let register = Toolkit => Toolkit.Radio =

// Radio button group manager
class Radio extends Toolkit.Checkbox {

    ///////////////////////// Initialization Methods //////////////////////////

    constructor(app, options) {
        super(app, options = Object.assign({
            class: "tk radio",
            role : "radio"
        }, options || {}));

        // Configure instance fields
        this._group = null;

        // Configure options
        if ("group" in options)
            this.group = options.group;
        if ("checked" in options) {
            this.checked = false;
            this.checked = options.checked;
        }

    }



    ///////////////////////////// Event Handlers //////////////////////////////

    // Key press
    onKeyDown(e) {

        // Error checking
        if (e.altKey || e.ctrlKey || e.shiftKey || this.disabled)
            return;

        // Processing by key
        let item = null;
        switch (e.key) {

            // Activate the radio button
            case " ":
            case "Enter":
                this.checked = true;
                break;

            // Focus the next button in the group
            case "ArrowDown":
            case "ArrowRight":
                if (this.group == null)
                    return;
                item = this.group.next(this);
                break;

            // Focus the previous button in the group
            case "ArrowLeft":
            case "ArrowUp":
                if (this.group == null)
                    return;
                item = this.group.previous(this);
                break;

            default: return;
        }

        // Select and focus another item in the group
        if (item != null && item != this) {
            this.group.active = item;
            item.focus();
            item.element.dispatchEvent(new Event("input"));
        }

        Toolkit.handle(e);
    }



    ///////////////////////////// Public Methods //////////////////////////////

    // The check box is checked
    get checked() { return super.checked; }
    set checked(checked) {
        super.checked = checked;
        if (this.group != null && this != this.group.active && checked)
            this.group.active = this;
    }

    // Managing radio button group
    get group() { return this._group; }
    set group(group) {
        if (group == this.group)
            return;
        if (group)
            group.add(this);
        this._group = group ? group : null;
    }



    ///////////////////////////// Private Methods /////////////////////////////

    // Specify the checked state
    setChecked(checked) {
        if (!checked || this.checked)
            return;
        this.checked = true;
        this.element.dispatchEvent(new Event("input"));
    }

}

export { register };