import React, { useState, useEffect, useCallback, useRef } from 'react';
import {
  View,
  Text,
  StyleSheet,
  ScrollView,
  TouchableOpacity,
  RefreshControl,
  Image,
  Modal,
  TextInput,
  Alert,
  KeyboardAvoidingView,
  Platform,
  ActivityIndicator,
} from 'react-native';
import { WebView } from 'react-native-webview';
import { useLocalSearchParams, router } from 'expo-router';
import { Ionicons } from '@expo/vector-icons';
import { SafeAreaView } from 'react-native-safe-area-context';
import * as ImagePicker from 'expo-image-picker';
import { api } from '@/services/api';
import { useBeneficiary } from '@/contexts/BeneficiaryContext';
import { LoadingSpinner } from '@/components/ui/LoadingSpinner';
import { FullScreenError } from '@/components/ui/ErrorMessage';
import { useToast } from '@/components/ui/Toast';
import { DevModeToggle } from '@/components/ui/DevModeToggle';
import MockDashboard from '@/components/MockDashboard';
import {
  AppColors,
  BorderRadius,
  FontSizes,
  Spacing,
  FontWeights,
  Shadows,
  AvatarSizes,
} from '@/constants/theme';
import type { Beneficiary } from '@/types';
import {
  hasBeneficiaryDevices,
  hasActiveSubscription,
  shouldShowSubscriptionWarning,
} from '@/services/BeneficiaryDetailController';

// WebView Dashboard URL - opens specific deployment directly
const getDashboardUrl = (deploymentId?: number) => {
  const baseUrl = 'https://react.eluxnetworks.net/dashboard';
  return deploymentId ? `${baseUrl}/${deploymentId}` : `${baseUrl}/21`;
};

// Ferdinand's default deployment ID (has sensor data)
const FERDINAND_DEPLOYMENT_ID = 21;

export default function BeneficiaryDetailScreen() {
  const { id } = useLocalSearchParams<{ id: string }>();
  const { setCurrentBeneficiary } = useBeneficiary();
  const toast = useToast();

  const [beneficiary, setBeneficiary] = useState<Beneficiary | null>(null);
  const [isLoading, setIsLoading] = useState(true);
  const [isRefreshing, setIsRefreshing] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [isMenuVisible, setIsMenuVisible] = useState(false);
  const [showWebView, setShowWebView] = useState(false);
  const [isWebViewReady, setIsWebViewReady] = useState(false);
  const [authToken, setAuthToken] = useState<string | null>(null);
  const [userName, setUserName] = useState<string | null>(null);
  const [userId, setUserId] = useState<number | null>(null);

  // Edit modal state
  const [isEditModalVisible, setIsEditModalVisible] = useState(false);
  const [editForm, setEditForm] = useState({ name: '', address: '', avatar: undefined as string | undefined });

  const webViewRef = useRef<WebView>(null);

  // Load legacy token for WebView dashboard
  useEffect(() => {
    const loadLegacyToken = async () => {
      try {
        const token = await api.getLegacyToken();
        const name = await api.getLegacyUserName();
        const id = await api.getLegacyUserId();
        setAuthToken(token);
        setUserName(name);
        setUserId(id);
        setIsWebViewReady(true);
      } catch (err) {
        console.log('[BeneficiaryDetail] Legacy token not available');
        setIsWebViewReady(true);
      }
    };
    loadLegacyToken();
  }, []);

  const loadBeneficiary = useCallback(async (showLoadingIndicator = true) => {
    if (!id) return;

    if (showLoadingIndicator && !isRefreshing) {
      setIsLoading(true);
    }
    setError(null);

    try {
      const response = await api.getWellNuoBeneficiary(parseInt(id, 10));
      if (response.ok && response.data) {
        const data = response.data;
        setBeneficiary(data);
        setCurrentBeneficiary(data);

        // WATERFALL REDIRECT LOGIC:
        // 1. First check devices (highest priority)
        if (!hasBeneficiaryDevices(data)) {
          const status = data.equipmentStatus;
          if (status && ['ordered', 'shipped', 'delivered'].includes(status)) {
            // Equipment is ordered/shipped/delivered → show status
            router.replace(`/(tabs)/beneficiaries/${id}/equipment-status`);
            return;
          } else {
            // No devices and no order → need to purchase
            router.replace(`/(tabs)/beneficiaries/${id}/purchase`);
            return;
          }
        }

