const express = require('express')
const app = express();
const fs = require('fs')
const port = 90;


function videoStream(expressApp, cameraOptions, resourcePath, isVerbose){
        const raspberryPiCamera = require('raspberry-pi-camera-native');

        if(!cameraOptions){
            cameraOptions = {
                width: 640,
                height: 480,
                fps: 16,
                encoding: 'JPEG',
                quality: 7
            };
        }

        // start capture
        raspberryPiCamera.start(cameraOptions);
        if(isVerbose) {
            console.log('Camera started.');
        }

        if(typeof resourcePath === 'undefined' || !resourcePath){
            resourcePath = '/stream.mjpg';
        }

        expressApp.get(resourcePath, (req, res) => {

            res.writeHead(200, {
                'Cache-Control': 'no-store, no-cache, must-revalidate, pre-check=0, post-check=0, max-age=0',
                Pragma: 'no-cache',
                Connection: 'close',
                'Content-Type': 'multipart/x-mixed-replace; boundary=--myboundary'
            });
            if(isVerbose)
                console.log('Accepting connection: '+req.hostname);

            // add frame data event listener
        
            let isReady = true;
        
            let frameHandler = (frameData) => {
                try{
                    if(!isReady){
                        return;
                    }
        
                    isReady = false;
        
                    if(isVerbose)
                        console.log('Writing frame: '+frameData.length);

                    res.write('--myboundary\nContent-Type: image/jpg\nContent-length: ${frameData.length}\n\n');
                    res.write(frameData, function(){
                        isReady = true;
                    });
        
        
                }
                catch(ex){
                    if(isVerbose)
                        console.log('Unable to send frame: '+ex);
                }
            }
        
            let frameEmitter = raspberryPiCamera.on('frame', frameHandler);
        
            req.on('close', ()=>{
                frameEmitter.removeListener('frame', frameHandler);

                if(isVerbose)
                    console.log('Connection terminated: '+req.hostname);
            });
        });
    }


videoStream(app, {
        width: 640,
        height: 480,
        fps: 16,
        encoding: 'JPEG',
        quality: 6 // lower is faster, less quality
    }, 
    '/stream.mjpg', true);

app.use(express.static(__dirname+'/public'));
app.listen(port, () => console.log(`App listening on port ${port}! In your web browser, navigate to https://lucy-cam.odbornaskola.cz/ or http://<IP_ADDRESS_OF_THIS_SERVER>:90`));