import React, { useState, useEffect, useRef, } from 'react';

const OTP = (props) => {



    const OTP = [];
    const ref_input = [];
    ref_input[0] = useRef();
    ref_input[1] = useRef();
    ref_input[2] = useRef();
    ref_input[3] = useRef();

    const focusNext = (text, index) => {
        if (index < ref_input.length - 1 && text) {
            ref_input[index + 1].current.focus();
        }
        if (index == ref_input.length - 1) {
            ref_input[index].current.blur();
        }
        OTP[index] = text;
    }
    const focusPrev = (key, index) => {
        if (key === "Backspace" && index !== 0) {
            ref_input[index - 1].current.focus();
        }
    }

    return (
        <SafeAreaView>
            <View>
                
                    <ScrollView contentInsetAdjustmentBehavior="automatic" showsVerticalScrollIndicator={false}>
                        <View style={loginScreenStyle.titleWrap}>
                            <Title style={loginScreenStyle.titleHeading}>Verify OTP</Title>
                            <Subheading style={loginScreenStyle.subTitle}>Enter the 4 digit code sent to your mobile number</Subheading>
                        </View>
                        <View style={loginScreenStyle.inputContainer}>
                            <TextInput
                                mode="flat"
                                selectionColor={Colors.primaryColor}
                                underlineColorAndroid="transparent"
                                textAlign='center'
                                maxLength={1}
                                keyboardType='numeric'
                                style={formScreenStyle.otpInputStyle}
                                autoFocus={true}
                                returnKeyType="next"
                                ref={ref_input[0]}
                                onChangeText={text => focusNext(text, 0)}
                                onKeyPress={e => focusPrev(e.nativeEvent.key, 0)}
                            />
                            <TextInput
                                mode="flat"
                                selectionColor={Colors.primaryColor}
                                underlineColorAndroid="transparent"
                                textAlign='center'
                                maxLength={1}
                                keyboardType='numeric'
                                style={formScreenStyle.otpInputStyle}
                                ref={ref_input[1]}
                                onChangeText={text => focusNext(text, 1)}
                                onKeyPress={e => focusPrev(e.nativeEvent.key, 1)}
                            />
                            <TextInput
                                mode="flat"
                                selectionColor={Colors.primaryColor}
                                underlineColorAndroid="transparent"
                                textAlign='center'
                                maxLength={1}
                                keyboardType='numeric'
                                style={formScreenStyle.otpInputStyle}
                                ref={ref_input[2]}
                                onChangeText={text => focusNext(text, 2)}
                                onKeyPress={e => focusPrev(e.nativeEvent.key, 2)}
                            />
                            <TextInput
                                mode="flat"
                                selectionColor={Colors.primaryColor}
                                underlineColorAndroid="transparent"
                                textAlign='center'
                                maxLength={1}
                                keyboardType='numeric'
                                style={formScreenStyle.otpInputStyle}
                                ref={ref_input[3]}
                                onChangeText={text => focusNext(text, 3)}
                                onKeyPress={e => focusPrev(e.nativeEvent.key, 3)}
                            />

                        </View>
                    </ScrollView>
            </View>
        </SafeAreaView >
    )
}

export default OTP;