const router = require('express').Router()
const mcache = require('memory-cache')
const md = require('markdown-it')({ html: true, typographer: true })
    md.use(require('markdown-it-anchor'), {permalink: true, level: 2, permalinkBefore: true, permalinkSymbol: "§"})
    md.use(require('markdown-it-title'), 0)
    md.use(require('markdown-it-attrs'))
const fs = require('fs')
const path = require('path')

module.exports = (plugin, app) => {
  const cache = function(duration) {
    return function(req, res, next) {
      let key = '__'+app.live.conf['shortname']+'__' + req.originalUrl || req.url
      let cached = mcache.get(key)
      if (cached) {
        res.send(cached)
        return
      } else {
        res.sendResponse = res.send
        res.send = function(body) {
          mcache.put(key, body, duration * 60 * 1000 )
          res.sendResponse(body)
        }
        next()
      }
    }
  }
  
  router.get('*', cache(1), async function(req, res) {
    let target = req.path
    if (target === "/") {                                 // Root
      target = '/index'
    } else if (target.charAt(target.length-1) == '/') { // Directory Index
      target = target.substring(0, target.length-1)
    }
  
    let md_file = path.join(app.config.srd, target+'.md')
    let json_file = path.join(app.config.srd, target+'.json')
  
    let output = ''
    let env    = {}
    let title  = ''
    let crumbs = target.split('/')

    // Attempt to read md
    try {
      // Process source data.
      let data = await fs.promises.readFile(md_file)
      // make a local copy of our dictionary and remove the current page, if existing
      let local_dictionary = Object.assign({}, app.live.dictionary)
      delete local_dictionary[crumbs[crumbs.length-1]]
      let text
      if (Object.keys(local_dictionary).length !== 0) {
        // replace words using our local dictionary
        let regexp = RegExp ('[^\[(]\\b(' + Object.keys (local_dictionary).join ('|') + ')\\b', 'g')
        text = data.toString().replace(regexp, function (_, word) { return _.charAt(0)+local_dictionary[word] })
      } else {
        text = data.toString()
      }

      output = md.render(text, env)
      title = env.title
    } catch(err) {
      output = '404'
      title  = '404'
    }

    // Check for json extra
    let extra = {
      scripts: [],
      styles: [],
    }
    try {
      let data = await fs.promises.readFile(json_file)
      extra = {...extra, ...JSON.parse(data)}
    } catch(err) {
      if (err.code !== 'ENOENT') {
        plugin.error(err)
      }
    }

    // build the location
    let loc = '<a href="/">'+app.live.conf['shortname']+'</a>'
    for (let i = 1; i < crumbs.length; i++) {
      if (crumbs[i] == '') continue
      loc += ' &#8594 <a href="'+crumbs.slice(0,i).join('/')+'/'+crumbs[i]+'">'+(i == crumbs.length-1 ? env.title : crumbs[i].replace('-', ' '))+'</a>'
    }

    // render with the engine
    res.render('index', {
      content: output,
      menu: app.live.menu,
      location: loc,
      title: (title != 'index' ? title : ''),
      www_name: app.live.conf.www_name,
      www_copyright: app.live.conf.www_copyright,
      scripts: extra.scripts,
      styles: extra.styles,
    })
  })

  return router
}