/** @module ProposalCalculations */

const LAMBDA_NAME = 'loanpal-getMonthlyPayments'
const LambdaHelper = require('./LambdaHelperV2.js')
const fs = require('fs')
const request = require('request')

exports.handler = async (event, context) => {
    const originalEvent = JSON.parse(JSON.stringify(event))

    try {
        LambdaHelper.validateEvent(event, ['body', 'alias', 'api_base_url', 'api_environment', 'api_version'])
        LambdaHelper.validateEvent(event.body, ['fundSetup', 'fund'])
        LambdaHelper.validateEvent(event.body.fundSetup, ['Term_In_Months__c', 'Interest_Rate__c'])
        LambdaHelper.validateEvent(event.body.fund, ['System_Price__c'])

        let loanpalResults = await getMonthlyPayments(event)

        let monthlyPayments = analyzeLoanpalResults(loanpalResults)

        if (event.responseType == 'file') {
            await new Promise(function(resolve, reject){
                fs.writeFile('myjsonfile.json', JSON.stringify(monthlyPayments, null, 4), function(err) {
                    if (err) {
                        reject(err)
                    } else {
                        resolve('Saved JSON')
                    }
                })
            })
        } else {
            return LambdaHelper.formatResponseData(null, originalEvent, monthlyPayments, LAMBDA_NAME)
        }

    } catch (error) {
        return LambdaHelper.formatResponseData(error, originalEvent, null, LAMBDA_NAME)
    }
}


/**********************************************************************************************
* @description Calls out to genability for the reduced usage savings
* @param {JSON} event - event passed in
* @param {JSON} proposalCalculationData - main proposal data
* @return {JSON} response from genability-reducedUsageSavings lamba function
***********************************************************************************************/
async function getMonthlyPayments(event) {
    let termInYears = parseInt(event.body.fundSetup.Term_In_Months__c) / 12,
        systemPrice = parseInt(event.body.fund.System_Price__c),
        netSystemPrice = systemPrice - (event.body.fund.Down_Payment__c != null ? parseFloat(event.body.fund.Down_Payment__c) : 0)

    let urlParamDict = {
        loanAmount: netSystemPrice,
        term: termInYears,
        rate: event.body.fundSetup.Interest_Rate__c
    }

    let urlParams = []

    for (let param of Object.keys(urlParamDict)) {
        if (urlParamDict.hasOwnProperty(param)) {
            urlParams.push(param + '=' + urlParamDict[param])
        }
    }

    let options = {
        url: 'https://' + event.api_base_url + event.api_environment + event.api_version + '/loanCalc?' + urlParams.join('&') + '&baseItcPct=0.26',
        method: 'GET'
    }

    return new Promise(function(resolve, reject) {
        request(options, function (error, response, body) {
            if (error){
                reject(error)
            } else {
                resolve(JSON.parse(body))
            }
        })
    })
}

function analyzeLoanpalResults(loanpalResults) {
    return {
        fund: {
            Monthly_Payment_1__c: parseFloat(loanpalResults[0].initialMonthlyPayment.replace("$", '').replace(/,/g, '')),
            No_Paydown_Payment__c: parseFloat(loanpalResults[0].adjustedMonthlyPayment.replace("$", '').replace(/,/g, '')),
            Monthly_Payment_2__c: parseFloat(loanpalResults[1].adjustedMonthlyPayment.replace("$", '').replace(/,/g, ''))
        }
    }
}