module.exports = (srv) => {
    const loki = require('lokijs');
    const db = new loki('DB');
    const mediaDB = db.addCollection("Media");
    const { Readable, PassThrough } = require('stream')

    srv.before('CREATE', 'Media', (req) => {
        const obj = mediaDB.insert({ media: "" });
        req.data.id = obj.$loki;
    })

    srv.on('UPDATE', 'Media', (req, next) => {
        try{ 
            const url = req._.req.path;
            if (url.indexOf("content")>0) {
                const id = req.data.id; 
                const obj = mediaDB.get(id);
                if(obj==null) {
                    req.reject(404,"No record found for the ID");
                    return;
                }
                const stream = new PassThrough();
                let chunks = [];
                stream.on('data',  (chunk) => {
                    chunks.push(chunk);
                });
                stream.on('end',  () =>{
                    obj.media = Buffer.concat(chunks).toString('base64');
                    mediaDB.update(obj);
                });
                req.data.content.pipe(stream);
            }  else return next()
        }catch(error){
            req.reject(404,"Media DB error")
            console.log(error)
            return 
        }

    })

    srv.on("READ", "Media", (req, next) => {
        try {
            const url = req._.req.path;
            if (url.indexOf("content") > 0) {
                const id = req.data.id;
                if (mediaDB.get(id) == null) {
                    req.reject(404, "Media not found for the ID");
                    return;
                }
                const decodedMedia = new Buffer(mediaDB.get(id).media.split(';base64,').pop(), 'base64');
                return _formatResult(decodedMedia);
            }
            else return next()  //> delegate to next/default handlers
        } catch (error) {
            req.reject(404, "Media DB error")
            return
        }
    })

    srv.on("DELETE", "Media", (req, next) => {
        try {
            const id = req.data.id;
            const obj = mediaDB.get(id);
            if (obj != null) {
                mediaDB.remove(obj)
            }
            return next()  //> delegate to next/default handlers
        } catch (error) {
            req.reject(404, "Media DB error ")
        }
    })

    function _formatResult(decodedMedia) {
        const readable = new Readable
        const result = new Array()
        readable.push(decodedMedia)
        readable.push(null)
        result.push({ value: readable })
        return result
    }

}