import React, { useState, useEffect } from 'react';
import {
  View,
  Text,
  StyleSheet,
  ScrollView,
  TouchableOpacity,
  SafeAreaView,
  Animated,
  Modal,
} from 'react-native';
import { LinearGradient } from 'expo-linear-gradient';
import { Ionicons, Feather, MaterialCommunityIcons, FontAwesome5 } from '@expo/vector-icons';
import { colors, typography, spacing, borderRadius, shadows } from '../theme/colors';
import { SystemStatus, KillSwitchLog } from '../types';
import VaultScreen from './VaultScreen';

// Animation timing constants
const ANIMATION_DURATION = {
  pulse: 1200,
  glow: 1500,
  rotate: 30000,
  heartbeatPress: 150,
} as const;

// Icon names type for type safety
type StatusIconName = 'checkmark-circle' | 'warning' | 'alert-circle';

// Status configuration with nautical theme
const statusConfig: Record<SystemStatus, {
  color: string;
  label: string;
  icon: StatusIconName;
  description: string;
  gradientColors: [string, string];
}> = {
  normal: {
    color: colors.sentinel.statusNormal,
    label: 'ALL CLEAR',
    icon: 'checkmark-circle',
    description: 'The lighthouse burns bright. All systems nominal.',
    gradientColors: ['#6BBF8A', '#4A9F6A'],
  },
  warning: {
    color: colors.sentinel.statusWarning,
    label: 'STORM WARNING',
    icon: 'warning',
    description: 'Anomaly detected. Captain\'s attention required.',
    gradientColors: ['#E5B873', '#C99953'],
  },
  releasing: {
    color: colors.sentinel.statusCritical,
    label: 'RELEASE ACTIVE',
    icon: 'alert-circle',
    description: 'Legacy release protocol initiated.',
    gradientColors: ['#E57373', '#C55353'],
  },
};

// Mock data
const initialLogs: KillSwitchLog[] = [
  { id: '1', action: 'HEARTBEAT_CONFIRMED', timestamp: new Date('2024-01-18T09:30:00') },
  { id: '2', action: 'SUBSCRIPTION_VERIFIED', timestamp: new Date('2024-01-17T00:00:00') },
  { id: '3', action: 'JOURNAL_ACTIVITY', timestamp: new Date('2024-01-16T15:42:00') },
  { id: '4', action: 'HEARTBEAT_CONFIRMED', timestamp: new Date('2024-01-15T11:20:00') },
];

export default function SentinelScreen() {
  const [status, setStatus] = useState<SystemStatus>('normal');
  const [lastSubscriptionCheck] = useState(new Date('2024-01-18T00:00:00'));
  const [lastFlowActivity] = useState(new Date('2024-01-18T10:30:00'));
  const [logs, setLogs] = useState<KillSwitchLog[]>(initialLogs);
  const [pulseAnim] = useState(new Animated.Value(1));
  const [glowAnim] = useState(new Animated.Value(0.5));
  const [rotateAnim] = useState(new Animated.Value(0));
  const [showVault, setShowVault] = useState(false);

  useEffect(() => {
    const pulseAnimation = Animated.loop(
      Animated.sequence([
        Animated.timing(pulseAnim, {
          toValue: 1.06,
          duration: ANIMATION_DURATION.pulse,
          useNativeDriver: true,
        }),
        Animated.timing(pulseAnim, {
          toValue: 1,
          duration: ANIMATION_DURATION.pulse,
          useNativeDriver: true,
        }),
      ])
    );
    pulseAnimation.start();

    const glowAnimation = Animated.loop(
      Animated.sequence([
        Animated.timing(glowAnim, {
          toValue: 1,
          duration: ANIMATION_DURATION.glow,
          useNativeDriver: true,
        }),
        Animated.timing(glowAnim, {
          toValue: 0.5,
          duration: ANIMATION_DURATION.glow,
          useNativeDriver: true,
        }),
      ])
    );
    glowAnimation.start();

    const rotateAnimation = Animated.loop(
      Animated.timing(rotateAnim, {
        toValue: 1,
        duration: ANIMATION_DURATION.rotate,
        useNativeDriver: true,
      })
    );
    rotateAnimation.start();

    return () => {
      pulseAnimation.stop();
      glowAnimation.stop();
      rotateAnimation.stop();
    };
  }, [pulseAnim, glowAnim, rotateAnim]);

  const openVault = () => setShowVault(true);

  const handleHeartbeat = () => {
    Animated.sequence([
      Animated.timing(pulseAnim, {
        toValue: 1.15,
        duration: ANIMATION_DURATION.heartbeatPress,
        useNativeDriver: true,
      }),
      Animated.timing(pulseAnim, {
        toValue: 1,
        duration: ANIMATION_DURATION.heartbeatPress,
        useNativeDriver: true,
      }),
    ]).start();

