import { useState } from "react";
import { Check, ChevronsUpDown } from "lucide-react";
import { cn } from "@/lib/utils";
import { Button } from "@/components/ui/button";
import {
  Command,
  CommandEmpty,
  CommandGroup,
  CommandInput,
  CommandItem,
  CommandList,
} from "@/components/ui/command";
import {
  Popover,
  PopoverContent,
  PopoverTrigger,
} from "@/components/ui/popover";
import { useListCategories, getListCategoriesQueryKey } from "@workspace/api-client-react";

interface CategoryComboboxProps {
  value: string;
  onChange: (value: string) => void;
  placeholder?: string;
}

export function CategoryCombobox({ value, onChange, placeholder = "Select or type a category..." }: CategoryComboboxProps) {
  const [open, setOpen] = useState(false);
  const [inputValue, setInputValue] = useState(value);
  const categories = useListCategories({
    query: {
      queryKey: getListCategoriesQueryKey(),
      refetchOnMount: "always",
      staleTime: 0,
    },
  });

  const known: string[] = categories.data ?? [];

  const filtered = inputValue.trim()
    ? known.filter((c) => c.toLowerCase().includes(inputValue.toLowerCase()))
    : known;

  const showCreateOption = inputValue.trim() !== "" && !known.some(
    (c) => c.toLowerCase() === inputValue.toLowerCase()
  );

  function select(val: string) {
    onChange(val);
    setInputValue(val);
    setOpen(false);
  }

  return (
    <Popover open={open} onOpenChange={setOpen}>
      <PopoverTrigger asChild>
        <Button
          variant="outline"
          role="combobox"
          aria-expanded={open}
          className="w-full justify-between font-normal h-9"
          data-testid="button-category-combobox"
        >
          <span className={cn(!value && "text-muted-foreground")}>
            {value || placeholder}
          </span>
          <ChevronsUpDown className="ml-2 h-4 w-4 shrink-0 opacity-50" />
        </Button>
      </PopoverTrigger>
      <PopoverContent className="w-full p-0" align="start">
        <Command shouldFilter={false}>
          <CommandInput
            placeholder="Search or enter new category..."
            value={inputValue}
            onValueChange={(v) => {
              setInputValue(v);
              onChange(v);
            }}
            data-testid="input-category-search"
          />
          <CommandList>
            {filtered.length === 0 && !showCreateOption && (
              <CommandEmpty>No categories found.</CommandEmpty>
            )}
            {filtered.length > 0 && (
              <CommandGroup heading="Known categories">
                {filtered.map((cat) => (
                  <CommandItem
                    key={cat}
                    value={cat}
                    onSelect={() => select(cat)}
                    data-testid={`item-category-${cat}`}
                  >
                    <Check
                      className={cn("mr-2 h-4 w-4", value === cat ? "opacity-100" : "opacity-0")}
                    />
                    {cat}
                  </CommandItem>
                ))}
              </CommandGroup>
            )}
            {showCreateOption && (
              <CommandGroup heading="Create new">
                <CommandItem
                  value={inputValue}
                  onSelect={() => select(inputValue.trim())}
                  data-testid="item-category-create-new"
                >
                  <span className="text-primary font-medium">+ Create</span>
                  <span className="ml-2 text-muted-foreground">&ldquo;{inputValue.trim()}&rdquo;</span>
                </CommandItem>
              </CommandGroup>
            )}
          </CommandList>
        </Command>
      </PopoverContent>
    </Popover>
  );
}