import React, { useEffect, useRef, useState } from 'react';
import { clsx } from 'clsx';
import { ChevronDown } from 'lucide-react';

export interface DropdownMenuItem {
  label: string;
  value: string;
  icon?: React.ReactNode;
  disabled?: boolean;
  divider?: boolean;
  onClick?: () => void;
}

export interface DropdownMenuProps {
  trigger: React.ReactNode;
  items: DropdownMenuItem[];
  onSelect?: (value: string) => void;
  align?: 'left' | 'right' | 'center';
  position?: 'top' | 'bottom';
  className?: string;
  triggerClassName?: string;
}

/**
 * Dropdown menu component
 */
export const DropdownMenu = ({
  trigger,
  items,
  onSelect,
  align = 'left',
  position = 'bottom',
  className,
  triggerClassName,
}: DropdownMenuProps) => {
  const [isOpen, setIsOpen] = useState(false);
  const menuRef = useRef<HTMLDivElement>(null);
  const triggerRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const handleClickOutside = (event: MouseEvent) => {
      if (
        menuRef.current &&
        triggerRef.current &&
        !menuRef.current.contains(event.target as Node) &&
        !triggerRef.current.contains(event.target as Node)
      ) {
        setIsOpen(false);
      }
    };

    const handleEscape = (event: KeyboardEvent) => {
      if (event.key === 'Escape') {
        setIsOpen(false);
      }
    };

    if (isOpen) {
      document.addEventListener('mousedown', handleClickOutside);
      document.addEventListener('keydown', handleEscape);
    }

    return () => {
      document.removeEventListener('mousedown', handleClickOutside);
      document.removeEventListener('keydown', handleEscape);
    };
  }, [isOpen]);

  const alignClasses = {
    left: 'left-0',
    right: 'right-0',
    center: 'left-1/2 -translate-x-1/2',
  };

  const positionClasses = {
    top: 'bottom-full mb-2',
    bottom: 'top-full mt-2',
  };

  const handleItemClick = (item: DropdownMenuItem) => {
    if (item.disabled) return;
    item.onClick?.();
    onSelect?.(item.value);
    setIsOpen(false);
  };

  return (
    <div className={clsx('relative inline-block', className)}>
      <div
        ref={triggerRef}
        onClick={() => setIsOpen(!isOpen)}
        className={clsx('cursor-pointer', triggerClassName)}
        role="button"
        aria-haspopup="true"
        aria-expanded={isOpen}
      >
        {trigger}
      </div>

      {isOpen && (
        <>
          <div
            className="fixed inset-0 z-40"
            onClick={() => setIsOpen(false)}
            aria-hidden="true"
          />
          <div
            ref={menuRef}
            className={clsx(
              'absolute z-50 min-w-[200px]',
              'bg-background border rounded-lg shadow-lg',
              'py-1',
              'animate-in fade-in-0 zoom-in-95 duration-200',
              alignClasses[align],
              positionClasses[position]
            )}
            role="menu"
          >
            {items.map((item, index) => {
              if (item.divider) {
                return (
                  <div
                    key={`divider-${index}`}
                    className="my-1 h-px bg-border"
                    role="separator"
                  />
                );
              }

              return (
                <button
                  key={item.value}
                  type="button"
                  onClick={() => handleItemClick(item)}
                  disabled={item.disabled}
                  className={clsx(
                    'w-full px-4 py-2 text-left text-sm',
                    'flex items-center gap-2',
                    'hover:bg-muted focus:bg-muted',
                    'focus:outline-none transition-colors',
                    {
                      'opacity-50 cursor-not-allowed': item.disabled,
                      'text-foreground': !item.disabled,
                    }
                  )}
                  role="menuitem"
                >
                  {item.icon && <span className="flex-shrink-0">{item.icon}</span>}
                  <span>{item.label}</span>
                </button>
              );
            })}
          </div>
        </>
      )}
    </div>
  );
};

/**
 * Simple select dropdown (alternative to native select)
 */
export interface SelectDropdownProps {
  value: string;
  onChange: (value: string) => void;
  options: Array<{ label: string; value: string; disabled?: boolean }>;
  placeholder?: string;
  className?: string;
  disabled?: boolean;
}

export const SelectDropdown = ({
  value,
  onChange,
  options,
  placeholder = 'Select...',
  className,
  disabled,
}: SelectDropdownProps) => {
  const selectedOption = options.find((opt) => opt.value === value);

  return (
    <DropdownMenu
      trigger={
        <div
          className={clsx(
            'flex items-center justify-between gap-2',
            'px-3 py-2 border rounded-md',
            'bg-background text-foreground',
            'hover:bg-accent focus:outline-none focus:ring-2 focus:ring-ring',
            'transition-colors',
            {
              'opacity-50 cursor-not-allowed': disabled,
            },
            className
          )}
        >
          <span className={clsx({ 'text-muted-foreground': !selectedOption })}>
            {selectedOption?.label || placeholder}
          </span>
          <ChevronDown className="h-4 w-4 text-muted-foreground flex-shrink-0" />
        </div>
      }
      items={options.map((opt) => ({
        label: opt.label,
        value: opt.value,
        disabled: opt.disabled,
        onClick: () => onChange(opt.value),
      }))}
      className="w-full"
      triggerClassName="w-full"
    />
  );
};