'use client';

import { normalizeAgencyCode, pickUtm, type Locale } from '@barev/core';
import { tFromMessages, type Messages } from '@barev/i18n';
import { Icon } from '@barev/ui';
import { createContext, useContext, useEffect, useMemo, useRef, useState, type ReactNode } from 'react';
import { BotLink } from './client';

const API = process.env.NEXT_PUBLIC_API_URL ?? 'http://localhost:4000';
const AGENCY_KEY = 'barev.agency';

const WHEN = ['month', 'quarter', 'later', 'date'] as const;
const PACKAGES = ['CONSULT', 'TURNKEY', 'CUSTOM'] as const;
const YES_NO = ['flat', 'socialCard', 'bankCard', 'registration', 'residence'] as const;
type When = (typeof WHEN)[number];
type Pkg = (typeof PACKAGES)[number];
type Step = 'contact' | 'moved' | 'when' | 'package' | 'custom' | 'done' | 'redirect';
const ORDER: Step[] = ['contact', 'moved', 'when', 'package', 'custom'];

interface Options {
  airport: 'none' | 'standard' | 'premium';
  stay: 'none' | 'flat' | 'hotel';
  stayBudgetFrom: string;
  stayBudgetTo: string;
  flat: boolean;
  socialCard: boolean;
  bankCard: boolean;
  registration: boolean;
  residence: boolean;
}
const EMPTY: Options = { airport: 'none', stay: 'none', stayBudgetFrom: '', stayBudgetTo: '', flat: false, socialCard: false, bankCard: false, registration: false, residence: false };

class ApiError extends Error {}

/** tRPC-мутация лендинга; ошибка — код домена (CONTACT_INVALID…) или пусто для сети */
async function mutate<T>(path: string, json: unknown): Promise<T> {
  let res: Response;
  try {
    res = await fetch(`${API}/trpc/public.${path}`, { method: 'POST', headers: { 'content-type': 'application/json' }, body: JSON.stringify({ json }) });
  } catch {
    throw new ApiError('');
  }
  const body = (await res.json().catch(() => null)) as { result?: { data?: { json?: T } }; error?: { json?: { message?: string; data?: { domainCode?: string | null } } } } | null;
  const data = body?.result?.data?.json;
  if (data === undefined) throw new ApiError(body?.error?.json?.data?.domainCode ?? body?.error?.json?.message ?? 'generic');
  return data;
}

const QuizCtx = createContext<() => void>(() => {});

/** Кнопка, открывающая квиз; на странице может быть несколько */
export function QuizButton({ className, children }: { className?: string; children: ReactNode }) {
  const open = useContext(QuizCtx);
  return (
    <button type="button" className={className} onClick={open} aria-haspopup="dialog">
      {children}
    </button>
  );
}

/**
 * Квиз «Подбор переезда» в модальном окне. Имя и контакт сохраняются сразу после первого шага,
 * дальше каждый ответ дописывается в ту же заявку — оператор видит её в админке, даже если человек не дошёл до конца.
 * «Уже живу в Армении» — переход на /live.
 */
export function QuizProvider({ locale, messages, consultPrice, children }: { locale: Locale; messages: Messages; consultPrice: string; children: ReactNode }) {
  const t = useMemo(() => tFromMessages(locale, messages), [locale, messages]);
  const dialog = useRef<HTMLDialogElement>(null);
  const heading = useRef<HTMLHeadingElement>(null);
  const [step, setStep] = useState<Step>('contact');
  const [dir, setDir] = useState<'fwd' | 'back'>('fwd');
  const [lead, setLead] = useState<{ id: string; key: string; number: number; name: string; contact: string } | null>(null);
  const [name, setName] = useState('');
  const [contact, setContact] = useState('');
  const [when, setWhen] = useState<When | null>(null);
  const [date, setDate] = useState('');
  const [pkg, setPkg] = useState<Pkg | null>(null);
  const [opts, setOpts] = useState<Options>(EMPTY);
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState<{ field?: 'name' | 'contact' | 'when' | 'custom'; text: string } | null>(null);
  const [today, setToday] = useState('');

  useEffect(() => setToday(new Date().toISOString().slice(0, 10)), []);
  // новый шаг — фокус на заголовок, чтобы экранный диктор прочитал вопрос
  useEffect(() => heading.current?.focus({ preventScroll: true }), [step]);

  const open = () => {
    dialog.current?.showModal();
    heading.current?.focus({ preventScroll: true });
  };
  const close = () => dialog.current?.close();

