/*
* Text
* Visit http://createjs.com/ for documentation, updates and examples.
*
* Copyright (c) 2010 gskinner.com, inc.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/

/**
 * @module EaselJS
 */

// namespace:
this.createjs = this.createjs||{};

(function() {
	"use strict";


// constructor:
	/**
	 * Display one or more lines of dynamic text (not user editable) in the display list. Line wrapping support (using the
	 * lineWidth) is very basic, wrapping on spaces and tabs only. Note that as an alternative to Text, you can position HTML
	 * text above or below the canvas relative to items in the display list using the {{#crossLink "DisplayObject/localToGlobal"}}{{/crossLink}}
	 * method, or using {{#crossLink "DOMElement"}}{{/crossLink}}.
	 *
	 * <b>Please note that Text does not support HTML text, and can only display one font style at a time.</b> To use
	 * multiple font styles, you will need to create multiple text instances, and position them manually.
	 *
	 * <h4>Example</h4>
	 *
	 *      var text = new createjs.Text("Hello World", "20px Arial", "#ff7700");
	 *      text.x = 100;
	 *      text.textBaseline = "alphabetic";
	 *
	 * CreateJS Text supports web fonts (the same rules as Canvas). The font must be loaded and supported by the browser
	 * before it can be displayed.
	 *
	 * <strong>Note:</strong> Text can be expensive to generate, so cache instances where possible. Be aware that not all
	 * browsers will render Text exactly the same.
	 * @class Text
	 * @extends DisplayObject
	 * @constructor
	 * @param {String} [text] The text to display.
	 * @param {String} [font] The font style to use. Any valid value for the CSS font attribute is acceptable (ex. "bold
	 * 36px Arial").
	 * @param {String} [color] The color to draw the text in. Any valid value for the CSS color attribute is acceptable (ex.
	 * "#F00", "red", or "#FF0000").
	 **/
	function Text(text, font, color) {
		this.DisplayObject_constructor();
		
		
	// public properties:
		/**
		 * The text to display.
		 * @property text
		 * @type String
		 **/
		this.text = text;
	
		/**
		 * The font style to use. Any valid value for the CSS font attribute is acceptable (ex. "bold 36px Arial").
		 * @property font
		 * @type String
		 **/
		this.font = font;
	
		/**
		 * The color to draw the text in. Any valid value for the CSS color attribute is acceptable (ex. "#F00"). Default is "#000".
		 * It will also accept valid canvas fillStyle values.
		 * @property color
		 * @type String
		 **/
		this.color = color;
	
		/**
		 * The horizontal text alignment. Any of "start", "end", "left", "right", and "center". For detailed
		 * information view the
		 * <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#text-styles">
		 * whatwg spec</a>. Default is "left".
		 * @property textAlign
		 * @type String
		 **/
		this.textAlign = "left";
	
		/**
		 * The vertical alignment point on the font. Any of "top", "hanging", "middle", "alphabetic", "ideographic", or
		 * "bottom". For detailed information view the <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#text-styles">
		 * whatwg spec</a>. Default is "top".
		 * @property textBaseline
		 * @type String
		*/
		this.textBaseline = "top";
	
		/**
		 * The maximum width to draw the text. If maxWidth is specified (not null), the text will be condensed or
		 * shrunk to make it fit in this width. For detailed information view the
		 * <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#text-styles">
		 * whatwg spec</a>.
		 * @property maxWidth
		 * @type Number
		*/
		this.maxWidth = null;
	
		/**
		 * If greater than 0, the text will be drawn as a stroke (outline) of the specified width.
		 * @property outline
		 * @type Number
		 **/
		this.outline = 0;
	
		/**
		 * Indicates the line height (vertical distance between baselines) for multi-line text. If null or 0,
		 * the value of getMeasuredLineHeight is used.
		 * @property lineHeight
		 * @type Number
		 **/
		this.lineHeight = 0;
	
		/**
		 * Indicates the maximum width for a line of text before it is wrapped to multiple lines. If null,
		 * the text will not be wrapped.
		 * @property lineWidth
		 * @type Number
		 **/
		this.lineWidth = null;
	}
	var p = createjs.extend(Text, createjs.DisplayObject);

	// TODO: deprecated
	// p.initialize = function() {}; // searchable for devs wondering where it is. REMOVED. See docs for details.

