/* Copyright (c) 2005 Tim Taylor Consulting (see LICENSE.txt) */

/* FIXME: assumes position styles are specified in 'px' */

ToolMan._coordinatesFactory = {

    create: function (x, y)
    {
        // FIXME: Safari won't parse 'throw' and aborts trying to do anything with this file
        //if (isNaN(x) || isNaN(y)) throw "invalid x,y: " + x + "," + y
        return new _ToolManCoordinate(this, x, y)
    },

    origin: function ()
    {
        return this.create(0, 0)
    },

    /*
    * FIXME: Safari 1.2, returns (0,0) on absolutely positioned elements
    */
    topLeftPosition: function (element)
    {
        var left = parseInt(ToolMan.css().readStyle(element, "left"))
        var left = isNaN(left) ? 0 : left
        var top = parseInt(ToolMan.css().readStyle(element, "top"))
        var top = isNaN(top) ? 0 : top

        return this.create(left, top)
    },

    bottomRightPosition: function (element)
    {
        return this.topLeftPosition(element).plus(this._size(element))
    },

    topLeftOffset: function (element)
    {
        var offset = this._offset(element)

        var parent = element.offsetParent
        while (parent)
        {
            offset = offset.plus(this._offset(parent))
            parent = parent.offsetParent
        }
        return offset
    },

    bottomRightOffset: function (element)
    {
        return this.topLeftOffset(element).plus(
				this.create(element.offsetWidth, element.offsetHeight))
    },

    scrollOffset: function ()
    {
        if (window.pageXOffset)
        {
            return this.create(window.pageXOffset, window.pageYOffset)
        } else if (document.documentElement)
        {
            return this.create(
					document.body.scrollLeft + document.documentElement.scrollLeft,
					document.body.scrollTop + document.documentElement.scrollTop)
        } else if (document.body.scrollLeft >= 0)
        {
            return this.create(document.body.scrollLeft, document.body.scrollTop)
        } else
        {
            return this.create(0, 0)
        }
    },

    clientSize: function ()
    {
        if (window.innerHeight >= 0)
        {
            return this.create(window.innerWidth, window.innerHeight)
        } else if (document.documentElement)
        {
            return this.create(document.documentElement.clientWidth,
					document.documentElement.clientHeight)
        } else if (document.body.clientHeight >= 0)
        {
            return this.create(document.body.clientWidth,
					document.body.clientHeight)
        } else
        {
            return this.create(0, 0)
        }
    },

    /**
    * mouse coordinate relative to the window (technically the
    * browser client area) i.e. the part showing your page
    *
    * NOTE: in Safari the coordinate is relative to the document
    */
    mousePosition: function (event)
    {
        event = ToolMan.events().fix(event)
        return this.create(event.clientX, event.clientY)
    },

    /**
    * mouse coordinate relative to the document
    */
    mouseOffset: function (event)
    {
        event = ToolMan.events().fix(event)
        if (event.pageX >= 0 || event.pageX < 0)
        {
            return this.create(event.pageX, event.pageY)
        } else if (event.clientX >= 0 || event.clientX < 0)
        {
            return this.mousePosition(event).plus(this.scrollOffset())
        }
    },

    _size: function (element)
    {
        /* TODO: move to a Dimension class */
        return this.create(element.offsetWidth, element.offsetHeight)
    },

    _offset: function (element)
    {
        return this.create(element.offsetLeft, element.offsetTop)
    }
}

function _ToolManCoordinate(factory, x, y)
{
    this.factory = factory
    this.x = isNaN(x) ? 0 : x
    this.y = isNaN(y) ? 0 : y
}

_ToolManCoordinate.prototype = {
    toString: function ()
    {
        return "(" + this.x + "," + this.y + ")"
    },

    plus: function (that)
    {
        return this.factory.create(this.x + that.x, this.y + that.y)
    },

    minus: function (that)
    {
        return this.factory.create(this.x - that.x, this.y - that.y)
    },

    min: function (that)
    {
        return this.factory.create(
				Math.min(this.x, that.x), Math.min(this.y, that.y))
    },

    max: function (that)
    {
        return this.factory.create(
				Math.max(this.x, that.x), Math.max(this.y, that.y))
    },

    constrainTo: function (one, two)
    {
        var min = one.min(two)
        var max = one.max(two)

        return this.max(min).min(max)
    },

    distance: function (that)
    {
        return Math.sqrt(Math.pow(this.x - that.x, 2) + Math.pow(this.y - that.y, 2))
    },

    reposition: function (element)
    {
        element.style["top"] = this.y + "px"
        element.style["left"] = this.x + "px"
    }
}