        // 2. Then check subscription (only if devices exist)
        if (!hasActiveSubscription(data)) {
          router.replace(`/(tabs)/beneficiaries/${id}/subscription`);
          return;
        }

        // 3. All good → show Dashboard (this screen)
      } else {
        setError(response.error?.message || 'Failed to load beneficiary');
      }
    } catch (err) {
      setError(err instanceof Error ? err.message : 'An error occurred');
    } finally {
      setIsLoading(false);
      setIsRefreshing(false);
    }
  }, [id, setCurrentBeneficiary, isRefreshing]);

  useEffect(() => {
    loadBeneficiary();
  }, [loadBeneficiary]);

  const handleRefresh = useCallback(() => {
    setIsRefreshing(true);
    loadBeneficiary(false);
  }, [loadBeneficiary]);

  const handleEditPress = () => {
    if (beneficiary) {
      setEditForm({
        name: beneficiary.name || '',
        address: beneficiary.address || '',
        avatar: beneficiary.avatar,
      });
      setIsEditModalVisible(true);
    }
  };

  const handlePickAvatar = async () => {
    const { status } = await ImagePicker.requestMediaLibraryPermissionsAsync();
    if (status !== 'granted') {
      toast.error('Permission needed', 'Please allow access to your photo library.');
      return;
    }

    const result = await ImagePicker.launchImageLibraryAsync({
      mediaTypes: ['images'],
      allowsEditing: true,
      aspect: [1, 1],
      quality: 0.5,
    });

    if (!result.canceled && result.assets[0]) {
      setEditForm(prev => ({ ...prev, avatar: result.assets[0].uri }));
    }
  };

  const handleSaveEdit = async () => {
    if (!editForm.name.trim() || !id) {
      toast.error('Error', 'Name is required');
      return;
    }

    try {
      const response = await api.updateWellNuoBeneficiary(parseInt(id, 10), {
        name: editForm.name.trim(),
        address: editForm.address.trim() || undefined,
      });

      if (response.ok) {
        setIsEditModalVisible(false);
        toast.success('Saved', 'Profile updated successfully');
        loadBeneficiary(false);
      } else {
        toast.error('Error', response.error?.message || 'Failed to save changes.');
      }
    } catch (err) {
      toast.error('Error', 'Failed to save changes.');
    }
  };

  const handleDeleteBeneficiary = () => {
    if (!id) return;

    Alert.alert(
      'Remove Beneficiary',
      `Are you sure you want to remove ${beneficiary?.name}? This action cannot be undone.`,
      [
        { text: 'Cancel', style: 'cancel' },
        {
          text: 'Remove',
          style: 'destructive',
          onPress: async () => {
            try {
              const response = await api.deleteBeneficiary(parseInt(id, 10));
              if (response.ok) {
                toast.success('Removed', 'Beneficiary has been removed');
                router.replace('/(tabs)');
              } else {
                toast.error('Error', response.error?.message || 'Failed to remove beneficiary');
              }
            } catch (err) {
              toast.error('Error', 'Failed to remove beneficiary');
            }
          },
        },
      ]
    );
  };

  // JavaScript to inject token into localStorage for WebView
  const injectedJavaScript = authToken
    ? `
      (function() {
        try {
          var authData = {
            username: '${userName || ''}',
            token: '${authToken}',
            user_id: ${userId || 'null'}
          };
          localStorage.setItem('auth2', JSON.stringify(authData));
          console.log('Auth data injected:', authData.username);
        } catch(e) {
          console.error('Failed to inject token:', e);
        }
      })();
      true;
    `
    : '';

  if (isLoading) {
    return <LoadingSpinner fullScreen message="Loading..." />;
  }

  if (error || !beneficiary) {
    return (
      <FullScreenError
        message={error || 'Beneficiary not found'}
        onRetry={() => loadBeneficiary()}
      />
    );
  }

  return (
    <SafeAreaView style={styles.container} edges={['top']}>
      {/* Header */}
      <View style={styles.header}>
        <TouchableOpacity style={styles.headerButton} onPress={() => router.replace('/(tabs)')}>
          <Ionicons name="arrow-back" size={22} color={AppColors.textPrimary} />
        </TouchableOpacity>

