vds_quiz/vds-app/App/screens/TrueFalse.js

import React from "react"
import { View, ScrollView, StyleSheet, StatusBar, Text, Dimensions, ImageBackground, BackHandler } from "react-native"
import SafeAreaView from 'react-native-safe-area-view'

import { Button, ButtonContainer } from "../components/Button"
import { Banner } from "../components/Banner"
import { texts, colors, examScheme, credentials } from "../components/Variables"

import aerodynamicsQuestions from "../data/aerodynamics"
import firstAidQuestions from "../data/firstAid"
import flightSafetyQuestions from "../data/flightSafety"
import instrumentsQuestions from "../data/instruments"
import legislationQuestions from "../data/legislation"
import materialsQuestions from "../data/materials"
import meteorologyQuestions from "../data/meteorology"
import physiopathologyQuestions from "../data/physiopathology"
import pilotingTechniquesQuestions from "../data/pilotingTechniques"

const allQuestions = {
  aerodynamics: aerodynamicsQuestions,
  firstAid: firstAidQuestions,
  flightSafety: flightSafetyQuestions,
  instruments: instrumentsQuestions,
  legislation: legislationQuestions,
  materials: materialsQuestions,
  meteorology: meteorologyQuestions,
  physiopathology: physiopathologyQuestions,
  pilotingTechniques: pilotingTechniquesQuestions
}

const bgImage = require("../assets/bg.jpg")
const screen = Dimensions.get("window")

const styles = StyleSheet.create({
  container: {
    flex: 1
  },
  text: {
    color: colors.white,
    fontSize: 20,
    textAlign: "center",
    fontWeight: "600",
    paddingTop: 5,
    paddingBottom: 20
  },
  textCode: {
    color: colors.white,
    fontSize: 12,
    textAlign: "center",
    fontWeight: "500",
    paddingTop: 20,
    paddingBottom: 0
  },
  textAnswer: {
    color: colors.black,
    backgroundColor: colors.white,
    fontSize: 18,
    textAlign: "center",
    fontWeight: "400",
    marginTop: 20,
    paddingVertical: 20,
    paddingHorizontal: 20,
    borderRadius: 10
  },
  safearea: {
    flex: 1,
    paddingHorizontal: 20,
    paddingTop: 40,
    justifyContent: "space-between"
  },
  box: {
    width: screen.width,
    paddingVertical: 10,
    overflow: "hidden"
  },
  scrollView: {
    //margin: 10,
    height: screen.height-150
  },

  bg: {
    width: "100%",
    height: "100%"
  },
  bannerContainer: {
    flex: 1,
    alignItems: "center",
    justifyContent: "center"
  }
})

class Quiz extends React.Component {

  state = {
    correctCount: 0,
    wrongCount: 0,
    wrongAnswers: [],
    totalCount: this.props.navigation.getParam("questions", []).length,
    availableIds: this.props.navigation.getParam("questions", []).map(a => a.id),
    activeQuestionId: this.props.navigation.getParam("questions", [])[
                        Math.floor(Math.random() * this.props.navigation.getParam("questions", []).length)
                      ].id,
    activeAnswerId: Math.floor(Math.random() * 3),
    clickedAnswer: false,
    answered: false,
    results: false
  }

  bannerError = (e) => {
    //console.log("Banner error (footer): ", e)
  }

  componentDidMount() {
    BackHandler.addEventListener('hardwareBackPress', this.handleBackButton)
  }

  componentWillUnmount() {
    BackHandler.removeEventListener('hardwareBackPress', this.handleBackButton)
  }

  handleBackButton = () => {

    let tmpQuestions = []
    let fullQuestions = []

    examScheme.forEach( (elem) => {
      let currentSection = allQuestions[elem.section]
      for(let i=0; i<currentSection.length; i++) {
        fullQuestions.push(currentSection[i])
      }
    })

