'use strict'

const fs = require('fs')
const path = require('path')
const markdownpdf = require('markdown-pdf')
const shortId = require('shortid')
const querystring = require('querystring')
const moment = require('moment')
const { Pandoc } = require('@hackmd/pandoc.js')

const config = require('../config')
const logger = require('../logger')
const { Note, Revision } = require('../models')
const { errorInternalError, errorNotFound } = require('../response')

function actionPublish (req, res, note) {
 res.redirect(config.serverURL + '/s/' + (note.alias || note.shortid))
}

function actionSlide (req, res, note) {
 res.redirect(config.serverURL + '/p/' + (note.alias || note.shortid))
}

function actionDownload (req, res, note) {
 const body = note.content
 const title = Note.decodeTitle(note.title)
 const filename = encodeURIComponent(title)
 res.set({
 'Access-Control-Allow-Origin': '*', // allow CORS as API
 'Access-Control-Allow-Headers': 'Range',
 'Access-Control-Expose-Headers': 'Cache-Control, Content-Encoding, Content-Range',
 'Content-Type': 'text/markdown; charset=UTF-8',
 'Cache-Control': 'private',
 'Content-disposition': 'attachment; filename=' + filename + '.md',
 'X-Robots-Tag': 'noindex, nofollow' // prevent crawling
 })
 res.send(body)
}

function actionInfo (req, res, note) {
 const body = note.content
 const extracted = Note.extractMeta(body)
 const markdown = extracted.markdown
 const meta = Note.parseMeta(extracted.meta)
 const createtime = note.createdAt
 const updatetime = note.lastchangeAt
 const title = Note.decodeTitle(note.title)

 const data = {
 title: meta.title || title,
 description: meta.description || (markdown ? Note.generateDescription(markdown) : null),
 viewcount: note.viewcount,
 createtime: createtime,
 updatetime: updatetime
 }

 res.set({
 'Access-Control-Allow-Origin': '*', // allow CORS as API
 'Access-Control-Allow-Headers': 'Range',
 'Access-Control-Expose-Headers': 'Cache-Control, Content-Encoding, Content-Range',
 'Cache-Control': 'private', // only cache by client
 'X-Robots-Tag': 'noindex, nofollow' // prevent crawling
 })
 res.send(data)
}

function actionPDF (req, res, note) {
 const url = config.serverURL || 'http://' + req.get('host')
 const body = note.content
 const extracted = Note.extractMeta(body)
 let content = extracted.markdown
 const title = Note.decodeTitle(note.title)

 const highlightCssPath = path.join(config.appRootPath, '/node_modules/highlight.js/styles/github-gist.css')

 if (!fs.existsSync(config.tmpPath)) {
 fs.mkdirSync(config.tmpPath)
 }
 const pdfPath = config.tmpPath + '/' + Date.now() + '.pdf'
 content = content.replace(/\]\(\//g, '](' + url + '/')
 const markdownpdfOptions = {
 highlightCssPath: highlightCssPath
 }
 markdownpdf(markdownpdfOptions).from.string(content).to(pdfPath, function () {
 if (!fs.existsSync(pdfPath)) {
 logger.error('PDF seems to not be generated as expected. File doesn\'t exist: ' + pdfPath)
 return errorInternalError(req, res)
 }
 const stream = fs.createReadStream(pdfPath)
 let filename = title
 // Be careful of special characters
 filename = encodeURIComponent(filename)
 // Ideally this should strip them
 res.setHeader('Content-disposition', 'attachment; filename="' + filename + '.pdf"')
 res.setHeader('Cache-Control', 'private')
 res.setHeader('Content-Type', 'application/pdf; charset=UTF-8')
 res.setHeader('X-Robots-Tag', 'noindex, nofollow') // prevent crawling
 stream.on('end', () => {
 stream.close()
 fs.unlinkSync(pdfPath)
 })
 stream.pipe(res)
 })
}

