/*
 * Copyright 2022 The Android Open Source Project
 *
 * 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.
 */

#include <jpegrecoverymap/jpegdecoderhelper.h>

#include <utils/Log.h>

#include <errno.h>
#include <setjmp.h>
#include <string>

using namespace std;

namespace android::jpegrecoverymap {

const uint32_t kAPP0Marker = JPEG_APP0;      // JFIF
const uint32_t kAPP1Marker = JPEG_APP0 + 1;  // EXIF, XMP
const uint32_t kAPP2Marker = JPEG_APP0 + 2;  // ICC

const std::string kXmpNameSpace = "http://ns.adobe.com/xap/1.0/";
const std::string kExifIdCode = "Exif";
constexpr uint32_t kICCMarkerHeaderSize = 14;
constexpr uint8_t kICCSig[] = {
        'I', 'C', 'C', '_', 'P', 'R', 'O', 'F', 'I', 'L', 'E', '\0',
};

struct jpegr_source_mgr : jpeg_source_mgr {
    jpegr_source_mgr(const uint8_t* ptr, int len);
    ~jpegr_source_mgr();

    const uint8_t* mBufferPtr;
    size_t mBufferLength;
};

struct jpegrerror_mgr {
    struct jpeg_error_mgr pub;
    jmp_buf setjmp_buffer;
};

static void jpegr_init_source(j_decompress_ptr cinfo) {
    jpegr_source_mgr* src = static_cast<jpegr_source_mgr*>(cinfo->src);
    src->next_input_byte = static_cast<const JOCTET*>(src->mBufferPtr);
    src->bytes_in_buffer = src->mBufferLength;
}

static boolean jpegr_fill_input_buffer(j_decompress_ptr /* cinfo */) {
    ALOGE("%s : should not get here", __func__);
    return FALSE;
}

static void jpegr_skip_input_data(j_decompress_ptr cinfo, long num_bytes) {
    jpegr_source_mgr* src = static_cast<jpegr_source_mgr*>(cinfo->src);

    if (num_bytes > static_cast<long>(src->bytes_in_buffer)) {
        ALOGE("jpegr_skip_input_data - num_bytes > (long)src->bytes_in_buffer");
    } else {
        src->next_input_byte += num_bytes;
        src->bytes_in_buffer -= num_bytes;
    }
}

static void jpegr_term_source(j_decompress_ptr /*cinfo*/) {}

jpegr_source_mgr::jpegr_source_mgr(const uint8_t* ptr, int len) :
        mBufferPtr(ptr), mBufferLength(len) {
    init_source = jpegr_init_source;
    fill_input_buffer = jpegr_fill_input_buffer;
    skip_input_data = jpegr_skip_input_data;
    resync_to_restart = jpeg_resync_to_restart;
    term_source = jpegr_term_source;
}

jpegr_source_mgr::~jpegr_source_mgr() {}

static void jpegrerror_exit(j_common_ptr cinfo) {
    jpegrerror_mgr* err = reinterpret_cast<jpegrerror_mgr*>(cinfo->err);
    longjmp(err->setjmp_buffer, 1);
}

JpegDecoderHelper::JpegDecoderHelper() {
  mExifPos = 0;
}

JpegDecoderHelper::~JpegDecoderHelper() {
}

bool JpegDecoderHelper::decompressImage(const void* image, int length, bool decodeToRGBA) {
    if (image == nullptr || length <= 0) {
        ALOGE("Image size can not be handled: %d", length);
        return false;
    }

    mResultBuffer.clear();
    mXMPBuffer.clear();
    if (!decode(image, length, decodeToRGBA)) {
        return false;
    }

    return true;
}

void* JpegDecoderHelper::getDecompressedImagePtr() {
    return mResultBuffer.data();
}

size_t JpegDecoderHelper::getDecompressedImageSize() {
    return mResultBuffer.size();
}

void* JpegDecoderHelper::getXMPPtr() {
    return mXMPBuffer.data();
}

size_t JpegDecoderHelper::getXMPSize() {
    return mXMPBuffer.size();
}

void* JpegDecoderHelper::getEXIFPtr() {
    return mEXIFBuffer.data();
}

size_t JpegDecoderHelper::getEXIFSize() {
    return mEXIFBuffer.size();
}

size_t JpegDecoderHelper::getDecompressedImageWidth() {
    return mWidth;
}

size_t JpegDecoderHelper::getDecompressedImageHeight() {
    return mHeight;
}

bool JpegDecoderHelper::decode(const void* image, int length, bool decodeToRGBA) {
    jpeg_decompress_struct cinfo;
    jpegr_source_mgr mgr(static_cast<const uint8_t*>(image), length);
    jpegrerror_mgr myerr;

    cinfo.err = jpeg_std_error(&myerr.pub);
    myerr.pub.error_exit = jpegrerror_exit;

    if (setjmp(myerr.setjmp_buffer)) {
        jpeg_destroy_decompress(&cinfo);
        return false;
    }
    jpeg_create_decompress(&cinfo);

    jpeg_save_markers(&cinfo, kAPP0Marker, 0xFFFF);
    jpeg_save_markers(&cinfo, kAPP1Marker, 0xFFFF);
    jpeg_save_markers(&cinfo, kAPP2Marker, 0xFFFF);

    cinfo.src = &mgr;
    jpeg_read_header(&cinfo, TRUE);

