#include <iostream>
#include <memory>
#include <cmath>
#include <complex>
#include <device_launch_parameters.h>
#include <cuda_runtime.h>
#include <cublas_v2.h>
#include <cuComplex.h>

#include "BaseConstVariable.h"
#include "GPUTool.cuh"
#include "GPUTBPImage.cuh"
#include "GPUBPTool.cuh"

#ifdef __CUDANVCC___
#define EPSILON 1e-12
#define MAX_ITER 50

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

 

__global__ void kernel_TimeBPImageGridNet(double* antPx, double* antPy, double* antPz,
	double* antDirx, double* antDiry, double* antDirz,
	double* imgx, double* imgy, double* imgz,
	long prfcount, long freqpoints, double meanH,
	double Rnear, double dx, double RefRange) {

	long idx = blockIdx.x * blockDim.x + threadIdx.x;
	long pixelcount = prfcount * freqpoints;
	long prfid = idx / freqpoints;
	long Rid = idx % freqpoints;
	if (idx < pixelcount) {
		// 计算坐标
		Vector3 S = { antPx[prfid], antPy[prfid], antPz[prfid] }; // 卫星位置 (m)
		Vector3 ray = { antDirx[prfid], antDiry[prfid], antDirz[prfid] };      // 视线方向
		double H = meanH;                    // 平均高程
		double R = Rnear + dx * Rid;                   // 目标距离
		// 参数校验
		if (R <= 0 || H < -WGS84_A * 0.1 || H > WGS84_A * 0.1) {
			//printf("参数错误：\n  H范围：±%.1f km\n  R必须>0\n", WGS84_A * 0.1 / 1000);
			imgx[idx] = NAN;
			imgy[idx] = NAN;
			imgz[idx] = NAN;
			//printf("idx=%d;prfid=%d;Rid=%d;S=[%f , %f ,%f ];ray=[%f ,%f ,%f ];H=%f;R=%f,imgP=[%f ,%f , %f ];Rextend\n",
			//	idx, prfid, Rid, S.x, S.y, S.z, ray.x, ray.y, ray.z, H, R,imgx[idx],imgy[idx],imgz[idx]);
			// 参数校验
			return;
		}

		// Step 1: 计算交点T
		Vector3 T = compute_T(S, ray, H);
		if (isnan(T.x)) {
			imgx[idx] = NAN;
			imgy[idx] = NAN;
			imgz[idx] = NAN;
			//printf("idx=%d;prfid=%d;Rid=%d;Tnan\n",
			//	idx, prfid, Rid, S.x, S.y, S.z, ray.x, ray.y, ray.z, H, R,T.x,T.y,T.z, imgx[idx], imgy[idx], imgz[idx]);
			return;
		}

		// Step 2: 计算目标点P
		 
		Vector3 P;// = compute_P(S, T, R, H);
		{ // 计算P
			Vector3 ex, ey, ez; // 平面基函数
			Vector3 ST = vec_normalize(vec_sub(T, S));// S->T 
			Vector3 SO = vec_normalize(vec_sub(Vector3{ 0, 0, 0 }, S)); // S->O 

			 
			Vector3 st1 = vec_sub(T, S);
			double R0 = sqrt(st1.x * st1.x + st1.y * st1.y + st1.z * st1.z);
			ez = vec_normalize(vec_cross(SO, ST)); // Z 轴
			ey = vec_normalize(vec_cross(ez, SO)); // Y 轴 与 ST 同向 --这个结论在星地几何约束，便是显然的；
			ex = vec_normalize(SO);  //X轴



			double h2 = (WGS84_A + H) * (WGS84_A + H);
			double b2 = WGS84_B * WGS84_B;
			double R2 = R * R;
			double A = R2 * ((ex.x * ex.x + ex.y * ex.y) / h2 + (ex.z * ex.z) / b2);
			double B = R2 * ((ex.x * ey.x + ex.y * ey.y) / h2 + (ex.z * ey.z) / b2) * 2;
			double C = R2 * ((ey.x * ey.x + ey.y * ey.y) / h2 + (ey.z * ey.z) / b2);
			double D = 1 - ((S.x * S.x + S.y * S.y) / h2 + (S.z * S.z) / b2);
			double E = 2*R * ((S.x * ex.x + S.y * ex.y) / h2 + (S.z * ex.z) / b2);
			double F = 2*R * ((S.x * ey.x + S.y * ey.y) / h2 + (S.z * ey.z) / b2);
			double Q0 = angleBetweenVectors(SO, ST, false);
			double dQ = 0;
			double fQ = 0;
			double dfQ = 0;
			double Q = R < R0 ? Q0 - 1e-3 : Q0 + 1e-3;

