import * as React from "react";
import { useState, useMemo } from "react";
import { Check, ChevronsUpDown, X } from "lucide-react";
import { cn } from "@/lib/utils";
import { Button } from "@/components/ui/button";
import { Badge } from "@/components/ui/badge";
import { Checkbox } from "@/components/ui/checkbox";
import {
  Command,
  CommandEmpty,
  CommandGroup,
  CommandInput,
  CommandItem,
  CommandList,
} from "@/components/ui/command";
import {
  Popover,
  PopoverContent,
  PopoverTrigger,
} from "@/components/ui/popover";

export interface MultiSelectOption {
  label: string;
  value: string;
}

interface MultiSelectComboboxProps {
  options: MultiSelectOption[];
  value?: string[];
  onValueChange: (values: string[]) => void;
  placeholder?: string;
  searchPlaceholder?: string;
  emptyText?: string;
  maxDisplay?: number;
  className?: string;
}

export function MultiSelectCombobox({
  options,
  value = [],
  onValueChange,
  placeholder = "Select options...",
  searchPlaceholder = "Search...",
  emptyText = "No options found.",
  maxDisplay = 2,
  className,
}: MultiSelectComboboxProps) {
  const [open, setOpen] = useState(false);

  const handleSelect = (selectedValue: string) => {
    const newValues = value.includes(selectedValue)
      ? value.filter((v) => v !== selectedValue)
      : [...value, selectedValue];
    onValueChange(newValues);
  };

  const handleRemove = (valueToRemove: string) => {
    onValueChange(value.filter((v) => v !== valueToRemove));
  };

  const displayText = useMemo(() => {
    if (value.length === 0) return placeholder;
    if (value.length <= maxDisplay) {
      return value
        .map((v) => options.find((o) => o.value === v)?.label)
        .filter(Boolean)
        .join(", ");
    }
    return `${value.length} selected`;
  }, [value, options, maxDisplay, placeholder]);

  return (
    <div className="space-y-2">
      <Popover open={open} onOpenChange={setOpen}>
        <PopoverTrigger asChild>
          <Button
            variant="outline"
            role="combobox"
            aria-expanded={open}
            className={cn("w-full justify-between", className)}
          >
            <span className="truncate">{displayText}</span>
            <ChevronsUpDown className="ml-2 h-4 w-4 shrink-0 opacity-50" />
          </Button>
        </PopoverTrigger>
        <PopoverContent className="w-full p-0 z-50" align="start">
          <Command>
            <CommandInput placeholder={searchPlaceholder} />
            <CommandList>
              <CommandEmpty>{emptyText}</CommandEmpty>
              <CommandGroup>
                {options.map((option) => (
                  <CommandItem
                    key={option.value}
                    value={option.value}
                    onSelect={() => handleSelect(option.value)}
                  >
                    <Checkbox
                      checked={value.includes(option.value)}
                      className="mr-2"
                    />
                    <span>{option.label}</span>
                  </CommandItem>
                ))}
              </CommandGroup>
            </CommandList>
          </Command>
        </PopoverContent>
      </Popover>

      {/* Selected Items Display */}
      {value.length > 0 && (
        <div className="flex flex-wrap gap-2">
          {value.map((v) => {
            const option = options.find((o) => o.value === v);
            return option ? (
              <Badge key={v} variant="secondary" className="gap-1">
                {option.label}
                <X
                  className="w-3 h-3 cursor-pointer hover:text-destructive"
                  onClick={(e) => {
                    e.stopPropagation();
                    handleRemove(v);
                  }}
                />
              </Badge>
            ) : null;
          })}
          {value.length > 1 && (
            <Button
              variant="ghost"
              size="sm"
              className="h-6 px-2 text-xs"
              onClick={() => onValueChange([])}
            >
              Clear all
            </Button>
          )}
        </div>
      )}
    </div>
  );
}