const express = require('express')

const url = require('url')

const _ = require('lodash')

function updateQueryString (target, sourceUrl) {

return ~sourceUrl.indexOf('?') ? _.assign(target, url.parse(sourceUrl, true).query) : {}

}

module.exports = (routes) => {

const router = express.Router()

router.get('/__rules', (req, res) => {

res.json(routes)

})

Object.keys(routes).forEach((route) => {

if (route.indexOf(':') !== -1) {

router.all(route, (req, res, next) => {

// Rewrite target url using params

let target = routes[route]

for (const param in req.params) {

target = target.replace(':' + param, req.params[param])

}

req.url = target

req.query = updateQueryString(req.query, req.url)

next()

})

} else {

router.all(route + '*', (req, res, next) => {

// Rewrite url by replacing prefix

req.url = req.url.replace(route, routes[route])

req.query = updateQueryString(req.query, req.url)

next()

})

}

})

return router

}