#ifndef PHISICS_H

#define PHISICS_H

#include "common.h"

typedef struct PhLink PhLink;

typedef struct PhNode PhNode;

typedef struct PhGroup PhGroup;

typedef struct Physics Physics;

typedef PhLink *PhCell;

struct PhLink {

  PhNode *node;

  PhCell *cell;

  PhLink *prev, *next;

};

struct PhNode {

  PhGroup *group;

  PhNode *prev, *next;

  PhLink l[4];

  double r;

  Vec p, gp, gk;

  size_t mark; // temporary mark

  PhNode *chain; // temporary chain

};

struct PhGroup {

  Physics *ph;

  PhGroup *prev, *next;

  PhNode *first, *last;

  int cnt;

  Vec go, o, dx;

};

struct Physics {

  PhGroup *first, *last;

  double cs;

  int hw, hh;

  PhCell *cells;

  size_t lastMark;

  Vec b0, b1;

  int fixangle;

};

void phLinkUnreg(PhLink *l);

void phLinkReg(PhLink *l, PhCell *c);

void phNodeUnregCell(PhNode *n);

void phNodeRegCell(PhNode *n, PhCell *c, int stride);

void phNodeUpdateCell(PhNode *n);

void phNodeUnreg(PhNode *n);

void phNodeReg(PhNode *n, PhGroup *g);

int phNodeBound(PhNode *n, Vec b0, Vec b1);

int phNodeCollision(PhNode *n);

static inline Vec phGroupTrans(PhGroup *g, Vec gp) { return vtrans(vsub(gp, g->go), g->dx, g->o); }

static inline Vec phGroupUntrans(PhGroup *g, Vec p) { return vadd(vuntrans(p, g->dx, g->o), g->go); }

void phGroupUpdateCells(PhGroup *g);

void phGroupUnreg(PhGroup *g);

void phGroupReg(PhGroup *g, Physics *ph);

void phGroupRecalc(PhGroup *g);

void phGroupPlaceNodes(PhGroup *g);

void phGroupFix(PhGroup *g, int fixangle);

void phGroupMove(PhGroup *g, Vec gp, Vec p, int fixangle);

void phGroupMerge(PhGroup *a, PhGroup *b);

void physicsAlloc(Physics *ph, int hw, int hh, double cs);

void physicsFree(Physics *ph);

PhCell* physicsCell(Physics *ph, Vec p);

void physicsClear(Physics *ph);

int physicsUpdate(Physics *ph);

void physicsDrawDebug(Physics *ph);

#endif