			//printf("A=%f;B=%f;C=%f;D=%f;E=%f;F=%f;Q=%f;\
			//	S=[%f , %f ,%f ];\
			//	T=[%f , %f ,%f ];\
			//	ex=[%f , %f ,%f ];\
			//	ey=[%f , %f ,%f ];\
			//	ez=[%f , %f ,%f ];\
			//ray=[%f ,%f ,%f ];\
			//H=%f;R=%f;;\n",A,B,C,D,E,F,Q,
			//	S.x,S.y,S.z,
			//	T.x,T.y,T.z ,
			//	ex.x,ex.y,ex.z,
			//	ey.x,ey.y,ey.z,
			//	ez.x,ez.y,ez.z,
			//	ray.x, ray.y, ray.z,
			//	H, R);
			//	return;

			// 牛顿迭代法
			for (int iter = 0; iter < MAX_ITER * 10; ++iter) {
				fQ = A * cos(Q) * cos(Q) + B * sin(Q) * cos(Q) + C * sin(Q) * sin(Q) + E * cos(Q) + F * sin(Q) - D;
				dfQ = (C - A) * sin(2 * Q) + B * cos(2 * Q) - E * sin(Q) + F * cos(Q);
				dQ = fQ / dfQ;
				if (abs(dQ) < 1e-8) {
					//printf("iter=%d;check Q0=%f;Q=%f;dQ=%f;fQ=%f;dfQ=%f;break\n", iter, Q0, Q, dQ, fQ, dfQ);
					break;
				}
				else {
					dQ = (abs(dQ) < d2r * 3) ? dQ :( abs(dQ) / dQ * d2r* 3);
					Q = Q - dQ;
					//printf("iter=%d;check Q0=%f;Q=%f;dQ=%f;fQ=%f;dfQ=%f;\n", iter, Q0, Q, dQ, fQ, dfQ);
				}
				
			}
			//printf("check Q0=%f;Q=%f;\n", Q0, Q);
			double t1 = R * cos(Q);
			double t2 = R * sin(Q);
			 P = Vector3{
			 S.x + t1 * ex.x + t2 * ey.x, //因为 t3=0；
			 S.y + t1 * ex.y + t2 * ey.y,
			 S.z + t1 * ex.z + t2 * ey.z,
			};
			double check = (P.x * P.x + P.y * P.y) / ((WGS84_A + H) * (WGS84_A + H))
				+ P.z * P.z / (WGS84_B * WGS84_B);
			if (isnan(Q) || isinf(Q) || fabs(check - 1.0) > 1e-6) {
				P = Vector3{ NAN,NAN,NAN };
			}
		}

		double Rt = sqrt(pow(S.x - T.x, 2) + pow(S.y - T.y, 2) + pow(S.z - T.z, 2));
		double Rp = sqrt(pow(S.x - P.x, 2) + pow(S.y - P.y, 2) + pow(S.z - P.z, 2));
		double Rop = sqrt(pow( P.x, 2) + pow( P.y, 2) + pow( P.z, 2));

		if (!isnan(P.x)&&( Rop>WGS84_A*0.3)&&(Rop<WGS84_A*3)) {

			imgx[idx] = P.x;
			imgy[idx] = P.y;
			imgz[idx] = P.z;

			//printf("idx=%d; S=[%f , %f ,%f ]; H=%f;R=%f;RP=%f;Rr=%f;imgT=[%f ,%f ,%f ];imgP=[%f ,%f , %f ]; \n",
			//	idx,   S.x, S.y, S.z,   H, R, Rp, Rt,T.x, T.y, T.z, P.x, P.y, P.z);
		}
		else {
			imgx[idx] = NAN;
			imgy[idx] = NAN;
			imgz[idx] = NAN;
			printf("idx=%d; S=[%f , %f ,%f ]; H=%f;R=%f;RP=%f;Rr=%f;imgT=[%f ,%f ,%f ];imgP=[%f ,%f , %f ]; ERROR\n",
				idx, S.x, S.y, S.z, H, R, Rp, Rt, T.x, T.y, T.z, P.x, P.y, P.z);
	 
		}
	}
	
}





__device__ double  computerR(double& Px, double& Py, double& Pz, double& Tx, double& Ty, double& Tz) {
	//double R= sqrt((Px - Tx) * (Px - Tx) + (Py - Ty) * (Py - Ty) + (Pz - Tz) * (Pz - Tz));
	//if (R > 900000) {
	//	printf("R=%f\n", R);
	//}
	//return R;

	return sqrt((Px - Tx) * (Px - Tx) + (Py - Ty) * (Py - Ty) + (Pz - Tz) * (Pz - Tz));
}



