import { useState } from 'react';
import { Bug, MessageCircle, Send } from 'lucide-react';
import { api, type TicketSummary } from '@/api';
import { useAsync } from '@/lib/useAsync';
import { useToast } from '@/components/Toast';
import { InlineError, PrimaryButton, Screen, ScreenBody, ScreenHeader, Sep } from '@/components/ui';
import { friendlyError } from '@/lib/errors';
import { toFa } from '@/lib/format';
import { MathText } from '@/lib/MathText';

const CATEGORIES = [
  { id: 'learning', label: 'درس و سوال‌ها' },
  { id: 'payment', label: 'پرداخت و اشتراک' },
  { id: 'account', label: 'حساب و ورود' },
  { id: 'other', label: 'چیزِ دیگه' },
];

const STATUS_LABEL: Record<string, string> = {
  open: 'باز',
  in_progress: 'در حالِ بررسی',
  answered: 'پاسخ داده شد',
  closed: 'بسته',
};

export function SupportScreen() {
  const toast = useToast();
  const [mode, setMode] = useState<'ticket' | 'bug'>('ticket');
  const [category, setCategory] = useState('learning');
  const [subject, setSubject] = useState('');
  const [text, setText] = useState('');
  const [sending, setSending] = useState(false);
  const [error, setError] = useState('');
  // فهرست از سرور می‌آید، پس تیکت و پاسخش با عوض شدنِ گوشی هم دیده می‌شود.
  const tickets = useAsync(() => api.support.tickets(), []);

  async function submit() {
    if (!subject.trim() || !text.trim()) return;
    setSending(true);
    setError('');
    try {
      if (mode === 'bug') {
        await api.support.bugReport(subject.trim(), text.trim());
        toast('گزارشت رسید؛ ممنون!', 'success');
      } else {
        const t = await api.support.createTicket(subject.trim(), category);
        await api.support.reply(t.ticketId, text.trim());
        tickets.reload();
        toast('پیامت رسید؛ جواب همین‌جا و در اعلان‌ها میاد.', 'success');
      }
      setSubject('');
      setText('');
    } catch (err) {
      setError(friendlyError(err, 'ارسال نشد، دوباره امتحان کن'));
    } finally {
      setSending(false);
    }
  }

  return (
    <Screen>
      <ScreenHeader title="پشتیبانی" subtitle="سوال، مشکل یا پیشنهاد داری؟ بنویس." color="#4C5FD5" back mascot={{ char: 'sigma', mood: 'happy', size: 56 }} />
      <ScreenBody className="flex flex-col gap-4">
        <div className="flex gap-1 rounded-2xl bg-soft p-1">
          {([['ticket', 'پیام به پشتیبانی', MessageCircle], ['bug', 'گزارشِ خطای اپ', Bug]] as const).map(([id, label, Icon]) => (
            <button
              key={id}
              type="button"
              onClick={() => setMode(id)}
              className={`flex flex-1 items-center justify-center gap-1.5 rounded-xl py-2.5 text-xs font-bold ${mode === id ? 'bg-white text-indigo shadow-sm' : 'text-muted'}`}
            >
              <Icon size={14} /> {label}
            </button>
          ))}
        </div>

        {mode === 'ticket' && (
          <div className="flex flex-wrap gap-2">
            {CATEGORIES.map((c) => (
              <button
                key={c.id}
                type="button"
                onClick={() => setCategory(c.id)}
                className={`rounded-full border-2 px-3 py-1.5 text-xs font-bold ${category === c.id ? 'border-indigo bg-indigo text-white' : 'border-line bg-white text-body'}`}
              >
                {c.label}
              </button>
            ))}
          </div>
        )}

