import del from 'del'

import cp from 'recursive-copy'

import mkdirp from 'mkdirp-then'

import walk from 'walk'

import { extname, resolve, join, dirname, sep } from 'path'

import { existsSync, readFileSync, writeFileSync } from 'fs'

import getConfig from './config'

import { renderToHTML } from './render'

import { getAvailableChunks } from './utils'

import { printAndExit } from '../lib/utils'

export default async function (dir, options, configuration) {

dir = resolve(dir)

const config = configuration || getConfig(dir)

const nextDir = join(dir, config.distDir)

log(` using build directory: ${nextDir}`)

if (!existsSync(nextDir)) {

console.error(

`Build directory ${nextDir} does not exist. Make sure you run "next build" before running "next start" or "next export".`

)

process.exit(1)

}

const buildId = readFileSync(join(nextDir, 'BUILD_ID'), 'utf8')

const buildStats = require(join(nextDir, 'build-stats.json'))

// Initialize the output directory

const outDir = options.outdir

await del(join(outDir, '*'))

await mkdirp(join(outDir, '_next', buildStats['app.js'].hash))

await mkdirp(join(outDir, '_next', buildId))

// Copy files

await cp(

join(nextDir, 'app.js'),

join(outDir, '_next', buildStats['app.js'].hash, 'app.js')

)

// Copy static directory

if (existsSync(join(dir, 'static'))) {

log(' copying "static" directory')

await cp(

join(dir, 'static'),

join(outDir, 'static')

)

}

// Copy dynamic import chunks

if (existsSync(join(nextDir, 'chunks'))) {

log(' copying dynamic import chunks')

await mkdirp(join(outDir, '_next', buildId, 'webpack'))

await cp(

join(nextDir, 'chunks'),

join(outDir, '_next', buildId, 'webpack', 'chunks')

)

}

await copyPages(nextDir, outDir, buildId)

// Get the exportPathMap from the `next.config.js`

if (typeof config.exportPathMap !== 'function') {

printAndExit(

'> Could not find "exportPathMap" function inside "next.config.js"\n'

'> "next export" uses that function to build html pages.'

)

}

const exportPathMap = await config.exportPathMap()

const exportPaths = Object.keys(exportPathMap)

// Start the rendering process

const renderOpts = {

dir,

buildStats,

buildId,

nextExport: true,

assetPrefix: config.assetPrefix.replace(/\/$/, ''),

dev: false,

staticMarkup: false,

hotReloader: null,

availableChunks: getAvailableChunks(dir, config.distDir)

}

// We need this for server rendering the Link component.

global.__NEXT_DATA__ = {

nextExport: true

}

for (const path of exportPaths) {

log(` exporting path: ${path}`)

const { page, query = {} } = exportPathMap[path]

const req = { url: path }

const res = {}

let htmlFilename = `${path}${sep}index.html`

if (extname(path) !== '') {

// If the path has an extension, use that as the filename instead

htmlFilename = path

} else if (path === '/') {

// If the path is the root, just use index.html

htmlFilename = 'index.html'

}

const baseDir = join(outDir, dirname(htmlFilename))

const htmlFilepath = join(outDir, htmlFilename)

await mkdirp(baseDir)

const html = await renderToHTML(req, res, page, query, renderOpts)

writeFileSync(htmlFilepath, html, 'utf8')

}

// Add an empty line to the console for the better readability.

log('')

function log (message) {

if (options.silent) return

console.log(message)

}

}

function copyPages (nextDir, outDir, buildId) {

}