var net = require('net');
var events = require('events');

var binpack = require('/usr/lib/node_modules/binpack');

var util = require('./util.js');


var SubscriptionCounter = function(){
    var count = 0;
    var padding = 'deadbeefdeadbeef';
    return {
        next: function(){
            count++;
            if (Number.MAX_VALUE == count) count = 0;
            return padding + binpack.packUInt64(count, 'big').toString('hex');
        }
    };
};

var StratumClient = function(options){

    //private members

    var _this = this;

    (function init(){
        setupSocket();
    })();

    function handleMessage(message){
        switch(message.method){
            case 'mining.subscribe':
                handleSubscribe(message);
                break;
            case 'mining.authorize':
                handleAuthorize(message);
                break;
            case 'mining.submit':
                handleSubmit(message);
                break;
            default:
                console.dir('unknown stratum client message: ' + message);
                break;
        }
    }

    function handleSubscribe(message){
        _this.emit('subscription',
            {},
            function(extraNonce1, extraNonce2Size){
                _this.extraNonce = extraNonce1;
                sendJson({
                    id: message.id,
                    result: [
                        ["mining.notify", options.subscriptionId],
                        extraNonce1,
                        extraNonce2Size
                    ],
                    error: null
                });
            }
        );
    }

    function handleAuthorize(message){
        _this.emit('authorize',
            {
                name: message.params[0][0],
                password: message.params[0][1]
            },
            function(authorized){
                sendJson({
                    id: message.id,
                    result: authorized,
                    error: null
                });
            }
        );
    }

    function handleSubmit(message){
        _this.emit('submit',
            {
                name: message.params[0],
                jobId: message.params[1],
                extraNonce2: message.params[2],
                nTime: message.params[3],
                nonce: message.params[4]
            },
            function(accepted){
                sendJson({
                    id: message.id,
                    result: accepted,
                    error: null
                });
            }
        );
    }

    function sendJson(){
        var response = '';
        for (var i = 0; i < arguments.length; i++){
            response += JSON.stringify(arguments[i]) + '\n';
        }
        console.log('response: ' + response);
        options.socket.write(response);
    }

    function setupSocket(){
        var socket = options.socket;
        var dataBuffer = '';
        socket.setEncoding('utf8');
        socket.on('data', function(d){
            console.log('request: ' + d);
            dataBuffer += d;
            if (dataBuffer.slice(-1) === '\n'){
                var messages = dataBuffer.split('\n');
                messages.forEach(function(message){
                    var messageJson;
                    try{
                        messageJson = JSON.parse(message);
                    }
                    catch(e){
                        console.log('could not parse stratum client socket message: ' + message);
                    }
                    if (messageJson)
                        handleMessage(messageJson);
                });
                dataBuffer = '';
            }
        });
        socket.on('end', function() {
            _this.emit('socketDisconnect')
            console.log('stratum client disconnected');
        });
        socket.on('error', function(){
            _this.emit('socketError');
            console.log('stratum client socket error');
        });
    }


    //public members

    this.sendDifficulty = function(difficulty){
        sendJson({
            id: null,
            method: "mining.set_difficulty",
            params: [difficulty]//[512],
        });
    };
    this.sendMiningJob = function(jobParams){
        sendJson({
            id: null,
            method: "mining.notify",
            params: jobParams
        });
    };
};
StratumClient.prototype.__proto__ = events.EventEmitter.prototype;



var StratumServer = exports.Server = function StratumServer(options){

    //private members

    var _this = this;
    var _socketServer;
    var _stratumClients = {};
    var _subscriptionCounter = SubscriptionCounter();

    (function init(){
        _socketServer = socketServer = net.createServer(function(c){
            var subscriptionId = _subscriptionCounter.next();
            var client = new StratumClient({subscriptionId: subscriptionId, socket: c});
            _stratumClients[subscriptionId] = client;
            _this.emit('client', client);
        });
        _socketServer.listen(options.port, function(){});
    })();


    //public members

    this.broadcastMiningJobs = function(jobParams){
        for (var clientId in _stratumClients){
            _stratumClients[clientId].sendMiningJob(jobParams)
        }
    };
};
StratumServer.prototype.__proto__ = events.EventEmitter.prototype;