/*
* Copyright 2016-2021 Esri
*
* Author: Lucian Plesea
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

/*
* JPNG band, uses JPEG or PNG encoding, depending on the input data
*/

#include "marfa.h"

CPL_C_START
#include <jpeglib.h>
#include <png.h>
CPL_C_END

NAMESPACE_MRF_START

// Test that all alpha values are equal to N
template<int N> static bool AllAlpha(const buf_mgr &src, const ILImage &img) {
    int stride = img.pagesize.c;
    char *s = src.buffer + img.pagesize.c - 1;
    char *stop = src.buffer + img.pageSizeBytes;
    while (s < stop && N == static_cast<unsigned char>(*s))
        s += stride;
    return s >= stop;
}

// Strip the alpha from an RGBA buffer, safe to use in place
static void RGBA2RGB(const char *start, const char *stop, char *target) {
    while (start < stop) {
        *target++ = *start++;
        *target++ = *start++;
        *target++ = *start++;
        start++; // Skip the alpha
    }
}

// Add opaque alpha to an RGB buffer, safe to use in place
// works from stop to start, the last parameter is the end of the source region
static void RGB2RGBA(const char *start, char *stop, const char *source_end) {
    while (start < stop) {
        *--stop = ~static_cast<char>(0);
        *--stop = *--source_end;
        *--stop = *--source_end;
        *--stop = *--source_end;
    }
}

// Strip the alpha from an Luma Alpha buffer, safe to use in place
static void LA2L(const char *start, const char *stop, char *target) {
    while (start < stop) {
        *target++ = *start++;
        start++; // Skip the alpha
    }
}

// Add opaque alpha to a Luma buffer, safe to use in place
// works from stop to start, the last parameter is the end of the source region
static void L2LA(const char *start, char *stop, const char *source_end) {
    while (start < stop) {
        *--stop = ~static_cast<char>(0);
        *--stop = *--source_end;
    }
}

static CPLErr initBuffer(buf_mgr &b) {
    b.buffer = (char *)(CPLMalloc(b.size));
    if (b.buffer != nullptr)
        return CE_None;
    CPLError(CE_Failure, CPLE_OutOfMemory, "Allocating temporary JPNG buffer");
    return CE_Failure;
}

CPLErr JPNG_Band::Decompress(buf_mgr &dst, buf_mgr &src) {
    const static GUInt32 JPEG_SIG = 0xe0ffd8ff; // JPEG 4CC code
    const static GUInt32 PNG_SIG  = 0x474e5089;  // PNG 4CC code

    CPLErr retval = CE_None;
    ILImage image(img);
    GUInt32 signature;
    memcpy(&signature, src.buffer, sizeof(GUInt32));

    // test against an LSB signature
    if (JPEG_SIG == CPL_LSBWORD32(signature)) {
        image.pagesize.c -= 1;
        JPEG_Codec codec(image);

        // JPEG decoder expects the destination size to be accurate
        buf_mgr temp = dst; // dst still owns the storage
        temp.size = (image.pagesize.c == 3) ? dst.size / 4 * 3 : dst.size / 2;

        retval = codec.DecompressJPEG(temp, src);
        if (CE_None == retval) { // add opaque alpha, in place
            if (image.pagesize.c == 3)
                RGB2RGBA(dst.buffer, dst.buffer + dst.size, temp.buffer + temp.size);
            else
                L2LA(dst.buffer, dst.buffer + dst.size, temp.buffer + temp.size);
        }
    }
    else if (PNG_SIG == CPL_LSBWORD32(signature)) { // Should be PNG, it reads as 4 bands
        PNG_Codec codec(image);
        return codec.DecompressPNG(dst, src);
    }
    else {
        CPLError(CE_Failure, CPLE_NotSupported, "Not a JPEG or PNG tile");
        retval = CE_Failure;
    }

    return retval;
}

// The PNG internal palette is set on first band write
CPLErr JPNG_Band::Compress(buf_mgr &dst, buf_mgr &src) {
    ILImage image(img);
    buf_mgr temp = { nullptr, static_cast<size_t>(img.pageSizeBytes) };
    CPLErr retval = initBuffer(temp);
    if (retval != CE_None)
        return retval;

    if (AllAlpha<255>(src, image)) { // If all pixels are opaque, compress as JPEG
        if (image.pagesize.c == 4)
            RGBA2RGB(src.buffer, src.buffer + src.size, temp.buffer);
        else
            LA2L(src.buffer, src.buffer + src.size, temp.buffer);

        image.pagesize.c -= 1; // RGB or Grayscale only for JPEG
        JPEG_Codec codec(image);
        codec.rgb = rgb;
        codec.optimize = optimize;
        codec.sameres = sameres;
        retval = codec.CompressJPEG(dst, temp);
    }
    else if (!AllAlpha<0>(src, image)) {
        PNG_Codec codec(image);
        codec.deflate_flags = deflate_flags;
        retval = codec.CompressPNG(dst, src);
    }
    else dst.size = 0; // Don't store fully transparent pages

    CPLFree(temp.buffer);
    return retval;
}

/**
* \brief For PPNG, builds the data structures needed to write the palette
* The presence of the PNGColors and PNGAlpha is used as a flag for PPNG only
*/

JPNG_Band::JPNG_Band( MRFDataset *pDS, const ILImage &image,
                      int b, int level ) :
    MRFRasterBand(pDS, image, b, level),
    rgb(FALSE),
    sameres(FALSE),
    optimize(false)
{   // Check error conditions
    if (image.dt != GDT_Byte) {
        CPLError(CE_Failure, CPLE_NotSupported, "Data type not supported by MRF JPNG");
        return;
    }
    if (image.order != IL_Interleaved || (image.pagesize.c != 4 && image.pagesize.c != 2)) {
        CPLError(CE_Failure, CPLE_NotSupported, "MRF JPNG can only handle 2 or 4 interleaved bands");
        return;
    }

    if (img.pagesize.c == 4) { // RGBA can have storage flavors
        CPLString const &pm = pDS->GetPhotometricInterpretation();
        if (pm == "RGB" || pm == "MULTISPECTRAL") { // Explicit RGB or MS
            rgb = TRUE;
            sameres = TRUE;
        }
        if (pm == "YCC")
            sameres = TRUE;
    }

    optimize = GetOptlist().FetchBoolean("OPTIMIZE", FALSE) != FALSE;

    // PNGs and JPGs can be larger than the source, especially for
    // small page size.
    poDS->SetPBufferSize(image.pageSizeBytes + 100);
}

JPNG_Band::~JPNG_Band() {}

NAMESPACE_MRF_END