/*

 * Copyright (C) 2005, 2007 Apple Inc. All rights reserved.

 * Copyright (C) 2005 Ben La Monica <ben.lamonica@gmail.com>.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#define min min

#include <stdio.h>

#include <wtf/Platform.h>

#include <wtf/RetainPtr.h>

#if PLATFORM(WIN)

#include <winsock2.h>

#include <windows.h>

#include <fcntl.h>

#include <io.h>

#include <wtf/MathExtras.h>

#endif

#include <CoreGraphics/CGBitmapContext.h>

#include <CoreGraphics/CGImage.h>

#include <ImageIO/CGImageDestination.h>

#if PLATFORM(MAC)

#include <LaunchServices/UTCoreTypes.h>

#endif

#ifndef CGFLOAT_DEFINED

#ifdef __LP64__

typedef double CGFloat;

#else

typedef float CGFloat;

#endif

#define CGFLOAT_DEFINED 1

#endif

using namespace std;

#if PLATFORM(WIN)

static inline float strtof(const char *nptr, char **endptr)

{

    return strtod(nptr, endptr);

}

static const CFStringRef kUTTypePNG = CFSTR("public.png");

#endif

static RetainPtr<CGImageRef> createImageFromStdin(int bytesRemaining)

{

    unsigned char buffer[2048];

    RetainPtr<CFMutableDataRef> data(AdoptCF, CFDataCreateMutable(0, bytesRemaining));

    while (bytesRemaining > 0) {

        size_t bytesToRead = min(bytesRemaining, 2048);

        size_t bytesRead = fread(buffer, 1, bytesToRead, stdin);

        CFDataAppendBytes(data.get(), buffer, static_cast<CFIndex>(bytesRead));

        bytesRemaining -= static_cast<int>(bytesRead);

    }

    RetainPtr<CGDataProviderRef> dataProvider(AdoptCF, CGDataProviderCreateWithCFData(data.get()));

    return RetainPtr<CGImageRef>(AdoptCF, CGImageCreateWithPNGDataProvider(dataProvider.get(), 0, false, kCGRenderingIntentDefault));

}

static void releaseMallocBuffer(void* info, const void* data, size_t size)

{

    free((void*)data);

}

static RetainPtr<CGImageRef> createDifferenceImage(CGImageRef baseImage, CGImageRef testImage, float& difference)

{

    size_t width = CGImageGetWidth(baseImage);

    size_t height = CGImageGetHeight(baseImage);

    size_t rowBytes = width * 4;

    // Draw base image in bitmap context

    void* baseBuffer = calloc(height, rowBytes);

    RetainPtr<CGContextRef> baseContext(AdoptCF, CGBitmapContextCreate(baseBuffer, width, height, 8, rowBytes, CGImageGetColorSpace(baseImage), kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host));

    CGContextDrawImage(baseContext.get(), CGRectMake(0, 0, width, height), baseImage);

    // Draw test image in bitmap context

    void* buffer = calloc(height, rowBytes);

    RetainPtr<CGContextRef> context(AdoptCF, CGBitmapContextCreate(buffer, width, height, 8, rowBytes, CGImageGetColorSpace(testImage), kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host));

    CGContextDrawImage(context.get(), CGRectMake(0, 0, width, height), testImage);

    // Compare the content of the 2 bitmaps

    void* diffBuffer = malloc(width * height);

    float count = 0.0f;

    float sum = 0.0f;

    float maxDistance = 0.0f;

    unsigned char* basePixel = (unsigned char*)baseBuffer;

    unsigned char* pixel = (unsigned char*)buffer;

    unsigned char* diff = (unsigned char*)diffBuffer;

    for (size_t y = 0; y < height; ++y) {

        for (size_t x = 0; x < width; ++x) {

            float red = (pixel[0] - basePixel[0]) / max<float>(255 - basePixel[0], basePixel[0]);

            float green = (pixel[1] - basePixel[1]) / max<float>(255 - basePixel[1], basePixel[1]);

            float blue = (pixel[2] - basePixel[2]) / max<float>(255 - basePixel[2], basePixel[2]);

            float alpha = (pixel[3] - basePixel[3]) / max<float>(255 - basePixel[3], basePixel[3]);

            float distance = sqrtf(red * red + green * green + blue * blue + alpha * alpha) / 2.0f;

            *diff++ = (unsigned char)(distance * 255.0f);

            if (distance >= 1.0f / 255.0f) {

                count += 1.0f;

                sum += distance;

                if (distance > maxDistance)

                    maxDistance = distance;

            }

            basePixel += 4;

            pixel += 4;