    const newLog: KillSwitchLog = {
      id: Date.now().toString(),
      action: 'HEARTBEAT_CONFIRMED',
      timestamp: new Date(),
    };
    setLogs((prevLogs) => [newLog, ...prevLogs]);

    if (status === 'warning') {
      setStatus('normal');
    }
  };

  const formatDateTime = (date: Date) =>
    date.toLocaleString('en-US', {
      year: 'numeric',
      month: '2-digit',
      day: '2-digit',
      hour: '2-digit',
      minute: '2-digit',
    });

  const formatTimeAgo = (date: Date) => {
    const now = new Date();
    const diff = now.getTime() - date.getTime();
    const hours = Math.floor(diff / (1000 * 60 * 60));
    const minutes = Math.floor((diff % (1000 * 60 * 60)) / (1000 * 60));
    if (hours > 24) return `${Math.floor(hours / 24)} days ago`;
    if (hours > 0) return `${hours}h ${minutes}m ago`;
    return `${minutes}m ago`;
  };

  const currentStatus = statusConfig[status];
  const spin = rotateAnim.interpolate({
    inputRange: [0, 1],
    outputRange: ['0deg', '360deg'],
  });

  return (
    <View style={styles.container}>
      <LinearGradient
        colors={[colors.sentinel.backgroundGradientStart, colors.sentinel.backgroundGradientEnd]}
        style={styles.gradient}
      >
        <SafeAreaView style={styles.safeArea}>
          <ScrollView
            style={styles.scrollView}
            showsVerticalScrollIndicator={false}
            contentContainerStyle={styles.scrollContent}
          >
            {/* Header */}
            <View style={styles.header}>
              <View style={styles.headerTitleRow}>
                <FontAwesome5 name="anchor" size={24} color={colors.sentinel.primary} />
                <Text style={styles.title}>LIGHTHOUSE</Text>
              </View>
              <Text style={styles.subtitle}>The Watchful Guardian</Text>
            </View>

            {/* Status Display */}
            <View style={styles.statusContainer}>
              <Animated.View
                style={[
                  styles.statusCircleOuter,
                  {
                    transform: [{ scale: pulseAnim }],
                    opacity: glowAnim,
                    backgroundColor: `${currentStatus.color}20`,
                  },
                ]}
              />
              <Animated.View style={{ transform: [{ scale: pulseAnim }] }}>
                <LinearGradient
                  colors={currentStatus.gradientColors}
                  style={styles.statusCircle}
                >
                  <Ionicons name={currentStatus.icon} size={56} color="#fff" />
                </LinearGradient>
              </Animated.View>
              <Text style={[styles.statusLabel, { color: currentStatus.color }]}>
                {currentStatus.label}
              </Text>
              <Text style={styles.statusDescription}>
                {currentStatus.description}
              </Text>
            </View>

            {/* Ship Wheel Watermark */}
            <View style={styles.wheelWatermark}>
              <Animated.View style={{ transform: [{ rotate: spin }] }}>
                <MaterialCommunityIcons
                  name="ship-wheel"
                  size={200}
                  color={colors.sentinel.primary}
                  style={{ opacity: 0.03 }}
                />
              </Animated.View>
            </View>

            {/* Metrics Grid */}
            <View style={styles.metricsGrid}>
              <View style={styles.metricCard}>
                <View style={styles.metricIconContainer}>
                  <FontAwesome5 name="anchor" size={16} color={colors.sentinel.primary} />
                </View>
                <Text style={styles.metricLabel}>SUBSCRIPTION</Text>
                <Text style={styles.metricValue}>{formatTimeAgo(lastSubscriptionCheck)}</Text>
                <Text style={styles.metricTime}>{formatDateTime(lastSubscriptionCheck)}</Text>
              </View>
              <View style={styles.metricCard}>
                <View style={styles.metricIconContainer}>
                  <Feather name="edit-3" size={16} color={colors.sentinel.primary} />
                </View>
                <Text style={styles.metricLabel}>LAST JOURNAL</Text>
                <Text style={styles.metricValue}>{formatTimeAgo(lastFlowActivity)}</Text>
                <Text style={styles.metricTime}>{formatDateTime(lastFlowActivity)}</Text>
              </View>
            </View>

            {/* Shadow Vault Access */}
            <View style={styles.vaultAccessCard}>
              <View style={styles.vaultAccessIcon}>
                <MaterialCommunityIcons name="treasure-chest" size={22} color={colors.nautical.teal} />
              </View>
              <View style={styles.vaultAccessContent}>
                <Text style={styles.vaultAccessTitle}>Shadow Vault</Text>
                <Text style={styles.vaultAccessText}>
                  Access sealed assets from the Lighthouse.
                </Text>
              </View>
              <TouchableOpacity
                style={styles.vaultAccessButton}
                onPress={openVault}
                activeOpacity={0.8}
                accessibilityLabel="Open Shadow Vault"
                accessibilityRole="button"
              >
                <Text style={styles.vaultAccessButtonText}>Open</Text>
              </TouchableOpacity>
            </View>

