import { Ionicons } from '@expo/vector-icons';
import { BlurView } from 'expo-blur';
import { LinearGradient } from 'expo-linear-gradient';
import { useRouter } from 'expo-router';
import React, { useEffect } from 'react';
import { Dimensions, StyleSheet, Text, TouchableOpacity, View } from 'react-native';
import Animated, { Easing, useAnimatedStyle, useSharedValue, withDelay, withRepeat, withSequence, withTiming } from 'react-native-reanimated';
import { useSafeAreaInsets } from 'react-native-safe-area-context';

import { HeaderBar } from '@/components/ui/HeaderBar';
import { Colors } from '@/constants/Colors';

const { width: SCREEN_WIDTH, height: SCREEN_HEIGHT } = Dimensions.get('window');

export default function AIPostureProcessingScreen() {
  const insets = useSafeAreaInsets();
  const router = useRouter();
  const theme = Colors.dark;

  // Core looping animations
  const spin = useSharedValue(0);
  const pulse = useSharedValue(0);
  const scanY = useSharedValue(0);
  const particle = useSharedValue(0);

  useEffect(() => {
    spin.value = withRepeat(withTiming(1, { duration: 6000, easing: Easing.linear }), -1);
    pulse.value = withRepeat(withSequence(
      withTiming(1, { duration: 1600, easing: Easing.inOut(Easing.quad) }),
      withTiming(0, { duration: 1600, easing: Easing.inOut(Easing.quad) })
    ), -1, true);
    scanY.value = withRepeat(withTiming(1, { duration: 3800, easing: Easing.inOut(Easing.cubic) }), -1, false);
    particle.value = withDelay(400, withRepeat(withTiming(1, { duration: 5200, easing: Easing.inOut(Easing.quad) }), -1, true));
  }, []);

  const ringStyleOuter = useAnimatedStyle(() => ({
    transform: [{ rotate: `${spin.value * 360}deg` }],
    opacity: 0.8,
  }));
  const ringStyleInner = useAnimatedStyle(() => ({
    transform: [{ rotate: `${-spin.value * 360}deg` }, { scale: 0.98 + pulse.value * 0.04 }],
  }));
  const scannerStyle = useAnimatedStyle(() => ({
    transform: [{ translateY: (scanY.value * (SCREEN_HEIGHT * 0.45)) - (SCREEN_HEIGHT * 0.225) }],
    opacity: 0.6 + Math.sin(scanY.value * Math.PI) * 0.2,
  }));
  const particleStyleA = useAnimatedStyle(() => ({
    transform: [
      { translateX: Math.sin(particle.value * Math.PI * 2) * 40 },
      { translateY: Math.cos(particle.value * Math.PI * 2) * 24 },
      { rotate: `${particle.value * 360}deg` },
    ],
    opacity: 0.5 + 0.5 * Math.abs(Math.sin(particle.value * Math.PI)),
  }));

  return (
    <View style={[styles.screen, { backgroundColor: theme.background }]}>
      <HeaderBar title="AI评估进行中" onBack={() => router.back()} tone="light" transparent />

      {/* Layered background */}
      <View style={[StyleSheet.absoluteFill, { zIndex: -1 }]} pointerEvents="none">
        <LinearGradient
          colors={["#F7FFE8", "#F0FBFF", "#FFF6E8"]}
          start={{ x: 0.1, y: 0 }}
          end={{ x: 0.9, y: 1 }}
          style={StyleSheet.absoluteFill}
        />
        <BlurView intensity={20} tint="light" style={styles.blurBlobA} />
        <BlurView intensity={20} tint="light" style={styles.blurBlobB} />
      </View>

      {/* Hero visualization */}
      <View style={styles.hero}>
        <View style={styles.heroBackdrop} />
        <Animated.View style={[styles.ringOuter, ringStyleOuter]} />
        <Animated.View style={[styles.ringInner, ringStyleInner]} />

        <View style={styles.grid}>
          {Array.from({ length: 9 }).map((_, i) => (
            <View key={`row-${i}`} style={styles.gridRow}>
              {Array.from({ length: 9 }).map((__, j) => (
                <View key={`cell-${i}-${j}`} style={styles.gridCell} />
              ))}
            </View>
          ))}
          <Animated.View style={[styles.scanner, scannerStyle]} />
        </View>

        <Animated.View style={[styles.particleA, particleStyleA]} />
        <Animated.View style={[styles.particleB, particleStyleA, { right: undefined, left: SCREEN_WIDTH * 0.2, top: undefined, bottom: 60 }]} />
      </View>

      {/* Copy & actions */}
      <View style={[styles.panel, { paddingBottom: insets.bottom + 16 }]}>
        <Text style={styles.title}>正在进行体态特征提取与矢量评估</Text>
        <Text style={styles.subtitle}>这通常需要 10-30 秒。你可以停留在此页面等待结果，或点击返回稍后在个人中心查看。</Text>