    // Save XMP data and EXIF data.
    // Here we only handle the first XMP / EXIF package.
    // The parameter pos is used for capturing start offset of EXIF, which is hacky, but working...
    // We assume that all packages are starting with two bytes marker (eg FF E1 for EXIF package),
    // two bytes of package length which is stored in marker->original_length, and the real data
    // which is stored in marker->data. The pos is adding up all previous package lengths (
    // 4 bytes marker and length, marker->original_length) before EXIF appears. Note that here we
    // we are using marker->original_length instead of marker->data_length because in case the real
    // package length is larger than the limitation, jpeg-turbo will only copy the data within the
    // limitation (represented by data_length) and this may vary from original_length / real offset.
    // A better solution is making jpeg_marker_struct holding the offset, but currently it doesn't.
    bool exifAppears = false;
    bool xmpAppears = false;
    size_t pos = 2;  // position after SOI
    for (jpeg_marker_struct* marker = cinfo.marker_list;
         marker && !(exifAppears && xmpAppears);
         marker = marker->next) {

        pos += 4;
        pos += marker->original_length;

        if (marker->marker != kAPP1Marker) {
            continue;
        }

        const unsigned int len = marker->data_length;
        if (!xmpAppears &&
            len > kXmpNameSpace.size() &&
            !strncmp(reinterpret_cast<const char*>(marker->data),
                     kXmpNameSpace.c_str(),
                     kXmpNameSpace.size())) {
            mXMPBuffer.resize(len+1, 0);
            memcpy(static_cast<void*>(mXMPBuffer.data()), marker->data, len);
            xmpAppears = true;
        } else if (!exifAppears &&
                   len > kExifIdCode.size() &&
                   !strncmp(reinterpret_cast<const char*>(marker->data),
                            kExifIdCode.c_str(),
                            kExifIdCode.size())) {
            mEXIFBuffer.resize(len, 0);
            memcpy(static_cast<void*>(mEXIFBuffer.data()), marker->data, len);
            exifAppears = true;
            mExifPos = pos - marker->original_length;
        }
    }

    mWidth = cinfo.image_width;
    mHeight = cinfo.image_height;

    if (decodeToRGBA) {
        if (cinfo.jpeg_color_space == JCS_GRAYSCALE) {
            // We don't intend to support decoding grayscale to RGBA
            return false;
        }
        // 4 bytes per pixel
        mResultBuffer.resize(cinfo.image_width * cinfo.image_height * 4);
        cinfo.out_color_space = JCS_EXT_RGBA;
    } else {
        if (cinfo.jpeg_color_space == JCS_YCbCr) {
            // 1 byte per pixel for Y, 0.5 byte per pixel for U+V
            mResultBuffer.resize(cinfo.image_width * cinfo.image_height * 3 / 2, 0);
        } else if (cinfo.jpeg_color_space == JCS_GRAYSCALE) {
            mResultBuffer.resize(cinfo.image_width * cinfo.image_height, 0);
        }
        cinfo.out_color_space = cinfo.jpeg_color_space;
        cinfo.raw_data_out = TRUE;
    }

    cinfo.dct_method = JDCT_IFAST;

    jpeg_start_decompress(&cinfo);

    if (!decompress(&cinfo, static_cast<const uint8_t*>(mResultBuffer.data()),
            cinfo.jpeg_color_space == JCS_GRAYSCALE)) {
        return false;
    }

    jpeg_finish_decompress(&cinfo);
    jpeg_destroy_decompress(&cinfo);

    return true;
}

bool JpegDecoderHelper::decompress(jpeg_decompress_struct* cinfo, const uint8_t* dest,
        bool isSingleChannel) {
    if (isSingleChannel) {
        return decompressSingleChannel(cinfo, dest);
    }
    if (cinfo->out_color_space == JCS_EXT_RGBA)
        return decompressRGBA(cinfo, dest);
    else
        return decompressYUV(cinfo, dest);
}

bool JpegDecoderHelper::getCompressedImageParameters(const void* image, int length,
                              size_t *pWidth, size_t *pHeight,
                              std::vector<uint8_t> *iccData , std::vector<uint8_t> *exifData) {
    jpeg_decompress_struct cinfo;
    jpegr_source_mgr mgr(static_cast<const uint8_t*>(image), length);
    jpegrerror_mgr myerr;
    cinfo.err = jpeg_std_error(&myerr.pub);
    myerr.pub.error_exit = jpegrerror_exit;

    if (setjmp(myerr.setjmp_buffer)) {
        jpeg_destroy_decompress(&cinfo);
        return false;
    }
    jpeg_create_decompress(&cinfo);

    jpeg_save_markers(&cinfo, kAPP1Marker, 0xFFFF);
    jpeg_save_markers(&cinfo, kAPP2Marker, 0xFFFF);

    cinfo.src = &mgr;
    if (jpeg_read_header(&cinfo, TRUE) != JPEG_HEADER_OK) {
        jpeg_destroy_decompress(&cinfo);
        return false;
    }

