import {
    Image,
    View,
    Text,
    Pressable,
    Dimensions,
    StyleSheet,
    Modal,
    Animated,
    ScrollView,
    Button,
    BackHandler,
    Alert
} from 'react-native';

import { SafeAreaView } from 'react-native-safe-area-context';
import { router, useFocusEffect } from 'expo-router';
import { CrossLogoSvg } from '../../../../component/global/SVG';
import CouponTabViewComponent from '../../../../component/global/couponTabView';
import { useCallback, useEffect, useState } from 'react';
import { useChargingStore } from '../../../../providers/scan_qr_payload_store';
import { ArrowRightSvg } from '../../../../component/global/SVG';
import { useRef } from 'react';
import NormalButton from '../../../../component/global/normal_button';

//this is from optionPage => 優惠券
const SelectCouponComponent = () => {
    const screenHeight = Dimensions.get('window').height;
    const {
        promotion_code,
        coupon_detail,
        stationID,

        setSumOfCoupon,
        setCurrentPriceStore,
        current_price_store,
        setProcessedCouponStore,
        setPromotionCode,
        setCouponDetail,
        setTotalPower
    } = useChargingStore();
    const [scaleValue, setScaleValue] = useState(1);
    const [isBottomSheetVisible, setIsBottomSheetVisible] = useState(false);
    const [processedCoupons, setProcessedCoupons] = useState([]);
    const translateY = useRef(new Animated.Value(300)).current;
    const showBottomSheet = () => {
        setIsBottomSheetVisible(true);
        Animated.timing(translateY, {
            toValue: 0,
            duration: 300,
            useNativeDriver: true
        }).start();
    };
    const hideBottomSheet = () => {
        Animated.timing(translateY, {
            toValue: 0,
            duration: 0,
            useNativeDriver: true
        }).start(() => setIsBottomSheetVisible(false));
    };
    //process coupon so that coupons with same expire date and amount are grouped together to show abcoupon x 2
    useEffect(() => {
        if (Array.isArray(coupon_detail) && coupon_detail.length > 0) {
            const processed = processCoupons(coupon_detail);
            setProcessedCoupons(processed);
            setProcessedCouponStore(processed);
        }
    }, [coupon_detail]);

    //fetch original price for coupon valid calculation

    const processCoupons = (coupon_details_array: any) => {
        //coupon_details_array contains all information. i skim it down here.
        if (!coupon_details_array || coupon_details_array.length === 0) {
            return [];
        }
        const skimmedDownArray = coupon_details_array?.map((couponDetailObj: any) => ({
            amount: couponDetailObj.coupon.amount,
            id: couponDetailObj.id,
            expire_date: couponDetailObj.expire_date || '永久'
        }));

        const totalCouponAmount = skimmedDownArray.reduce((acc: number, coupon: any) => acc + coupon.amount, 0);
        setSumOfCoupon(totalCouponAmount);
        //process the skimmed array by combining coupons with same expire_date and amount
        const processedArray = (skimmedDownArray: { amount: number; id: string; expire_date: string }[]) => {
            const groupedCoupons: { [key: string]: any } = {};

            for (const coupon of skimmedDownArray) {
                const key = `${coupon.amount}-${coupon.expire_date}`;
                if (!groupedCoupons[key]) {
                    groupedCoupons[key] = {
                        coupon_detail: {
                            amount: coupon.amount,
                            expire_date: coupon.expire_date
                        },
                        frequency: 1
                    };
                } else {
                    groupedCoupons[key].frequency++;
                }
            }
            return Object.values(groupedCoupons);
        };
        return processedArray(skimmedDownArray);
    };
    const cleanupData = () => {
        setPromotionCode([]);
        setCouponDetail([]);
        setProcessedCouponStore([]);
        setSumOfCoupon(0);
        setTotalPower(null);
    };

    // Add this effect to handle Android back button
    useFocusEffect(
        useCallback(() => {
            const onBackPress = () => {
                cleanupData();
                if (router.canGoBack()) {
                    router.back();
                } else {
                    router.replace('/scanQrPage');
                }
                return true;
            };

