var Transform = require("stream").Transform;

/**
 * A Transform Stream implementation that output full VNB protocol messages
 * 
 * @constructor
 * @this {VNBMessageParser}
 */
function VNBMessageTransform(opts) {
    "use strict";
    Transform.call(this,opts);

    var buffer;

    /**
     * Transform stream Write implementation
     * @param {string} data Upstream data already converted as string
     * @param {string} encoding String encoding (should be utf8, but should be checked upward)
     * @param {function} callback Downstream Stream receiving only full VNB messages
     **/
    this._transform = function(data, encoding, callback) {
        var endpos = data.indexOf("\n");

        if (endpos > -1) {
            if (buffer !== undefined) {
                this.push(buffer);
                buffer = undefined;
            }

            if (endpos > 0) {
                this.push(data.substr(0, endpos));
            }
            callback();

            if (endpos < data.length - 1) {
                buffer = data.substr(endpos + 1);
            }
        }
        else {
            buffer = buffer.concat(data);
        }
    };

    /**
     * Flush still data. Remaining data is lost since it can only be an incomplete message
     * @param {function} callback Callback to call when data has been flushed 
     **/
    this._flush = function (callback) {
        buffer = undefined;
        callback(); 
    };
}


/**
 * VNB Client implementation (communication from vim to the netbeans server)
 * @constructor
 * @this {VNBMessageClient}
 * @param {stream.Readable} data Incomming stream
 * @param {function} onEvent Callback function called when an Event message is received
 * @param {function} onReply Callback function called when a Reply to a previous Function called is received
 */
function VNBMessageClient(data, onEvent, onReply) {
    "use strict";
    
    data.setEncoding("utf8");

    var messageTransform = new VNBMessageTransform();
    
    messageTransform.on("data",function (message) {
        var iName = 0;      //Index of the name separator in case of an Event
        var iSeqno = 0;     //Index of the seqno separator in case of an Event

        //Header of the message
        for (var i = 0 ; i < message.length && message[i] !== " "; ++i) {
            if (message[i] === ":") {
                iName = i;
            }
            else if (message[i] === "=") {
                iSeqno = i;
            }
        }

        var isEvent = false;
        var args = [];

        if (iName > 0 && iSeqno > 0) {
            isEvent = true;
            args.push(Number.parseInt(message.substr(0, iName), 10));
            args.push(message.substring(iName + 1, iSeqno));
            args.push(Number.parseInt(message.substring(iSeqno + 1, i), 10));
        }
        else if (iName === 0 && iSeqno === 0) {
            args.push(Number.parseInt(message.substr(0, i), 10));
        }
        else {
            //Unknown message type
        }
        
        //Arguments of the message
        for (++i ; i < message.length ; ++i) {
            
        }

        if (isEvent) {
            onEvent(...args);            
        }
        else {
            onReply(...args);
        }
    });

    messageTransform.on("error", function (error) {

    });

    messageTransform.on("end",function () {

    });

    messageTransform.on("close", function () {

    });


    data.pipe(messageTransform);

    
}