import { useEffect, useMemo, useRef, useState } from 'react';
import { IconServer } from '@tabler/icons-react';

/**
 * Красивый selector серверов с автодополнением.
 * Похож по UX на CommunityAutocompleteInput, но заточен под поля серверов.
 */
function ServerAutocompleteInput({
  value,
  onChange,
  servers = [],
  placeholder = '',
  className = 'form-control',
  onSelectMeta,
  maxSuggestions = 12,
}) {
  const containerRef = useRef(null);
  const inputRef = useRef(null);
  const [open, setOpen] = useState(false);
  const [activeIndex, setActiveIndex] = useState(-1);

  const suggestions = useMemo(() => {
    const q = String(value || '').toLowerCase();

    const list = (servers || []).map((s) => {
      const id = s.id || s.ip;
      const labelIp = s.ip || '—';
      const labelDns = s.dns || '';
      const labelProvider = s.provider || '';
      const label =
        labelDns && labelProvider
          ? `${labelIp} (${labelDns}) – ${labelProvider}`
          : labelDns
          ? `${labelIp} (${labelDns})`
          : labelProvider
          ? `${labelIp} – ${labelProvider}`
          : `${labelIp}`;

      return {
        raw: s,
        value: id,
        label,
        search: [
          id,
          s.ip,
          s.extIp,
          s.internalIp,
          s.dns,
          s.provider,
          s.country,
          s.gateway,
        ]
          .filter(Boolean)
          .join(' ')
          .toLowerCase(),
      };
    });

    if (!q) return list.slice(0, maxSuggestions);
    const filtered = list.filter((item) => item.search.includes(q));
    return filtered.slice(0, maxSuggestions);
  }, [value, servers, maxSuggestions]);

  useEffect(() => {
    const handleOutside = (e) => {
      if (!containerRef.current) return;
      if (!containerRef.current.contains(e.target)) setOpen(false);
    };
    document.addEventListener('click', handleOutside);
    return () => document.removeEventListener('click', handleOutside);
  }, []);

  const selectItem = (item) => {
    onChange(item.value);
    if (onSelectMeta) onSelectMeta(item.raw);
    setOpen(false);
    setActiveIndex(-1);
    if (inputRef.current) inputRef.current.focus();
  };

  const handleKeyDown = (e) => {
    if (!open && (e.key === 'ArrowDown' || e.key === 'ArrowUp')) {
      setOpen(true);
      return;
    }
    if (!open) return;
    if (e.key === 'ArrowDown') {
      e.preventDefault();
      setActiveIndex((prev) => Math.min(prev + 1, suggestions.length - 1));
    } else if (e.key === 'ArrowUp') {
      e.preventDefault();
      setActiveIndex((prev) => Math.max(prev - 1, 0));
    } else if (e.key === 'Enter') {
      if (activeIndex >= 0 && activeIndex < suggestions.length) {
        e.preventDefault();
        selectItem(suggestions[activeIndex]);
      }
    } else if (e.key === 'Escape') {
      setOpen(false);
      setActiveIndex(-1);
    }
  };

  // Текст в input: ищем label по выбранному serverId
  const displayValue = useMemo(() => {
    if (!value) return '';
    const found = (servers || []).find((s) => (s.id || s.ip) === value);
    if (!found) return '';
    const ip = found.ip || '—';
    const dns = found.dns || '';
    const provider = found.provider || '';
    if (dns && provider) return `${ip} (${dns}) – ${provider}`;
    if (dns) return `${ip} (${dns})`;
    if (provider) return `${ip} – ${provider}`;
    return ip;
  }, [value, servers]);

  return (
    <div ref={containerRef} className="position-relative" style={{ width: '100%' }}>
      <div className="input-icon">
        <span className="input-icon-addon">
          <IconServer size={18} />
        </span>
        <input
          ref={inputRef}
          type="text"
          className={className}
          placeholder={placeholder}
          value={open ? displayValue || value : displayValue}
          onChange={(e) => {
            onChange(e.target.value);
            setOpen(true);
          }}
          onFocus={() => setOpen(true)}
          onKeyDown={handleKeyDown}
          autoComplete="off"
        />
      </div>

      {open && suggestions.length > 0 && (
        <div
          className="dropdown-menu show"
          style={{
            display: 'block',
            width: '100%',
            maxHeight: 280,
            overflowY: 'auto',
          }}
        >
          <button
            type="button"
            className={`dropdown-item${activeIndex === -1 ? ' active' : ''}`}
            onMouseDown={(e) => {
              e.preventDefault();
              onChange('');
              if (onSelectMeta) onSelectMeta(null);
              setOpen(false);
              setActiveIndex(-1);
            }}
          >
            <div className="d-flex align-items-center text-muted small">
              <span className="me-2">Без привязки</span>
            </div>
          </button>

          {suggestions.map((s, idx) => (
            <button
              type="button"
              key={`${s.value}-${idx}`}
              className={`dropdown-item${idx === activeIndex ? ' active' : ''}`}
              onMouseDown={(e) => {
                e.preventDefault();
                selectItem(s);
              }}
              onMouseEnter={() => setActiveIndex(idx)}
            >
              <div className="d-flex align-items-start">
                <span className="avatar me-2 bg-blue-lt text-blue border-0" style={{ width: 24, height: 24 }}>
                  <IconServer size={14} />
                </span>
                <div className="flex-fill text-start">
                  <div className="fw-medium">{s.label}</div>
                  <div className="text-muted small text-truncate" style={{ maxWidth: '100%' }}>
                    {s.raw.country && <span className="me-2">{s.raw.country}</span>}
                    {s.raw.tunnel && <span className="me-2">{s.raw.tunnel}</span>}
                    {s.raw.gateway && <span className="me-2">{s.raw.gateway}</span>}
                  </div>
                </div>
              </div>
            </button>
          ))}
        </div>
      )}
    </div>
  );
}

export default ServerAutocompleteInput;