__device__ void updateBPImage(
	long prfid, long pixelidx,double R,double LRrange,
	cuComplex* TimeEchoArr, long prfcount, long pointCount,
	cuComplex* imgArr,  
	double startLamda, double Rnear, double dx, double RefRange, double Rfar
) {
	double ridx = (R - LRrange) / dx; // 获取范围
	if (ridx < 0 || ridx >= pointCount) {
		return;
	}
	else {}

	long Ridx0 = floor(ridx);
	long Ridx1 = ceil(ridx);

	long pid0 = prfid * pointCount + Ridx0;
	long pid1 = prfid * pointCount + Ridx1;

	cuComplex s0 = TimeEchoArr[pid0];
	cuComplex s1 = TimeEchoArr[pid1];


	if (isinf(s0.x) || isinf(s0.y) || isinf(s1.x) || isinf(s1.y)) {
		return;
	}

	cuComplex s = make_cuComplex(
		s0.x + (s1.x - s0.x) * (ridx-Ridx0),  // real
		s0.y + (s1.y - s0.y) * (ridx-Ridx0)   // imag
	);
	double phi = 4 * PI / startLamda * (R - RefRange);

	// exp(ix)=cos(x)+isin(x)
	cuComplex phiCorr = make_cuComplex(cos(phi), sin(phi));
	s = cuCmulf(s, phiCorr); // 校正后

	imgArr[pixelidx] = cuCaddf(imgArr[pixelidx], s);
	//imgArr[pixelidx] = cuCaddf(imgArr[pixelidx], make_cuComplex(1,1));
	return;
}




// 分块计算
__device__ void segmentBPImage(
	double* antPx, double* antPy, double* antPz,
	double Tx, double Ty, double Tz,
	cuComplex* TimeEchoArr, long prfcount, long pointCount,
	cuComplex* imgArr,  
	double startLamda, double Rnear, double dx, double RefRange, double Rfar,
	long startSegmentPrfId,long pixelID // 分段起始prfid
) {
	// 计算单条脉冲范围
	double Rrange = pointCount * dx;// 成像范围
	double LRrange = RefRange - Rrange / 2;//左范围
	double RRrange = RefRange + Rrange / 2;
 
	long currentprfid = 0;
	// 0
	currentprfid = startSegmentPrfId + 0;
	double Px = antPx[currentprfid];
	double Py = antPy[currentprfid];
	double Pz = antPz[currentprfid];
	double R0 = computerR(Px, Py, Pz, Tx, Ty, Tz);


	if (LRrange <= R0 && R0 <= RRrange) {
		updateBPImage(
			currentprfid, pixelID, R0, LRrange,
			TimeEchoArr, prfcount, pointCount,
			imgArr,
			startLamda, Rnear, dx, RefRange, Rfar
		);
	}

	// 10
	currentprfid = startSegmentPrfId + 10;
	Px = antPx[currentprfid];
	Py = antPy[currentprfid];
	Pz = antPz[currentprfid];
	double R10 = computerR(Px, Py, Pz, Tx, Ty, Tz);
	if (Rnear <= R10 && R10 <= RRrange) {
		updateBPImage(
			currentprfid, pixelID, R10, LRrange,
			TimeEchoArr, prfcount, pointCount,
			imgArr,
			startLamda, Rnear, dx, RefRange, Rfar
		);
	}


	//19
	currentprfid = startSegmentPrfId + 19;
	Px = antPx[currentprfid];
	Py = antPy[currentprfid];
	Pz = antPz[currentprfid];
	double R19 = computerR(Px, Py, Pz, Tx, Ty, Tz);
	if (Rnear <= R19 && R19 <= RRrange) {
		updateBPImage(
			currentprfid, pixelID, R19, LRrange,
			TimeEchoArr, prfcount, pointCount,
			imgArr,
			startLamda, Rnear, dx, RefRange, Rfar
		);
	}

	// 判断是否需要处理
	
	if (R0 < LRrange && R10 < LRrange && R19 < LRrange ) { // 越界、不处理
		return;
	}
	else if (R0 > RRrange && R10 > RRrange && R19 > RRrange) {// 越界、不处理
		return;
	}
	else {}




	double R = 0;
#pragma unroll
	for (long i = 1; i < 10; i++) {
		currentprfid = startSegmentPrfId + i;
		if (currentprfid < prfcount) {
			Px = antPx[currentprfid];
			Py = antPy[currentprfid];
			Pz = antPz[currentprfid];
			R = computerR(Px, Py, Pz, Tx, Ty, Tz);
			updateBPImage(
				currentprfid, pixelID, R, LRrange,
				TimeEchoArr, prfcount, pointCount,
				imgArr,
				startLamda, Rnear, dx, RefRange, Rfar
			);
		}
	}