	
// static properties:
	/**
	 * @property _workingContext
	 * @type CanvasRenderingContext2D
	 * @private
	 **/
	var canvas = (createjs.createCanvas?createjs.createCanvas():document.createElement("canvas"));
	if (canvas.getContext) { Text._workingContext = canvas.getContext("2d"); canvas.width = canvas.height = 1; }
	
	
// constants:
	/**
	 * Lookup table for the ratio to offset bounds x calculations based on the textAlign property.
	 * @property H_OFFSETS
	 * @type Object
	 * @protected
	 * @static
	 **/
	Text.H_OFFSETS = {start: 0, left: 0, center: -0.5, end: -1, right: -1};
	
	/**
	 * Lookup table for the ratio to offset bounds y calculations based on the textBaseline property.
	 * @property H_OFFSETS
	 * @type Object
	 * @protected
	 * @static
	 **/
	Text.V_OFFSETS = {top: 0, hanging: -0.01, middle: -0.4, alphabetic: -0.8, ideographic: -0.85, bottom: -1};


// public methods:
	/**
	 * Returns true or false indicating whether the display object would be visible if drawn to a canvas.
	 * This does not account for whether it would be visible within the boundaries of the stage.
	 * NOTE: This method is mainly for internal use, though it may be useful for advanced uses.
	 * @method isVisible
	 * @return {Boolean} Whether the display object would be visible if drawn to a canvas
	 **/
	p.isVisible = function() {
		var hasContent = this.cacheCanvas || (this.text != null && this.text !== "");
		return !!(this.visible && this.alpha > 0 && this.scaleX != 0 && this.scaleY != 0 && hasContent);
	};

	/**
	 * Draws the Text into the specified context ignoring its visible, alpha, shadow, and transform.
	 * Returns true if the draw was handled (useful for overriding functionality).
	 * NOTE: This method is mainly for internal use, though it may be useful for advanced uses.
	 * @method draw
	 * @param {CanvasRenderingContext2D} ctx The canvas 2D context object to draw into.
	 * @param {Boolean} ignoreCache Indicates whether the draw operation should ignore any current cache.
	 * For example, used for drawing the cache (to prevent it from simply drawing an existing cache back
	 * into itself).
	 **/
	p.draw = function(ctx, ignoreCache) {
		if (this.DisplayObject_draw(ctx, ignoreCache)) { return true; }

		var col = this.color || "#000";
		if (this.outline) { ctx.strokeStyle = col; ctx.lineWidth = this.outline*1; }
		else { ctx.fillStyle = col; }
		
		this._drawText(this._prepContext(ctx));
		return true;
	};

	/**
	 * Returns the measured, untransformed width of the text without wrapping. Use getBounds for a more robust value.
	 * @method getMeasuredWidth
	 * @return {Number} The measured, untransformed width of the text.
	 **/
	p.getMeasuredWidth = function() {
		return this._getMeasuredWidth(this.text);
	};

	/**
	 * Returns an approximate line height of the text, ignoring the lineHeight property. This is based on the measured
	 * width of a "M" character multiplied by 1.2, which provides an approximate line height for most fonts.
	 * @method getMeasuredLineHeight
	 * @return {Number} an approximate line height of the text, ignoring the lineHeight property. This is
	 * based on the measured width of a "M" character multiplied by 1.2, which approximates em for most fonts.
	 **/
	p.getMeasuredLineHeight = function() {
		return this._getMeasuredWidth("M")*1.2;
	};

	/**
	 * Returns the approximate height of multi-line text by multiplying the number of lines against either the
	 * <code>lineHeight</code> (if specified) or {{#crossLink "Text/getMeasuredLineHeight"}}{{/crossLink}}. Note that
	 * this operation requires the text flowing logic to run, which has an associated CPU cost.
	 * @method getMeasuredHeight
	 * @return {Number} The approximate height of the untransformed multi-line text.
	 **/
	p.getMeasuredHeight = function() {
		return this._drawText(null,{}).height;
	};

	/**
	 * Docced in superclass.
	 */
	p.getBounds = function() {
		var rect = this.DisplayObject_getBounds();
		if (rect) { return rect; }
		if (this.text == null || this.text === "") { return null; }
		var o = this._drawText(null, {});
		var w = (this.maxWidth && this.maxWidth < o.width) ? this.maxWidth : o.width;
		var x = w * Text.H_OFFSETS[this.textAlign||"left"];
		var lineHeight = this.lineHeight||this.getMeasuredLineHeight();
		var y = lineHeight * Text.V_OFFSETS[this.textBaseline||"top"];
		return this._rectangle.setValues(x, y, w, o.height);
	};
	
	/**
	 * Returns an object with width, height, and lines properties. The width and height are the visual width and height
	 * of the drawn text. The lines property contains an array of strings, one for
	 * each line of text that will be drawn, accounting for line breaks and wrapping. These strings have trailing
	 * whitespace removed.
	 * @method getMetrics
	 * @return {Object} An object with width, height, and lines properties.
	 **/
	p.getMetrics = function() {
		var o = {lines:[]};
		o.lineHeight = this.lineHeight || this.getMeasuredLineHeight();
		o.vOffset = o.lineHeight * Text.V_OFFSETS[this.textBaseline||"top"];
		return this._drawText(null, o, o.lines);
	};

