import * as fs from 'fs'

import * as config from './config'
import * as logger from './log'

import * as express from 'express'


function getPageOptions(contentStr: string) : any {
    let pageOptions : any = {}
    try {
        let lines = contentStr.split("\n")
        let firstLine = lines[0]
        let pageOptionsStr = firstLine.replace(/^\s*<!-- (\{.+\}) -->[\s\S]*$/, "\$1")
        pageOptions = JSON.parse(pageOptionsStr)
    } catch {
        logger.info("No pageOptions found")
    }
    return pageOptions
}

function getToc() : string {
    logger.info("building toc")
    let toc : string = ""
    let posts = fs.readdirSync('./docroot/posts')
    posts.sort().reverse().forEach((v) => {
        let content = fs.readFileSync(`./docroot/posts/${v}/article.pag`)
        let contentStr = content.toString()
        let pageOptions = getPageOptions(contentStr)
        toc += `<li><a href="posts/${v}">${v} - ${pageOptions.title}</a></li>`
    })
    return toc
}




logger.info("Homepage starting")

let app = express()

let masterTmpl: string
let toc: string
let cache: any = {}



app.engine('pag', (filePath: string, options: any, callback: any) => {
    // logger.info(JSON.stringify(options))
    if (! (filePath in cache)) {
        logger.info(`${filePath} not yet in cache`)

        fs.readFile(filePath, (err, content) => {
            if (err) {
                return callback(new Error(err.message))
            }
            
            let contentStr = content.toString()
            let pageOptions = getPageOptions(contentStr)
            let renderedPhase1 = contentStr
            .replace(/#bla#/g, 'blu')
            
            let renderedPhase2 = masterTmpl
            .replace(/#maincontent#/g, renderedPhase1)
            .replace(/#base#/g, options.base)
            
            for (let key in pageOptions) {
                let value = pageOptions[key]
                if (key == 'toc' && value == 'compute') {
                    value = toc
                }
                renderedPhase2 = renderedPhase2.replace(new RegExp(`#${key}#`, 'g'), value)
            }

            cache[filePath] = renderedPhase2

            return callback(null, renderedPhase2)
        })
    } else {
        logger.info(`${filePath} served from cache`)
        return callback(null, cache[filePath])
    }
})

app.set('views', './docroot')
app.set('view engine', 'pag')

app.get('/index', (req, res) => {
    res.render('index', { "base": req.headers['x-proxy-original-url'] || "/"})
})

app.get('/posts/:date', (req, res) => {
    res.render(`posts/${req.params.date}/article`, { "base": req.headers['x-proxy-original-url'] || "/"})
})

app.get('/pages/:file', (req, res) => {
    res.render(`pages/${req.params.file}`, { "base": req.headers['x-proxy-original-url'] || "/"})
})

app.get('/', (req, res) => {
    logger.info('redirecting / to /index')
    let base = req.headers['x-proxy-original-url'] || "/"
    res.redirect(`${base}index`)
})

app.get('/reload', (req, res) => {
    logger.info('truncating cache')
    cache = {}
    toc = getToc()
    masterTmpl = fs.readFileSync('./docroot/master.tmpl').toString()
    let base = req.headers['x-proxy-original-url'] || "/"
    res.redirect(`${base}index`)
})

app.use('/files', express.static('files'))


masterTmpl = fs.readFileSync('./docroot/master.tmpl').toString()
toc = getToc()

app.listen(config.dict.httpPort, () => {
    logger.info("Homepage is listening")
})
logger.info("Homepage running")