// Copyright (c) 2020, The Monero Project
//
// 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.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
//    used to endorse or promote products derived from this software without specific
//    prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER 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.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits>
#include <QDebug>
#include <QString>
#include "Decoder.h"
#include "quirc.h"


QrDecoder::QrDecoder()
        : m_qr(quirc_new())
{
    if (m_qr == nullptr)
    {
        throw std::runtime_error("QUIRC: failed to allocate memory");
    }
}

QrDecoder::~QrDecoder()
{
    quirc_destroy(m_qr);
}

std::vector<std::string> QrDecoder::decode(const QImage &image)
{
    if (image.format() == QImage::Format_Grayscale8)
    {
        return decodeGrayscale8(image);
    }
    return decodeGrayscale8(image.convertToFormat(QImage::Format_Grayscale8));
}

std::vector<std::string> QrDecoder::decodePNG(QString pngPath) {
    struct quirc *q;
    std::vector<std::string> result;
    auto pngPathStd = pngPath.toStdString();
    auto pngPathCstr = pngPathStd.c_str();

    q = quirc_new();
    if (!q) {
        qWarning() << "can't create quirc object";
        return result;
    }

    int status = -1;
    if (check_if_png(pngPathCstr)) {
        status = load_png(q, pngPathCstr);
    } else {
        qWarning() << QString("Image is not a PNG: %1").arg(pngPath);
        return result;
    }
    if (status < 0) {
        quirc_destroy(q);
        return result;
    }

    quirc_end(q);
    auto count = quirc_count(q);
    result.reserve(static_cast<size_t>(count));

    for (int index = 0; index < count; ++index)
    {
        quirc_code code;
        quirc_extract(q, index, &code);

        quirc_data data;
        const quirc_decode_error_t err = quirc_decode(&code, &data);
        if (err == QUIRC_SUCCESS)
        {
            result.emplace_back(&data.payload[0], &data.payload[data.payload_len]);
        }
    }

    quirc_destroy(q);
    return result;
}

// I can't seem to get this function to work, we'll use dgbutil.h instead
std::vector<std::string> QrDecoder::decodeGrayscale8(const QImage &image)
{
    if (quirc_resize(m_qr, image.width(), image.height()) < 0)
    {
        throw std::runtime_error("QUIRC: failed to allocate video memory");
    }

    uint8_t *rawImage = quirc_begin(m_qr, nullptr, nullptr);
    if (rawImage == nullptr)
    {
        throw std::runtime_error("QUIRC: failed to get image buffer");
    }
#if QT_VERSION >= QT_VERSION_CHECK(5, 10, 0)
    std::copy(image.constBits(), image.constBits() + image.sizeInBytes(), rawImage);
#else
    std::copy(image.constBits(), image.constBits() + image.byteCount(), rawImage);
#endif
    quirc_end(m_qr);

    const int count = quirc_count(m_qr);
    if (count < 0)
    {
        throw std::runtime_error("QUIRC: failed to get the number of recognized QR-codes");
    }

    std::vector<std::string> result;
    result.reserve(static_cast<size_t>(count));
    for (int index = 0; index < count; ++index)
    {
        quirc_code code;
        quirc_extract(m_qr, index, &code);

        quirc_data data;
        const quirc_decode_error_t err = quirc_decode(&code, &data);
        if (err == QUIRC_SUCCESS)
        {
            result.emplace_back(&data.payload[0], &data.payload[data.payload_len]);
        }
    }

    return result;
}

/* quirc -- QR-code recognition library
 * Copyright (C) 2010-2012 Daniel Beer <dlbeer@gmail.com>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

static const char *data_type_str(int dt)
{
    switch (dt) {
        case QUIRC_DATA_TYPE_NUMERIC: return "NUMERIC";
        case QUIRC_DATA_TYPE_ALPHA:   return "ALPHA";
        case QUIRC_DATA_TYPE_BYTE:    return "BYTE";
        case QUIRC_DATA_TYPE_KANJI:   return "KANJI";
    }

    return "unknown";
}

void QrDecoder::dump_data(const struct quirc_data *data)
{
    printf("    Version: %d\n", data->version);
    printf("    ECC level: %c\n", "MLHQ"[data->ecc_level]);
    printf("    Mask: %d\n", data->mask);
    printf("    Data type: %d (%s)\n",
           data->data_type, data_type_str(data->data_type));
    printf("    Length: %d\n", data->payload_len);
    printf("    Payload: %s\n", data->payload);

    if (data->eci)
        printf("    ECI: %d\n", data->eci);
}

void QrDecoder::dump_cells(const struct quirc_code *code)
{
    int u, v;

    printf("    %d cells, corners:", code->size);
    for (u = 0; u < 4; u++)
        printf(" (%d,%d)", code->corners[u].x,
               code->corners[u].y);
    printf("\n");

    for (v = 0; v < code->size; v++) {
        printf("    ");
        for (u = 0; u < code->size; u++) {
            int p = v * code->size + u;

            if (code->cell_bitmap[p >> 3] & (1 << (p & 7)))
                printf("[]");
            else
                printf("  ");
        }
        printf("\n");
    }
}

