import { Ionicons } from '@expo/vector-icons';
import { BlurView } from 'expo-blur';
import { Tabs } from 'expo-router/js-tabs';
import type { BottomTabBarProps } from 'expo-router/js-tabs';
import { useEffect, useRef } from 'react';
import type { ComponentProps, ReactNode } from 'react';
import { Animated, Pressable, StyleSheet, Text, View, type ColorValue } from 'react-native';
import { colors } from '../../src/theme';

type IconName = ComponentProps<typeof Ionicons>['name'];
type TabIconProps = { focused: boolean; color: ColorValue; size: number };

/** 内容底部预留高度：悬浮 Tab 栏高度 + 悬浮间距 + 余量 */
const TAB_BAR_FLOAT_SPACE = 84;

/**
 * 选中/未选中切换实心与描边图标
 */
function tabIcon(filled: IconName, outline: IconName) {
  return ({ color, size, focused }: TabIconProps) => (
    <Ionicons name={focused ? filled : outline} size={size} color={color} />
  );
}

/** 单个 Tab 项：选中时图标轻弹 + 浅蓝胶囊高亮 */
function TabItem({
  focused,
  label,
  icon,
  onPress,
  onLongPress,
}: {
  focused: boolean;
  label: string;
  icon?: (props: TabIconProps) => ReactNode;
  onPress: () => void;
  onLongPress: () => void;
}) {
  // 图标弹跳动画：选中 1.15，未选中回到 1
  const scale = useRef(new Animated.Value(1)).current;
  useEffect(() => {
    Animated.spring(scale, {
      toValue: focused ? 1.15 : 1,
      useNativeDriver: true,
      friction: 6,
      tension: 200,
    }).start();
  }, [focused, scale]);

  const color = focused ? colors.primary : colors.textSecondary;
  return (
    <Pressable
      style={styles.tabItem}
      onPress={onPress}
      onLongPress={onLongPress}
      accessibilityRole="button"
      accessibilityState={{ selected: focused }}
    >
      <View style={[styles.tabItemContent, focused && styles.tabItemContentActive]}>
        <Animated.View style={{ transform: [{ scale }] }}>
          {icon?.({ focused, color, size: 22 })}
        </Animated.View>
        <Text style={[styles.tabLabel, { color }]}>{label}</Text>
      </View>
    </Pressable>
  );
}

/** 悬浮毛玻璃 Tab 栏 */
function FloatingTabBar({ state, descriptors, navigation, insets }: BottomTabBarProps) {
  return (
    <View style={styles.tabBarWrap} pointerEvents="box-none">
      <View style={[styles.tabBarShadow, { marginBottom: insets.bottom + 12 }]}>
        <BlurView intensity={80} tint="light" blurMethod="dimezisBlurViewSdk31Plus" style={styles.tabBar}>
          {state.routes.map((route, index) => {
            const { options } = descriptors[route.key];
            const focused = state.index === index;
            const label =
              typeof options.tabBarLabel === 'string' ? options.tabBarLabel : options.title ?? '';

            const onPress = () => {
              const event = navigation.emit({
                type: 'tabPress',
                target: route.key,
                canPreventDefault: true,
              });
              if (!focused && !event.defaultPrevented) {
                navigation.navigate(route.name);
              }
            };
            const onLongPress = () =>
              navigation.emit({ type: 'tabLongPress', target: route.key });

            return (
              <TabItem
                key={route.key}
                focused={focused}
                label={label}
                icon={options.tabBarIcon}
                onPress={onPress}
                onLongPress={onLongPress}
              />
            );
          })}
        </BlurView>
      </View>
    </View>
  );
}

/**
 * 底部 Tab 导航：悬浮毛玻璃胶囊 + 选中高亮 + 图标弹跳
 */
export default function TabLayout() {
  return (
    <Tabs
      screenOptions={{
        headerShown: false,
        // 悬浮 Tab 栏不占布局空间，给每个页面内容底部预留空间，避免被遮挡
        sceneStyle: { paddingBottom: TAB_BAR_FLOAT_SPACE },
      }}
      tabBar={(props) => <FloatingTabBar {...props} />}
    >
      <Tabs.Screen name="index" options={{ title: '首页', tabBarIcon: tabIcon('home', 'home-outline') }} />
      <Tabs.Screen name="jobs" options={{ title: '岗位', tabBarIcon: tabIcon('briefcase', 'briefcase-outline') }} />
      <Tabs.Screen name="chat" options={{ title: '沟通', tabBarIcon: tabIcon('chatbubbles', 'chatbubbles-outline') }} />
      <Tabs.Screen name="growth" options={{ title: '成长', tabBarIcon: tabIcon('trending-up', 'trending-up-outline') }} />
      <Tabs.Screen name="profile" options={{ title: '我的', tabBarIcon: tabIcon('person', 'person-outline') }} />
    </Tabs>
  );
}

const styles = StyleSheet.create({
  tabBarWrap: {
    position: 'absolute',
    left: 16,
    right: 16,
    bottom: 0,
  },
  // 外层负责 iOS 阴影（不裁剪，阴影在圆角外正常显示）
  tabBarShadow: {
    borderRadius: 24,
    shadowColor: colors.textPrimary,
    shadowOffset: { width: 0, height: 6 },
    shadowOpacity: 0.15,
    shadowRadius: 16,
  },
  // 内层 BlurView：真毛玻璃（iOS）/ 半透明（Android 31 以下降级）+ Android 阴影
  tabBar: {
    flexDirection: 'row',
    alignItems: 'center',
    borderRadius: 24,
    paddingHorizontal: 6,
    paddingVertical: 8,
    overflow: 'hidden',
    elevation: 10,
  },
  tabItem: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
  },
  tabItemContent: {
    alignItems: 'center',
    justifyContent: 'center',
    paddingHorizontal: 12,
    paddingVertical: 6,
    borderRadius: 18,
  },
  tabItemContentActive: {
    backgroundColor: colors.primaryLight,
  },
  tabLabel: {
    marginTop: 4,
    fontSize: 11,
    fontWeight: '600',
  },
});