import React, { useState } from 'react';
import { useTranslation } from 'react-i18next';
import { Button, Column, Text } from '../../components/ui';
import { Theme } from '../../components/ui/styleUtils';
import {
  Dimensions,
  Keyboard,
  KeyboardAvoidingView, TouchableWithoutFeedback,
  View,
  ModalProps
} from 'react-native';
import { isIOS } from '../../shared/constants';
import { SvgImage } from '../../components/ui/svg';
import { getScreenHeight } from '../../shared/commonUtil';
import { PinInput } from '../../components/PinInput';
import { Modal } from '../../components/ui/Modal';
import { CancelDownloadModal } from './ConfirmationModal';
import { Icon, Input } from 'react-native-elements';

export const TransactionCodeModal: React.FC<ExtendedModalProps> = props => {
  const { t } = useTranslation('transactionCodeScreen');
  const { isSmallScreen, screenHeight } = getScreenHeight();
  const [transactionCode, setTransactionCode] = useState('');
  const [errorMessage, setErrorMessage] = useState('');
  const [showCancelConfirm, setShowCancelConfirm] = useState(false);
  const [showCode, setShowCode] = useState(false);
  const [touched, setTouched] = useState(false);
  const [showFullDescription, setShowFullDescription] = useState(false);
  const [textLineCount, setTextLineCount] = useState(0);
  const maxLines = 2;


  const validateCode = (code: string): string => {
    if (!code.trim()) return t('emptyCodeError');
    if (!/^[a-zA-Z0-9]+$/.test(code)) return t('invalidCharacters');
    return '';
  };

  const handleVerify = () => {
    const error = validateCode(transactionCode);
    if (error) {
      setErrorMessage(error);
      return;
    }
    setErrorMessage('');
    props.onVerify?.(transactionCode);
  };

  const handleChange = (text: string) => {
    if (!touched)
      setTouched(true);
    setTransactionCode(text);
    let error;
    if (touched)
      error = validateCode(text);
    setErrorMessage(error);
  };

  return (
    <>
      {showCancelConfirm ? (
        <CancelDownloadModal onCancel={() => setShowCancelConfirm(false)} onConfirm={props.onDismiss ?? (() => { })} visible={showCancelConfirm} />
      ) : (
        <Modal isVisible={props.visible ?? false} onDismiss={() => setShowCancelConfirm(true)}>
          <KeyboardAvoidingView
            style={
              isSmallScreen
                ? { flex: 1, paddingHorizontal: 10 }
                : Theme.Styles.keyboardAvoidStyle
            }
            behavior={isIOS() ? 'padding' : 'height'}>
            <TouchableWithoutFeedback onPress={Keyboard.dismiss} accessible={false}>
              <View style={{ height: 700 }}>
                <Column
                  crossAlign="center"
                  style={
                    isSmallScreen
                      ? null
                      : {
                        maxHeight: screenHeight,
                        flex: 1,
                        justifyContent: 'space-around',
                        marginBottom: 20,
                      }
                  }>
                  {SvgImage.OtpVerificationIcon()}
                  <View>
                    <Column crossAlign="center">
                      <Text
                        testID="otpVerificationHeader"
                        weight="bold"
                        style={Theme.TextStyles.header}>
                        {t('TransactionCode')}
                      </Text>
                      <Text
                        style={{ marginTop: 15 }}
                        testID="otpVerificationDescription"
                        color={Theme.Colors.RetrieveIdLabel}
                        numLines={showFullDescription ? undefined : 2}
                        ellipsizeMode='tail'
                        weight="semibold"
                        size="small"
                        align="center"
                        onTextLayout={(e) => {
                          if (textLineCount !== e.nativeEvent.lines.length) {
                            setTextLineCount(e.nativeEvent.lines.length);
                          }
                        }}
                      >
                        {t(
                          `${props.description ||
                          t('description')
                          }`,
                        )}
                      </Text>
                      {textLineCount >= maxLines && <Text
                        onPress={() => setShowFullDescription(prev => !prev)}
                        style={Theme.TransactionCodeScreenStyle.showMoreButton}
                      >
                        {showFullDescription ? t('Show less ↑') : t('Show more ↓')}
                      </Text>}
                      </Column>
                  </View>

                  {(props.error || errorMessage) && (
                    <View
                      style={Theme.TransactionCodeScreenStyle.errorView}
                    >
                      <Text
                        testID="otpVerificationError"
                        align="center"
                        color={Theme.Colors.errorMessage}>
                        {errorMessage || props.error}
                      </Text>
                    </View>
                  )}

                  <View style={{ alignItems: 'center' }}>
                    {((!props.inputMode ||
                      (props.inputMode && props.inputMode === 'numeric')) &&
                      props.length &&
                      props.length <= 6) ? (
                      <>
                        <PinInput
                          testID="pinInput"
                          length={props.length}
                          autosubmit={false}
                          onChange={handleChange}
                          onDone={(code: string) => {
                            const error = validateCode(code);
                            if (error) {
                              setErrorMessage(error);
                              return;
                            }
                            setErrorMessage('');
                            props.onVerify?.(code);
                            props.onDismiss?.();
                          }}
                        />
                        <Button styles={{ marginTop: 30 }} disabled={transactionCode.length == 0} title={t('verify')} type="gradient" onPress={handleVerify} />
                      </>
                    ) : (
                      <>
                        <Input
                          containerStyle={{
                            width: Dimensions.get('window').width - 80,
                            alignSelf: 'center',
                          }}
                          placeholder={t('placeholder')}
                          placeholderTextColor="#ACACAC"
                          inputContainerStyle={{
                            borderBottomColor: '#C1C1C1',
                            borderBottomWidth: 1,
                            marginBottom: 16,
                          }}
                          inputStyle={Theme.TransactionCodeScreenStyle.inputStyle}
                          maxLength={props.length ?? 30}
                          autoFocus
                          secureTextEntry={!showCode}
                          value={transactionCode}
                          keyboardType={props.inputMode === 'numeric' ? 'numeric' : 'default'}
                          onChangeText={handleChange}
                          rightIcon={
                            <Icon
                              name={showCode ? 'eye-off' : 'eye'}
                              type="feather"
                              size={20}
                              color="#888"
                              onPress={() => setShowCode(prev => !prev)}
                            />
                          }
                        />
                        <Button disabled={transactionCode.length == 0} title="Verify" type="gradient" onPress={handleVerify} />
                      </>
                    )}
                  </View>
                </Column>
              </View>
            </TouchableWithoutFeedback>
          </KeyboardAvoidingView>
        </Modal>
      )}
    </>
  );

};

interface ExtendedModalProps extends ModalProps {
  onVerify?: (transactionCode: string) => void;
  error?: string;
  description?: string;
  inputMode?: 'text' | 'numeric';
  length?: number;
}