/*
 * Copyright (C) 2017, 2018 "IoT.bzh"
 * Author: José Bollo <jose.bollo@iot.bzh>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
AFB = function(base, initialtoken){

if (typeof base != "object")
    base = { base: base, token: initialtoken };

var initial = {
    base: base.base || "api",
    token: base.token || initialtoken || "HELLO",
    host: base.host || window.location.host,
    url: base.url || undefined
};

var urlws = initial.url || "ws://"+initial.host+"/"+initial.base;

/*********************************************/
/****                                     ****/
/****             AFB_context             ****/
/****                                     ****/
/*********************************************/
var AFB_context;
{
    var UUID = undefined;
    var TOKEN = initial.token;

    var context = function(token, uuid) {
        this.token = token;
        this.uuid = uuid;
    }

    context.prototype = {
        get token() {return TOKEN;},
        set token(tok) {if(tok) TOKEN=tok;},
        get uuid() {return UUID;},
        set uuid(id) {if(id) UUID=id;}
    };

    AFB_context = new context();
}
/*********************************************/
/****                                     ****/
/****             AFB_websocket           ****/
/****                                     ****/
/*********************************************/
var AFB_websocket;
{
    var CALL = 2;
    var RETOK = 3;
    var RETERR = 4;
    var EVENT = 5;

    var PROTO1 = "x-afb-ws-json1";

    AFB_websocket = function(on_open, on_abort) {
        var u = urlws, p = '?';
        if (AFB_context.token) {
            u = u + '?x-afb-token=' + AFB_context.token;
            p = '&';
        }
        if (AFB_context.uuid)
            u = u + p + 'x-afb-uuid=' + AFB_context.uuid;
        this.ws = new WebSocket(u, [ PROTO1 ]);
        this.url = u;
        this.pendings = {};
        this.awaitens = {};
        this.counter = 0;
        this.ws.onopen = onopen.bind(this);
        this.ws.onerror = onerror.bind(this);
        this.ws.onclose = onclose.bind(this);
        this.ws.onmessage = onmessage.bind(this);
        this.onopen = on_open;
        this.onabort = on_abort;
    }

    function onerror(event) {
        var f = this.onabort;
        if (f) {
            delete this.onopen;
            delete this.onabort;
            f && f(this);
        }
        this.onerror && this.onerror(this);
    }

    function onopen(event) {
        var f = this.onopen;
        delete this.onopen;
        delete this.onabort;
        f && f(this);
    }

    function onclose(event) {
        var err = {
            jtype: 'afb-reply',
            request: {
                status:    'disconnected',
                info: 'server hung up'
            }
        };
        for (var id in this.pendings) {
            try { this.pendings[id][1](err); } catch (x) {/*NOTHING*/}
        }
        this.pendings = {};
        this.onclose && this.onclose();
    }

    function fire(awaitens, name, data) {
        var a = awaitens[name];
        if (a)
            a.forEach(function(handler){handler(data);});
        var i = name.indexOf("/");
        if (i >= 0) {
            a = awaitens[name.substring(0,i)];
            if (a)
                a.forEach(function(handler){handler(data);});
        }
        a = awaitens["*"];
        if (a)
            a.forEach(function(handler){handler(data);});
    }

    function reply(pendings, id, ans, offset) {
        if (id in pendings) {
            var p = pendings[id];
            delete pendings[id];
            try { p[offset](ans); } catch (x) {/*TODO?*/}
        }
    }

    function onmessage(event) {
        var obj = JSON.parse(event.data);
        var code = obj[0];
        var id = obj[1];
        var ans = obj[2];
        AFB_context.token = obj[3];
        switch (code) {
        case RETOK:
            reply(this.pendings, id, ans, 0);
            break;
        case RETERR:
            reply(this.pendings, id, ans, 1);
            break;
        case EVENT:
        default:
            fire(this.awaitens, id, ans);
            break;
        }
    }

    function close() {
        this.ws.close();
        this.ws.onopen =
        this.ws.onerror =
        this.ws.onclose =
        this.ws.onmessage =
        this.onopen =
        this.onabort = function(){};
    }

    function call(method, request, callid) {
        return new Promise((function(resolve, reject){
            var id, arr;
            if (callid) {
                id = String(callid);
                if (id in this.pendings)
                    throw new Error("pending callid("+id+") exists");
            } else {
                do {
                    id = String(this.counter = 4095 & (this.counter + 1));
                } while (id in this.pendings);
            }
            this.pendings[id] = [ resolve, reject ];
            arr = [CALL, id, method, request ];
            if (AFB_context.token) arr.push(AFB_context.token);
            this.ws.send(JSON.stringify(arr));
        }).bind(this));
    }

    function onevent(name, handler) {
        var id = name;
        var list = this.awaitens[id] || (this.awaitens[id] = []);
        list.push(handler);
    }

    AFB_websocket.prototype = {
        close: close,
        call: call,
        onevent: onevent
    };
}
/*********************************************/
/****                                     ****/
/****                                     ****/
/****                                     ****/
/*********************************************/
return {
    context: AFB_context,
    ws: AFB_websocket
};
};
