const Axios     = require('axios')
const Cheerio   = require('cheerio')

const Constants = require('./constants')

class Lotto {
    static #SessionID   = undefined
    static #LottoDirect = undefined

    static #_request(method, url, data) {
        const requestOpts = {
            method,
            url,
            data,
            headers: Constants.DEFAULT_HEADERS,
            timeout: Constants.DEFAULT_TIMEOUT,
        }
        if(this.#SessionID)
            requestOpts.headers.Cookie = this.#SessionID
        return Axios(requestOpts).catch(err => err)
    }
    static async #_syncSession() {
        const sessionResponse = await this.#_request('GET', Constants.DEFAULT_SESSION_URL)
        if(sessionResponse instanceof Error) 
            return sessionResponse

        if(sessionResponse.request.res.responseUrl === Constants.SYSTEM_CHECK_URL)
            return new Error('동행복권 사이트가 현재 시스템 점검중입니다.')

        const sessionId = sessionResponse.headers['set-cookie']
            .find(cookieStr => cookieStr.indexOf('JSESSIONID') !== -1)
        if(!sessionId)
            return new Error('쿠키가 정상적으로 세팅되지 않았습니다.')
    
        this.#SessionID = sessionId
    }
    static async #_getRound() {
        const roundResponse = await this.#_request('GET', Constants.ROUND_INFO_URL)
        if(roundResponse instanceof Error)
            return roundResponse

        const $ = Cheerio.load(roundResponse.data)
        const lastDrawnRound = parseInt($("strong#lottoDrwNo").text(), 10)
        const round = lastDrawnRound + 1
        return round
    }

    static async Login(userId, userPw) {
        const sessionSyncError = await this.#_syncSession()
        if(sessionSyncError instanceof Error)
            return sessionSyncError

        const loginData = {
            returnUrl: Constants.MAIN_PAGE_URL,
            userId,
            password: userPw,
            checkSave: 'off',
            newsEventYn: '',
        }
        const loginResult = await this.#_request('POST', Constants.LOGIN_REQUEST_URL, loginData)
        if(loginResult instanceof Error)
            return loginResult

        let $ = Cheerio.load(loginResult.data)

        /**
         * 비밀번호 변경 감지
         *
         * 비밀번호가 변경이 될 경우 'https://www.dhlottery.co.kr/userSsl.do?method=pwdPlyChngNoti'로 redirect 됨
         * 비밀번호를 유지할 지 변경할 지 고르는 페이지인데, 여기에 있는 chngTgtId 및 pwdChgToken를 추출해서
         *
         * POST 'https://www.dhlottery.co.kr/userSsl.do?method=pspnPwChng'
         * payload로 chngTgtId, pwdChgToken을 보내면 다음에 하기 처리됨.
         *
         * 성공하면 'https://www.dhlottery.co.kr/user.do?method=login&returnUrl=https%3A%2F%2Fwww.dhlottery.co.kr%2Fcommon.do%3Fmethod%3Dmain'
         * redirect 진행되며, 마지막으로 MAIN_PAGE_URL로 redirect됨
         */
        const targetInput = $('#chngTgtId')
        if(targetInput.length !== 0) {
            const chngTgtId = targetInput.val()
            const pwdChgToken = $('#pwdChgToken').val()

            const pwChgNextData = { chngTgtId, pwdChgToken }
            const pgChgNextResult = await this.#_request('POST', Constants.PW_CHANGE_NEXT_URL, pwChgNextData)
            if(pgChgNextResult instanceof Error)
                return pgChgNextResult

            $ = Cheerio.load(pgChgNextResult.data)
        }


        const btnCommonElements = $('a.btn_common')
        if(btnCommonElements.length > 0)
            return new Error('로그인에 실패했습니다. 아이디 또는 비밀번호를 확인해주세요.')

        return true
    }
    static async Buy(lotteryInputs = []) {
        if(lotteryInputs.length === 0)
            return new Error('구매할 로또 정보를 입력해주세요.')
        if(lotteryInputs.length > 5)
            lotteryInputs = lotteryInputs.slice(0, 5)

        const round = await this.#_getRound()

        const readySocketResponse = await this.#_request('POST', Constants.BUY_READY_SOCKET_URL)
        if(readySocketResponse instanceof Error)
            return readySocketResponse

        this.#LottoDirect = readySocketResponse.data.ready_ip

        const requestParams = lotteryInputs.map((lotto, idx) => {
            return {
                genType: lotto === 'auto' ? '0' : '1',
                arrGameChoiceNum: lotto === 'auto' ? null : lotto.sort().map(num => String(num).padStart(2, 0)).join(','),
                alpabet: String.fromCharCode(65 + idx)
            }
        })
        const requestData = {
            round: String(round),
            direct: this.#LottoDirect,
            nBuyAmount: `${requestParams.length * 1000}`,
            param: JSON.stringify(requestParams),
            gameCnt: `${requestParams.length}`,
        }
        const buyResponse = await this.#_request('POST', Constants.BUY_LOTTO_645_URL, requestData)
        if(buyResponse instanceof Error)
            return buyResponse

        const { result } = buyResponse.data

        if ((result.resultMsg || "FAILURE").toUpperCase() !== "SUCCESS")
            return new Error(result.resultMsg)

        return {
            round: result.buyRound,
            barcode: Object.keys(result)
                .filter(k => k.startsWith('barCode'))
                .map(k => result[k])
                .join(' '),
            cost: result.nBuyAmount,
            numbers: result.arrGameChoiceNum,
            message: result.resultMsg,
        }
    }
}

module.exports = Lotto