var Node = require("./node"),
    Selector = require("./selector");

var Extend = function Extend(selector, option, index, currentFileInfo, visibilityInfo) {
    this.selector = selector;
    this.option = option;
    this.index = index;
    this.object_id = Extend.next_id++;
    this.parent_ids = [this.object_id];
    this.currentFileInfo = currentFileInfo || {};
    this.copyVisibilityInfo(visibilityInfo);

    switch(option) {
        case "all":
            this.allowBefore = true;
            this.allowAfter = true;
            break;
        default:
            this.allowBefore = false;
            this.allowAfter = false;
            break;
    }
};
Extend.next_id = 0;

Extend.prototype = new Node();
Extend.prototype.type = "Extend";
Extend.prototype.accept = function (visitor) {
    this.selector = visitor.visit(this.selector);
};
Extend.prototype.eval = function (context) {
    return new Extend(this.selector.eval(context), this.option, this.index, this.currentFileInfo, this.visibilityInfo());
};
Extend.prototype.clone = function (context) {
    return new Extend(this.selector, this.option, this.index, this.currentFileInfo, this.visibilityInfo());
};
//it concatenates (joins) all selectors in selector array
Extend.prototype.findSelfSelectors = function (selectors) {
    var selfElements = [],
        i,
        selectorElements;

    for (i = 0; i < selectors.length; i++) {
        selectorElements = selectors[i].elements;
        // duplicate the logic in genCSS function inside the selector node.
        // future TODO - move both logics into the selector joiner visitor
        if (i > 0 && selectorElements.length && selectorElements[0].combinator.value === "") {
            selectorElements[0].combinator.value = ' ';
        }
        selfElements = selfElements.concat(selectors[i].elements);
    }

    this.selfSelectors = [new Selector(selfElements)];
    this.selfSelectors[0].copyVisibilityInfo(this.visibilityInfo());
};
module.exports = Extend;