    for(let i=0; i<10; i++) {
      const currentIndex = Math.floor(Math.random() * fullQuestions.length)
      tmpQuestions.push(fullQuestions[currentIndex])
      fullQuestions = fullQuestions.filter( (item, index) => index != currentIndex)
    }

    this.props.navigation.navigate("Splash", {
      trueFalseQuestions: tmpQuestions
    })
    return true
  }

  answer = (answer, correct, id, question) => {
    this.setState(
      state => {
        const nextState = { answered: true, clickedId: id, clickedAnswer: answer }

        if ((correct && answer) || (!correct && !answer)) {
          //console.log('ok')
          nextState.correctCount = state.correctCount + 1
        } else {
          //console.log('ko')
          nextState.wrongCount = state.wrongCount + 1
          nextState.wrongAnswers = state.wrongAnswers
          nextState.wrongAnswers.push(
            { question: question.question,
              id: question.id,
              clicked: question.answers[state.activeAnswerId].id,
              answers: question.answers
            }
          )

        }

        return nextState
      },
      () => {
        setTimeout(() => this.nextQuestion(), 2000)
      }
    )
  }

  nextQuestion = () => {

    const updatedIndexes = this.state.availableIds.filter( item => item != this.state.activeQuestionId)
    const nextId = updatedIndexes[Math.floor(Math.random() * updatedIndexes.length)]

    if (!updatedIndexes.length) {
      //console.log(this.state.wrongAnswers)
      this.props.navigation.navigate("ResultsTrueFalse", {
        results: {
          isExam: false,
          total: this.state.totalCount,
          correct: this.state.correctCount,
          wrong: this.state.wrongCount,
          wrongAnswers: this.state.wrongAnswers
        }
      })

    } else {
      this.setState( (state) => {
        return {
          availableIds: updatedIndexes,
          activeQuestionId: nextId,
          activeAnswerId: Math.floor(Math.random() * 3),
          answered: false
        }
      })
    }
  }

  render() {
    const questions = this.props.navigation.getParam("questions", [])
    const question = questions.filter(item => item.id == this.state.activeQuestionId)[0] || questions[0]
    const randomAnswer = question.answers[this.state.activeAnswerId]

    //console.log({id: randomAnswer.id, clicked: this.state.clickedId, answered: this.state.answered, isCorrect: randomAnswer.correct || false})

    return (
      <ImageBackground source={bgImage} style={styles.bg} resizeMode="cover">
        <View style={styles.box}>
          <View style={styles.scrollView}>

            <ScrollView style={ styles.container } >
              <StatusBar barStyle="light-content" />

              {!this.state.results ?
              <SafeAreaView style={styles.safearea}>
                <View>
                  <Text style={styles.textCode}>{question.id}</Text>
                  <Text style={styles.text}>{question.question}</Text>
                  <Text style={styles.textAnswer}>{randomAnswer.text}</Text>

                  <ButtonContainer>
                    <Button
                      halfSize={true}
                      text={texts.true}
                      colorize={{id: randomAnswer.id, clicked: this.state.clickedAnswer ? randomAnswer.id : false, answered: this.state.answered, isCorrect: randomAnswer.correct || false}}
                      onPress={() => this.answer(true, randomAnswer.correct || false, randomAnswer.id, question)}
                    />

                    <Button
                      halfSize={true}
                      text={texts.false}
                      colorize={{id: randomAnswer.id, clicked: !this.state.clickedAnswer ? randomAnswer.id : false, answered: this.state.answered, isCorrect: !randomAnswer.correct}}
                      onPress={() => this.answer(false, randomAnswer.correct || false, randomAnswer.id, question)}
                    />
                  </ButtonContainer>

                </View>

                <Text style={styles.text}>
                  {`${this.state.correctCount+this.state.wrongCount}/${this.state.totalCount}`}
                </Text>
              </SafeAreaView>
              : <SafeAreaView></SafeAreaView>}

            </ScrollView>
          </View>
        </View>
        <View style={styles.bannerContainer}>
          <Banner />
        </View>
      </ImageBackground>
    )
  }
}

export default Quiz