import type { DsProps } from './props';
import * as React from 'react';
import { Check, ChevronDown, X } from 'lucide-react';
import { cn } from '@/lib/utils';
import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover';
import { Badge } from '@/components/ui/badge';
import { SearchInput } from '@/components/ds/SearchInput';
import { useTranslation } from 'react-i18next';

/**
 * MultiSelect — pick several values from a list.
 *
 * Selections render as removable chips in the trigger. Above `searchThreshold`
 * options a filter field appears, so short lists stay uncluttered and long ones
 * stay usable. Options may be strings or `{ value, label, count }`.
 */
/** @param {any} props */
export function MultiSelect({
  options = [],
  value = [],
  onChange,
  placeholder = 'Select...',
  /** Chips shown before collapsing into "+N more". */
  maxChips = 2,
  searchThreshold = 8,
  disabled = false,
  className = '',
  align = 'start',
  emptyMessage = 'No options',
}: DsProps) {
  const { t } = useTranslation();
  const [open, setOpen] = React.useState(false);
  const [query, setQuery] = React.useState('');

  const normalized = React.useMemo(
    () => options.map((o) => (typeof o === 'string' ? { value: o, label: o } : o)),
    [options]
  );

  const filtered = React.useMemo(() => {
    if (!query) return normalized;
    const q = query.toLowerCase();
    return normalized.filter((o) => o.label.toLowerCase().includes(q));
  }, [normalized, query]);

  const labelFor = (v) => normalized.find((o) => o.value === v)?.label ?? v;

  const toggle = (optionValue) => {
    const next = value.includes(optionValue)
      ? value.filter((v) => v !== optionValue)
      : [...value, optionValue];
    onChange?.(next);
  };

  const remove = (optionValue, event) => {
    // The chip's X sits inside the trigger — don't open the popover.
    event.stopPropagation();
    onChange?.(value.filter((v) => v !== optionValue));
  };

  const visible = value.slice(0, maxChips);
  const overflow = value.length - visible.length;

  return (
    <Popover open={open} onOpenChange={setOpen}>
      <PopoverTrigger asChild>
        <button
          type="button"
          role="combobox"
          aria-expanded={open}
          disabled={disabled}
          className={cn(
            'flex min-h-10 w-full items-center gap-1.5 rounded-lg border border-border bg-surface px-3 py-1.5 text-left shadow-xs',
            'transition-all duration-base ease-out',
            'outline-none focus-visible:border-krow-blue focus-visible:ring-2 focus-visible:ring-krow-blue/20',
            'disabled:cursor-not-allowed disabled:bg-surface-sunken disabled:opacity-60',
            open && 'border-krow-blue ring-2 ring-krow-blue/20',
            className
          )}
        >
          <span className="flex flex-1 flex-wrap items-center gap-1 min-w-0">
            {value.length === 0 && <span className="text-body-sm text-ink-4">{placeholder}</span>}
            {visible.map((v) => (
              <Badge key={v} variant="soft" size="lg" className="max-w-[160px] pr-1">
                <span className="truncate">{labelFor(v)}</span>
                <span
                  role="button"
                  tabIndex={-1}
                  aria-label={`Remove ${labelFor(v)}`}
                  onClick={(e) => remove(v, e)}
                  className="grid place-items-center w-3.5 h-3.5 rounded-full hover:bg-krow-blue/20 shrink-0"
                >
                  <X className="w-2.5 h-2.5" aria-hidden="true" />
                </span>
              </Badge>
            ))}
            {overflow > 0 && (
              <Badge variant="neutral" size="lg">+{overflow} more</Badge>
            )}
          </span>
          <ChevronDown
            className={cn(
              'w-4 h-4 text-ink-4 shrink-0 transition-transform duration-base',
              open && 'rotate-180'
            )}
            aria-hidden="true"
          />
        </button>
      </PopoverTrigger>

      <PopoverContent align={align} className="w-[--radix-popover-trigger-width] min-w-52 p-0">
        {normalized.length >= searchThreshold && (
          <div className="p-2 border-b border-border">
            <SearchInput
              value={query}
              onChange={setQuery}
              placeholder={t('multiSelect.filterOptions')}
              size="sm"
              debounce={0}
              autoFocus
            />
          </div>
        )}

        <div className="max-h-64 overflow-y-auto p-1.5">
          {filtered.length === 0 && (
            <p className="px-2 py-6 text-center text-body-sm text-ink-3">{emptyMessage}</p>
          )}
          {filtered.map((option) => {
            const selected = value.includes(option.value);
            return (
              <button
                key={option.value}
                type="button"
                role="option"
                aria-selected={selected}
                onClick={() => toggle(option.value)}
                className={cn(
                  'flex w-full items-center gap-2.5 rounded-md px-2 py-1.5 text-left text-body-sm transition-colors duration-fast',
                  'hover:bg-krow-blue-tint focus-ring-inset',
                  selected ? 'text-krow-blue font-medium' : 'text-ink-2'
                )}
              >
                <span
                  className={cn(
                    'grid place-items-center w-4 h-4 rounded border shrink-0 transition-colors duration-fast',
                    selected ? 'bg-krow-blue border-krow-blue text-white' : 'border-border'
                  )}
                >
                  {selected && <Check className="w-3 h-3" aria-hidden="true" />}
                </span>
                <span className="flex-1 truncate">{option.label}</span>
                {option.count != null && (
                  <span className="text-caption text-ink-4 tabular-nums">{option.count}</span>
                )}
              </button>
            );
          })}
        </div>

        {value.length > 0 && (
          <div className="border-t border-border p-1.5">
            <button
              type="button"
              onClick={() => onChange?.([])}
              className="w-full rounded-md px-2 py-1.5 text-body-sm text-ink-3 hover:bg-surface-sunken hover:text-ink-1 transition-colors focus-ring-inset"
            >
              {t('multiSelect.clearSelection')}
            </button>
          </div>
        )}
      </PopoverContent>
    </Popover>
  );
}