const outputFormats = {
 asciidoc: 'text/plain',
 context: 'application/x-latex',
 epub: 'application/epub+zip',
 epub3: 'application/epub+zip',
 latex: 'application/x-latex',
 odt: 'application/vnd.oasis.opendocument.text',
 pdf: 'application/pdf',
 rst: 'text/plain',
 rtf: 'application/rtf',
 textile: 'text/plain',
 docx: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'
}

async function actionPandoc (req, res, note) {
 var url = config.serverURL || 'http://' + req.get('host')
 var body = note.content
 var extracted = Note.extractMeta(body)
 var content = extracted.markdown
 var title = Note.decodeTitle(note.title)

 if (!fs.existsSync(config.tmpPath)) {
 fs.mkdirSync(config.tmpPath)
 }
 const pandoc = new Pandoc()

 var path = config.tmpPath + '/' + Date.now()
 content = content.replace(/\]\(\//g, '](' + url + '/')

 const { exportType } = req.query
 const contentType = outputFormats[exportType]

 try {
 // TODO: timeout rejection
 if (!contentType) {
 return res.sendStatus(400)
 }

 await pandoc.convertToFile(content, 'markdown', exportType, path, [
 '--metadata', `title=${title}`, '--sandbox'
 ])

 var stream = fs.createReadStream(path)
 var filename = title
 // Be careful of special characters
 filename = encodeURIComponent(filename)
 // Ideally this should strip them
 res.setHeader('Content-disposition', `attachment; filename="${filename}.${exportType}"`)
 res.setHeader('Cache-Control', 'private')
 res.setHeader('Content-Type', `${contentType}; charset=UTF-8`)
 res.setHeader('X-Robots-Tag', 'noindex, nofollow') // prevent crawling
 stream.pipe(res)
 } catch (err) {
 // TODO: handle error
 res.json({
 message: err.message
 })
 }
}

function actionGist (req, res, note) {
 const data = {
 client_id: config.github.clientID,
 redirect_uri: config.serverURL + '/auth/github/callback/' + Note.encodeNoteId(note.id) + '/gist',
 scope: 'gist',
 state: shortId.generate()
 }
 const query = querystring.stringify(data)
 res.redirect('https://github.com/login/oauth/authorize?' + query)
}

function actionRevision (req, res, note) {
 const actionId = req.params.actionId
 if (actionId) {
 const time = moment(parseInt(actionId))
 if (!time.isValid()) {
 return errorNotFound(req, res)
 }
 Revision.getPatchedNoteRevisionByTime(note, time, function (err, content) {
 if (err) {
 logger.error(err)
 return errorInternalError(req, res)
 }
 if (!content) {
 return errorNotFound(req, res)
 }
 res.set({
 'Access-Control-Allow-Origin': '*', // allow CORS as API
 'Access-Control-Allow-Headers': 'Range',
 'Access-Control-Expose-Headers': 'Cache-Control, Content-Encoding, Content-Range',
 'Cache-Control': 'private', // only cache by client
 'X-Robots-Tag': 'noindex, nofollow' // prevent crawling
 })
 res.send(content)
 })
 } else {
 Revision.getNoteRevisions(note, function (err, data) {
 if (err) {
 logger.error(err)
 return errorInternalError(req, res)
 }
 const result = {
 revision: data
 }
 res.set({
 'Access-Control-Allow-Origin': '*', // allow CORS as API
 'Access-Control-Allow-Headers': 'Range',
 'Access-Control-Expose-Headers': 'Cache-Control, Content-Encoding, Content-Range',
 'Cache-Control': 'private', // only cache by client
 'X-Robots-Tag': 'noindex, nofollow' // prevent crawling
 })
 res.send(result)
 })
 }
}

exports.actionPublish = actionPublish
exports.actionSlide = actionSlide
exports.actionDownload = actionDownload
exports.actionInfo = actionInfo
exports.actionPDF = actionPDF
exports.actionGist = actionGist
exports.actionPandoc = actionPandoc
exports.actionRevision = actionRevision