  function go(next: Step) {
    setDir(ORDER.indexOf(next) < ORDER.indexOf(step) ? 'back' : 'fwd');
    setError(null);
    setStep(next);
  }
  function back() {
    const prev: Partial<Record<Step, Step>> = { moved: 'contact', when: 'moved', package: 'when', custom: 'package' };
    if (prev[step]) go(prev[step]!);
  }

  async function run(fn: () => Promise<void>, field?: 'name' | 'contact' | 'when' | 'custom') {
    setBusy(true);
    setError(null);
    try {
      await fn();
    } catch (e) {
      const code = e instanceof ApiError ? e.message : '';
      const text = !code ? t('landing.quiz.errNetwork') : messages[`errors.${code}`] ? t(`errors.${code}`) : t('errors.generic');
      setError({ field: code === 'CONTACT_INVALID' ? 'contact' : code === 'NAME_REQUIRED' ? 'name' : field, text });
    } finally {
      setBusy(false);
    }
  }

  const update = (json: Record<string, unknown>) => mutate<{ number: number; submitted: boolean }>('leadUpdate', { id: lead!.id, key: lead!.key, ...json });

  function submitContact() {
    if (!name.trim()) return setError({ field: 'name', text: t('landing.quiz.errName') });
    const c = contact.trim();
    const looksOk = /^(?:https?:\/\/)?(?:t\.me\/)?@?[a-zA-Z][a-zA-Z0-9_]{4,31}$/.test(c) || /^\+?\d{8,15}$/.test(c.replace(/[\s()\-.]/g, ''));
    if (!looksOk) return setError({ field: 'contact', text: t('landing.quiz.errContact') });
    // вернулись назад и ничего не поменяли — заявка уже есть
    if (lead && lead.name === name.trim() && lead.contact === c) return go('moved');
    void run(async () => {
      const search = new URLSearchParams(window.location.search);
      let agency = search.get('a') ? normalizeAgencyCode(search.get('a')!) : null;
      try {
        agency ??= localStorage.getItem(AGENCY_KEY);
      } catch {
        /* приватный режим */
      }
      const utm = pickUtm(search);
      const r = await mutate<{ id: string; key: string; number: number }>('leadStart', {
        name: name.trim(),
        contact: c,
        locale,
        agency: agency ?? undefined,
        utm: Object.keys(utm).length ? utm : undefined,
        consent: true,
      });
      setLead({ ...r, name: name.trim(), contact: c });
      go('moved');
    });
  }

  function answerMoved(moved: boolean) {
    void run(async () => {
      await update({ moved });
      if (!moved) return go('when');
      setStep('redirect');
      window.location.assign(`/${locale}/live${window.location.search}`);
    });
  }

  function submitWhen() {
    if (!when || (when === 'date' && !date)) return setError({ field: 'when', text: t('landing.quiz.errWhen') });
    void run(async () => {
      await update({ moveWhen: when, moveDate: when === 'date' ? date : undefined });
      go('package');
    }, 'when');
  }

  function choosePackage(p: Pkg) {
    setPkg(p);
    void run(async () => {
      await update({ package: p, submit: p !== 'CUSTOM' });
      go(p === 'CUSTOM' ? 'custom' : 'done');
    });
  }

  function submitCustom() {
    const any = opts.airport !== 'none' || opts.stay !== 'none' || YES_NO.some((k) => opts[k]);
    if (!any) return setError({ field: 'custom', text: t('landing.quiz.errEmpty') });
    const num = (v: string) => (v.trim() ? Math.max(0, Math.round(Number(v.replace(/\D/g, '')))) : undefined);
    void run(async () => {
      await update({
        options: {
          ...opts,
          stayBudgetFrom: opts.stay === 'none' ? undefined : num(opts.stayBudgetFrom),
          stayBudgetTo: opts.stay === 'none' ? undefined : num(opts.stayBudgetTo),
        },
        submit: true,
      });
      go('done');
    }, 'custom');
  }

  const index = ORDER.indexOf(step);
  const total = pkg && pkg !== 'CUSTOM' ? 4 : 5;
  const err = (field: string) => (error?.field === field ? error.text : null);
  const set = <K extends keyof Options>(k: K, v: Options[K]) => setOpts((o) => ({ ...o, [k]: v }));

