const express = require('express');
// A genareted db with all the pages
const siteMap = require('./siteMap');
// All compilers for all page source types
const compile = require('./compile');
const settings = require('./settings');

console.log("siteMap:", siteMap) //DEBUG

// create webserver
const app = express()
app.set('view engine', 'ejs');
app.set('views', __dirname + '/views')

//TODO: make the uri routing more universal. Probebly ad the siteMap creation
// routing
app.use('/:vak/static', renderStatic)
app.use('/:vak/:page', renderPage)
app.use('/:vak', renderVak)
app.use('/', renderIndex)
app.use(render404)

/** This function can be used for as callback for errors
 * 
 * @param {Req} req Request object from Express.
 * @param {Res} res Responce object from Express.
 * @param {Function} next The next function from Espress.
 * 
 * @returns {Function(err)} a function that renders the 404 page if err is true.
 */
function onError404(req, res, next){
  return function(err){
    if(err)
      render404(req, res, next)
  }
}

/** Render static content
 * 
 * looks for the content in the folder static
 * 
 * @param {Req} req Request object from Express.
 * @param {Res} res Responce object from Express.
 * @param {Function} next The next function from Espress.
 */
function renderStatic(req, res, next){
  if(typeof siteMap[req.params.vak] == 'undefined') return next();
  vak = siteMap[req.params.vak]

  dir = __dirname.split('/'); dir.pop() // remove dir of this code
  dir = `${dir.join('/')}/${vak.title}/notes/static${req.path}`

  res.sendFile(dir, onError404(req, res, next))
}

/** Render a normal page
 * 
 * lookup the page in siteMap db and renders the page
 * 
 * @param {Req} req Request object from Express.
 * @param {Res} res Responce object from Express.
 * @param {Function} next The next function from Espress.
 */
function renderPage(req, res, next){
  if(typeof siteMap[req.params.vak] == 'undefined') return next();
  vak = siteMap[req.params.vak]

  if(typeof vak.pages[req.params.page] == 'undefined') return next();
  page = vak.pages[req.params.page]


  compile(page, function(html){
    if(typeof html != 'string'){ return next() }

    res.render('main', {
      siteMap,
      title: "notes",
      topNav: vak.pages,
      vak: req.params.vak,
      page: req.params.page,
      main: html
    })
  })
}

/** Render the index of a topic
 * 
 * lookup the topic in siteMap db and renders the index.
 * if the index is not set it set the topic name as headers on the page.
 * 
 * @param {Req} req Request object from Express.
 * @param {Res} res Responce object from Express.
 * @param {Function} next The next function from Espress.
 */
function renderVak(req, res, next){
  if(typeof siteMap[req.params.vak] == 'undefined') return next();
  vak = siteMap[req.params.vak]

  if(vak.index == null){ // no index page for this topic
    res.render('main', {
      siteMap,
      title: "notes",
      topNav: vak.pages,
      vak: req.params.vak,
      main: `<h1>${vak.title}</h1>` // default index page
    })
  }else{
    compile(vak.index, function(html){
      if(typeof html != 'string'){ return next() }

      res.render('main', {
        siteMap,
        title: "notes",
        topNav: vak.pages,
        vak: req.params.vak,
        main: html
      }, onError404(req, res, next))
    })
  }
}

//TODO: remove playholder and acualy create the renderIndex function
/** Render the index of the site
 * 
 * lookup the index in siteMap db and renders the index.
 * if the index is not set it set the topic name as headers on the page.
 * 
 * @param {Req} req Request object from Express.
 * @param {Res} res Responce object from Express.
 * @param {Function} next The next function from Espress.
 */
function renderIndex(req, res, next){
  res.render('main', {
    siteMap,
    title: "notes",
    topNav: siteMap,
    main: "<h1>Hoi</h1>"
  }, onError404(req, res, next))
}

//TODO: add a custom or smarter 404 page
/** Render the 404 page
 * 
 * renders a simple 404 page.
 * 
 * @param {Req} req Request object from Express.
 * @param {Res} res Responce object from Express.
 * @param {Function} next The next function from Espress.
 */
function render404(req, res, next){
  res.status(404)
  res.render('main', {
    siteMap,
    title: "notes",
    topNav: vak.pages,
    vak: req.params.vak,
    main: "<h1>404 - Page not found</h1>"
  }, (err) => {
    if(err){
      res.send("<h1>404 - Page not found</h1>")
    }
  })
}

// start the actial web server
app.listen(settings.serverPort, ()=>{console.log("server listening on port", settings.serverPort)})