// Call SimpleButton to wire an HTML button (typically an <img> tag) to a JS callback

// 

// (As opposed to ActionButton which is served all the way through QT Actions)

//

// Params:

//   id - the id of the button.  Ex:  <img id="buttonId" .../>

//   upImg - the path to the "up" image for the button.

//   downImg - the path to the "down" image for the button.  Note: not yet working...

//   disabledImg - the path to the "disabled" image for the button.

//   handler - the javascript callback to be called when triggered

//

function SimpleButton(id, upImg, downImg, disabledImg, handler) {

    this.id = id;

    this.upImg = upImg;

    this.downImg = downImg;

    this.disabledImg = disabledImg;

    this.handler = handler;

    this.isDown = false;

    this.enabled = true;

    // attach this class to the item as "button" for later access

    // delete/cleanup existing button (if any) and attach this as button

    dom = document.getElementById(this.id);

    if(dom.button) {

        delete dom.button;

    }

    dom.button = this;

    this.element = function() {

        return document.getElementById(this.id);

    }

    this.updateImages = function(upImg, downImg, disabledImg) {

        this.upImg = upImg;

        this.downImg = downImg;

        this.disableImg = disabledImg;

        this.updateButton();

    }

    this.updateButton = function() {

        if(this.enabled) {

            if(this.isDown) {

                this.element().src = this.downImg;

            }

            else {

                this.element().src = this.upImg;

            }

        }

        else {

            this.element().src = this.disabledImg;

        }

    }

    this.setEnabled = function(state) {

        this.enabled = state;

        this.updateButton();

    }

    // Make sure we can find the element.

    if(!this.element()) {

        alert("SimpleButton: element not found, " + id);

        return;

    }

// Commented out because onclick is not reliable.  Slight movements between mouse down

// and mouse up seem to cancel the onclick.

//    this.onClick = function() {

//        //window.chrome.alert("SimpleButton::onClick: " + this);

//        this.handler();

//    }

    this.onMouseDown = function() {

        //window.chrome.alert("SimpleButton::onMouseDown " + this);

        this.isDown = true;

        this.updateButton.call(this);

    }

    this.onMouseUp = function() {

        //window.chrome.alert("SimpleButton::onMouseUp " + this);

        this.isDown = false;

        this.updateButton.call(this);

        this.handler();

    }

    this.onMouseOut = function() {

        //window.chrome.alert("SimpleButton::onMouseOut " + this);

        if (this.isDown ) {

            this.isDown = false;

            this.updateButton.call(this);

        }

    }

    // Set up element event handlers.

    this.element().onmousedown = this.onMouseDown.bind(this);

    this.element().onmouseup = this.onMouseUp.bind(this);

    this.element().onmouseout = this.onMouseOut.bind(this);

//    this.element().onclick = this.onClick.bind(this);

    // Set the initial state of the button.

    this.updateButton();

}