import React, { useState } from 'react';
import {
  View,
  Text,
  StyleSheet,
  TextInput,
  TouchableOpacity,
  Alert,
  ActivityIndicator,
  ScrollView,
  KeyboardAvoidingView,
  Platform,
} from 'react-native';
import { Ionicons } from '@expo/vector-icons';
import { SafeAreaView } from 'react-native-safe-area-context';
import { router, useLocalSearchParams } from 'expo-router';
import { useBeneficiary } from '@/contexts/BeneficiaryContext';
import {
  AppColors,
  BorderRadius,
  FontSizes,
  FontWeights,
  Spacing,
  Shadows,
} from '@/constants/theme';

type Role = 'caretaker' | 'guardian';

export default function ShareAccessScreen() {
  const { id } = useLocalSearchParams<{ id: string }>();
  const { currentBeneficiary } = useBeneficiary();

  const [email, setEmail] = useState('');
  const [label, setLabel] = useState('');
  const [role, setRole] = useState<Role>('caretaker');
  const [isLoading, setIsLoading] = useState(false);

  const beneficiaryName = currentBeneficiary?.name || 'this person';

  const validateEmail = (email: string): boolean => {
    const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
    return emailRegex.test(email);
  };

  const handleSendInvite = async () => {
    const trimmedEmail = email.trim().toLowerCase();
    const trimmedLabel = label.trim();

    if (!trimmedEmail) {
      Alert.alert('Email Required', 'Please enter an email address.');
      return;
    }

    if (!validateEmail(trimmedEmail)) {
      Alert.alert('Invalid Email', 'Please enter a valid email address.');
      return;
    }

    setIsLoading(true);

    try {
      // TODO: Send invitation via API
      // await api.sendInvitation({
      //   beneficiaryId: id,
      //   email: trimmedEmail,
      //   label: trimmedLabel,
      //   role: role,
      // });

      // For now, show success message
      Alert.alert(
        'Invitation Sent',
        `An invitation has been sent to ${trimmedEmail} to ${role === 'guardian' ? 'manage' : 'view'} ${beneficiaryName}.`,
        [{ text: 'OK', onPress: () => router.back() }]
      );
    } catch (error) {
      console.error('Failed to send invitation:', error);
      Alert.alert('Error', 'Failed to send invitation. Please try again.');
    } finally {
      setIsLoading(false);
    }
  };

  return (
    <SafeAreaView style={styles.container} edges={['top', 'bottom']}>
      {/* Header */}
      <View style={styles.header}>
        <TouchableOpacity style={styles.backButton} onPress={() => router.back()}>
          <Ionicons name="arrow-back" size={24} color={AppColors.textPrimary} />
        </TouchableOpacity>
        <Text style={styles.headerTitle}>Share Access</Text>
        <View style={styles.placeholder} />
      </View>

      <KeyboardAvoidingView
        style={styles.content}
        behavior={Platform.OS === 'ios' ? 'padding' : undefined}
      >
        <ScrollView
          contentContainerStyle={styles.scrollContent}
          showsVerticalScrollIndicator={false}
        >
          {/* Info Banner */}
          <View style={styles.infoBanner}>
            <Ionicons name="people" size={24} color={AppColors.primary} />
            <Text style={styles.infoBannerText}>
              Invite family members or caregivers to help monitor {beneficiaryName}
            </Text>
          </View>

          {/* Email Input */}
          <View style={styles.inputGroup}>
            <Text style={styles.inputLabel}>Email Address</Text>
            <View style={styles.inputContainer}>
              <Ionicons name="mail-outline" size={20} color={AppColors.textMuted} />
              <TextInput
                style={styles.input}
                placeholder="Enter email address"
                placeholderTextColor={AppColors.textMuted}
                value={email}
                onChangeText={setEmail}
                autoCapitalize="none"
                autoCorrect={false}
                keyboardType="email-address"
                editable={!isLoading}
              />
            </View>
          </View>

          {/* Label Input */}
          <View style={styles.inputGroup}>
            <Text style={styles.inputLabel}>Label (optional)</Text>
            <View style={styles.inputContainer}>
              <Ionicons name="pricetag-outline" size={20} color={AppColors.textMuted} />
              <TextInput
                style={styles.input}
                placeholder="e.g., Sister, Nurse, Neighbor"
                placeholderTextColor={AppColors.textMuted}
                value={label}
                onChangeText={setLabel}
                autoCapitalize="words"
                editable={!isLoading}
              />
            </View>
          </View>

          {/* Role Selection */}
          <View style={styles.inputGroup}>
            <Text style={styles.inputLabel}>Access Level</Text>

            <TouchableOpacity
              style={[styles.roleOption, role === 'caretaker' && styles.roleOptionSelected]}
              onPress={() => setRole('caretaker')}
              disabled={isLoading}
            >
              <View style={styles.roleHeader}>
                <View style={[styles.roleIcon, role === 'caretaker' && styles.roleIconSelected]}>
                  <Ionicons
                    name="eye-outline"
                    size={20}
                    color={role === 'caretaker' ? AppColors.white : AppColors.primary}
                  />
                </View>
                <View style={styles.roleInfo}>
                  <Text style={[styles.roleTitle, role === 'caretaker' && styles.roleTitleSelected]}>
                    Caretaker
                  </Text>
                  <Text style={styles.roleDescription}>
                    Can view activity and chat with Julia
                  </Text>
                </View>
                {role === 'caretaker' && (
                  <Ionicons name="checkmark-circle" size={24} color={AppColors.primary} />
                )}
              </View>
            </TouchableOpacity>