        <View style={styles.actions}>
          <TouchableOpacity
            style={[styles.primaryBtn, { backgroundColor: theme.primary }]}
            activeOpacity={0.9}
            // TODO: 评估完成后恢复为停留当前页面等待结果（不要跳转）
            onPress={() => router.replace('/ai-posture-result')}
          >
            <Ionicons name="time-outline" size={16} color="#192126" />
            <Text style={styles.primaryBtnText}>保持页面等待</Text>
          </TouchableOpacity>
          <TouchableOpacity style={styles.secondaryBtn} activeOpacity={0.9} onPress={() => router.replace('/(tabs)/personal')}>
            <Text style={styles.secondaryBtnText}>返回个人中心</Text>
          </TouchableOpacity>
        </View>
      </View>
    </View>
  );
}

const RING_SIZE = Math.min(SCREEN_WIDTH, SCREEN_HEIGHT) * 0.62;
const INNER_RING_SIZE = RING_SIZE * 0.72;

const styles = StyleSheet.create({
  screen: {
    flex: 1,
  },
  hero: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
  },
  blurBlobA: {
    position: 'absolute',
    top: -80,
    right: -60,
    width: 240,
    height: 240,
    borderRadius: 120,
    backgroundColor: 'rgba(187,242,70,0.20)',
  },
  blurBlobB: {
    position: 'absolute',
    bottom: 120,
    left: -40,
    width: 220,
    height: 220,
    borderRadius: 110,
    backgroundColor: 'rgba(89, 198, 255, 0.16)',
  },
  heroBackdrop: {
    position: 'absolute',
    width: RING_SIZE * 1.08,
    height: RING_SIZE * 1.08,
    borderRadius: (RING_SIZE * 1.08) / 2,
    backgroundColor: 'rgba(25,33,38,0.25)',
  },
  ringOuter: {
    position: 'absolute',
    width: RING_SIZE,
    height: RING_SIZE,
    borderRadius: RING_SIZE / 2,
    borderWidth: 1,
    borderColor: 'rgba(25,33,38,0.16)',
  },
  ringInner: {
    position: 'absolute',
    width: INNER_RING_SIZE,
    height: INNER_RING_SIZE,
    borderRadius: INNER_RING_SIZE / 2,
    borderWidth: 2,
    borderColor: 'rgba(187,242,70,0.65)',
    shadowColor: Colors.light.accentGreen,
    shadowOffset: { width: 0, height: 0 },
    shadowOpacity: 0.35,
    shadowRadius: 24,
  },
  grid: {
    width: RING_SIZE * 0.9,
    height: RING_SIZE * 0.9,
    borderRadius: RING_SIZE * 0.45,
    overflow: 'hidden',
    padding: 10,
    backgroundColor: 'rgba(25,33,38,0.08)',
  },
  gridRow: {
    flexDirection: 'row',
  },
  gridCell: {
    flex: 1,
    aspectRatio: 1,
    margin: 2,
    borderRadius: 3,
    backgroundColor: 'rgba(255,255,255,0.16)',
  },
  scanner: {
    position: 'absolute',
    left: 0,
    right: 0,
    top: '50%',
    height: 60,
    marginTop: -30,
    backgroundColor: 'rgba(187,242,70,0.10)',
    borderWidth: 1,
    borderColor: 'rgba(187,242,70,0.25)',
  },
  particleA: {
    position: 'absolute',
    right: SCREEN_WIDTH * 0.18,
    top: 40,
    width: 14,
    height: 14,
    borderRadius: 7,
    backgroundColor: Colors.light.accentGreen,
    shadowColor: Colors.light.accentGreen,
    shadowOffset: { width: 0, height: 0 },
    shadowOpacity: 0.4,
    shadowRadius: 16,
  },
  particleB: {
    position: 'absolute',
    right: SCREEN_WIDTH * 0.08,
    top: 120,
    width: 8,
    height: 8,
    borderRadius: 4,
    backgroundColor: 'rgba(89, 198, 255, 1)',
    shadowColor: 'rgba(89, 198, 255, 1)',
    shadowOffset: { width: 0, height: 0 },
    shadowOpacity: 0.4,
    shadowRadius: 12,
  },
  panel: {
    paddingHorizontal: 20,
    paddingTop: 8,
  },
  title: {
    color: '#ECEDEE',
    fontSize: 18,
    fontWeight: '800',
    marginBottom: 8,
  },
  subtitle: {
    color: 'rgba(255,255,255,0.75)',
    fontSize: 14,
    lineHeight: 20,
  },
  actions: {
    flexDirection: 'row',
    gap: 10,
    marginTop: 14,
  },
  primaryBtn: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'center',
    gap: 6,
    height: 44,
    paddingHorizontal: 16,
    borderRadius: 12,
  },
  primaryBtnText: {
    color: '#192126',
    fontSize: 14,
    fontWeight: '800',
  },
  secondaryBtn: {
    flex: 1,
    height: 44,
    borderRadius: 12,
    alignItems: 'center',
    justifyContent: 'center',
    borderWidth: 1,
    borderColor: 'rgba(255,255,255,0.18)',
  },
  secondaryBtnText: {
    color: 'rgba(255,255,255,0.85)',
    fontSize: 14,
    fontWeight: '700',
  },
});