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

/** 无 index 路由，默认进入「岗位」Tab 作为落地页 */
export const unstable_settings = {
  initialRouteName: 'jobs',
};

/** 未选中用 -outline 线性，选中用填充实心 */
const ICON_MAP = {
  jobs: { outline: 'briefcase-outline', filled: 'briefcase' },
  chat: { outline: 'chatbubble-outline', filled: 'chatbubble' },
  growth: { outline: 'trending-up-outline', filled: 'trending-up' },
  profile: { outline: 'person-outline', filled: 'person' },
} as const;

type TabRoute = keyof typeof ICON_MAP;

/**
 * 单个 Tab 项：极简图标 + 文字。
 * 点击选中时：
 *   - 图标/文字从「灰色描边」平滑渐变到「主色填充」
 *     （灰层 + 主色层叠放，opacity 交叉淡入，200ms，纯原生驱动）
 *   - 图标上浮 2px（150ms）
 *   - 按压反馈：轻微缩放 0.92
 */
function TabItem({
  focused,
  route,
  label,
  onPress,
  onLongPress,
}: {
  focused: boolean;
  route: TabRoute;
  label: string;
  onPress: () => void;
  onLongPress: () => void;
}) {
  const { outline, filled } = ICON_MAP[route];
  // 图标纵向位移：选中上浮 2px，未选中复位
  const translateY = useRef(new Animated.Value(focused ? -2 : 0)).current;
  // 选中进度：0 = 未选中，1 = 选中
  const progress = useRef(new Animated.Value(focused ? 1 : 0)).current;

  useEffect(() => {
    const translateAnim = Animated.timing(translateY, {
      toValue: focused ? -2 : 0,
      duration: 150,
      easing: Easing.out(Easing.ease),
      useNativeDriver: true,
    });
    const progressAnim = Animated.timing(progress, {
      toValue: focused ? 1 : 0,
      duration: 200,
      easing: Easing.inOut(Easing.ease),
      useNativeDriver: true,
    });

    translateAnim.start();
    progressAnim.start();

    // 清理：组件卸载或 focused 变化前停止动画，避免更新已卸载的节点
    return () => {
      translateAnim.stop();
      progressAnim.stop();
    };
  }, [focused, translateY, progress]);

  // 未选中层（灰 + 描边）透明度：1 → 0；选中层（主色 + 填充）透明度：0 → 1
  const inactiveOpacity = progress.interpolate({
    inputRange: [0, 1],
    outputRange: [1, 0],
  });

  return (
    <Pressable
      style={({ pressed }) => [styles.tabItem, pressed && styles.tabItemPressed]}
      onPress={onPress}
      onLongPress={onLongPress}
      accessibilityRole="button"
      accessibilityState={{ selected: focused }}
    >
      <Animated.View style={{ transform: [{ translateY }] }}>
        <View style={styles.iconBox}>
          {/* 未选中层：灰色描边图标 */}
          <Animated.View
            style={[StyleSheet.absoluteFill, styles.center, { opacity: inactiveOpacity }]}
          >
            <Ionicons name={outline} size={22} color={colors.textHint} />
          </Animated.View>
          {/* 选中层：主色填充图标 */}
          <Animated.View style={[StyleSheet.absoluteFill, styles.center, { opacity: progress }]}>
            <Ionicons name={filled} size={22} color={colors.primary} />
          </Animated.View>
        </View>
      </Animated.View>

      <View style={styles.labelBox}>
        {/* 未选中文字：灰色常规字重 */}
        <Animated.Text style={[styles.tabLabel, styles.labelLayer, { opacity: inactiveOpacity }]}>
          {label}
        </Animated.Text>
        {/* 选中文字：主色加粗 */}
        <Animated.Text
          style={[styles.tabLabel, styles.tabLabelActive, styles.labelLayer, { opacity: progress }]}
        >
          {label}
        </Animated.Text>
      </View>
    </Pressable>
  );
}

/**
 * 底部 Tab 栏：占据底部布局空间（非悬浮），纯白底、无分割线，
 * 内容只在 tab 栏上方滚动，不会从图标后面穿出。
 */
function TabBar({ state, descriptors, navigation, insets }: BottomTabBarProps) {
  return (
    <View style={[styles.tabBar, { paddingBottom: insets.bottom + 4 }]}>
      {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}
            route={route.name as TabRoute}
            focused={focused}
            label={label}
            onPress={onPress}
            onLongPress={onLongPress}
          />
        );
      })}
    </View>
  );
}

/**
 * 底部 Tab 导航：4 个 Tab（岗位/沟通/成长/我的），高级感极简风格
 */
export default function TabLayout() {
  return (
    <Tabs
      screenOptions={{ headerShown: false }}
      tabBar={(props) => <TabBar {...props} />}
    >
      <Tabs.Screen name="jobs" options={{ title: '岗位' }} />
      <Tabs.Screen name="chat" options={{ title: '沟通' }} />
      <Tabs.Screen name="growth" options={{ title: '成长' }} />
      <Tabs.Screen name="profile" options={{ title: '我的' }} />
    </Tabs>
  );
}

const styles = StyleSheet.create({
  // 纯白底、无分割线、无阴影，占底部布局空间
  tabBar: {
    flexDirection: 'row',
    alignItems: 'center',
    backgroundColor: colors.white,
    paddingTop: 4,
  },
  tabItem: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
    paddingVertical: 2,
  },
  tabItemPressed: {
    transform: [{ scale: 0.92 }],
  },
  iconBox: {
    width: 22,
    height: 22,
  },
  center: {
    alignItems: 'center',
    justifyContent: 'center',
  },
  labelBox: {
    height: 14,
    marginTop: 1,
    alignSelf: 'stretch',
  },
  labelLayer: {
    position: 'absolute',
    top: 0,
    left: 0,
    right: 0,
  },
  tabLabel: {
    fontSize: 11,
    lineHeight: 14,
    fontWeight: '400',
    textAlign: 'center',
    color: colors.textHint,
  },
  tabLabelActive: {
    fontWeight: '600',
    color: colors.primary,
  },
});