import { useState } from 'react';
import { Check, Lock, Sparkles } from 'lucide-react';
import { api, type Character } from '@/api';
import { useAppData } from '@/state/AppData';
import { useAsync } from '@/lib/useAsync';
import { SeyarMascot } from '@/mascots/SeyarMascot';
import { SEYAR_INFO, seyarFromSlug } from '@/mascots/seyar';
import { useToast } from '@/components/Toast';
import { EmptyState, ErrorState, LoadingState, Screen, ScreenHeader, Sep } from '@/components/ui';
import { friendlyError } from '@/lib/errors';
import { toFa } from '@/lib/format';

/**
 * همراه‌ها (کاتالوگِ کاراکترهای بک‌اند). همراهِ انتخابی در خانه، درس و تمرین
 * نشان داده می‌شود. باز شدن فقط با امتیاز است.
 */
export function CharactersScreen() {
  const { summary, setCompanion } = useAppData();
  const toast = useToast();
  const list = useAsync(() => api.characters.list(), []);
  const [busy, setBusy] = useState<string | null>(null);

  async function select(c: Character) {
    if (!c.unlocked || c.selected || busy) return;
    setBusy(c.characterId);
    try {
      await api.characters.select(c.characterId);
      list.setData((prev) => prev?.map((x) => ({ ...x, selected: x.characterId === c.characterId })));
      setCompanion(c);
      toast(`${c.name} حالا همراهته!`, 'success');
    } catch (err) {
      toast(friendlyError(err), 'error');
    } finally {
      setBusy(null);
    }
  }

  return (
    <Screen>
      <ScreenHeader
        title="همراهت رو انتخاب کن"
        subtitle={<>امتیازِ تو: {toFa(summary?.xp ?? 0)}<Sep />با امتیازِ بیشتر همراه‌های بیشتری باز می‌شن</>}
        color="#9B7BFF"
        back
      />
      <div className="flex-1 overflow-y-auto px-4 py-5">
        {list.loading ? (
          <LoadingState />
        ) : list.error ? (
          <ErrorState error={list.error} onRetry={list.reload} />
        ) : !list.data?.length ? (
          <EmptyState text="فعلاً همراهی تعریف نشده" />
        ) : (
          <div className="grid grid-cols-2 gap-3">
            {list.data.map((c) => {
              const seyar = seyarFromSlug(c.slug);
              return (
                <button
                  key={c.characterId}
                  type="button"
                  disabled={!c.unlocked || busy !== null}
                  onClick={() => void select(c)}
                  aria-pressed={c.selected}
                  className={`relative flex flex-col items-center gap-2 rounded-3xl border-2 p-4 transition-transform ${
                    c.selected ? 'border-violet bg-[#F5F1FF]' : c.unlocked ? 'border-line bg-white active:scale-95' : 'border-line bg-[#f4f3fa]'
                  }`}
                >
                  {c.selected && (
                    <span className="absolute left-2 top-2 flex h-5 w-5 items-center justify-center rounded-full bg-violet">
                      <Check size={11} className="text-white" strokeWidth={3} />
                    </span>
                  )}
                  <span className={`relative ${c.unlocked ? '' : 'opacity-50 grayscale'}`}>
                    {seyar ? (
                      <SeyarMascot char={seyar} mood={c.unlocked ? 'happy' : 'idle'} size={84} />
                    ) : (
                      <span className="flex h-20 w-20 items-center justify-center rounded-full bg-[#EEF1FF]">
                        <Sparkles size={28} className="text-violet" />
                      </span>
                    )}
                  </span>
                  {!c.unlocked && (
                    <span className="absolute top-12 flex h-9 w-9 items-center justify-center rounded-full bg-white shadow">
                      <Lock size={16} className="text-[#5a5580]" />
                    </span>
                  )}
                  <span className="text-sm font-bold text-ink">{c.name}</span>
                  <span className="text-center text-[10px] leading-5 text-muted">
                    {!c.unlocked
                      ? `با ${toFa(c.unlockXp)} امتیاز باز می‌شه`
                      : c.selected
                        ? 'همراهِ فعلی'
                        : seyar
                          ? SEYAR_INFO[seyar].role
                          : 'بازشده'}
                  </span>
                </button>
              );
            })}
          </div>
        )}
      </div>
    </Screen>
  );
}