import type { ComponentType, SVGProps } from 'react';
import { Menu, UnstyledButton, Text, Group, rem } from '@mantine/core';
import { IconCheck, IconChevronDown, IconWorld } from '@tabler/icons-react';
import { GB, ET } from 'country-flag-icons/react/3x2';
import { useTranslation } from 'react-i18next';

interface LanguageSwitcherProps {
  supportedLanguages: readonly string[];
  /** `icon` renders a compact flag button; `button` shows the language label. */
  variant?: 'icon' | 'button';
}

type FlagComponentType = ComponentType<SVGProps<SVGSVGElement>>;

const LANGUAGE_CONFIG: Record<
  string,
  { Flag: FlagComponentType; nativeName: string; shortCode: string }
> = {
  en: { Flag: GB, nativeName: 'English', shortCode: 'EN' },
  am: { Flag: ET, nativeName: 'አማርኛ', shortCode: 'AM' },
};

export function LanguageSwitcher({
  supportedLanguages,
  variant = 'icon',
}: LanguageSwitcherProps) {
  const { t, i18n } = useTranslation();
  const current = i18n.language || 'en';

  const change = (lng: string) => {
    if (lng !== current) i18n.changeLanguage(lng);
  };

  const currentConfig = LANGUAGE_CONFIG[current] || {
    Flag: null,
    nativeName: current.toUpperCase(),
    shortCode: current.toUpperCase(),
  };

  const CurrentFlag = currentConfig.Flag;

  return (
    <Menu
      shadow="lg"
      width={190}
      position="bottom-end"
      withinPortal
      transitionProps={{ transition: 'pop-top-right', duration: 150 }}
    >
      <Menu.Target>
        <UnstyledButton
          aria-label={t('language.label', 'Language')}
          style={{
            display: 'inline-flex',
            alignItems: 'center',
            justifyContent: 'center',
            gap: rem(6),
            width: variant === 'icon' ? rem(38) : 'auto',
            height: rem(38),
            padding: variant === 'icon' ? 0 : '0 12px',
            borderRadius: rem(12),
            background: 'var(--mantine-color-body)',
            color: 'var(--mantine-color-gray-7)',
            boxShadow: '0 1px 3px rgba(0,0,0,0.06), 0 0 0 1px rgba(0,0,0,0.08)',
            transition: 'all 200ms ease',
            cursor: 'pointer',
            border: 'none',
          }}
          onMouseEnter={(e) => {
            e.currentTarget.style.transform = 'translateY(-1px)';
            e.currentTarget.style.boxShadow =
              '0 4px 12px rgba(0,0,0,0.1), 0 0 0 1px var(--mantine-primary-color-3)';
          }}
          onMouseLeave={(e) => {
            e.currentTarget.style.transform = 'translateY(0)';
            e.currentTarget.style.boxShadow =
              '0 1px 3px rgba(0,0,0,0.06), 0 0 0 1px rgba(0,0,0,0.08)';
          }}
        >
          {CurrentFlag ? (
            <CurrentFlag
              style={{
                width: rem(20),
                height: rem(14),
                borderRadius: rem(2),
                display: 'block',
                boxShadow: '0 1px 2px rgba(0,0,0,0.2)',
              }}
            />
          ) : (
            <IconWorld size={19} />
          )}

          {variant !== 'icon' && (
            <Group gap={6} wrap="nowrap">
              <Text size="sm" fw={600}>
                {t(`language.${current}`, currentConfig.nativeName)}
              </Text>
              <IconChevronDown size={14} stroke={2} style={{ opacity: 0.7 }} />
            </Group>
          )}
        </UnstyledButton>
      </Menu.Target>
      <Menu.Dropdown
        style={{
          borderRadius: rem(14),
          padding: rem(6),
          boxShadow: '0 10px 30px rgba(0,0,0,0.15)',
          backdropFilter: 'blur(8px)',
        }}
      >
        <Menu.Label
          style={{
            fontWeight: 600,
            fontSize: rem(11),
            letterSpacing: '0.5px',
            textTransform: 'uppercase',
          }}
        >
          {t('language.label', 'Language')}
        </Menu.Label>
        {supportedLanguages.map((lng) => {
          const config = LANGUAGE_CONFIG[lng] || {
            Flag: null,
            nativeName: lng.toUpperCase(),
            shortCode: lng.toUpperCase(),
          };
          const Flag = config.Flag;
          const isSelected = current === lng;

          return (
            <Menu.Item
              key={lng}
              onClick={() => change(lng)}
              leftSection={
                Flag ? (
                  <Flag
                    style={{
                      width: rem(20),
                      height: rem(14),
                      borderRadius: rem(2),
                      display: 'block',
                      boxShadow: '0 1px 2px rgba(0,0,0,0.15)',
                    }}
                  />
                ) : (
                  <IconWorld size={16} />
                )
              }
              rightSection={
                isSelected ? (
                  <IconCheck
                    size={16}
                    stroke={2.4}
                    style={{ color: 'var(--mantine-primary-color-filled)' }}
                  />
                ) : undefined
              }
              style={{
                borderRadius: rem(8),
                fontWeight: isSelected ? 600 : 400,
                backgroundColor: isSelected
                  ? 'var(--mantine-primary-color-light)'
                  : undefined,
                color: isSelected ? 'var(--mantine-primary-color-filled)' : undefined,
              }}
            >
              <Group justify="space-between" wrap="nowrap" style={{ width: '100%' }}>
                <Text size="sm">{t(`language.${lng}`, config.nativeName)}</Text>
              </Group>
            </Menu.Item>
          );
        })}
      </Menu.Dropdown>
    </Menu>
  );
}