'use strict'

// Do a two-pass walk, first to get the list of packages that need to be
// bundled, then again to get the actual files and folders.
// Keep a cache of node_modules content and package.json data, so that the
// second walk doesn't have to re-do all the same work.

const bundleWalk = require('npm-bundled')
const BundleWalker = bundleWalk.BundleWalker
const BundleWalkerSync = bundleWalk.BundleWalkerSync

const ignoreWalk = require('ignore-walk')
const IgnoreWalker = ignoreWalk.Walker
const IgnoreWalkerSync = ignoreWalk.WalkerSync

const rootBuiltinRules = Symbol('root-builtin-rules')
const packageNecessaryRules = Symbol('package-necessary-rules')
const path = require('path')

const defaultRules = [
  '.npmignore',
  '.gitignore',
  '**/.git',
  '**/.svn',
  '**/.hg',
  '**/CVS',
  '**/.git/**',
  '**/.svn/**',
  '**/.hg/**',
  '**/CVS/**',
  '/.lock-wscript',
  '/.wafpickle-*',
  '/build/config.gypi',
  'npm-debug.log',
  '**/.npmrc',
  '.*.swp',
  '.DS_Store',
  '**/.DS_Store/**',
  '._*',
  '**/._*/**',
  '*.orig',
  '/package-lock.json',
  '/yarn.lock',
  'archived-packages/**',
  'core',
  '!core/',
  '!**/core/',
  '*.core',
  '*.vgcore',
  'vgcore.*',
  'core.+([0-9])',
]

// a decorator that applies our custom rules to an ignore walker
const npmWalker = Class => class Walker extends Class {
  constructor (opt) {
    opt = opt || {}

    // the order in which rules are applied.
    opt.ignoreFiles = [
      rootBuiltinRules,
      'package.json',
      '.npmignore',
      '.gitignore',
      packageNecessaryRules
    ]

    opt.includeEmpty = false
    opt.path = opt.path || process.cwd()
    const dirName = path.basename(opt.path)
    const parentName = path.basename(path.dirname(opt.path))
    opt.follow =
      dirName === 'node_modules' ||
      (parentName === 'node_modules' && /^@/.test(dirName))
    super(opt)

    // ignore a bunch of things by default at the root level.
    // also ignore anything in node_modules, except bundled dependencies
    if (!this.parent) {
      this.bundled = opt.bundled || []
      this.bundledScopes = Array.from(new Set(
        this.bundled.filter(f => /^@/.test(f))
        .map(f => f.split('/')[0])))
      const rules = defaultRules.join('\n') + '\n'
      this.packageJsonCache = opt.packageJsonCache || new Map()
      super.onReadIgnoreFile(rootBuiltinRules, rules, _=>_)
    } else {
      this.bundled = []
      this.bundledScopes = []
      this.packageJsonCache = this.parent.packageJsonCache
    }
  }

  onReaddir (entries) {
    if (!this.parent) {
      entries = entries.filter(e =>
        e !== '.git' &&
        !(e === 'node_modules' && this.bundled.length === 0)
      )
    }
    return super.onReaddir(entries)
  }

  filterEntry (entry, partial) {
    // get the partial path from the root of the walk
    const p = this.path.substr(this.root.length + 1)
    const pkgre = /^node_modules\/(@[^\/]+\/?[^\/]+|[^\/]+)(\/.*)?$/
    const isRoot = !this.parent
    const pkg = isRoot && pkgre.test(entry) ?
      entry.replace(pkgre, '$1') : null
    const rootNM = isRoot && entry === 'node_modules'
    const rootPJ = isRoot && entry === 'package.json'

    return (
      // if we're in a bundled package, check with the parent.
      /^node_modules($|\/)/i.test(p) ? this.parent.filterEntry(
          this.basename + '/' + entry, partial)

      // if package is bundled, all files included
      // also include @scope dirs for bundled scoped deps
      // they'll be ignored if no files end up in them.
      // However, this only matters if we're in the root.
      // node_modules folders elsewhere, like lib/node_modules,
      // should be included normally unless ignored.
      : pkg ? -1 !== this.bundled.indexOf(pkg) ||
        -1 !== this.bundledScopes.indexOf(pkg)

      // only walk top node_modules if we want to bundle something
      : rootNM ? !!this.bundled.length

