// Variables à changer
var upH = 14; // Hauteur de up-arrow
var upW = 12; // Largeur de up-arrow
var downH = 13; // Hauteur de down-arrow
var downW = 12; // Largeur de down-arrow
var dragH = 11; // Hauteur du dragbar
var dragW = 11; // Largeur du dragbar
var scrollH = 150; // Hauteur du scroll
var speed = 5; // Vitesse du scroll

// Ne rien Toucher à partir d'ici

// Browser detection
var dom = document.getElementById ? true:false;
var nn4 = document.layers ? true:false;
var ie4 = document.all ? true:false;

var mouseY; // Mouse Y position onclick
var mouseX; // Mouse X position onclick

var clickUp = false; // If click on up-arrow
var clickDown = false; // If click on down-arrow
var clickDrag = false; // If click on scrollbar
var clickAbove = false; // If click above scrollbar
var clickBelow = false; // If click below scrollbar

var timer = setTimeout("",500); // Repeat variable
var upL; // Up-arrow X
var upT; // Up-arrow Y
var downL; // Down-arrow X
var downT; // Down-arrow Y
var dragL; // Scrollbar X
var dragT; // Scrollbar Y
var rulerL; // Ruler X
var rulerT; // Ruler Y
var contentT; // Content layer Y;
var contentH; // Content height
var contentClipH; // Content clip height
var scrollLength; // Number of pixels scrollbar should move
var startY; // Keeps track of offset between mouse and span

// Mousedown
function down(e){
    if((document.layers && e.which!=1) || (document.all && event.button!=1)) return true; // Enables the right mousebutton
    getMouse(e);
    startY = (mouseY - dragT);
    
// If click on up-arrow
    if(mouseX >= upL && (mouseX <= (upL + upW)) && mouseY >= upT && (mouseY <= (upT + upH))){
        clickUp = true;
        return scrollUp();
    }
// Else if click on down-arrow
    else if(mouseX >= downL && (mouseX <= (downL + downW)) && mouseY >= downT && (mouseY <= (downT + downH))){
        clickDown = true;
        return scrollDown();
    }
// Else if click on scrollbar
    else if(mouseX >= dragL && (mouseX <= (dragL + dragW)) && mouseY >= dragT && (mouseY <= (dragT + dragH))){
        clickDrag = true;
        return false;
    }
    else if(mouseX >= dragL && (mouseX <= (dragL + dragW)) && mouseY >= rulerT && (mouseY <= (rulerT + scrollH))){
// If click above drag
        if(mouseY < dragT){
            clickAbove = true;
            clickUp = true;
            return scrollUp();
        }
// Else click below drag
        else{
            clickBelow = true;
            clickDown = true;
            return scrollDown();
        }
    }
// If no scrolling is to take place
    else{
        return true;
    }
}

// Drag function
function move(e){
    if(clickDrag && contentH > contentClipH){
        getMouse(e);
        dragT = (mouseY - startY);
        
        if(dragT < (rulerT))
            dragT = rulerT;
        if(dragT > (rulerT + scrollH - dragH))
            dragT = (rulerT + scrollH - dragH);
        
        contentT = ((dragT - rulerT)*(1/scrollLength));
        contentT = eval('-' + contentT);

        moveTo();

        // So ie-pc doesn't select gifs
        if(ie4)
            return false;
    }
}

function up(){
    clearTimeout(timer);
    // Resetting variables
    clickUp = false;
    clickDown = false;
    clickDrag = false;
    clickAbove = false;
    clickBelow = false;
    return true;
}

// Reads content layer top
function getT(){
    if(ie4)
        contentT = document.all.content.style.pixelTop;
    else if(nn4)
        contentT = document.contentClip.document.content.top;
    else if(dom)
        contentT = parseInt(document.getElementById("content").style.top);
}

// Reads mouse X and Y coordinates
function getMouse(e){
    if(ie4){
        mouseY = event.clientY + document.body.scrollTop;
        mouseX = event.clientX + document.body.scrollLeft;

    } else if(nn4 || dom){
        mouseY = e.pageY;
        mouseX = e.pageX;
    }
}