        {/* Avatar + Name */}
        <View style={styles.headerCenter}>
          {beneficiary.avatar && beneficiary.avatar.trim() !== '' && !beneficiary.avatar.includes('placeholder') ? (
            <Image source={{ uri: beneficiary.avatar }} style={styles.headerAvatarImage} />
          ) : (
            <View style={styles.headerAvatar}>
              <Text style={styles.headerAvatarText}>
                {beneficiary.name.charAt(0).toUpperCase()}
              </Text>
            </View>
          )}
          <Text style={styles.headerTitle}>{beneficiary.name}</Text>
        </View>

        <View>
          <TouchableOpacity style={styles.headerButton} onPress={() => setIsMenuVisible(!isMenuVisible)}>
            <Ionicons name="ellipsis-vertical" size={22} color={AppColors.textPrimary} />
          </TouchableOpacity>

          {/* Dropdown Menu */}
          {isMenuVisible && (
            <View style={styles.dropdownMenu}>
              <TouchableOpacity
                style={styles.dropdownItem}
                onPress={() => {
                  setIsMenuVisible(false);
                  handleEditPress();
                }}
              >
                <Ionicons name="create-outline" size={20} color={AppColors.textPrimary} />
                <Text style={styles.dropdownItemText}>Edit</Text>
              </TouchableOpacity>

              <TouchableOpacity
                style={styles.dropdownItem}
                onPress={() => {
                  setIsMenuVisible(false);
                  router.push(`/(tabs)/beneficiaries/${id}/share`);
                }}
              >
                <Ionicons name="share-outline" size={20} color={AppColors.textPrimary} />
                <Text style={styles.dropdownItemText}>Access</Text>
              </TouchableOpacity>

              <TouchableOpacity
                style={styles.dropdownItem}
                onPress={() => {
                  setIsMenuVisible(false);
                  router.push(`/(tabs)/beneficiaries/${id}/subscription`);
                }}
              >
                <Ionicons name="diamond-outline" size={20} color={AppColors.textPrimary} />
                <Text style={styles.dropdownItemText}>Subscription</Text>
              </TouchableOpacity>

              <TouchableOpacity
                style={styles.dropdownItem}
                onPress={() => {
                  setIsMenuVisible(false);
                  router.push(`/(tabs)/beneficiaries/${id}/equipment`);
                }}
              >
                <Ionicons name="hardware-chip-outline" size={20} color={AppColors.textPrimary} />
                <Text style={styles.dropdownItemText}>Equipment</Text>
              </TouchableOpacity>

              <TouchableOpacity
                style={[styles.dropdownItem, styles.dropdownItemDanger]}
                onPress={() => {
                  setIsMenuVisible(false);
                  handleDeleteBeneficiary();
                }}
              >
                <Ionicons name="trash-outline" size={20} color={AppColors.error} />
                <Text style={[styles.dropdownItemText, styles.dropdownItemTextDanger]}>Remove</Text>
              </TouchableOpacity>
            </View>
          )}
        </View>
      </View>

      {/* Backdrop to close menu */}
      {isMenuVisible && (
        <TouchableOpacity
          style={styles.menuBackdrop}
          activeOpacity={1}
          onPress={() => setIsMenuVisible(false)}
        />
      )}

      {/* DEBUG PANEL */}
      {__DEV__ && (
        <View style={styles.debugPanel}>
          <Text style={styles.debugTitle}>DEBUG INFO (tap to copy)</Text>
          <TouchableOpacity onPress={() => {
            const debugData = JSON.stringify({
              hasDevices: hasBeneficiaryDevices(beneficiary),
              equipmentStatus: beneficiary.equipmentStatus,
              subscription: beneficiary.subscription,
              deviceId: beneficiary.device_id,
              devices: beneficiary.devices,
            }, null, 2);
            console.log('DEBUG DATA:', debugData);
          }}>
            <Text style={styles.debugText}>hasDevices: {String(hasBeneficiaryDevices(beneficiary))}</Text>
            <Text style={styles.debugText}>equipmentStatus: {beneficiary.equipmentStatus || 'none'}</Text>
            <Text style={styles.debugText}>subscription: {beneficiary.subscription ? JSON.stringify(beneficiary.subscription) : 'none'}</Text>
            <Text style={styles.debugText}>device_id: {beneficiary.device_id || 'null'}</Text>
            <Text style={styles.debugText}>devices: {beneficiary.devices ? String(beneficiary.devices) : '0'}</Text>
          </TouchableOpacity>
        </View>
      )}

