const express = require('express')
const fs = require('fs')

const app = express()
const cors = require("cors");


const videoFileMap={
    'cdn':'videos/v1.mp4',
    'generate-pass':'videos/v2.mp4',
    'get-post':'videos/v3.mp4',
}

console.log("Finding File");

var corsOptions = {
    origin: 'http://127.0.0.1:3000/',
    optionsSuccessStatus: 200 // some legacy browsers (IE11, various SmartTVs) choke on 204
}

app.use(cors(corsOptions));
 //   ,cors(corsOptions)

app.get('/videos/:filename', (req, res)=>{
    const fileName = req.params.filename;
    const filePath = videoFileMap[fileName]
    if(!filePath){
        console.log("Finding File Not Found ", filePath);
        return res.status(404).send('File not found')
    }

    console.log("Finding File Found ", filePath);

    const stat = fs.statSync(filePath);
    const fileSize = stat.size;
    const range = req.headers.range;

    if(range){
        const parts = range.replace(/bytes=/, '').split('-')
        const start = parseInt(parts[0], 10);
        const end = parts[1] ? parseInt(parts[1], 10) : fileSize - 1;

        const chunksize = end - start + 1;
        const file = fs.createReadStream(filePath, {start, end});
        const head = {
            'Content-Range': `bytes ${start}-${end}/${fileSize}`,
            'Accept-Ranges': 'bytes',
            'Content-Length': chunksize,
            'Content-Type': 'video/mp4'
        };
        res.writeHead(206, head);
        file.pipe(res);
    }
    else{
        const head = {
            'Content-Length': fileSize,
            'Content-Type': 'video/mp4'
        };
        res.writeHead(200, head);
        fs.createReadStream(filePath).pipe(res)
    }
})

app.listen(3036, ()=>{
    console.log('server is listening on post 3036')
})