        }

    }

    // Compute the difference as a percentage combining both the number of different pixels and their difference amount i.e. the average distance over the entire image

    if (count > 0.0f)

        difference = 100.0f * sum / (height * width);

    else

        difference = 0.0f;

    RetainPtr<CGImageRef> diffImage;

    // Generate a normalized diff image if there is any difference

    if (difference > 0.0f) {

        if (maxDistance < 1.0f) {

            diff = (unsigned char*)diffBuffer;

            for(size_t p = 0; p < height * width; ++p)

                diff[p] = diff[p] / maxDistance;

        }

        static CGColorSpaceRef diffColorspace = CGColorSpaceCreateDeviceGray();

        RetainPtr<CGDataProviderRef> provider(AdoptCF, CGDataProviderCreateWithData(0, diffBuffer, width * height, releaseMallocBuffer));

        diffImage.adoptCF(CGImageCreate(width, height, 8, 8, width, diffColorspace, 0, provider.get(), 0, false, kCGRenderingIntentDefault));

    }

    else

        free(diffBuffer);

    // Destroy drawing buffers

    if (buffer)

        free(buffer);

    if (baseBuffer)

        free(baseBuffer);

    return diffImage;

}

static inline bool imageHasAlpha(CGImageRef image)

{

    CGImageAlphaInfo info = CGImageGetAlphaInfo(image);

    return (info >= kCGImageAlphaPremultipliedLast) && (info <= kCGImageAlphaFirst);

}

int main(int argc, const char* argv[])

{

#if PLATFORM(WIN)

    _setmode(0, _O_BINARY);

    _setmode(1, _O_BINARY);

#endif

    float tolerance = 0.0f;

    for (int i = 1; i < argc; ++i) {

        if (!strcmp(argv[i], "-t") || !strcmp(argv[i], "--tolerance")) {

            if (i >= argc - 1)

                exit(1);

            tolerance = strtof(argv[i + 1], 0);

            ++i;

            continue;

        }

    }

    char buffer[2048];

    RetainPtr<CGImageRef> actualImage;

    RetainPtr<CGImageRef> baselineImage;

    while (fgets(buffer, sizeof(buffer), stdin)) {

        // remove the CR

        char* newLineCharacter = strchr(buffer, '\n');

        if (newLineCharacter)

            *newLineCharacter = '\0';

        if (!strncmp("Content-Length: ", buffer, 16)) {

            strtok(buffer, " ");

            int imageSize = strtol(strtok(0, " "), 0, 10);

            if (imageSize > 0 && !actualImage)

                actualImage = createImageFromStdin(imageSize);

            else if (imageSize > 0 && !baselineImage)

                baselineImage = createImageFromStdin(imageSize);

            else

                fputs("error, image size must be specified.\n", stdout);

        }

        if (actualImage && baselineImage) {

            RetainPtr<CGImageRef> diffImage;

            float difference = 100.0f;

            if ((CGImageGetWidth(actualImage.get()) == CGImageGetWidth(baselineImage.get())) && (CGImageGetHeight(actualImage.get()) == CGImageGetHeight(baselineImage.get())) && (imageHasAlpha(actualImage.get()) == imageHasAlpha(baselineImage.get()))) {

                diffImage = createDifferenceImage(actualImage.get(), baselineImage.get(), difference); // difference is passed by reference

                if (difference <= tolerance)

                    difference = 0.0f;

                else {

                    difference = roundf(difference * 100.0f) / 100.0f;

                    difference = max(difference, 0.01f); // round to 2 decimal places

                }

            } else

                fputs("error, test and reference image have different properties.\n", stderr);

            if (difference > 0.0f) {

                if (diffImage) {

                    RetainPtr<CFMutableDataRef> imageData(AdoptCF, CFDataCreateMutable(0, 0));

                    RetainPtr<CGImageDestinationRef> imageDest(AdoptCF, CGImageDestinationCreateWithData(imageData.get(), kUTTypePNG, 1, 0));

                    CGImageDestinationAddImage(imageDest.get(), diffImage.get(), 0);

                    CGImageDestinationFinalize(imageDest.get());

                    printf("Content-Length: %lu\n", CFDataGetLength(imageData.get()));

                    fwrite(CFDataGetBytePtr(imageData.get()), 1, CFDataGetLength(imageData.get()), stdout);

                }

                fprintf(stdout, "diff: %01.2f%% failed\n", difference);

            } else

                fprintf(stdout, "diff: %01.2f%% passed\n", difference);

            actualImage = 0;

            baselineImage = 0;

        }

        fflush(stdout);

    }

    return 0;

}