#include "Scaler.h"
#include <stdexcept>

namespace ffcpp {

	ffcpp::Scaler::Scaler(int srcWidth, int srcHeight, AVPixelFormat srcPixFmt, int dstWidth, int dstHeight,
	                      AVPixelFormat dstPixFmt) {
		_dstWidth = dstWidth;
		_dstHeight = dstHeight;
		_dstPixFmt = dstPixFmt;
		_swsContext = sws_getContext(srcWidth, srcHeight, srcPixFmt, dstWidth, dstHeight, dstPixFmt, SWS_BICUBIC,
		                             nullptr, nullptr, nullptr);
		if(!_swsContext) {
			throw new std::runtime_error("cannot create scale context");
		}
	}

	Scaler::Scaler(AVCodecContext *decoderCtx, AVCodecContext *encoderCtx)
			: Scaler(decoderCtx->width, decoderCtx->height, decoderCtx->pix_fmt,
			         encoderCtx->width, encoderCtx->height, encoderCtx->pix_fmt) {
	}


	Frame Scaler::scale(Frame &inFrame) {
		Frame outFrame(_dstWidth, _dstHeight, _dstPixFmt);

		AVFrame* fin = inFrame;
		AVFrame* fout = outFrame;
		fout->pts = fin->pts;

		int res = sws_scale(_swsContext, (uint8_t const * const *)fin->data, fin->linesize, 0, fin->height, fout->data, fout->linesize);
		if(res < 0) {
			throw new std::runtime_error("scale error");
		}

		return outFrame;
	}

	bool Scaler::needScaling(AVCodecContext *decoderCtx, AVCodecContext *encoderCtx) {
		return (decoderCtx->width != encoderCtx->width ||
				decoderCtx->height != encoderCtx->height ||
				decoderCtx->pix_fmt != encoderCtx->pix_fmt);
	}

}