            {/* Heartbeat Button */}
            <TouchableOpacity
              style={styles.heartbeatButton}
              onPress={handleHeartbeat}
              activeOpacity={0.9}
              accessibilityLabel="Signal the watch - Confirm your presence"
              accessibilityRole="button"
            >
              <LinearGradient
                colors={[colors.nautical.teal, colors.nautical.seafoam]}
                style={styles.heartbeatGradient}
                start={{ x: 0, y: 0 }}
                end={{ x: 1, y: 0 }}
              >
                <View style={styles.heartbeatContent}>
                  <MaterialCommunityIcons name="lighthouse" size={32} color="#fff" />
                  <View>
                    <Text style={styles.heartbeatText}>SIGNAL THE WATCH</Text>
                    <Text style={styles.heartbeatSubtext}>Confirm your presence, Captain</Text>
                  </View>
                </View>
              </LinearGradient>
            </TouchableOpacity>

            {/* Watch Log */}
            <View style={styles.logsSection}>
              <View style={styles.logsSectionHeader}>
                <Feather name="activity" size={18} color={colors.sentinel.primary} />
                <Text style={styles.logsSectionTitle}>WATCH LOG</Text>
              </View>
              {logs.map((log) => (
                <View key={log.id} style={styles.logItem}>
                  <View style={styles.logDot} />
                  <View style={styles.logContent}>
                    <Text style={styles.logAction}>{log.action}</Text>
                    <Text style={styles.logTime}>{formatDateTime(log.timestamp)}</Text>
                  </View>
                </View>
              ))}
            </View>
          </ScrollView>
        </SafeAreaView>
      </LinearGradient>

      {/* Vault Modal */}
      <Modal
        visible={showVault}
        animationType="slide"
        onRequestClose={() => setShowVault(false)}
      >
        <View style={styles.vaultModalContainer}>
          {showVault ? <VaultScreen /> : null}
          <TouchableOpacity
            style={styles.vaultCloseButton}
            onPress={() => setShowVault(false)}
            activeOpacity={0.85}
            accessibilityLabel="Close vault"
            accessibilityRole="button"
          >
            <Ionicons name="close" size={20} color={colors.nautical.cream} />
          </TouchableOpacity>
        </View>
      </Modal>
    </View>
  );
}

