const fs = require('fs')
const fetch = require('node-fetch')
import { apiEndpoints } from 'utils/store'
import { formatDate } from 'utils/functions'


// Variables
let baseURL
const pages = ['']

// Get routes and push it to array
const routesExclude = ['sitemap', 'index', 'location', 'viewer']
fs.readdirSync('./src/routes').forEach(file => {
    const filename = file.split('.')[0]
    if (!file.startsWith('.') && !filename.startsWith('_') && routesExclude.indexOf(filename) === -1) {
        pages.push(filename)
    }
})


// Render function
const render = (pages, locations) => {
    return `<?xml version="1.0" encoding="UTF-8" ?>
<urlset
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
    xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd"
>
    ${pages.map(page => `
    <url>
        <loc>${baseURL}/${page}</loc>
        <priority>0.75</priority>
    </url>`).join('\n')}

    ${locations.map(loc => `
    <url>
        <loc>${baseURL}/location/${loc.country.slug}/${loc.slug}</loc>
        <priority>1</priority>
        <lastmod>${formatDate(loc.updated, 'DATETIME')}</lastmod>
        <changefreq>weekly</changefreq>
    </url>`).join('\n')
    }
</urlset>`
}

// Get function
export async function get (req, res, next) {
    // Define base url from request
    baseURL = `https://${req.headers.host}`

    // Get locations
    const locationsReq = await fetch(`${apiEndpoints.rest}/items/locations?fields=slug,country.slug,modified_on&status=published`)
    const locationsData = await locationsReq.json()
    const locations = locationsData.data

    // Add last modified date to each location from its last photo
    const updatedLocations = locations.map(async (location, i) => {
        const latestPhotoReq = await fetch(`${apiEndpoints.rest}/items/photos?fields=created_on&limit=1&sort=created_on&status=published&filter[location.slug][rlike]=%${location.slug}`)
        const latestPhotoData = await latestPhotoReq.json()
        const latestPhoto = latestPhotoData.data[0]
        location.updated = latestPhoto ? latestPhoto.created_on : location.modified_on
        return location
    })
    await Promise.all(updatedLocations)

    // Set headers
    res.setHeader('Cache-Control', 'max-age=0, s-max-age=600') // 10 minutes
    res.setHeader('Content-Type', 'application/rss+xml')

    // Render sitemap
    const sitemap = render(pages, locations)
    res.end(sitemap)
}