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#include "precomp.hpp"
#include "grfmt_hdr.hpp"
#include "rgbe.hpp"

#ifdef HAVE_IMGCODEC_HDR

namespace cv
{

HdrDecoder::HdrDecoder()
{
    m_signature = "#?RGBE";
    m_signature_alt = "#?RADIANCE";
    file = NULL;
    m_type = CV_32FC3;
}

HdrDecoder::~HdrDecoder()
{
    if(file) {
        fclose(file);
    }
}

size_t HdrDecoder::signatureLength() const
{
    return m_signature.size() > m_signature_alt.size() ?
           m_signature.size() : m_signature_alt.size();
}

bool  HdrDecoder::readHeader()
{
    file = fopen(m_filename.c_str(), "rb");
    if(!file) {
        return false;
    }
    RGBE_ReadHeader(file, &m_width, &m_height, NULL);
    if(m_width <= 0 || m_height <= 0) {
        fclose(file);
        file = NULL;
        return false;
    }
    return true;
}

bool HdrDecoder::readData(Mat& _img)
{
    Mat img(m_height, m_width, CV_32FC3);
    if(!file) {
        if(!readHeader()) {
            return false;
        }
    }
    RGBE_ReadPixels_RLE(file, const_cast<float*>(img.ptr<float>()), img.cols, img.rows);
    fclose(file); file = NULL;

    // NOTE: 'img' has type CV32FC3
    switch (_img.depth())
    {
        case CV_8U: img.convertTo(img, _img.depth(), 255); break;
        case CV_32F: break;
        default: CV_Error(Error::StsError, "Wrong expected image depth, allowed: CV_8U and CV_32F");
    }
    switch (_img.channels())
    {
        case 1: cvtColor(img, _img, COLOR_BGR2GRAY); break;
        case 3:
        // TODO, try to modify RGBE_ReadPixels_RLE to load rgb data directly.
        if (m_use_rgb)
            cv::cvtColor(img, _img, cv::COLOR_BGR2RGB);
        else
            img.copyTo(_img);
        break;
        default: CV_Error(Error::StsError, "Wrong expected image channels, allowed: 1 and 3");
    }
    return true;
}

bool HdrDecoder::checkSignature( const String& signature ) const
{
    if (signature.size() >= m_signature.size() &&
        0 == memcmp(signature.c_str(), m_signature.c_str(), m_signature.size())
    )
        return true;
    if (signature.size() >= m_signature_alt.size() &&
        0 == memcmp(signature.c_str(), m_signature_alt.c_str(), m_signature_alt.size())
    )
        return true;
    return false;
}

ImageDecoder HdrDecoder::newDecoder() const
{
    return makePtr<HdrDecoder>();
}

HdrEncoder::HdrEncoder()
{
    m_description = "Radiance HDR (*.hdr;*.pic)";
}

HdrEncoder::~HdrEncoder()
{
}

bool HdrEncoder::write( const Mat& input_img, const std::vector<int>& params )
{
    Mat img;
    CV_Assert(input_img.channels() == 3 || input_img.channels() == 1);
    if(input_img.channels() == 1) {
         std::vector<Mat> splitted(3, input_img);
         merge(splitted, img);
    } else {
        input_img.copyTo(img);
    }
    if(img.depth() != CV_32F) {
        img.convertTo(img, CV_32FC3, 1/255.0f);
    }

    int compression = IMWRITE_HDR_COMPRESSION_RLE;
    for (size_t i = 0; i + 1 < params.size(); i += 2)
    {
        switch (params[i])
        {
        case IMWRITE_HDR_COMPRESSION:
            compression = params[i + 1];
            break;
        default:
            break;
        }
    }
    CV_Check(compression, compression == IMWRITE_HDR_COMPRESSION_NONE || compression == IMWRITE_HDR_COMPRESSION_RLE, "");

    FILE *fout = fopen(m_filename.c_str(), "wb");
    if(!fout) {
        return false;
    }

    RGBE_WriteHeader(fout, img.cols, img.rows, NULL);
    if (compression == IMWRITE_HDR_COMPRESSION_RLE) {
        RGBE_WritePixels_RLE(fout, const_cast<float*>(img.ptr<float>()), img.cols, img.rows);
    } else {
        RGBE_WritePixels(fout, const_cast<float*>(img.ptr<float>()), img.cols * img.rows);
    }

    fclose(fout);
    return true;
}

ImageEncoder HdrEncoder::newEncoder() const
{
    return makePtr<HdrEncoder>();
}

bool HdrEncoder::isFormatSupported( int depth ) const {
    return depth != CV_64F;
}

}

#endif // HAVE_IMGCODEC_HDR