// Moves the layer
function moveTo(){
    if(ie4) {
        document.all.content.style.top = contentT;
        document.all.ruler.style.top = dragT;
        document.all.drag.style.top = dragT;

    } else if(nn4) {
        document.contentClip.document.content.top = contentT;
        document.ruler.top = dragT;
        document.drag.top = dragT;

    } else if(dom) {
        document.getElementById("content").style.top = contentT + "px";
        document.getElementById("drag").style.top = dragT + "px";
        document.getElementById("ruler").style.top = dragT + "px";
    }
}

// Scrolls up
function scrollUp(){
    getT();

    if(clickAbove){
        if(dragT <= (mouseY-(dragH/2)))
            return up();
    }
    
    if(clickUp){
        if(contentT < 0){
            dragT = dragT - (speed*scrollLength);

            if(dragT < (rulerT))
                dragT = rulerT;

            contentT = contentT + speed;
            if(contentT > 0)
                contentT = 0;

            moveTo();
            timer = setTimeout("scrollUp()",25);
        }
    }
    return false;
}

// Scrolls down
function scrollDown(){
    getT();

    if(clickBelow){
        if(dragT >= (mouseY-(dragH/2)))
            return up();
    }

    if(clickDown){
        if(contentT > -(contentH - contentClipH)) {
            dragT = dragT + (speed*scrollLength);
            if(dragT > (rulerT + scrollH - dragH))
                dragT = (rulerT + scrollH - dragH);

            contentT = contentT - speed;
            if(contentT < -(contentH - contentClipH))
                contentT = -(contentH - contentClipH);
            
            moveTo();
            timer = setTimeout("scrollDown()",25);
        }
    }
    return false;
}

// reloads page to position the layers again
function reloadPage(){
    location.reload();
}

// Preload
function eventLoader(){
    if(ie4){
        // Up-arrow X and Y variables
        upL = document.all.up.style.pixelLeft;
        upT = document.all.up.style.pixelTop;

        // Down-arrow X and Y variables
        downL = document.all.down.style.pixelLeft;
        downT = document.all.down.style.pixelTop;

        // Scrollbar X and Y variables
        dragL = document.all.drag.style.pixelLeft;
        dragT = document.all.drag.style.pixelTop;

        // Ruler Y variable
        rulerT = document.all.ruler.style.pixelTop;

        // Height of content layer and clip layer
        contentH = parseInt(document.all.content.scrollHeight);
        contentClipH = parseInt(document.all.contentClip.style.height);

    }else if(nn4){
        // Up-arrow X and Y variables
        upL = document.up.left;
        upT = document.up.top;

        // Down-arrow X and Y variables
        downL = document.down.left;
        downT = document.down.top;

        // Scrollbar X and Y variables
        dragL = document.drag.left;
        dragT = document.drag.top;

        // Ruler Y variable
        rulerT = document.ruler.top;

        // Height of content layer and clip layer
        contentH = document.contentClip.document.content.clip.bottom;
        contentClipH = document.contentClip.clip.bottom;

    } else if(dom){
        // Up-arrow X and Y variables
        upL = parseInt(document.getElementById("up").style.left);
        upT = parseInt(document.getElementById("up").style.top);

        // Down-arrow X and Y variables
        downL = parseInt(document.getElementById("down").style.left);
        downT = parseInt(document.getElementById("down").style.top);

        // Scrollbar X and Y variables
        dragL = parseInt(document.getElementById("drag").style.left);
        dragT = parseInt(document.getElementById("drag").style.top);

        // Ruler Y variable
        rulerT = parseInt(document.getElementById("ruler").style.top);

        // Height of content layer and clip layer
        contentH = parseInt(document.getElementById("content").offsetHeight);
        contentClipH = parseInt(document.getElementById("contentClip").offsetHeight);
        document.getElementById("content").style.top = 0 + "px";
    }
    // Number of pixels scrollbar should move
    scrollLength = ((scrollH-dragH)/(contentH-contentClipH));
    // Initializes event capturing
    if(nn4){
        document.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE | Event.MOUSEUP);
        window.onresize = reloadPage;
    }
    document.onmousedown = down;
    document.onmousemove = move;
    document.onmouseup = up;
}