      {/* Dashboard Content */}
      <View style={styles.dashboardContainer}>
        {shouldShowSubscriptionWarning(beneficiary) && (
          <View style={styles.subscriptionWarning}>
            <Ionicons name="alert-circle" size={16} color={AppColors.warning} />
            <Text style={styles.subscriptionWarningText}>
              Subscription expiring soon
            </Text>
          </View>
        )}

        {/* Developer Toggle */}
        <View style={styles.devToggleSection}>
          <DevModeToggle value={showWebView} onValueChange={setShowWebView} />
        </View>

        {/* Content area - WebView or MockDashboard */}
        <View style={styles.dashboardContent}>
          {showWebView ? (
            isWebViewReady && authToken ? (
              <WebView
                ref={webViewRef}
                source={{ uri: getDashboardUrl(FERDINAND_DEPLOYMENT_ID) }}
                style={styles.webView}
                javaScriptEnabled={true}
                domStorageEnabled={true}
                startInLoadingState={true}
                allowsBackForwardNavigationGestures={true}
                injectedJavaScriptBeforeContentLoaded={injectedJavaScript}
                injectedJavaScript={injectedJavaScript}
                onMessage={(event) => {
                  console.log('[WebView] Message:', event.nativeEvent.data);
                }}
                renderLoading={() => (
                  <View style={styles.webViewLoading}>
                    <ActivityIndicator size="large" color={AppColors.primary} />
                    <Text style={styles.webViewLoadingText}>Loading dashboard...</Text>
                  </View>
                )}
              />
            ) : (
              <View style={styles.webViewLoading}>
                <ActivityIndicator size="large" color={AppColors.primary} />
                <Text style={styles.webViewLoadingText}>
                  {isWebViewReady ? 'Loading dashboard...' : 'Connecting to sensors...'}
                </Text>
              </View>
            )
          ) : (
            <ScrollView
              style={styles.nativeScrollView}
              contentContainerStyle={styles.nativeScrollContent}
              showsVerticalScrollIndicator={false}
              refreshControl={
                <RefreshControl
                  refreshing={isRefreshing}
                  onRefresh={handleRefresh}
                  tintColor={AppColors.primary}
                />
              }
            >
              <MockDashboard beneficiaryName={beneficiary.name} />
            </ScrollView>
          )}
        </View>
      </View>

      {/* Edit Modal */}
      <Modal visible={isEditModalVisible} animationType="slide" transparent>
        <KeyboardAvoidingView
          behavior={Platform.OS === 'ios' ? 'padding' : 'height'}
          style={styles.modalOverlay}
        >
          <View style={styles.modalContainer}>
            <View style={styles.modalHeader}>
              <Text style={styles.modalTitle}>Edit Profile</Text>
              <TouchableOpacity onPress={() => setIsEditModalVisible(false)}>
                <Ionicons name="close" size={24} color={AppColors.textPrimary} />
              </TouchableOpacity>
            </View>

            <ScrollView style={styles.modalContent}>
              {/* Avatar */}
              <TouchableOpacity style={styles.avatarPicker} onPress={handlePickAvatar}>
                {editForm.avatar ? (
                  <Image source={{ uri: editForm.avatar }} style={styles.avatarPickerImage} />
                ) : (
                  <View style={styles.avatarPickerPlaceholder}>
                    <Ionicons name="camera" size={32} color={AppColors.textMuted} />
                  </View>
                )}
                <View style={styles.avatarPickerBadge}>
                  <Ionicons name="pencil" size={12} color={AppColors.white} />
                </View>
              </TouchableOpacity>