            const subscription = BackHandler.addEventListener('hardwareBackPress', onBackPress);
            return () => subscription.remove()
        }, [])
    );
    return (
        <SafeAreaView className="flex-1 bg-white" edges={['top', 'right', 'left']}>
            <View style={{ minHeight: screenHeight, flex: 1 }}>
                <View className="mx-[5%]" style={{ marginTop: 25 }}>
                    <Pressable
                        onPress={() => {
                            cleanupData();
                            if (router.canGoBack()) {
                                router.back();
                            } else {
                                router.replace('/optionPage');
                            }
                        }}
                    >
                        <CrossLogoSvg />
                    </Pressable>
                    <Text style={{ fontSize: 45, marginVertical: 25 }}>優惠券</Text>
                </View>
                <View className="flex-1">
                    <CouponTabViewComponent titles={['可用優惠券', '已使用/失效']} />
                    {promotion_code.length > 0 && (
                        <View
                            style={{
                                position: 'absolute',
                                alignItems: 'center',
                                left: 0,
                                right: 0,
                                padding: 20,
                                height: '100%',
                                top: '65%'
                            }}
                        >
                            <Pressable
                                className="bg-white rounded-full items-center justify-center w-full flex flex-row"
                                style={[styles.floatingButton, { transform: [{ scale: scaleValue }] }]}
                                onPressIn={() => setScaleValue(0.96)}
                                onPressOut={() => setScaleValue(1)}
                                onPress={showBottomSheet}
                            >
                                <Text className="text-[#02677D] text-2xl lg:text-4xl text-center py-1  pr-4 lg:pr-6 font-[600] lg:py-4">
                                    馬上使用
                                </Text>
                                <View className="flex mb-2 bg-[#02677D] rounded-full items-center justify-center w-10 h-10 relative">
                                    <ArrowRightSvg />
                                    <View className="rounded-full bg-[#02677D] h-5 w-5 absolute bottom-7 left-7 z-10 border border-white flex items-center justify-center">
                                        <Text className="text-white text-xs text-center">{promotion_code.length}</Text>
                                    </View>
                                </View>
                            </Pressable>
                        </View>
                    )}
                </View>
            </View>
            <Modal transparent={true} visible={isBottomSheetVisible} animationType="none">
                <View style={{ flex: 1 }}>
                    <Pressable style={{ flex: 1 }} onPress={hideBottomSheet}>
                        <View className="flex-1 bg-black/50" />
                    </Pressable>
                    <Animated.View
                        style={{
                            position: 'absolute',
                            bottom: 0,
                            left: 0,
                            right: 0,
                            height: '80%',
                            backgroundColor: 'white',
                            transform: [{ translateY }],
                            borderTopLeftRadius: 30,
                            borderTopRightRadius: 30,
                            overflow: 'hidden'
                        }}
                    >
                        <ScrollView
                            className="flex-1 flex-col bg-white p-8 "
                            contentContainerStyle={{ paddingBottom: 100 }}
                        >
                            <Text className="text-lg md:text-xl lg:text-2xl">優惠券細節</Text>
                            <View style={{ height: 1, backgroundColor: '#ccc', marginVertical: 24 }} />
                            {/* coupon row */}
                            {processedCoupons &&
                                processedCoupons?.map((couponObj: any) => (
                                    <View
                                        key={`${couponObj.coupon_detail.amount}-${couponObj.coupon_detail.expire_date}`}
                                        className="flex flex-row items-center justify-between"
                                    >
                                        <View className="flex flex-row items-start ">
                                            <Image
                                                className="w-6 lg:w-8 xl:w-10 h-6 lg:h-8 xl:h-10"
                                                source={require('../../../../assets/couponlogo.png')}
                                            />
                                            <View
                                                key={couponObj.coupon_detail.id}
                                                className="flex flex-col ml-2 lg:ml-4 "
                                            >
                                                <Text className="text-base lg:text-xl ">
                                                    ${couponObj.coupon_detail.amount} 現金劵
                                                </Text>
                                                <Text className=" text-sm lg:text-base my-1 lg:mt-2 lg:mb-4 ">
                                                    有效期{'  '}
                                                    <Text className="font-[500] text-[#02677D]">
                                                        至 {couponObj.coupon_detail.expire_date.slice(0, 10)}
                                                    </Text>
                                                </Text>
                                            </View>
                                        </View>

                                        {/* x 1 */}
                                        <View className="flex flex-row items-center ">
                                            <Text>X </Text>
                                            <View className="w-8 h-8 rounded-full bg-[#02677D] flex items-center justify-center">
                                                <Text className="text-white text-center text-lg">
                                                    {couponObj.frequency}
                                                </Text>
                                            </View>
                                        </View>
                                    </View>
                                ))}
                            <View style={{ height: 1, backgroundColor: '#ccc', marginVertical: 12 }} />
                            {/* 服務條款 */}
                            <NormalButton
                                title={<Text className="text-white text-sm lg:text-lg">立即使用</Text>}
                                onPress={() => {
                                    setIsBottomSheetVisible(false);
                                    router.push('/totalPayment');
                                }}
                                extendedStyle={{ marginTop: 12, marginBottom: 24 }}
                            />
                            <View>
                                <View className="">
                                    <Text className="text-base md:text-lg lg:text-xl pb-2 lg:pb-3 xl:pb-4">
                                        服務條款與細則
                                    </Text>
                                    <View className="flex flex-col items-center space-y-2">
                                        <Text className="text-xs md:text-sm font-[300]">
                                            ・ 此券持有人可在本券有效期內於任何位於Crazy Charge
                                            之香港分店換取同等價值充電服務，逾期無效。
                                        </Text>
                                        <Text className="text-xs lg:text-sm  font-[300]">
                                            ・
                                            此優惠券使用時，電費將以正常價格$3.5元/每度電計算，不適用於貓頭鷹時段或其他折扣時段的電力價格計算。
                                        </Text>
                                        <Text className="text-xs lg:text-sm  font-[300]">
                                            ・ 此券不能用以套换現金或其他面值之現金券，持有人不獲現金或其他形式之找贖。
                                        </Text>
                                        <Text className="text-xs lg:text-sm  font-[300]">
                                            ・ 使用者一旦在本 APP
                                            內確認使用電子優惠券，即視為同意依優惠券規則進行消費抵扣，相關優惠券將立即從帳戶中扣除，且扣除後不得退還。
                                        </Text>
                                        <Text className="text-xs lg:text-sm  font-[300]">
                                            ・
                                            即便實際充電消費金額未達到電子優惠券的面額，亦不會就差額部分進行退款。優惠券的使用旨在為用戶提供充電優惠，而非現金兌換或退款工具。
                                        </Text>
                                        <Text className="text-xs lg:text-sm  font-[300]">
                                            ・如有任何爭議，Crazy Charge
                                            保留更改有關使用此現金券之條款及細則，而毋須另行通知。
                                        </Text>
                                    </View>
                                </View>
                            </View>
                        </ScrollView>
                    </Animated.View>
                </View>
            </Modal>
        </SafeAreaView>
    );
};

const styles = StyleSheet.create({
    floatingButton: {
        elevation: 5,
        shadowColor: '#000',
        shadowOffset: { width: 0, height: 2 },
        shadowOpacity: 0.25,
        shadowRadius: 3.84
    }
});

export default SelectCouponComponent;