  let body: ReactNode;
  if (step === 'contact') {
    body = (
      <form
        className="q-form"
        noValidate
        onSubmit={(e) => {
          e.preventDefault();
          submitContact();
        }}
      >
        <h2 ref={heading} tabIndex={-1} className="q-title">
          {t('landing.quiz.contactTitle')}
        </h2>
        <label className="q-field" data-error={!!err('name')}>
          <span>{t('landing.quiz.name')}</span>
          <input className="q-input" value={name} onChange={(e) => setName(e.target.value)} autoComplete="given-name" maxLength={80} aria-invalid={!!err('name')} />
          {err('name') && <small role="alert">{err('name')}</small>}
        </label>
        <label className="q-field" data-error={!!err('contact')}>
          <span>{t('landing.quiz.contact')}</span>
          <input
            className="q-input"
            value={contact}
            onChange={(e) => setContact(e.target.value)}
            placeholder={t('landing.quiz.contactHint')}
            autoComplete="tel"
            inputMode="text"
            maxLength={60}
            aria-invalid={!!err('contact')}
          />
          {err('contact') && <small role="alert">{err('contact')}</small>}
        </label>
        {error && !error.field && <p className="q-error" role="alert">{error.text}</p>}
        <button type="submit" className="bc-btn q-primary" disabled={busy}>
          {busy ? t('landing.quiz.sending') : t('landing.quiz.next')}
        </button>
        <p className="q-consent">
          {t('landing.quiz.consentPre')}
          <a href={`/${locale}/privacy`} target="_blank" rel="noopener">
            {t('landing.quiz.consentLink')}
          </a>
        </p>
      </form>
    );
  } else if (step === 'moved') {
    body = (
      <div className="q-form">
        <h2 ref={heading} tabIndex={-1} className="q-title">
          {t('landing.quiz.movedTitle')}
        </h2>
        <div className="q-choices">
          <button type="button" className="q-choice" disabled={busy} onClick={() => answerMoved(false)}>
            <b>{t('landing.quiz.movedNo')}</b>
          </button>
          <button type="button" className="q-choice" disabled={busy} onClick={() => answerMoved(true)}>
            <b>{t('landing.quiz.movedYes')}</b>
          </button>
        </div>
        {error && <p className="q-error" role="alert">{error.text}</p>}
      </div>
    );
  } else if (step === 'when') {
    body = (
      <form
        className="q-form"
        noValidate
        onSubmit={(e) => {
          e.preventDefault();
          submitWhen();
        }}
      >
        <h2 ref={heading} tabIndex={-1} className="q-title" id="q-when">
          {t('landing.quiz.whenTitle')}
        </h2>
        <div className="q-choices" role="radiogroup" aria-labelledby="q-when">
          {WHEN.map((w) => (
            <button key={w} type="button" role="radio" aria-checked={when === w} className="q-choice" onClick={() => setWhen(w)}>
              <b>{t(`landing.quiz.when_${w}`)}</b>
            </button>
          ))}
        </div>
        {when === 'date' && (
          <label className="q-field">
            <span>{t('landing.quiz.date')}</span>
            <input className="q-input" type="date" min={today} value={date} onChange={(e) => setDate(e.target.value)} />
          </label>
        )}
        {error && <p className="q-error" role="alert">{error.text}</p>}
        <button type="submit" className="bc-btn q-primary" disabled={busy}>
          {busy ? t('landing.quiz.sending') : t('landing.quiz.next')}
        </button>
      </form>
    );
  } else if (step === 'package') {
    body = (
      <div className="q-form">
        <h2 ref={heading} tabIndex={-1} className="q-title">
          {t('landing.quiz.packageTitle')}
        </h2>
        <div className="q-choices">
          {PACKAGES.map((p) => (
            <button key={p} type="button" className="q-choice q-choice--tall" disabled={busy} onClick={() => choosePackage(p)}>
              <span className="q-choice__head">
                <b>{t(`landing.quiz.package_${p}`)}</b>
                {p === 'CONSULT' && <span className="q-price">{consultPrice}</span>}
                {p === 'TURNKEY' && <span className="q-price">{t('landing.quiz.package_TURNKEY_price')}</span>}
              </span>
              <span>{t(`landing.quiz.package_${p}_text`)}</span>
            </button>
          ))}
        </div>
        {error && <p className="q-error" role="alert">{error.text}</p>}
      </div>
    );
  } else if (step === 'custom') {
    body = (
      <form
        className="q-form"
        noValidate
        onSubmit={(e) => {
          e.preventDefault();
          submitCustom();
        }}
      >
        <h2 ref={heading} tabIndex={-1} className="q-title">
          {t('landing.quiz.customTitle')}
        </h2>
        <Segmented label={t('landing.quiz.airport')} value={opts.airport} options={['none', 'standard', 'premium'] as const} text={(v) => t(`landing.quiz.airport_${v}`)} onChange={(v) => set('airport', v)} />
        <Segmented label={t('landing.quiz.stay')} value={opts.stay} options={['none', 'flat', 'hotel'] as const} text={(v) => t(`landing.quiz.stay_${v}`)} onChange={(v) => set('stay', v)}>
          {opts.stay !== 'none' && (
            <fieldset className="q-budget">
              <legend>{t('landing.quiz.budget')}</legend>
              <label>
                <span>{t('landing.quiz.budgetFrom')}</span>
                <input className="q-input" inputMode="numeric" value={opts.stayBudgetFrom} onChange={(e) => set('stayBudgetFrom', e.target.value.replace(/\D/g, '').slice(0, 7))} placeholder="20 000" />
              </label>
              <label>
                <span>{t('landing.quiz.budgetTo')}</span>
                <input className="q-input" inputMode="numeric" value={opts.stayBudgetTo} onChange={(e) => set('stayBudgetTo', e.target.value.replace(/\D/g, '').slice(0, 7))} placeholder="40 000" />
              </label>
            </fieldset>
          )}
        </Segmented>
        {YES_NO.map((k) => (
          <Segmented
            key={k}
            label={t(`landing.quiz.${k}`)}
            value={opts[k] ? 'yes' : 'no'}
            options={['no', 'yes'] as const}
            text={(v) => t(`landing.quiz.${v}`)}
            onChange={(v) => set(k, v === 'yes')}
            hint={opts[k] ? t('landing.quiz.yesHint') : undefined}
          />
        ))}
        {error && <p className="q-error" role="alert">{error.text}</p>}
        <button type="submit" className="bc-btn q-primary" disabled={busy}>
          {busy ? t('landing.quiz.sending') : t('landing.quiz.submit')}
        </button>
      </form>
    );
  } else if (step === 'done') {
    body = (
      <div className="q-form q-done">
        <span className="q-done__mark" aria-hidden="true">
          <Icon name="check" size={30} strokeWidth={2.6} />
        </span>
        <h2 ref={heading} tabIndex={-1} className="q-title">
          {t('landing.quiz.doneTitle', { number: lead?.number ?? '' })}
        </h2>
        <p className="q-lead">{t('landing.quiz.doneText', { contact: lead?.contact ?? '' })}</p>
        <BotLink className="bc-btn q-primary">{t('landing.quiz.doneBot')}</BotLink>
        <button type="button" className="q-link" onClick={close}>
          {t('landing.quiz.doneClose')}
        </button>
      </div>
    );
  } else {
    body = (
      <div className="q-form">
        <h2 ref={heading} tabIndex={-1} className="q-title" aria-live="polite">
          {t('landing.quiz.movingToLive')}
        </h2>
      </div>
    );
  }