/* hacked from https://dev.w3.org/Amaya/libpng/example.c
 *
 * Check if a file is a PNG image using png_sig_cmp(). Returns 1 if the given
 * file is a PNG and 0 otherwise.
 */
#define PNG_BYTES_TO_CHECK 4
int QrDecoder::check_if_png(const char *filename)
{
    int ret = 0;
    FILE *infile = NULL;
    unsigned char buf[PNG_BYTES_TO_CHECK];

    /* Open the prospective PNG file. */
    if ((infile = fopen(filename, "rb")) == NULL)
        goto out;

    /* Read in some of the signature bytes */
    if (fread(buf, 1, PNG_BYTES_TO_CHECK, infile) != PNG_BYTES_TO_CHECK)
        goto out;

    /*
     * Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
     * png_sig_cmp() returns zero if the image is a PNG and nonzero if it
     * isn't a PNG.
     */
    if (png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK) == 0)
        ret = 1;

    /* FALLTHROUGH */
    out:
    if (infile)
        fclose(infile);
    return (ret);
}

int QrDecoder::load_png(struct quirc *q, const char *filename)
{
    int width, height, rowbytes, interlace_type, number_passes = 1;
    png_uint_32 trns;
    png_byte color_type, bit_depth;
    png_structp png_ptr = NULL;
    png_infop info_ptr = NULL;
    FILE *infile = NULL;
    uint8_t *image;
    int ret = -1;
    int pass;

    if ((infile = fopen(filename, "rb")) == NULL)
        goto out;

    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
    if (!png_ptr)
        goto out;

    info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr)
        goto out;

    if (setjmp(png_jmpbuf(png_ptr)))
        goto out;

    png_init_io(png_ptr, infile);

    png_read_info(png_ptr, info_ptr);

    color_type     = png_get_color_type(png_ptr, info_ptr);
    bit_depth      = png_get_bit_depth(png_ptr, info_ptr);
    interlace_type = png_get_interlace_type(png_ptr, info_ptr);

    // Read any color_type into 8bit depth, Grayscale format.
    // See http://www.libpng.org/pub/png/libpng-manual.txt

    // PNG_COLOR_TYPE_GRAY_ALPHA is always 8 or 16bit depth.
    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
        png_set_expand_gray_1_2_4_to_8(png_ptr);

    if ((trns = png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
        png_set_tRNS_to_alpha(png_ptr);

    if (bit_depth == 16)
#if PNG_LIBPNG_VER >= 10504
        png_set_scale_16(png_ptr);
#else
        png_set_strip_16(png_ptr);
#endif

    if ((trns) || color_type & PNG_COLOR_MASK_ALPHA)
        png_set_strip_alpha(png_ptr);

    if (color_type == PNG_COLOR_TYPE_PALETTE)
        png_set_palette_to_rgb(png_ptr);

    if (color_type == PNG_COLOR_TYPE_PALETTE ||
        color_type == PNG_COLOR_TYPE_RGB ||
        color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
        png_set_rgb_to_gray_fixed(png_ptr, 1, -1, -1);
    }

    if (interlace_type != PNG_INTERLACE_NONE)
        number_passes = png_set_interlace_handling(png_ptr);

    png_read_update_info(png_ptr, info_ptr);

    width    = png_get_image_width(png_ptr, info_ptr);
    height   = png_get_image_height(png_ptr, info_ptr);
    rowbytes = png_get_rowbytes(png_ptr, info_ptr);
    if (rowbytes != width) {
        fprintf(stderr,
                "load_png: expected rowbytes to be %u but got %u\n",
                width, rowbytes);
        goto out;
    }

    if (quirc_resize(q, width, height) < 0)
        goto out;

    image = quirc_begin(q, NULL, NULL);

    for (pass = 0; pass < number_passes; pass++) {
        int y;

        for (y = 0; y < height; y++) {
            png_bytep row_pointer = image + y * width;
            png_read_rows(png_ptr, &row_pointer, NULL, 1);
        }
    }

    png_read_end(png_ptr, info_ptr);

    ret = 0;
    /* FALLTHROUGH */
    out:
    /* cleanup */
    if (png_ptr) {
        if (info_ptr)
            png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
        else
            png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
    }
    if (infile)
        fclose(infile);
    return (ret);
}