      // always include package.json at the root.
      : rootPJ ? true

      // otherwise, follow ignore-walk's logic
      : super.filterEntry(entry, partial)
    )
  }

  filterEntries () {
    if (this.ignoreRules['package.json'])
      this.ignoreRules['.gitignore'] = this.ignoreRules['.npmignore'] = null
    else if (this.ignoreRules['.npmignore'])
      this.ignoreRules['.gitignore'] = null
    this.filterEntries = super.filterEntries
    super.filterEntries()
  }

  addIgnoreFile (file, then) {
    const ig = path.resolve(this.path, file)
    if (this.packageJsonCache.has(ig))
      this.onPackageJson(ig, this.packageJsonCache.get(ig), then)
    else
      super.addIgnoreFile(file, then)
  }

  onPackageJson (ig, pkg, then) {
    this.packageJsonCache.set(ig, pkg)

    // if there's a bin, browser or main, make sure we don't ignore it
    // also, don't ignore the package.json itself!
    //
    // Weird side-effect of this: a readme (etc) file will be included
    // if it exists anywhere within a folder with a package.json file.
    // The original intent was only to include these files in the root,
    // but now users in the wild are dependent on that behavior for
    // localized documentation and other use cases.  Adding a `/` to
    // these rules, while tempting and arguably more "correct", is a
    // breaking change.
    const rules = [
      pkg.browser ? '!' + pkg.browser : '',
      pkg.main ? '!' + pkg.main : '',
      '!package.json',
      '!@(readme|copying|license|licence|notice|changes|changelog|history){,.*[^~$]}'
    ]
    if (pkg.bin)
      if (typeof pkg.bin === "object")
        for (const key in pkg.bin)
          rules.push('!' + pkg.bin[key])
      else
        rules.push('!' + pkg.bin)

    const data = rules.filter(f => f).join('\n') + '\n'
    super.onReadIgnoreFile(packageNecessaryRules, data, _=>_)

    if (Array.isArray(pkg.files))
      super.onReadIgnoreFile('package.json', '*\n' + pkg.files.map(
        f => '!' + f + '\n!' + f.replace(/\/+$/, '') + '/**'
      ).join('\n') + '\n', then)
    else
      then()
  }

  // override parent onstat function to nix all symlinks
  onstat (st, entry, file, dir, then) {
    if (st.isSymbolicLink())
      then()
    else
      super.onstat(st, entry, file, dir, then)
  }

  onReadIgnoreFile (file, data, then) {
    if (file === 'package.json')
      try {
        const ig = path.resolve(this.path, file)
        this.onPackageJson(ig, JSON.parse(data), then)
      } catch (er) {
        // ignore package.json files that are not json
        then()
      }
    else
      super.onReadIgnoreFile(file, data, then)
  }

  sort (a, b) {
    return sort(a, b)
  }
}

class Walker extends npmWalker(IgnoreWalker) {
  walker (entry, then) {
    new Walker(this.walkerOpt(entry)).on('done', then).start()
  }
}

class WalkerSync extends npmWalker(IgnoreWalkerSync) {
  walker (entry, then) {
    new WalkerSync(this.walkerOpt(entry)).start()
    then()
  }
}

const walk = (options, callback) => {
  options = options || {}
  const p = new Promise((resolve, reject) => {
    const bw = new BundleWalker(options)
    bw.on('done', bundled => {
      options.bundled = bundled
      options.packageJsonCache = bw.packageJsonCache
      new Walker(options).on('done', resolve).on('error', reject).start()
    })
    bw.start()
  })
  return callback ? p.then(res => callback(null, res), callback) : p
}

const walkSync = options => {
  options = options || {}
  const bw = new BundleWalkerSync(options).start()
  options.bundled = bw.result
  options.packageJsonCache = bw.packageJsonCache
  const walker = new WalkerSync(options)
  walker.start()
  return walker.result
}

// optimize for compressibility
// extname, then basename, then locale alphabetically
// https://twitter.com/isntitvacant/status/1131094910923231232
const sort = (a, b) => {
  const exta = path.extname(a).toLowerCase()
  const extb = path.extname(b).toLowerCase()
  const basea = path.basename(a).toLowerCase()
  const baseb = path.basename(b).toLowerCase()

  return exta.localeCompare(extb) ||
    basea.localeCompare(baseb) ||
    a.localeCompare(b)
}


module.exports = walk
walk.sync = walkSync
walk.Walker = Walker
walk.WalkerSync = WalkerSync