  return (
    <QuizCtx.Provider value={open}>
      {children}
      <dialog
        ref={dialog}
        className="q"
        aria-label={t('landing.quiz.dialog')}
        onClick={(e) => {
          // клик по затемнению вокруг окна закрывает квиз; ответы остаются
          if (e.target === e.currentTarget) close();
        }}
      >
        <div className="q-panel">
          <div className="q-top">
            {index > 0 ? (
              <button type="button" className="q-icon" onClick={back} aria-label={t('landing.quiz.back')}>
                <Icon name="back" size={20} />
              </button>
            ) : (
              <span />
            )}
            {index < 0 ? (
              <span />
            ) : (
              <ol className="q-dots" aria-label={t('landing.quiz.progress', { n: index + 1, total })}>
                {ORDER.slice(0, total).map((s, i) => (
                  <li key={s} data-state={i < index ? 'past' : i === index ? 'now' : 'next'} />
                ))}
              </ol>
            )}
            <button type="button" className="q-icon" onClick={close} aria-label={t('landing.quiz.close')}>
              <Icon name="close" size={20} />
            </button>
          </div>
          <div key={step} className="q-step" data-dir={dir}>
            {body}
          </div>
        </div>
      </dialog>
    </QuizCtx.Provider>
  );
}

/** Строка конструктора: подпись и переключатель из 2–3 вариантов */
function Segmented<V extends string>({
  label,
  value,
  options,
  text,
  onChange,
  hint,
  children,
}: {
  label: string;
  value: V;
  options: readonly V[];
  text: (v: V) => string;
  onChange: (v: V) => void;
  hint?: string;
  children?: ReactNode;
}) {
  return (
    <div className="q-row">
      <div className="q-row__head">
        <span className="q-row__label">{label}</span>
        <div className="q-seg" role="radiogroup" aria-label={label}>
          {options.map((o) => (
            <button key={o} type="button" role="radio" aria-checked={value === o} onClick={() => onChange(o)}>
              {text(o)}
            </button>
          ))}
        </div>
      </div>
      {hint && <small className="q-row__hint">{hint}</small>}
      {children}
    </div>
  );
}