/*
 * CPStringDrawing.j
 * AppKit
 *
 * Created by Francisco Tolmasky.
 * Copyright 2008, 280 North, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

@import <Foundation/CPString.j>

@import "CGGeometry.j"
@import "CPPlatformString.j"
@import "CPFont.j"
@import "CPCompatibility.j"


var CPStringSizeWithFontInWidthCache = [],
    CPStringSizeWithFontHeightCache = [],
    CPStringSizeMeasuringContext;

CPCanvasStringSizingIsFunctional = NO;

@implementation CPString (CPStringDrawing)

/*!
    Returns a dictionary with the items "ascender", "descender", "lineHeight"
*/
+ (CPDictionary)metricsOfFont:(CPFont)aFont
{
    return [CPPlatformString metricsOfFont:aFont];
}

/*!
    Returns the string
*/
- (CPString)cssString
{
    return self;
}

- (CGSize)sizeWithFont:(CPFont)aFont
{
    return [self sizeWithFont:aFont inWidth:NULL];
}

+ (void) initialize
{
    if ([self class] != [CPString class])
        return;

#if PLATFORM(DOM)
    if (CPFeatureIsCompatible(CPHTMLCanvasFeature))
    {
        if (!CPStringSizeMeasuringContext)
            CPStringSizeMeasuringContext = CGBitmapGraphicsContextCreate();

        // This is to make sure that Canvas based string sizing is functional before we use it.
        // Unfortunately, as of today canvas sizing is not funtional any more. Neither in Chrome nor in FF

        CPCanvasStringSizingIsFunctional = NO;
    }
#endif
}

- (CGSize)sizeWithFont:(CPFont)aFont inWidth:(float)aWidth
{
    var size;

#if PLATFORM(DOM)
    var sizeCacheForFont = CPStringSizeWithFontInWidthCache[self];

    if (sizeCacheForFont === undefined)
        sizeCacheForFont = CPStringSizeWithFontInWidthCache[self] = [];

    var cssString = [aFont cssString],
        cacheKey = cssString + '_' + (aWidth ? aWidth : '0');

    size = sizeCacheForFont[cacheKey];

    if (size !== undefined && sizeCacheForFont.hasOwnProperty(cacheKey))
        return CGSizeMakeCopy(size);

    if (!CPCanvasStringSizingIsFunctional || aWidth)
        size = [CPPlatformString sizeOfString:self withFont:aFont forWidth:aWidth];
    else
    {
        if (CPPlatformHasBug(CPTextSizingAlwaysNeedsSetFontBug) || CPStringSizeMeasuringContext.font !== cssString)
            CPStringSizeMeasuringContext.font = cssString;

        var fontHeight = CPStringSizeWithFontHeightCache[cssString];

        if (fontHeight === undefined)
            fontHeight = CPStringSizeWithFontHeightCache[cssString] = [aFont defaultLineHeightForFont];

        size = CGSizeMake(CPStringSizeMeasuringContext.measureText(self).width, fontHeight);
    }

    sizeCacheForFont[cacheKey] = size;
#else
    size = CGSizeMake(0, 0);
#endif
    return CGSizeMakeCopy(size);
}

@end