              {/* Name */}
              <View style={styles.inputGroup}>
                <Text style={styles.inputLabel}>Name</Text>
                <TextInput
                  style={styles.textInput}
                  value={editForm.name}
                  onChangeText={(text) => setEditForm(prev => ({ ...prev, name: text }))}
                  placeholder="Full name"
                  placeholderTextColor={AppColors.textMuted}
                />
              </View>

              {/* Address */}
              <View style={styles.inputGroup}>
                <Text style={styles.inputLabel}>Address</Text>
                <TextInput
                  style={[styles.textInput, styles.textArea]}
                  value={editForm.address}
                  onChangeText={(text) => setEditForm(prev => ({ ...prev, address: text }))}
                  placeholder="Street address"
                  placeholderTextColor={AppColors.textMuted}
                  multiline
                  numberOfLines={3}
                />
              </View>
            </ScrollView>

            <View style={styles.modalFooter}>
              <TouchableOpacity
                style={styles.cancelButton}
                onPress={() => setIsEditModalVisible(false)}
              >
                <Text style={styles.cancelButtonText}>Cancel</Text>
              </TouchableOpacity>
              <TouchableOpacity style={styles.saveButton} onPress={handleSaveEdit}>
                <Text style={styles.saveButtonText}>Save</Text>
              </TouchableOpacity>
            </View>
          </View>
        </KeyboardAvoidingView>
      </Modal>
    </SafeAreaView>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: AppColors.background,
  },
  // Header
  header: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'space-between',
    paddingHorizontal: Spacing.md,
    paddingVertical: Spacing.sm,
    borderBottomWidth: 1,
    borderBottomColor: AppColors.border,
    backgroundColor: AppColors.surface,
    zIndex: 10,
  },
  headerButton: {
    width: 36,
    height: 36,
    borderRadius: BorderRadius.md,
    justifyContent: 'center',
    alignItems: 'center',
  },
  headerCenter: {
    flexDirection: 'row',
    alignItems: 'center',
    gap: Spacing.sm,
  },
  headerAvatar: {
    width: AvatarSizes.sm,
    height: AvatarSizes.sm,
    borderRadius: AvatarSizes.sm / 2,
    backgroundColor: AppColors.primary,
    justifyContent: 'center',
    alignItems: 'center',
  },
  headerAvatarText: {
    fontSize: FontSizes.base,
    fontWeight: FontWeights.bold,
    color: AppColors.white,
  },
  headerAvatarImage: {
    width: AvatarSizes.sm,
    height: AvatarSizes.sm,
    borderRadius: AvatarSizes.sm / 2,
  },
  headerTitle: {
    fontSize: FontSizes.lg,
    fontWeight: FontWeights.semibold,
    color: AppColors.textPrimary,
  },
  // Dropdown Menu
  dropdownMenu: {
    position: 'absolute',
    top: 44,
    right: 0,
    backgroundColor: AppColors.surface,
    borderRadius: BorderRadius.lg,
    minWidth: 160,
    ...Shadows.lg,
    zIndex: 100,
  },
  dropdownItem: {
    flexDirection: 'row',
    alignItems: 'center',
    padding: Spacing.md,
    gap: Spacing.sm,
  },
  dropdownItemText: {
    fontSize: FontSizes.base,
    color: AppColors.textPrimary,
  },
  dropdownItemDanger: {
    borderTopWidth: 1,
    borderTopColor: AppColors.border,
  },
  dropdownItemTextDanger: {
    color: AppColors.error,
  },
  menuBackdrop: {
    position: 'absolute',
    top: 0,
    left: 0,
    right: 0,
    bottom: 0,
    zIndex: 5,
  },
  // Debug Panel
  debugPanel: {
    backgroundColor: '#FFF9C4',
    padding: Spacing.sm,
    borderBottomWidth: 1,
    borderBottomColor: '#F9A825',
