'use strict'
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const fs = require('fs')
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const { PassThrough, Writable, pipeline } = require('stream')
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const process = require('process')
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const { join } = require('path')
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const defaults = {
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ext: '.txt',
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help: 'help'
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}
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function isDirectory (path) {
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try {
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const stat = fs.lstatSync(path)
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return stat.isDirectory()
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} catch (err) {
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return false
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}
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}
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function createDefaultStream () {
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return new Writable({
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write (chunk, encoding, callback) {
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process.stdout.write(chunk, callback)
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}
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})
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}
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function helpMe (opts) {
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opts = Object.assign({}, defaults, opts)
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if (!opts.dir) {
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throw new Error('missing dir')
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}
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if (!isDirectory(opts.dir)) {
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throw new Error(`${opts.dir} is not a directory`)
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}
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return {
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createStream: createStream,
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toStdout: toStdout
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}
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function createStream (args) {
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if (typeof args === 'string') {
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args = args.split(' ')
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} else if (!args || args.length === 0) {
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args = [opts.help]
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}
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const out = new PassThrough()
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const re = new RegExp(
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args
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.map(function (arg) {
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return arg + '[a-zA-Z0-9]*'
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})
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.join('[ /]+')
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)
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if (process.platform === 'win32') {
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opts.dir = opts.dir.split('\\').join('/')
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}
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fs.readdir(opts.dir, function (err, files) {
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if (err) return out.emit('error', err)
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const regexp = new RegExp('.*' + opts.ext + '$')
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files = files
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.filter(function (file) {
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const matched = file.match(regexp)
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return !!matched
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})
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.map(function (relative) {
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return { file: join(opts.dir, relative), relative }
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})
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.filter(function (file) {
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return file.relative.match(re)
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})
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if (files.length === 0) {
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return out.emit('error', new Error('no such help file'))
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} else if (files.length > 1) {
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const exactMatch = files.find(
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(file) => file.relative === `${args[0]}${opts.ext}`
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)
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if (!exactMatch) {
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out.write('There are ' + files.length + ' help pages ')
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out.write('that matches the given request, please disambiguate:\n')
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files.forEach(function (file) {
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out.write(' * ')
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out.write(file.relative.replace(opts.ext, ''))
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out.write('\n')
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})
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out.end()
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return
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}
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files = [exactMatch]
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}
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pipeline(fs.createReadStream(files[0].file), out, () => {})
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})
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return out
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}
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function toStdout (args = [], opts) {
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opts = opts || {}
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const stream = opts.stream || createDefaultStream()
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const _onMissingHelp = opts.onMissingHelp || onMissingHelp
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return new Promise((resolve, reject) => {
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createStream(args)
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.on('error', (err) => {
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_onMissingHelp(err, args, stream).then(resolve, reject)
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})
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.pipe(stream)
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.on('close', resolve)
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.on('end', resolve)
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})
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}
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function onMissingHelp (_, args, stream) {
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stream.write(`no such help file: ${args.join(' ')}.\n\n`)
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return toStdout([], { stream, async onMissingHelp () {} })
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}
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}
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function help (opts, args) {
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return helpMe(opts).toStdout(args, opts)
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}
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module.exports = helpMe
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module.exports.help = help
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