const moment = require('moment')
const crypto = require('crypto')
const qs = require('querystring')
const url = require('url')
const _ = require('lodash')
const cdn_config = require('../config/cdn_config')

const config = cdn_config.qcloud;

module.exports = {
    SHA1(str) {
        return crypto.createHash('sha1').update(str).digest('hex')
    },
    HMACSHA1(str, secret) {
        return crypto.createHmac('sha1', secret).update(str).digest('hex')
    },
    sort(obj){
        const newData = {};

        Object.keys(obj).sort().forEach(key => {
            newData[key] = String(obj[key]);
        });

        return newData
    },
    sign(data) {
        // https://cloud.tencent.com/document/product/614/12445
        data.headers = data.headers  || {}
        data.headers.host = url.parse(data.baseUrl).host

        data.headers = this.sort(data.headers) || {}
        data.qs = this.sort(data.qs) || {}

        const formatedParameters = qs.stringify(data.qs)
        const formatedHeaders = qs.stringify(data.headers)

        const httpRequestInfo = [data.method, data.uri, formatedParameters, formatedHeaders].join('\n') + '\n'

        const qSignTime = `${moment().unix()};${moment(Date.now() + 60 * 1000).unix()}`
        const stringToSign = ['sha1', qSignTime, this.SHA1(httpRequestInfo)].join('\n') + '\n'

        const qKeyTime = qSignTime
        const signKey = this.HMACSHA1(qKeyTime, config.SecretKey)

        const signature = this.HMACSHA1(stringToSign, signKey)

        const authorization = `q-sign-algorithm=sha1&q-ak=${config.SecretId}&q-sign-time=${qSignTime}&q-key-time=${qKeyTime}&q-header-list=${Object.keys(data.headers).join(';')}&q-url-param-list=${Object.keys(data.qs).join(';')}&q-signature=${signature}`

        data.headers.Authorization = authorization

        return data
    }
}