            <TouchableOpacity
              style={[styles.roleOption, role === 'guardian' && styles.roleOptionSelected]}
              onPress={() => setRole('guardian')}
              disabled={isLoading}
            >
              <View style={styles.roleHeader}>
                <View style={[styles.roleIcon, role === 'guardian' && styles.roleIconSelected]}>
                  <Ionicons
                    name="shield-outline"
                    size={20}
                    color={role === 'guardian' ? AppColors.white : AppColors.accent}
                  />
                </View>
                <View style={styles.roleInfo}>
                  <Text style={[styles.roleTitle, role === 'guardian' && styles.roleTitleSelected]}>
                    Guardian
                  </Text>
                  <Text style={styles.roleDescription}>
                    Full access: edit info, manage subscription, invite others
                  </Text>
                </View>
                {role === 'guardian' && (
                  <Ionicons name="checkmark-circle" size={24} color={AppColors.accent} />
                )}
              </View>
            </TouchableOpacity>
          </View>

          {/* Send Button */}
          <TouchableOpacity
            style={[styles.sendButton, isLoading && styles.sendButtonDisabled]}
            onPress={handleSendInvite}
            disabled={isLoading}
          >
            {isLoading ? (
              <ActivityIndicator color={AppColors.white} />
            ) : (
              <>
                <Ionicons name="send" size={20} color={AppColors.white} />
                <Text style={styles.sendButtonText}>Send Invitation</Text>
              </>
            )}
          </TouchableOpacity>

          {/* Help Text */}
          <Text style={styles.helpText}>
            The person will receive an email with instructions to access {beneficiaryName}'s information.
          </Text>
        </ScrollView>
      </KeyboardAvoidingView>
    </SafeAreaView>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: AppColors.background,
  },
  header: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'space-between',
    paddingHorizontal: Spacing.md,
    paddingVertical: Spacing.sm,
    borderBottomWidth: 1,
    borderBottomColor: AppColors.border,
  },
  backButton: {
    padding: Spacing.xs,
  },
  headerTitle: {
    fontSize: FontSizes.lg,
    fontWeight: FontWeights.semibold,
    color: AppColors.textPrimary,
  },
  placeholder: {
    width: 32,
  },
  content: {
    flex: 1,
  },
  scrollContent: {
    padding: Spacing.lg,
    paddingBottom: Spacing.xxl,
  },
  infoBanner: {
    flexDirection: 'row',
    alignItems: 'center',
    backgroundColor: AppColors.primaryLighter,
    padding: Spacing.md,
    borderRadius: BorderRadius.lg,
    marginBottom: Spacing.xl,
    gap: Spacing.md,
  },
  infoBannerText: {
    flex: 1,
    fontSize: FontSizes.sm,
    color: AppColors.textPrimary,
    lineHeight: 20,
  },
  inputGroup: {
    marginBottom: Spacing.lg,
  },
  inputLabel: {
    fontSize: FontSizes.sm,
    fontWeight: FontWeights.medium,
    color: AppColors.textSecondary,
    marginBottom: Spacing.sm,
  },
  inputContainer: {
    flexDirection: 'row',
    alignItems: 'center',
    backgroundColor: AppColors.surface,
    borderRadius: BorderRadius.lg,
    paddingHorizontal: Spacing.md,
    borderWidth: 1,
    borderColor: AppColors.border,
  },
  input: {
    flex: 1,
    paddingVertical: Spacing.md,
    marginLeft: Spacing.sm,
    fontSize: FontSizes.base,
    color: AppColors.textPrimary,
  },
  roleOption: {
    backgroundColor: AppColors.surface,
    borderRadius: BorderRadius.lg,
    padding: Spacing.md,
    marginBottom: Spacing.sm,
    borderWidth: 2,
    borderColor: AppColors.border,
  },
  roleOptionSelected: {
    borderColor: AppColors.primary,
    backgroundColor: AppColors.primaryLighter,
  },
  roleHeader: {
    flexDirection: 'row',
    alignItems: 'center',
  },
  roleIcon: {
    width: 40,
    height: 40,
    borderRadius: BorderRadius.md,
    backgroundColor: AppColors.surfaceSecondary,
    justifyContent: 'center',
    alignItems: 'center',
    marginRight: Spacing.md,
  },
  roleIconSelected: {
    backgroundColor: AppColors.primary,
  },
  roleInfo: {
    flex: 1,
  },
  roleTitle: {
    fontSize: FontSizes.base,
    fontWeight: FontWeights.semibold,
    color: AppColors.textPrimary,
  },
  roleTitleSelected: {
    color: AppColors.primary,
  },
  roleDescription: {
    fontSize: FontSizes.sm,
    color: AppColors.textSecondary,
    marginTop: 2,
  },
  sendButton: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'center',
    backgroundColor: AppColors.primary,
    paddingVertical: Spacing.md,
    borderRadius: BorderRadius.lg,
    marginTop: Spacing.lg,
    gap: Spacing.sm,
    ...Shadows.primary,
  },
  sendButtonDisabled: {
    opacity: 0.7,
  },
  sendButtonText: {
    fontSize: FontSizes.base,
    fontWeight: FontWeights.semibold,
    color: AppColors.white,
  },
  helpText: {
    fontSize: FontSizes.sm,
    color: AppColors.textMuted,
    textAlign: 'center',
    marginTop: Spacing.lg,
    lineHeight: 20,
  },
});