    *pWidth = cinfo.image_width;
    *pHeight = cinfo.image_height;

    if (iccData != nullptr) {
        for (jpeg_marker_struct* marker = cinfo.marker_list; marker;
             marker = marker->next) {
            if (marker->marker != kAPP2Marker) {
                continue;
            }
            if (marker->data_length <= kICCMarkerHeaderSize ||
                memcmp(marker->data, kICCSig, sizeof(kICCSig)) != 0) {
                continue;
            }

            const unsigned int len = marker->data_length - kICCMarkerHeaderSize;
            const uint8_t *src = marker->data + kICCMarkerHeaderSize;
            iccData->insert(iccData->end(), src, src+len);
        }
    }

    if (exifData != nullptr) {
        bool exifAppears = false;
        for (jpeg_marker_struct* marker = cinfo.marker_list; marker && !exifAppears;
             marker = marker->next) {
            if (marker->marker != kAPP1Marker) {
                continue;
            }

            const unsigned int len = marker->data_length;
            if (len >= kExifIdCode.size() &&
                !strncmp(reinterpret_cast<const char*>(marker->data), kExifIdCode.c_str(),
                         kExifIdCode.size())) {
                exifData->resize(len, 0);
                memcpy(static_cast<void*>(exifData->data()), marker->data, len);
                exifAppears = true;
            }
        }
    }

    jpeg_destroy_decompress(&cinfo);
    return true;
}

bool JpegDecoderHelper::decompressRGBA(jpeg_decompress_struct* cinfo, const uint8_t* dest) {
    JSAMPLE* decodeDst = (JSAMPLE*) dest;
    uint32_t lines = 0;
    // TODO: use batches for more effectiveness
    while (lines < cinfo->image_height) {
        uint32_t ret = jpeg_read_scanlines(cinfo, &decodeDst, 1);
        if (ret == 0) {
            break;
        }
        decodeDst += cinfo->image_width * 4;
        lines++;
    }
    return lines == cinfo->image_height;
}

bool JpegDecoderHelper::decompressYUV(jpeg_decompress_struct* cinfo, const uint8_t* dest) {

    JSAMPROW y[kCompressBatchSize];
    JSAMPROW cb[kCompressBatchSize / 2];
    JSAMPROW cr[kCompressBatchSize / 2];
    JSAMPARRAY planes[3] {y, cb, cr};

    size_t y_plane_size = cinfo->image_width * cinfo->image_height;
    size_t uv_plane_size = y_plane_size / 4;
    uint8_t* y_plane = const_cast<uint8_t*>(dest);
    uint8_t* u_plane = const_cast<uint8_t*>(dest + y_plane_size);
    uint8_t* v_plane = const_cast<uint8_t*>(dest + y_plane_size + uv_plane_size);
    std::unique_ptr<uint8_t[]> empty(new uint8_t[cinfo->image_width]);
    memset(empty.get(), 0, cinfo->image_width);

    while (cinfo->output_scanline < cinfo->image_height) {
        for (int i = 0; i < kCompressBatchSize; ++i) {
            size_t scanline = cinfo->output_scanline + i;
            if (scanline < cinfo->image_height) {
                y[i] = y_plane + scanline * cinfo->image_width;
            } else {
                y[i] = empty.get();
            }
        }
        // cb, cr only have half scanlines
        for (int i = 0; i < kCompressBatchSize / 2; ++i) {
            size_t scanline = cinfo->output_scanline / 2 + i;
            if (scanline < cinfo->image_height / 2) {
                int offset = scanline * (cinfo->image_width / 2);
                cb[i] = u_plane + offset;
                cr[i] = v_plane + offset;
            } else {
                cb[i] = cr[i] = empty.get();
            }
        }

        int processed = jpeg_read_raw_data(cinfo, planes, kCompressBatchSize);
        if (processed != kCompressBatchSize) {
            ALOGE("Number of processed lines does not equal input lines.");
            return false;
        }
    }
    return true;
}

bool JpegDecoderHelper::decompressSingleChannel(jpeg_decompress_struct* cinfo, const uint8_t* dest) {
    JSAMPROW y[kCompressBatchSize];
    JSAMPARRAY planes[1] {y};

    uint8_t* y_plane = const_cast<uint8_t*>(dest);
    std::unique_ptr<uint8_t[]> empty(new uint8_t[cinfo->image_width]);
    memset(empty.get(), 0, cinfo->image_width);

    while (cinfo->output_scanline < cinfo->image_height) {
        for (int i = 0; i < kCompressBatchSize; ++i) {
            size_t scanline = cinfo->output_scanline + i;
            if (scanline < cinfo->image_height) {
                y[i] = y_plane + scanline * cinfo->image_width;
            } else {
                y[i] = empty.get();
            }
        }

        int processed = jpeg_read_raw_data(cinfo, planes, kCompressBatchSize);
        if (processed != kCompressBatchSize / 2) {
            ALOGE("Number of processed lines does not equal input lines.");
            return false;
        }
    }
    return true;
}

} // namespace jpegrecoverymap