const styles = StyleSheet.create({
  container: { flex: 1 },
  gradient: { flex: 1 },
  safeArea: { flex: 1 },
  scrollView: { flex: 1 },
  scrollContent: {
    padding: spacing.lg,
    paddingBottom: 120,
  },
  header: { marginBottom: spacing.xl },
  headerTitleRow: {
    flexDirection: 'row',
    alignItems: 'center',
    gap: spacing.sm,
    marginBottom: spacing.xs,
  },
  title: {
    fontSize: typography.fontSize.xl,
    fontWeight: '700',
    color: colors.sentinel.text,
    letterSpacing: typography.letterSpacing.widest,
    fontFamily: typography.fontFamily.serif,
  },
  subtitle: {
    fontSize: typography.fontSize.sm,
    color: colors.sentinel.textSecondary,
    marginLeft: spacing.xl + spacing.sm,
    fontStyle: 'italic',
  },
  statusContainer: {
    alignItems: 'center',
    paddingVertical: spacing.xl,
    marginBottom: spacing.lg,
    position: 'relative',
  },
  statusCircleOuter: {
    position: 'absolute',
    width: 170,
    height: 170,
    borderRadius: 85,
  },
  statusCircle: {
    width: 140,
    height: 140,
    borderRadius: 70,
    justifyContent: 'center',
    alignItems: 'center',
    marginBottom: spacing.md,
    ...shadows.glow,
  },
  statusLabel: {
    fontSize: typography.fontSize.xl,
    fontWeight: '700',
    letterSpacing: typography.letterSpacing.widest,
    marginBottom: spacing.sm,
  },
  statusDescription: {
    fontSize: typography.fontSize.base,
    color: colors.sentinel.textSecondary,
    textAlign: 'center',
    maxWidth: 280,
    fontStyle: 'italic',
  },
  wheelWatermark: {
    position: 'absolute',
    top: 200,
    right: -60,
    opacity: 0.5,
  },
  metricsGrid: {
    flexDirection: 'row',
    gap: spacing.md,
    marginBottom: spacing.lg,
  },
  metricCard: {
    flex: 1,
    backgroundColor: colors.sentinel.cardBackground,
    borderRadius: borderRadius.xl,
    padding: spacing.base,
    borderWidth: 1,
    borderColor: colors.sentinel.cardBorder,
  },
  metricIconContainer: {
    width: 40,
    height: 40,
    borderRadius: 20,
    backgroundColor: `${colors.sentinel.primary}15`,
    justifyContent: 'center',
    alignItems: 'center',
    marginBottom: spacing.sm,
  },
  metricLabel: {
    fontSize: typography.fontSize.xs,
    color: colors.sentinel.textSecondary,
    letterSpacing: typography.letterSpacing.wide,
    marginBottom: spacing.xs,
    fontWeight: '600',
  },
  metricValue: {
    fontSize: typography.fontSize.md,
    color: colors.sentinel.text,
    fontWeight: '700',
    marginBottom: spacing.xs,
  },
  metricTime: {
    fontSize: typography.fontSize.xs,
    color: colors.sentinel.textSecondary,
    fontFamily: typography.fontFamily.mono,
  },
  heartbeatButton: {
    borderRadius: borderRadius.xl,
    overflow: 'hidden',
    marginBottom: spacing.xl,
    ...shadows.medium,
  },
  heartbeatGradient: { padding: spacing.lg },
  heartbeatContent: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'center',
    gap: spacing.md,
  },
  heartbeatText: {
    fontSize: typography.fontSize.lg,
    fontWeight: '700',
    color: '#fff',
    letterSpacing: typography.letterSpacing.wider,
  },
  heartbeatSubtext: {
    fontSize: typography.fontSize.sm,
    color: 'rgba(255, 255, 255, 0.8)',
    marginTop: 2,
    fontStyle: 'italic',
  },
  logsSection: {
    backgroundColor: colors.sentinel.cardBackground,
    borderRadius: borderRadius.xl,
    padding: spacing.base,
    borderWidth: 1,
    borderColor: colors.sentinel.cardBorder,
  },
  logsSectionHeader: {
    flexDirection: 'row',
    alignItems: 'center',
    gap: spacing.sm,
    marginBottom: spacing.md,
    paddingBottom: spacing.sm,
    borderBottomWidth: 1,
    borderBottomColor: colors.sentinel.cardBorder,
  },
  logsSectionTitle: {
    fontSize: typography.fontSize.xs,
    color: colors.sentinel.textSecondary,
    letterSpacing: typography.letterSpacing.widest,
    fontWeight: '700',
  },
  logItem: {
    flexDirection: 'row',
    alignItems: 'flex-start',
    paddingVertical: spacing.sm,
  },
  logDot: {
    width: 8,
    height: 8,
    borderRadius: 4,
    backgroundColor: colors.sentinel.primary,
    marginTop: 6,
    marginRight: spacing.md,
  },
  logContent: { flex: 1 },
  logAction: {
    fontSize: typography.fontSize.sm,
    color: colors.sentinel.text,
    fontFamily: typography.fontFamily.mono,
    fontWeight: '500',
    marginBottom: 2,
  },
  logTime: {
    fontSize: typography.fontSize.xs,
    color: colors.sentinel.textSecondary,
    fontFamily: typography.fontFamily.mono,
  },
  vaultAccessCard: {
    flexDirection: 'row',
    alignItems: 'center',
    backgroundColor: colors.sentinel.cardBackground,
    borderRadius: borderRadius.xl,
    padding: spacing.base,
    marginBottom: spacing.lg,
    borderWidth: 1,
    borderColor: colors.sentinel.cardBorder,
  },
  vaultAccessIcon: {
    width: 44,
    height: 44,
    borderRadius: 22,
    backgroundColor: `${colors.nautical.teal}20`,
    alignItems: 'center',
    justifyContent: 'center',
    marginRight: spacing.md,
  },
  vaultAccessContent: { flex: 1 },
  vaultAccessTitle: {
    fontSize: typography.fontSize.base,
    fontWeight: '600',
    color: colors.sentinel.text,
    marginBottom: 2,
  },
  vaultAccessText: {
    fontSize: typography.fontSize.sm,
    color: colors.sentinel.textSecondary,
  },
  vaultAccessButton: {
    backgroundColor: colors.nautical.teal,
    paddingHorizontal: spacing.md,
    paddingVertical: spacing.sm,
    borderRadius: borderRadius.full,
  },
  vaultAccessButtonText: {
    color: colors.nautical.cream,
    fontWeight: '700',
    fontSize: typography.fontSize.sm,
  },
  vaultModalContainer: {
    flex: 1,
    backgroundColor: colors.vault.background,
  },
  vaultCloseButton: {
    position: 'absolute',
    top: spacing.xl + spacing.lg,
    right: spacing.lg,
    width: 36,
    height: 36,
    borderRadius: 18,
    backgroundColor: 'rgba(26, 58, 74, 0.65)',
    alignItems: 'center',
    justifyContent: 'center',
  },
});