import React, { useState, useEffect } from 'react';
import {
  View,
  Text,
  StyleSheet,
  ScrollView,
  TextInput,
  TouchableOpacity,
  Alert,
  KeyboardAvoidingView,
  Platform,
  Image,
  ActivityIndicator,
} from 'react-native';
import { Ionicons } from '@expo/vector-icons';
import { SafeAreaView } from 'react-native-safe-area-context';
import { router } from 'expo-router';
import * as ImagePicker from 'expo-image-picker';
import { useAuth } from '@/contexts/AuthContext';
import { api } from '@/services/api';
import { PageHeader } from '@/components/PageHeader';
import {
  AppColors,
  BorderRadius,
  FontSizes,
  Spacing,
  FontWeights,
  Shadows,
} from '@/constants/theme';

export default function EditProfileScreen() {
  const { user, updateUser } = useAuth();

  const [displayName, setDisplayName] = useState('');
  const [phone, setPhone] = useState('');
  const [isLoading, setIsLoading] = useState(true);
  const [isSaving, setIsSaving] = useState(false);
  const [avatarUri, setAvatarUri] = useState<string | null>(null);

  // Load profile from API
  useEffect(() => {
    const loadProfile = async () => {
      try {
        const response = await api.getProfile();
        if (response.ok && response.data) {
          // /auth/me returns { user: {...}, beneficiaries: [...] }
          const userData = response.data.user || response.data;
          const { firstName, lastName, phone: userPhone } = userData;
          // Combine first and last name for display
          const fullName = [firstName, lastName].filter(Boolean).join(' ');
          setDisplayName(fullName || '');
          setPhone(userPhone || '');
        }
      } catch (err) {
        console.error('Failed to load profile:', err);
      } finally {
        setIsLoading(false);
      }
    };
    loadProfile();
  }, []);

  const handleSave = async () => {
    if (!displayName.trim()) {
      Alert.alert('Error', 'Display name is required');
      return;
    }

    setIsSaving(true);

    try {
      // Parse display name into first and last name
      const nameParts = displayName.trim().split(' ');
      const firstName = nameParts[0] || '';
      const lastName = nameParts.slice(1).join(' ') || '';

      console.log('[EditProfile] Saving:', { firstName, lastName, phone });

      // Save to server API
      const response = await api.updateProfile({
        firstName,
        lastName,
        phone: phone || undefined,
      });

      console.log('[EditProfile] Response:', response);

      if (response.ok) {
        // Update user in AuthContext (will refetch from API)
        if (updateUser) {
          updateUser({
            user_name: displayName.trim(),
            firstName,
            lastName,
            phone,
          });
        }

        Alert.alert(
          'Profile Updated',
          'Your profile has been updated successfully.',
          [{ text: 'OK', onPress: () => router.back() }]
        );
      } else {
        Alert.alert('Error', response.error?.message || 'Failed to save profile');
      }
    } catch (error) {
      console.error('Failed to save profile:', error);
      Alert.alert('Error', 'Failed to save profile. Please try again.');
    }

    setIsSaving(false);
  };

  const handleChangePhoto = async () => {
    const { status } = await ImagePicker.requestMediaLibraryPermissionsAsync();
    if (status !== 'granted') {
      Alert.alert('Permission needed', 'Please allow access to your photo library to change avatar.');
      return;
    }

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

    if (!result.canceled && result.assets[0]) {
      const uri = result.assets[0].uri;
      setAvatarUri(uri);
      // TODO: Upload avatar to server when endpoint is available
    }
  };

  const userInitial = displayName?.charAt(0).toUpperCase() || user?.email?.charAt(0).toUpperCase() || 'U';

  if (isLoading) {
    return (
      <SafeAreaView style={styles.container} edges={['top', 'bottom']}>
        <PageHeader title="Edit Profile" />
        <View style={styles.loadingContainer}>
          <ActivityIndicator size="large" color={AppColors.primary} />
          <Text style={styles.loadingText}>Loading profile...</Text>
        </View>
      </SafeAreaView>
    );
  }

  return (
    <SafeAreaView style={styles.container} edges={['top', 'bottom']}>
      <PageHeader title="Edit Profile" />
      <KeyboardAvoidingView
        style={styles.keyboardView}
        behavior={Platform.OS === 'ios' ? 'padding' : 'height'}
      >
        <ScrollView showsVerticalScrollIndicator={false}>
          {/* Avatar Section */}
          <View style={styles.avatarSection}>
            <TouchableOpacity style={styles.avatarWrapper} onPress={handleChangePhoto}>
              {avatarUri ? (
                <Image source={{ uri: avatarUri }} style={styles.avatarImage} />
              ) : (
                <View style={styles.avatarContainer}>
                  <Text style={styles.avatarText}>{userInitial}</Text>
                </View>
              )}
              <View style={styles.changePhotoButton}>
                <Ionicons name="camera" size={16} color={AppColors.white} />
              </View>
            </TouchableOpacity>
            <Text style={styles.changePhotoText}>Tap to change photo</Text>
          </View>

          {/* Form */}
          <View style={styles.form}>
            <View style={styles.inputGroup}>
              <Text style={styles.label}>Display Name *</Text>
              <View style={styles.inputContainer}>
                <Ionicons name="person-outline" size={20} color={AppColors.textMuted} />
                <TextInput
                  style={styles.input}
                  value={displayName}
                  onChangeText={setDisplayName}
                  placeholder="Enter your display name"
                  placeholderTextColor={AppColors.textMuted}
                />
              </View>
            </View>