	/**
	 * Returns a clone of the Text instance.
	 * @method clone
	 * @return {Text} a clone of the Text instance.
	 **/
	p.clone = function() {
		return this._cloneProps(new Text(this.text, this.font, this.color));
	};

	/**
	 * Returns a string representation of this object.
	 * @method toString
	 * @return {String} a string representation of the instance.
	 **/
	p.toString = function() {
		return "[Text (text="+  (this.text.length > 20 ? this.text.substr(0, 17)+"..." : this.text) +")]";
	};


// private methods:
	/**
	 * @method _cloneProps
	 * @param {Text} o
	 * @protected
	 * @return {Text} o
	 **/
	p._cloneProps = function(o) {
		this.DisplayObject__cloneProps(o);
		o.textAlign = this.textAlign;
		o.textBaseline = this.textBaseline;
		o.maxWidth = this.maxWidth;
		o.outline = this.outline;
		o.lineHeight = this.lineHeight;
		o.lineWidth = this.lineWidth;
		return o;
	};

	/**
	 * @method _getWorkingContext
	 * @param {CanvasRenderingContext2D} ctx
	 * @return {CanvasRenderingContext2D}
	 * @protected
	 **/
	p._prepContext = function(ctx) {
		ctx.font = this.font||"10px sans-serif";
		ctx.textAlign = this.textAlign||"left";
		ctx.textBaseline = this.textBaseline||"top";
		return ctx;
	};

	/**
	 * Draws multiline text.
	 * @method _drawText
	 * @param {CanvasRenderingContext2D} ctx
	 * @param {Object} o
	 * @param {Array} lines
	 * @return {Object}
	 * @protected
	 **/
	p._drawText = function(ctx, o, lines) {
		var paint = !!ctx;
		if (!paint) {
			ctx = Text._workingContext;
			ctx.save();
			this._prepContext(ctx);
		}
		var lineHeight = this.lineHeight||this.getMeasuredLineHeight();
		
		var maxW = 0, count = 0;
		var hardLines = String(this.text).split(/(?:\r\n|\r|\n)/);
		for (var i=0, l=hardLines.length; i<l; i++) {
			var str = hardLines[i];
			var w = null;
			
			if (this.lineWidth != null && (w = ctx.measureText(str).width) > this.lineWidth) {
				// text wrapping:
				var words = str.split(/(\s)/);
				str = words[0];
				w = ctx.measureText(str).width;
				
				for (var j=1, jl=words.length; j<jl; j+=2) {
					// Line needs to wrap:
					var wordW = ctx.measureText(words[j] + words[j+1]).width;
					if (w + wordW > this.lineWidth) {
						if (paint) { this._drawTextLine(ctx, str, count*lineHeight); }
						if (lines) { lines.push(str); }
						if (w > maxW) { maxW = w; }
						str = words[j+1];
						w = ctx.measureText(str).width;
						count++;
					} else {
						str += words[j] + words[j+1];
						w += wordW;
					}
				}
			}
			
			if (paint) { this._drawTextLine(ctx, str, count*lineHeight); }
			if (lines) { lines.push(str); }
			if (o && w == null) { w = ctx.measureText(str).width; }
			if (w > maxW) { maxW = w; }
			count++;
		}
		
		if (o) {
			o.width = maxW;
			o.height = count*lineHeight;
		}
		if (!paint) { ctx.restore(); }
		return o;
	};

	/**
	 * @method _drawTextLine
	 * @param {CanvasRenderingContext2D} ctx
	 * @param {String} text
	 * @param {Number} y
	 * @protected
	 **/
	p._drawTextLine = function(ctx, text, y) {
		// Chrome 17 will fail to draw the text if the last param is included but null, so we feed it a large value instead:
		if (this.outline) { ctx.strokeText(text, 0, y, this.maxWidth||0xFFFF); }
		else { ctx.fillText(text, 0, y, this.maxWidth||0xFFFF); }
	};
	
	
	/**
	 * @method _getMeasuredWidth
	 * @param {String} text
	 * @protected
	 **/
	p._getMeasuredWidth = function(text) {
		var ctx = Text._workingContext;
		ctx.save();
		var w = this._prepContext(ctx).measureText(text).width;
		ctx.restore();
		return w;
	};


	createjs.Text = createjs.promote(Text, "DisplayObject");
}());
