'use strict';

var vsm = require('lrs/virtualServerModule');
var parseRange = require('range-parser');

// Change config as needed.
var config = {
    vs: 'vs_http',           // name of virtual-server
    max_range_value: 1e9,    // 1 GB
    max_ranges: 10
};

function bail_4xx(servResp, code, message) {
    code = code || 404;
    message = message || '';
    servResp.writeHead(code);
    servResp.end(message); 
    return;
}

function onRequest(servReq, servResp, cliReq) {
    if ('range' in servReq.headers) {

        // parse range header
        var range = parseRange(1e12, servReq.headers.range);

        // check from parsing error code
        if (typeof range  === 'number' && range < 0) {
            bail_4xx(servResp, 416, 'Malformed header or invalid range');
            return;
        }

        // check if number of ranges exceeds max
        if (range.length > config.max_ranges) {
            bail_4xx(servResp, 416, 'Too many ranges');
            return;
        }

        // check if range values exceed max
        if (range.type === 'bytes') {
            for(var i = 0; i < range.length; i++) {
                if (r.start > config.max_range_value || r.end > config.max_range_value) {
                    bail_4xx(servResp, 416, 'Range value exceeds allowed maximum');   
                    return;
                }
            }
        }
    }

    // all checks passed; process the request
    cliReq();
}

vsm.on('exist', config.vs, function(vs) {
    console.log("Script '" + __scriptname +
                "' installed on Virtual Server '" +
                vs.id + "'");
    vs.on('request', onRequest);
});