  },
  debugTitle: {
    fontSize: FontSizes.xs,
    fontWeight: FontWeights.bold,
    color: '#F57F17',
    marginBottom: 4,
  },
  debugText: {
    fontSize: FontSizes.xs,
    color: '#5D4037',
    fontFamily: Platform.OS === 'ios' ? 'Menlo' : 'monospace',
  },
  // Dashboard
  dashboardContainer: {
    flex: 1,
  },
  subscriptionWarning: {
    flexDirection: 'row',
    alignItems: 'center',
    backgroundColor: AppColors.warningLight,
    paddingHorizontal: Spacing.md,
    paddingVertical: Spacing.sm,
    gap: Spacing.xs,
  },
  subscriptionWarningText: {
    fontSize: FontSizes.sm,
    color: AppColors.warning,
    fontWeight: FontWeights.medium,
  },
  devToggleSection: {
    paddingHorizontal: Spacing.md,
    paddingVertical: Spacing.sm,
    backgroundColor: AppColors.surface,
    borderBottomWidth: 1,
    borderBottomColor: AppColors.border,
  },
  dashboardContent: {
    flex: 1,
  },
  webView: {
    flex: 1,
  },
  webViewLoading: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    gap: Spacing.md,
  },
  webViewLoadingText: {
    fontSize: FontSizes.base,
    color: AppColors.textSecondary,
  },
  nativeScrollView: {
    flex: 1,
  },
  nativeScrollContent: {
    padding: Spacing.md,
  },
  // Edit Modal
  modalOverlay: {
    flex: 1,
    backgroundColor: 'rgba(0, 0, 0, 0.5)',
    justifyContent: 'flex-end',
  },
  modalContainer: {
    backgroundColor: AppColors.surface,
    borderTopLeftRadius: BorderRadius.xl,
    borderTopRightRadius: BorderRadius.xl,
    maxHeight: '80%',
  },
  modalHeader: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'space-between',
    padding: Spacing.md,
    borderBottomWidth: 1,
    borderBottomColor: AppColors.border,
  },
  modalTitle: {
    fontSize: FontSizes.lg,
    fontWeight: FontWeights.bold,
    color: AppColors.textPrimary,
  },
  modalContent: {
    padding: Spacing.lg,
  },
  avatarPicker: {
    alignSelf: 'center',
    marginBottom: Spacing.lg,
  },
  avatarPickerImage: {
    width: 100,
    height: 100,
    borderRadius: 50,
  },
  avatarPickerPlaceholder: {
    width: 100,
    height: 100,
    borderRadius: 50,
    backgroundColor: AppColors.surfaceSecondary,
    justifyContent: 'center',
    alignItems: 'center',
  },
  avatarPickerBadge: {
    position: 'absolute',
    bottom: 0,
    right: 0,
    width: 28,
    height: 28,
    borderRadius: 14,
    backgroundColor: AppColors.primary,
    justifyContent: 'center',
    alignItems: 'center',
    borderWidth: 2,
    borderColor: AppColors.surface,
  },
  inputGroup: {
    marginBottom: Spacing.md,
  },
  inputLabel: {
    fontSize: FontSizes.sm,
    fontWeight: FontWeights.medium,
    color: AppColors.textSecondary,
    marginBottom: Spacing.xs,
  },
  textInput: {
    backgroundColor: AppColors.surfaceSecondary,
    borderRadius: BorderRadius.md,
    padding: Spacing.md,
    fontSize: FontSizes.base,
    color: AppColors.textPrimary,
  },
  textArea: {
    minHeight: 80,
    textAlignVertical: 'top',
  },
  modalFooter: {
    flexDirection: 'row',
    padding: Spacing.md,
    gap: Spacing.md,
    borderTopWidth: 1,
    borderTopColor: AppColors.border,
  },
  cancelButton: {
    flex: 1,
    padding: Spacing.md,
    borderRadius: BorderRadius.md,
    backgroundColor: AppColors.surfaceSecondary,
    alignItems: 'center',
  },
  cancelButtonText: {
    fontSize: FontSizes.base,
    fontWeight: FontWeights.semibold,
    color: AppColors.textSecondary,
  },
  saveButton: {
    flex: 1,
    padding: Spacing.md,
    borderRadius: BorderRadius.md,
    backgroundColor: AppColors.primary,
    alignItems: 'center',
  },
  saveButtonText: {
    fontSize: FontSizes.base,
    fontWeight: FontWeights.semibold,
    color: AppColors.white,
  },
});