#pragma unroll
	for (long i = 11; i < 20; i++) {
		currentprfid = startSegmentPrfId + i;
		if (currentprfid < prfcount) {
			Px = antPx[currentprfid];
			Py = antPy[currentprfid];
			Pz = antPz[currentprfid];
			R = computerR(Px, Py, Pz, Tx, Ty, Tz);
			updateBPImage(
				currentprfid, pixelID, R, LRrange,
				TimeEchoArr, prfcount, pointCount,
				imgArr,
				startLamda, Rnear, dx, RefRange, Rfar
			);
		}
	}
}





__global__ void kernel_pixelTimeBP(
	double* antPx, double* antPy, double* antPz,
	double* imgx, double* imgy, double* imgz,
	cuComplex* TimeEchoArr, long prfcount, long pointCount,
	cuComplex* imgArr, long imH, long imW,
	double startLamda, double Rnear, double dx,double RefRange,double Rfar
) {
	long idx = blockIdx.x * blockDim.x + threadIdx.x;
	long pixelcount = imH * imW;
	if (idx < pixelcount) {
 
		double Tx = imgx[idx]; // 地面坐标点
		double Ty = imgy[idx];
		double Tz = imgz[idx];
		double Rrange = pointCount * dx;// 成像范围
		double LRrange = RefRange - Rrange / 2;//左范围
		double RRrange = RefRange + Rrange / 2;

		for (long segid = 0; segid < prfcount; segid = segid + 20) {			
			long seglen = prfcount - segid;
			if (seglen < 20) {
				for (long i = 1; i < 10; i++) {
					long currentprfid = segid + i;
					if (currentprfid < prfcount) {
						double Px = antPx[currentprfid];
						double Py = antPy[currentprfid];
						double Pz = antPz[currentprfid];
						double R = computerR(Px, Py, Pz, Tx, Ty, Tz);
						updateBPImage(
							currentprfid, idx, R, LRrange,
							TimeEchoArr, prfcount, pointCount,
							imgArr,
							startLamda, Rnear, dx, RefRange, Rfar
						);
					}
				}
			}
			else {
				// 判断范围
				segmentBPImage(
					antPx, antPy, antPz,
					Tx, Ty, Tz,
					TimeEchoArr, prfcount, pointCount,
					imgArr,
					startLamda, Rnear, dx, RefRange, Rfar,
					segid, idx
				);
			}

		}
	}
}





extern "C" {
	void TIMEBPCreateImageGrid(double* antPx, double* antPy, double* antPz,
		double* antDirx, double* antDiry, double* antDirz, 
		double* imgx, double* imgy, double* imgz, 
		long prfcount, long freqpoints,   double meanH,
		double Rnear, double dx, double RefRange
	)
	{
		long pixelcount = prfcount * freqpoints;
		int grid_size = (pixelcount + BLOCK_SIZE - 1) / BLOCK_SIZE;

		kernel_TimeBPImageGridNet << <grid_size, BLOCK_SIZE >> > (
			antPx, antPy, antPz,
			antDirx, antDiry, antDirz,
			imgx, imgy, imgz,
			prfcount, freqpoints, meanH,
			Rnear, dx, RefRange);
		PrintLasterError("TIMEBPCreateImageGrid");
		cudaDeviceSynchronize();
	}



 
	void TimeBPImage(
		double* antPx, double* antPy, double* antPz,
		double* imgx, double* imgy, double* imgz,
		cuComplex* TimeEchoArr, long prfcount, long pointCount,
		cuComplex* imgArr, long imH, long imW,
		double startLamda, double Rnear, double dx, double RefRange,double Rfar
	)
	{
		long pixelcount = imH * imW;
		int grid_size = (pixelcount + BLOCK_SIZE - 1) / BLOCK_SIZE;

		kernel_pixelTimeBP << <grid_size, BLOCK_SIZE >> > (
			antPx, antPy, antPz,
			imgx, imgy, imgz,
			TimeEchoArr, prfcount, pointCount,
			imgArr, imH, imW,
			startLamda, Rnear, dx, RefRange, Rfar
			);

		PrintLasterError("TimeBPImage");
		cudaDeviceSynchronize();

	}

}

#endif