// This file is part of OpenCV project.
// It is subject to the license terms in the LICENSE file found in the top-level directory
// of this distribution and at http://opencv.org/license.html.

#include "precomp.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/core.hpp"
#include "opencv2/dnn.hpp"

#include <fstream>
#include <algorithm>

using namespace cv::dnn;

namespace cv
{
namespace text
{

class TextDetectorCNNImpl : public TextDetectorCNN
{
protected:
    Net net_;
    std::vector<Size> sizes_;
    int inputChannelCount_;

    void getOutputs(const float* buffer,int nbrTextBoxes,int nCol,
                               std::vector<Rect>& Bbox, std::vector<float>& confidence, Size inputShape)
    {
        for(int k = 0; k < nbrTextBoxes; k++)
        {
            float confidence_ = buffer[k*nCol + 2];
            if (confidence_ <= FLT_EPSILON) continue;

            float x_min_f = buffer[k*nCol + 3]*inputShape.width;
            float y_min_f = buffer[k*nCol + 4]*inputShape.height;

            float x_max_f = buffer[k*nCol + 5]*inputShape.width;
            float y_max_f = buffer[k*nCol + 6]*inputShape.height;

            int x_min = cvRound(std::max(0.f, x_min_f));
            int y_min = cvRound(std::max(0.f, y_min_f));

            int x_max = std::min(inputShape.width - 1,  cvRound(x_max_f));
            int y_max = std::min(inputShape.height - 1,  cvRound(y_max_f));

            if (x_min >= x_max) continue;
            if (y_min >= y_max) continue;

            int wd = x_max - x_min;
            int ht = y_max - y_min;

            Bbox.push_back(Rect(x_min, y_min, wd, ht));
            confidence.push_back(confidence_);
        }
    }

public:
    TextDetectorCNNImpl(const String& modelArchFilename, const String& modelWeightsFilename, std::vector<Size> detectionSizes) :
        sizes_(detectionSizes)
    {
        net_ = readNetFromCaffe(modelArchFilename, modelWeightsFilename);
        CV_Assert(!net_.empty());
        inputChannelCount_ = 3;
    }

    void detect(InputArray inputImage_, std::vector<Rect>& Bbox, std::vector<float>& confidence) CV_OVERRIDE
    {
        CV_CheckEQ(inputImage_.channels(), inputChannelCount_, "");
        Mat inputImage = inputImage_.getMat();
        Bbox.resize(0);
        confidence.resize(0);

        for(size_t i = 0; i < sizes_.size(); i++)
        {
            Size inputGeometry = sizes_[i];
            net_.setInput(blobFromImage(inputImage, 1, inputGeometry, Scalar(123, 117, 104), false, false), "data");
            Mat outputNet = net_.forward();
            int nbrTextBoxes = outputNet.size[2];
            int nCol = outputNet.size[3];
            int outputChannelCount = outputNet.size[1];
            CV_CheckEQ(outputChannelCount, 1, "");
            getOutputs((float*)(outputNet.data), nbrTextBoxes, nCol, Bbox, confidence, inputImage.size());
        }
     }
};

Ptr<TextDetectorCNN> TextDetectorCNN::create(const String &modelArchFilename, const String &modelWeightsFilename, std::vector<Size> detectionSizes)
{
    return makePtr<TextDetectorCNNImpl>(modelArchFilename, modelWeightsFilename, detectionSizes);
}

Ptr<TextDetectorCNN> TextDetectorCNN::create(const String &modelArchFilename, const String &modelWeightsFilename)
{
    return create(modelArchFilename, modelWeightsFilename, std::vector<Size>(1, Size(300, 300)));
}
} //namespace text
} //namespace cv