/*!
 * \file SampleInstance.h
 * \date 2019/12/17
 *
 * \author Lin, Chi
 * Contact: lin.chi@hzleaper.com
 *
 *
 * \note
*/

#ifndef __SampleInstance_h_
#define __SampleInstance_h_

#include "StdUtils.h"
#include "DetectRoi.h"
#include <unordered_map>

/*! \brief Define a sample instance used for training or test, organized and stored by SampleDBManager
*/
struct SampleInstance
{
	/*! filename(or rather relative path to root folder) */
	std::string name;
	/*! original image, could be empty if the instance is unloaded */
	Mat img;
	/*! original mask, generated by detection roi */
	Mat mask;
	/*! detect roi on original image, could be empty if the instance is unloaded */
	DetectRoi droi;

	/*! cached size-uniformed image */
	Mat simg;
	/*! cached size-uniformed mask */
	Mat smask; 
	/*! cached feature vector */
	Mat fv;

	/*! User-defined properties. */
	typedef std::map<int, Mat> UserDataMap;
	UserDataMap userData;

	SampleInstance() : rootFolder("") {}
	SampleInstance(const std::string& dir, const std::string& n) : rootFolder(dir), name(n) {}

	/*! load image and roi from disk
	* @forceReload whether to always reload sample image from disk
	* @size resize sample image to provided size, do nothing for null size
	* @return true if already loaded or successfully loaded
	*/
	virtual bool load(bool forceReload = false, const Size& size = Size());

	/** @overload */
	virtual bool load(const Mat& sampleImg, DetectRoi& roi, const Size& size = Size());

	/** @overload */
	virtual bool load(const Mat& sampleImg, const Size& size = Size());

	/*! cleanup loaded image and roi */
	virtual void unload();

	/*! save sample image and roi to disk */
	virtual bool save();

	/*! get thumbnail for preview */
	virtual Mat getThumb();

	/*! get full path to the sample file */
	std::string getFullPath() const { return rootFolder + name; }

	/*! clean up cached feature vector */
	void cleanup() { fv = Mat(); }

	/*! check whether the sample instance is located in provided folder */
	bool isInFolder(const string& folderPath) const { return rootFolder == folderPath; }

	/*! get where the sample instance is located */
	const std::string& getFolder() const { return rootFolder; }

	/*! query user data */
	Mat getUserData(int idx) const {
		auto it = userData.find(idx);
		if (it == userData.end()) return Mat();
		else return it->second;
	}

	/*! generate a new sample instance after apply transformation(shift, scale, rotate) */
	virtual bool convert(double alpha, double beta, double dx, double dy,
		std::shared_ptr<SampleInstance>& siPtr);

	/*! whether this is a generated sample */
	virtual bool isGenerated() const { return generated; }

private:
	void refreshImgCache(const Size& size = Size());
	Mat resizeImg(const Mat& src, const Size& size, int interFlag);

private:
	const std::string& rootFolder; // root folder
	bool generated = false;

};
typedef std::shared_ptr<SampleInstance> SampleInstPtr;
typedef std::vector<SampleInstPtr> SampleInstVec;
typedef std::unordered_map<std::string, SampleInstPtr> SampleInstMap;
typedef ObjectVectorIterator<SampleInstPtr> SampleInstIterator;


#endif // SampleInstance_h_