/*
    This file is part of rhizi, a collaborative knowledge graph editor.
    Copyright (C) 2014-2015  Rhizi

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

"use strict";

var DEBUG_NODE_POSITION = false;

/**
 * core model module - currently unused
 */
define(['util'], function(util) {

    /**
     * return a random id
     */
    var random_id;

    var random_id__hash = function() {
        return Math.random().toString(36).substring(2, 10);
    };

    var random_id__seq = function () {
        var id = 0;
        function get_next() {
            var next = id;
            id += 1;
            return next;
        }
        return get_next;
    };

    function random_node_name() {
        return random_id__hash();
    }

    function init(config){
        if (config.rand_id_generator === 'hash') {
            random_id = random_id__hash;
        }
        if (config.rand_id_generator === 'seq') {
            random_id = random_id__seq();
        }
    }

    function NodePlain() {
    }
    function NodeWithNaNXTest() {
        Object.defineProperty(this, "x", {
            set: function (new_x) {
                if (isNaN(new_x) && !isNaN(this._x)) {
                    console.log('Node ' + this.id + '.x changed to Nan from ' + this._x);
                }
                this._x = new_x;
            },
            get: function () {
                return this._x;
            }
        });
    }
    if (DEBUG_NODE_POSITION) {
        Node = NodeWithNaNXTest;
    } else {
        Node = NodePlain;
    }
    Node.prototype.equals = function(other_node){
        return this.id === other_node.id;
    };

    function Link() {
    }
    // adapt Link to force_layout create __src,__dst aliases
    Link.prototype.__defineGetter__('source', function(){
        return this.__src;
    });
    Link.prototype.__defineGetter__('target', function(){
        return this.__dst;
    });

    /**
     * the most flexible way to create a node: - perform spec field validation -
     * fill-in missing spec fields
     */
    function create_node_from_spec(node_spec) {

        util.assert(undefined !== node_spec.name, 'create_node_from_spec: name missing');

        var ret = new Node();

        if (undefined !== node_spec.id) {
            // reuse id if present
            __set_obj_id(ret, node_spec.id);
        }

        // type
        if (undefined === node_spec.type) {
            console.debug('create_node_from_spec: undefined type, falling back to \'perm\'');
            node_spec.type = 'perm';
        }

        // copy spec
        for (var k in node_spec) {
            if (k === 'id') {
                continue;
            }
            ret[k] = node_spec[k];
        }

        // default values
        ret.status = ret.status || 'unknown';

        return ret;
    }

    function __set_obj_id(obj, id) {
        Object.defineProperty(obj, "id", {
            value: id,
            enumerable: true,
            writable: false
        });
    }

    /**
     * @param node_spec: id must not be defined
     */
    function create_node__set_random_id(node_spec) {
        if (undefined == node_spec) {
            node_spec = {};
        }

        var ret = create_node_from_spec(node_spec);

        util.assert(undefined == ret.id); // id must not be defined in spec
        __set_obj_id(ret, random_id());

        return ret;
    }

    function create_link__set_random_id(src, dst, link_spec) {
        var ret = create_link_from_spec(src, dst, link_spec);
        __set_obj_id(ret, random_id());
        return ret;
    }

    /**
     * determine if nodes are equal by name
     *
     * @param other_node
     * @returns {Boolean}
     */
    Node.prototype.equal_by_name = function(other) {
        ret = this.name.toLowerCase() == other.name.toLowerCase();
        if (false == ret) {
            console.debug(this.id + ' != ' + other.id);
        }
        return ret;
    };

    function create_link_from_spec(src, dst, link_spec) {
        var ret = new Link();

        if (undefined !== link_spec.id) {
            // reuse id if present
            __set_obj_id(ret, link_spec.id);
        }

        util.assert(undefined != src, 'create_link_from_spec: src missing');
        util.assert(undefined != dst, 'create_link_from_spec: dst missing');
        util.assert(undefined != src.id, 'create_link_from_spec: src missing id');
        util.assert(undefined != dst.id, 'create_link_from_spec: dst missing id');
        util.assert(undefined != link_spec.name, 'create_link_from_spec: name missing, unable to deduce type');

        ret.__src = src;
        ret.__dst = dst;
        ret.__type = link_spec.name;

        if (undefined == link_spec.name){
            console.warn('create_link_from_spec: name: ' + link_spec.name);
            link_spec.name = "";
        }
        ret.name = link_spec.name.trim();

        ret.state = link_spec.state;
        return ret;
    }

    /**
     * determine if links are equal by ID
     *
     * @param other_node
     * @returns {Boolean}
     */
    Link.prototype.equal_by_id = function(other) {
        return this.id.toLowerCase() == other.id.toLowerCase();
    };

    return {
        init : init,
        Node: Node, // allow model adaptation
        Link: Link, // allow model adaptation
        random_node_name : random_node_name,
        create_node_from_spec : create_node_from_spec,
        create_node__set_random_id : create_node__set_random_id,
        create_link_from_spec : create_link_from_spec,
        create_link__set_random_id : create_link__set_random_id,
    };
});