'statement' ? (
                  <div className="text-sm text-gray-700 whitespace-pre-line">{f.label}</div>
                ) : f.type === 'paragraph' ? (
                  <div className="text-sm text-gray-700">
                    {f.label && <div className="font-medium mb-1 whitespace-pre-line">{f.label}</div>}
                    {f.helpText && <div className="whitespace-pre-line">{f.helpText}</div>}
                  </div>
                ) : (
                  <>
                    <label className="block text-xs text-gray-600 mb-1">{f.label}{f.isRequired ? ' *' : ''}</label>
                    {f.type === 'yes_no' ? (
                      <select className="border rounded px-2 py-1 text-sm" value={formsData[idx]?.[f.id] || ''} onChange={e => update(idx, f.id, e.target.value)}>
                        <option value="">Select</option>
                        <option value="yes">Yes</option>
                        <option value="no">No</option>
                      </select>
                    ) : f.type === 'date' ? (
                      <input type="date" className="border rounded px-2 py-1 text-sm" value={formsData[idx]?.[f.id] || ''} onChange={e => update(idx, f.id, e.target.value)} />
                    ) : f.type === 'numeric' ? (
                      <input type="number" className="border rounded px-2 py-1 text-sm" value={formsData[idx]?.[f.id] || ''} onChange={e => update(idx, f.id, e.target.value)} />
                    ) : (
                      <input type="text" className="border rounded px-2 py-1 text-sm w-full" value={formsData[idx]?.[f.id] || ''} onChange={e => update(idx, f.id, e.target.value)} />
                    )}
                    {f.helpText && <div className="text-xs text-gray-500 mt-1">{f.helpText}</div>}
                  </>
                )}
              </div>
            ))}
          </div>
        ))}
      </div>
      <button className="mt-3 px-3 py-1.5 text-sm rounded bg-brand-600 text-white hover:bg-brand-700 disabled:opacity-50" disabled={submitting || !canSubmit} onClick={submit}>{submitting ? 'Submitting…' : 'Submit forms'}</button>
    </div>
  );
}