module.exports = function() {

    var module={};

    module.connection = function(socket) {

        //var sys = require('sys');
        var proc = require('child_process');

        console.log("new client");

        function emit(signal, data, info) {
            if (typeof data == 'string' && !data.match("\n")) {
                console.log("<- signal: "+signal+"("+data+")");
            } else {
                console.log("<- signal: "+signal);
            }
            if (info) console.log(info);
            socket.emit(signal, data);
        }

        function broadcast(signal, data) {
            console.log("<= signal: "+signal);
            socket.broadcast.emit(signal, data);
        }

        function exec(cmd, callback) {
            console.log("== "+cmd);
            proc.exec(cmd, callback);
        }

        function fail(txt, data) {
            console.log("** "+txt, data);
            emit("fail", txt);
        }

        function containerinspect(error, stdout, stderr) {
            if (error || stderr)
                return fail("inspect docker containers failed", {
                    error: error, stderr: stderr, stdout: stdout
                });
            emit("containers", stdout);
        }
        
        function containerlist(error, stdout, stderr) {
            if (error || stderr)
                return fail("list docker containers failed", {
                    error: error, stderr: stderr, stdout: stdout
                });
            exec("docker inspect "+stdout.trim().replace(/\n/g, " "), containerinspect);
        }

        function updatecontainers(error, stdout, stderr) {
            if (error || stderr)
                return fail("update docker container failed", {
                    error: error, stderr: stderr, stdout: stdout
                });
            exec("docker ps -aq", containerlist);
        }

        function modify(cmd, name) {
            if (!name.match(/^[a-z0-9][-_:.+a-z0-9]*$/i))
                return fail("illegal instance name", {
                    error: error, stderr: stderr, stdout: stdout
                });
            exec("docker "+cmd+" "+name, updatecontainers);
        }

        function containers() {
            console.log("-> containers");
            updatecontainers();
        }
        
        function start(name) {
            console.log("-> start("+name+")");
            modify("start", name);
        }

        function stop(name) {
            console.log("-> stop("+name+")");
            modify("stop", name);
        }

        function pause(name) {
            console.log("-> pause("+name+")");
            modify("pause", name);
        }

        function unpause(name) {
            console.log("-> unpause("+name+")");
            modify("unpause", name);
        }

        function remove(name) {
            console.log("-> remove("+name+")");
            modify("rm", name);
        }

        socket
            .on("containers", containers)
            .on("start", start)
            .on("stop", stop)
            .on("pause", pause)
            .on("unpause", unpause)
            .on("remove", remove);
                
    }
    
    return module;
}