#include <stdio.h>
#include <string.h>
#include "ChainCal.h"
#include "Func.h"
#include "types.h"
#include <math.h>


/* これは必須 */
SchedDefineTask(ChainCal);

#define CHAIN_LEN 50

static double m = 100.0;
static double k = 7000.0;
static double g = 9.8;
static double dt = 0.003;
static double chain_width = 10;
static double safe = 0.995;

typedef struct {
    double x, y, next_x, next_y;
    double vx, vy, next_vx, next_vy;
    double angle[3];
    int can_move;
    uint32 parent;
    int id;
    //int parent;
} CHAIN_VARS;

int
ChainCal::run(void *rbuf, void *wbuf)
{
    CHAIN_VARS *property = (CHAIN_VARS*)get_input(rbuf, 0);
    CHAIN_VARS *update_property = (CHAIN_VARS*)get_output(wbuf, 0);
 
    CHAIN_VARS* property = (CHAIN_VARS*)rbuf;
    int id = get_param(0);
    
    for(int cnt = 0; cnt < 600; cnt++) {
	for(int i = 0; i < CHAIN_LEN; i++) {
	    if(property[i].can_move) {
		double dx = property[i-1].x - property[i].x;
		double dy = property[i-1].y - property[i].y;
		double l = sqrt(dx * dx + dy * dy);
		double a = k * (l - chain_width) / m;
		double ax = a * dx / l;
		double ay = a * dy / l;
		if(i < CHAIN_LEN - 1) {
		    dx = property[i+1].x - property[i].x;
		    dy = property[i+1].y - property[i].y;
		    l = sqrt(dx * dx + dy * dy);
		    a = k * (l - chain_width) / m;
		    ax += a * dx / l;
		    ay += a * dy / l;
		}
		ay += g;
		property[i].vx *= safe;
		property[i].vy *= safe;
		property[i].next_vx = property[i].vx + ax * dt;
		property[i].next_vy = property[i].vy + ay * dt;
		property[i].next_x = property[i].x + property[i].vx * dt;
		property[i].next_y = property[i].y + property[i].vy * dt;
	    } else {
		property[i].next_x = property[i].x;
		property[i].next_y = property[i].y;
	    }
	}
	for(int i = 0; i < CHAIN_LEN; i++) {
	    property[i].vx = property[i].next_vx;
	    property[i].vy = property[i].next_vy;
	    property[i].x = property[i].next_x;
	    property[i].y = property[i].next_y;
	}
    }
	
    for (int j = 0; j < CHAIN_LEN; j++) {
	int p, n;
	id = property[j].id;
	p = n = id;
	if(p != 0) {
	    p--;
	}
	if(n != CHAIN_LEN - 1) {
	    n++;
	}
	property[j].angle[2-(id%2)*2]
	    = 90 + atan((property[p].next_y - property[n].next_y) / (property[p].next_x - property[n].next_x)) * 180 / M_PI;
    }
    memcpy((void*)update_property, (void*)property, sizeof(CHAIN_VARS) * CHAIN_LEN);
    return 0;
}