import React, {useState, useRef} from 'react';
import {RouteProp} from '@react-navigation/native';
import {StackNavigationProp} from '@react-navigation/stack';
import {
  View,
  Text,
  StyleSheet,
  StatusBar,
  Alert,
  Platform,
  TouchableOpacity,
  KeyboardAvoidingView,
} from 'react-native';

import {OnboardingStackParams} from '../../routes';
import {
  ArrowButton,
  RegistrationWizard,
  TaggInput,
  Background,
} from '../../components';
import {nameRegex, emailRegex} from '../../constants';

type RegistrationScreenOneRouteProp = RouteProp<
  OnboardingStackParams,
  'RegistrationOne'
>;
type RegistrationScreenOneNavigationProp = StackNavigationProp<
  OnboardingStackParams,
  'RegistrationOne'
>;
interface RegistrationOneProps {
  route: RegistrationScreenOneRouteProp;
  navigation: RegistrationScreenOneNavigationProp;
}
/**
 * Registration screen 1 for First Name, Last Name, and email
 * @param navigation react-navigation navigation object
 */
const RegistrationOne: React.FC<RegistrationOneProps> = ({navigation}) => {
  // refs for changing focus
  const lnameRef = useRef();
  const emailRef = useRef();
  /**
   * Handles focus change to the next input field.
   * @param field key for field to move focus onto
   */
  const handleFocusChange = (field: string): void => {
    switch (field) {
      case 'lname':
        const lnameField: any = lnameRef.current;
        lnameField.focus();
        break;
      case 'email':
        const emailField: any = emailRef.current;
        emailField.focus();
        break;
      default:
        return;
    }
  };

  // registration form state
  const [form, setForm] = useState({
    fname: '',
    lname: '',
    email: '',
    isValidFname: false,
    isValidLname: false,
    isValidEmail: false,
    attemptedSubmit: false,
  });

  /*
   * Handles changes to the first name field value and verifies the input by updating state and running a validation function.
   */
  const handleFnameUpdate = (fname: string) => {
    let isValidFname: boolean = nameRegex.test(fname);
    setForm({
      ...form,
      fname,
      isValidFname,
    });
  };
  /*
   * Handles changes to the last name field value and verifies the input by updating state and running a validation function.
   */
  const handleLnameUpdate = (lname: string) => {
    let isValidLname: boolean = nameRegex.test(lname);
    setForm({
      ...form,
      lname,
      isValidLname,
    });
  };

  /*
   * Handles changes to the email field value and verifies the input by updating state and running a validation function.
   */
  const handleEmailUpdate = (email: string) => {
    let isValidEmail: boolean = emailRegex.test(email);
    setForm({
      ...form,
      email,
      isValidEmail,
    });
  };

  /**
   * Handles a click on the "next" arrow button by navigating to RegistrationTwo if First Name and Last Name are filled
   */
  const goToRegisterTwo = async () => {
    if (!form.attemptedSubmit) {
      setForm({
        ...form,
        attemptedSubmit: true,
      });
    }
    try {
      if (form.isValidFname && form.isValidLname && form.isValidEmail) {
        navigation.navigate('RegistrationTwo', {
          firstName: form.fname,
          lastName: form.lname,
          email: form.email,
        });
      } else {
        setForm({...form, attemptedSubmit: false});
        setTimeout(() => setForm({...form, attemptedSubmit: true}));
      }
    } catch (error) {
      Alert.alert(
        'Looks like our servers are down. 😓',
        "Try again in a couple minutes. We're sorry for the inconvenience.",
      );
      return {
        name: 'Registration error',
        description: error,
      };
    }
  };

  const Footer = () => (
    <View style={styles.footer}>
      <ArrowButton
        direction="backward"
        onPress={() => navigation.navigate('Login')}
      />
      <TouchableOpacity onPress={goToRegisterTwo}>
        <ArrowButton
          direction="forward"
          disabled={
            !(form.isValidFname && form.isValidLname && form.isValidEmail)
          }
          onPress={() =>
            navigation.navigate('RegistrationTwo', {
              firstName: form.fname,
              lastName: form.lname,
              email: form.email,
            })
          }
        />
      </TouchableOpacity>
    </View>
  );

  return (
    <Background style={styles.container}>
      <StatusBar barStyle="light-content" />
      <RegistrationWizard style={styles.wizard} step="one" />
      <KeyboardAvoidingView
        behavior={Platform.OS === 'ios' ? 'padding' : 'height'}
        style={styles.container}>
        <View>
          <Text style={styles.formHeader}>SIGN UP</Text>
        </View>
        <TaggInput
          accessibilityHint="Enter your first name."
          accessibilityLabel="First name input field."
          placeholder="First Name"
          autoCompleteType="name"
          textContentType="name"
          returnKeyType="next"
          onChangeText={handleFnameUpdate}
          onSubmitEditing={() => handleFocusChange('lname')}
          blurOnSubmit={false}
          valid={form.isValidFname}
          invalidWarning="Please enter a valid first name."
          attemptedSubmit={form.attemptedSubmit}
          width={280}
        />
        <TaggInput
          accessibilityHint="Enter your last name."
          accessibilityLabel="Last name input field."
          placeholder="Last Name"
          autoCompleteType="name"
          textContentType="name"
          returnKeyType="next"
          onChangeText={handleLnameUpdate}
          onSubmitEditing={() => handleFocusChange('email')}
          blurOnSubmit={false}
          ref={lnameRef}
          valid={form.isValidLname}
          invalidWarning="Please enter a valid last name."
          attemptedSubmit={form.attemptedSubmit}
          width={280}
        />
        <TaggInput
          accessibilityHint="Enter your email."
          accessibilityLabel="Email input field."
          placeholder="Email"
          autoCompleteType="email"
          textContentType="emailAddress"
          autoCapitalize="none"
          returnKeyType="next"
          keyboardType="email-address"
          onChangeText={handleEmailUpdate}
          blurOnSubmit={false}
          ref={emailRef}
          valid={form.isValidEmail}
          invalidWarning={'Please enter a valid email address.'}
          attemptedSubmit={form.attemptedSubmit}
          width={280}
          onSubmitEditing={goToRegisterTwo}
        />
      </KeyboardAvoidingView>
      <Footer />
    </Background>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
  },
  wizard: {
    ...Platform.select({
      ios: {
        top: 50,
      },
      android: {
        bottom: 40,
      },
    }),
  },
  formHeader: {
    color: '#fff',
    fontSize: 30,
    fontWeight: '600',
    marginBottom: '16%',
  },
  footer: {
    width: '100%',
    flexDirection: 'row',
    justifyContent: 'space-around',
    ...Platform.select({
      ios: {
        bottom: '20%',
      },
      android: {
        bottom: '10%',
      },
    }),
  },
});

export default RegistrationOne;