        <input
          value={subject}
          onChange={(e) => setSubject(e.target.value.slice(0, 120))}
          placeholder={mode === 'bug' ? 'چی خراب شد؟ (خلاصه)' : 'موضوع'}
          className="w-full rounded-2xl border-2 border-line bg-white px-4 py-3.5 text-sm outline-none focus:border-indigo"
        />
        <textarea
          value={text}
          onChange={(e) => setText(e.target.value.slice(0, 2000))}
          rows={5}
          placeholder={mode === 'bug' ? 'چه کار کردی و چه اتفاقی افتاد؟' : 'پیامت رو بنویس…'}
          className="w-full resize-none rounded-2xl border-2 border-line bg-white px-4 py-3.5 text-sm leading-7 outline-none focus:border-indigo"
        />
        {error && <InlineError>{error}</InlineError>}
        <PrimaryButton color="#4C5FD5" loading={sending} disabled={!subject.trim() || !text.trim()} onClick={() => void submit()}>
          <Send size={16} className="-scale-x-100" /> ارسال
        </PrimaryButton>

        {!!tickets.data?.length && (
          <section>
            <h2 className="mb-2 mt-2 text-sm font-black text-ink">پیام‌های قبلیِ تو</h2>
            <div className="flex flex-col gap-2">
              {tickets.data.map((t) => <TicketCard key={t.ticketId} summary={t} />)}
            </div>
          </section>
        )}
      </ScreenBody>
    </Screen>
  );
}

function TicketCard({ summary }: { summary: TicketSummary }) {
  const toast = useToast();
  const [open, setOpen] = useState(false);
  // پیام‌ها فقط وقتی کارت باز شود گرفته می‌شوند؛ فهرست خودش خلاصه را دارد.
  const detail = useAsync(() => (open ? api.support.ticket(summary.ticketId) : Promise.resolve(null)), [open, summary.ticketId]);
  const [reply, setReply] = useState('');
  const [sending, setSending] = useState(false);
  const t = detail.data;
  const status = t?.status ?? summary.status;
  const staffReplies = t ? t.messages.filter((m) => m.sender !== 'user').length : summary.supportReplies;

  async function send() {
    if (!reply.trim()) return;
    setSending(true);
    try {
      await api.support.reply(summary.ticketId, reply.trim());
      setReply('');
      detail.reload();
    } catch (err) {
      toast(friendlyError(err), 'error');
    } finally {
      setSending(false);
    }
  }

  return (
    <div className="rounded-2xl border border-line bg-white">
      <button type="button" onClick={() => setOpen((o) => !o)} className="flex w-full items-center gap-3 p-3.5 text-right">
        <span className="min-w-0 flex-1">
          <span className="block truncate text-sm font-bold text-ink">{summary.subject}</span>
          <span className="text-[11px] text-muted">
            {STATUS_LABEL[status] ?? status}
            {staffReplies > 0 && <><Sep />{toFa(staffReplies)} پاسخ</>}
          </span>
        </span>
        {staffReplies > 0 && !open && <span className="h-2 w-2 flex-shrink-0 rounded-full bg-indigo" aria-hidden />}
      </button>
      {open && (
        <div className="flex flex-col gap-2 border-t border-line p-3.5">
          {!t && (detail.error
            ? <InlineError>{friendlyError(detail.error)}</InlineError>
            : <div className="h-10 animate-pulse rounded-2xl bg-soft" />)}
          {t?.messages.map((m) => (
            <div
              key={m.id}
              className={`whitespace-pre-line rounded-2xl px-3.5 py-2.5 text-xs leading-6 ${m.sender === 'user' ? 'mr-8 bg-soft text-body' : 'ml-8 bg-[#EEF1FF] text-ink'}`}
            >
              <MathText text={m.text} />
            </div>
          ))}
          {t && status !== 'closed' && (
            <div className="mt-1 flex gap-2">
              <input
                value={reply}
                onChange={(e) => setReply(e.target.value.slice(0, 2000))}
                placeholder="جواب بده…"
                className="flex-1 rounded-full bg-soft px-4 py-2 text-xs outline-none"
              />
              <button type="button" disabled={!reply.trim() || sending} onClick={() => void send()} className="rounded-full bg-indigo px-3 text-xs font-bold text-white disabled:opacity-40">
                ارسال
              </button>
            </div>
          )}
        </div>
      )}
    </div>
  );
}