            <View style={styles.inputGroup}>
              <Text style={styles.label}>Email Address</Text>
              <View style={[styles.inputContainer, styles.disabledInput]}>
                <Ionicons name="mail-outline" size={20} color={AppColors.textMuted} />
                <Text style={styles.disabledText}>{user?.email || 'Not set'}</Text>
                <View style={styles.lockBadge}>
                  <Ionicons name="lock-closed" size={12} color={AppColors.textMuted} />
                </View>
              </View>
              <Text style={styles.hint}>Email cannot be changed</Text>
            </View>

            <View style={styles.inputGroup}>
              <Text style={styles.label}>Phone Number</Text>
              <View style={styles.inputContainer}>
                <Ionicons name="call-outline" size={20} color={AppColors.textMuted} />
                <TextInput
                  style={styles.input}
                  value={phone}
                  onChangeText={setPhone}
                  placeholder="+1 (555) 123-4567"
                  placeholderTextColor={AppColors.textMuted}
                  keyboardType="phone-pad"
                />
              </View>
              <Text style={styles.hint}>For emergency contact and SMS alerts</Text>
            </View>
          </View>
        </ScrollView>

        {/* Save Button */}
        <View style={styles.footer}>
          <TouchableOpacity
            style={[styles.saveButton, isSaving && styles.saveButtonDisabled]}
            onPress={handleSave}
            disabled={isSaving}
          >
            {isSaving ? (
              <Text style={styles.saveButtonText}>Saving...</Text>
            ) : (
              <>
                <Ionicons name="checkmark" size={20} color={AppColors.white} />
                <Text style={styles.saveButtonText}>Save Changes</Text>
              </>
            )}
          </TouchableOpacity>
        </View>
      </KeyboardAvoidingView>
    </SafeAreaView>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: AppColors.background,
  },
  keyboardView: {
    flex: 1,
  },
  loadingContainer: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
  },
  loadingText: {
    marginTop: Spacing.md,
    fontSize: FontSizes.base,
    color: AppColors.textSecondary,
  },
  avatarSection: {
    alignItems: 'center',
    paddingVertical: Spacing.xl,
    backgroundColor: AppColors.surface,
    marginBottom: Spacing.md,
  },
  avatarWrapper: {
    position: 'relative',
  },
  avatarContainer: {
    width: 100,
    height: 100,
    borderRadius: 50,
    backgroundColor: AppColors.primary,
    justifyContent: 'center',
    alignItems: 'center',
  },
  avatarImage: {
    width: 100,
    height: 100,
    borderRadius: 50,
  },
  avatarText: {
    fontSize: 40,
    fontWeight: FontWeights.bold,
    color: AppColors.white,
  },
  changePhotoButton: {
    position: 'absolute',
    bottom: 0,
    right: 0,
    width: 32,
    height: 32,
    borderRadius: 16,
    backgroundColor: AppColors.primary,
    justifyContent: 'center',
    alignItems: 'center',
    borderWidth: 3,
    borderColor: AppColors.surface,
  },
  changePhotoText: {
    marginTop: Spacing.sm,
    fontSize: FontSizes.sm,
    color: AppColors.textMuted,
  },
  form: {
    padding: Spacing.lg,
  },
  inputGroup: {
    marginBottom: Spacing.lg,
  },
  label: {
    fontSize: FontSizes.sm,
    fontWeight: FontWeights.medium,
    color: AppColors.textSecondary,
    marginBottom: Spacing.xs,
    marginLeft: Spacing.xs,
  },
  inputContainer: {
    flexDirection: 'row',
    alignItems: 'center',
    backgroundColor: AppColors.surface,
    borderRadius: BorderRadius.lg,
    paddingHorizontal: Spacing.md,
    paddingVertical: Spacing.md,
    borderWidth: 1.5,
    borderColor: AppColors.borderLight,
    gap: Spacing.sm,
    ...Shadows.xs,
  },
  input: {
    flex: 1,
    fontSize: FontSizes.base,
    color: AppColors.textPrimary,
  },
  disabledInput: {
    backgroundColor: AppColors.surfaceSecondary,
    borderColor: AppColors.border,
  },
  disabledText: {
    flex: 1,
    fontSize: FontSizes.base,
    color: AppColors.textSecondary,
  },
  lockBadge: {
    width: 24,
    height: 24,
    borderRadius: 12,
    backgroundColor: AppColors.border,
    justifyContent: 'center',
    alignItems: 'center',
  },
  hint: {
    fontSize: FontSizes.xs,
    color: AppColors.textMuted,
    marginTop: Spacing.xs,
    marginLeft: Spacing.xs,
  },
  footer: {
    padding: Spacing.lg,
    backgroundColor: AppColors.surface,
    borderTopWidth: 1,
    borderTopColor: AppColors.border,
  },
  saveButton: {
    flexDirection: 'row',
    backgroundColor: AppColors.primary,
    borderRadius: BorderRadius.lg,
    paddingVertical: Spacing.md,
    alignItems: 'center',
    justifyContent: 'center',
    gap: Spacing.xs,
    ...Shadows.primary,
  },
  saveButtonDisabled: {
    opacity: 0.6,
  },
  saveButtonText: {
    fontSize: FontSizes.base,
    fontWeight: FontWeights.semibold,
    color: AppColors.white,
  },
});