const GH_RESERVED_USER_NAMES = [
 'settings', 'orgs', 'organizations',
 'site', 'blog', 'about', 'explore',
 'styleguide', 'showcases', 'trending',
 'stars', 'dashboard', 'notifications',
 'search', 'developer', 'account',
 'pulls', 'issues', 'features', 'contact',
 'security', 'join', 'login', 'watching',
 'new', 'integrations', 'gist', 'business',
 'mirrors', 'open-source', 'personal',
 'pricing'
]
const GH_RESERVED_REPO_NAMES = ['followers', 'following', 'repositories']
const GH_404_SEL = '#parallax_wrapper'
const GH_PJAX_CONTAINER_SEL = '#js-repo-pjax-container, .context-loader-container, [data-pjax-container]'
const GH_CONTAINERS = '.container, .container-responsive'
const GH_RAW_CONTENT = 'body > pre'

class GitHub extends PjaxAdapter {

 constructor() {
 super(['jquery.pjax.js'])
 }

 // @override
 init($sidebar) {
 const pjaxContainer = $(GH_PJAX_CONTAINER_SEL)[0]
 super.init($sidebar, {'pjaxContainer': pjaxContainer})

 // Fix #151 by detecting when page layout is updated.
 // In this case, split-diff page has a wider layout, so need to recompute margin.
 // Note that couldn't do this in response to URL change, since new DOM via pjax might not be ready.
 const diffModeObserver = new window.MutationObserver((mutations) => {
 mutations.forEach((mutation) => {
 if (~mutation.oldValue.indexOf('split-diff') ||
 ~mutation.target.className.indexOf('split-diff')) {
 return $(document).trigger(EVENT.LAYOUT_CHANGE)
 }
 })
 })

 diffModeObserver.observe(document.body, {
 attributes: true,
 attributeFilter: ['class'],
 attributeOldValue: true
 })
 }

 // @override
 getCssClass() {
 return 'octotree_github_sidebar'
 }

 // @override
 canLoadEntireTree() {
 return true
 }

 // @override
 getCreateTokenUrl() {
 return `${location.protocol}//${location.host}/settings/tokens/new`
 }

 // @override
 updateLayout(togglerVisible, sidebarVisible, sidebarWidth) {
 const SPACING = 10
 const $containers = $(GH_CONTAINERS)
 const autoMarginLeft = ($(document).width() - $containers.width()) / 2
 const shouldPushLeft = sidebarVisible && (autoMarginLeft <= sidebarWidth + SPACING)

 $('html').css('margin-left', shouldPushLeft ? sidebarWidth : '')
 $containers.css('margin-left', shouldPushLeft ? SPACING : '')
 }

 // @override
 getRepoFromPath(showInNonCodePage, currentRepo, token, cb) {

 // 404 page, skip
 if ($(GH_404_SEL).length) {
 return cb()
 }

 // Skip raw page
 if ($(GH_RAW_CONTENT).length) {
 return cb()
 }

 // (username)/(reponame)[/(type)]
 const match = window.location.pathname.match(/([^\/]+)\/([^\/]+)(?:\/([^\/]+))?/)
 if (!match) {
 return cb()
 }

 const username = match[1]
 const reponame = match[2]

 // Not a repository, skip
 if (~GH_RESERVED_USER_NAMES.indexOf(username) ||
 ~GH_RESERVED_REPO_NAMES.indexOf(reponame)) {
 return cb()
 }

 // Skip non-code page unless showInNonCodePage is true
 if (!showInNonCodePage && match[3] && !~['tree', 'blob'].indexOf(match[3])) {
 return cb()
 }

 // Get branch by inspecting page, quite fragile so provide multiple fallbacks
 const branch =
 // Code page
 $('.branch-select-menu .select-menu-item.selected').data('name') ||
 // Pull requests page
 ($('.commit-ref.base-ref').attr('title') || ':').match(/:(.*)/)[1] ||
 // Reuse last selected branch if exist
 (currentRepo.username === username && currentRepo.reponame === reponame && currentRepo.branch) ||
 // Get default branch from cache
 this._defaultBranch[username + '/' + reponame]

 // Still no luck, get default branch for real
 const repo = {username: username, reponame: reponame, branch: branch}

 if (repo.branch) {
 cb(null, repo)
 }
 else {
 this._get(null, {repo, token}, (err, data) => {
 if (err) return cb(err)
 repo.branch = this._defaultBranch[username + '/' + reponame] = data.default_branch || 'master'
 cb(null, repo)
 })
 }
 }

 // @override
 selectFile(path) {
 const $pjaxContainer = $(GH_PJAX_CONTAINER_SEL)
 super.selectFile(path, {'$pjaxContainer': $pjaxContainer})
 }

 // @override
 loadCodeTree(opts, cb) {
 opts.encodedBranch = encodeURIComponent(decodeURIComponent(opts.repo.branch))
 opts.path = (opts.node && (opts.node.sha || opts.encodedBranch)) ||
 (opts.encodedBranch + '?recursive=1')
 this._loadCodeTree(opts, null, cb)
 }

 // @override
 _getTree(path, opts, cb) {
 this._get(`/git/trees/${path}`, opts, (err, res) => {
 if (err) cb(err)
 else cb(null, res.tree)
 })
 }

 // @override
 _getSubmodules(tree, opts, cb) {
 const item = tree.filter((item) => /^\.gitmodules$/i.test(item.path))[0]
 if (!item) return cb()

 this._get(`/git/blobs/${item.sha}`, opts, (err, res) => {
 if (err) return cb(err)
 const data = atob(res.content.replace(/\n/g,''))
 cb(null, parseGitmodules(data))
 })
 }

 _get(path, opts, cb) {
 const host = location.protocol + '//' +
 (location.host === 'github.com' ? 'api.github.com' : (location.host + '/api/v3'))
 const url = `${host}/repos/${opts.repo.username}/${opts.repo.reponame}${path || ''}`
 const cfg = { url, method: 'GET', cache: false }

 if (opts.token) {
 cfg.headers = { Authorization: 'token ' + opts.token }
 }

 $.ajax(cfg)
 .done((data) => {
 if (path && path.indexOf('/git/trees') === 0 && data.truncated) {
 this._handleError({status: 206}, cb)
 }
 else cb(null, data)
 })
 .fail((jqXHR) => this._handleError(jqXHR, cb))
 }
}