/**
 * 用模式匹配算法開火的機器人
 * @author xiemin
 */
#include <airobot/c/SimpleRobot.h>

//開火時的炮彈能量
#define POWER 0.5
//用于匹配段的長度
#define MATCH_LENGHT 20
//保留歷史紀錄的最大長度
#define HISTORY_LENGHT 2000

//對手的速度記錄
double velocityRecord[HISTORY_LENGHT];
//對手的方向記錄
double headingRecord[HISTORY_LENGHT];
//當前紀錄位置
int currentIndex;

//記錄當前的機器人狀態
void record(struct Bot* bot);
//計算最佳的匹配點
int getMatchIndex();
//得到開火的位置
void getFirePoint(int matchIndex, double power, double* fireX, double* fireY);

void onRoundBegin(struct RoundBeginAction* action)
{
	currentIndex = 0;
}

void onTick(struct TickAction* action)
{
	int matchIndex;
	double fireX, fireY;
	struct Bot* opponent = getFirstOpponent();
	if(opponent==NULL) return;
	
	record(opponent);
	matchIndex = getMatchIndex();
	getFirePoint(matchIndex, POWER, &fireX, &fireY);
	fireOnPoint(fireX, fireY, POWER);
}
		
//記錄當前的機器人狀態
void record(struct Bot* bot)
{
	velocityRecord[currentIndex] = bot->velocity;
	headingRecord[currentIndex] = bot->heading;
	currentIndex++;
}

//計算最佳的匹配點
int getMatchIndex()
{
	double beatSimilarity=1000000;
	int matchIndex=0, i, j;
	//這里取i<currentFrame-100是為了避免比較樣本和被比較樣本重復
	//和留取足夠的節點給遞推未來坐標用
	for(i=MATCH_LENGHT; i<currentIndex-MATCH_LENGHT; i++)
	{
		//取10個樣本節點計算相似度
		double similarity=0;
		for(j=1; j<=MATCH_LENGHT; j++)
		{
			similarity+=fabs(velocityRecord[i-j]-velocityRecord[currentIndex-j]);
			similarity+=fabs(headingRecord[i-j]-headingRecord[currentIndex-j]);
			//加了權值得匹配度計算
			//similarity+=fabs(velocityRecord[i-j]-velocityRecord[currentIndex-j])/8;
			//similarity+=fabs(headingRecord[i-j]-headingRecord[currentIndex-j])/PI;
		}
		//記錄最相似的相似度，以及對應的記錄節點下標
	   	if(similarity<beatSimilarity)
	   	{
		    matchIndex=i;
		   	beatSimilarity=similarity;
		}
	}
	return matchIndex;
}

//得到開火的位置
void getFirePoint(int matchIndex, double power, double* fireX, double* fireY)
{
	//預測位置
   	double x = getFirstOpponent()->x;
   	double y = getFirstOpponent()->y;
   	double dis;
    int time = 0;
    while(matchIndex+time<currentIndex)
    {
    	dis = distance(getX(), getY(), x, y);
    	if(dis/getBulletVelocity(power)<=time) break;
    	nextPoint(x, y, headingRecord[matchIndex+time], 
    		velocityRecord[matchIndex+time], &x, &y);
    	time++;
    }
	*fireX = x;
	*fireY = y;
}

//啟動機器人程序
int main(int argC, char* argV[])
{
	tickHook = onTick;
	roundBeginHook = onRoundBegin;
	return startup(argC, argV);
}