// CSE 143 
// Homework 5 
// http://www.cs.washington.edu/education/courses/143/00su/homework/ 
// 30 Jul 2000, Ken Yasuhara

// class FireworksDisplay


#ifndef _FIREWORKSDISPLAY_H_
#define _FIREWORKSDISPLAY_H_

#include "movingobject.h"
#include "fireworksscript.h"


// max. # of fireworks that can be active on screen at once
const int MAX_FIREWORK_COUNT = 32;

// max. # of background scene elements
const int MAX_BACKGROUND_OBJECT_COUNT = 16;


class FireworksDisplay {
public:
  // A FireworksDisplay instance is associated with a script file that
  // describes the sequence and parameters of the fireworks to be 
  // displayed.
  // slowdownFactor is periodicEventsPerFrame's init. value
  FireworksDisplay(const char scriptFilename[], 
                   const int slowdownFactor = 1);

  // deallocates any MovingObject (subclass) instances whose pointers
  // remain in arrays backgroundObjects and fireworks
  ~FireworksDisplay();

  //
  // methods
  //

  // "launches" given firework by adding to fireworks array; must
  // pass in a dynamically allocated MovingObject or subclass
  // instance; deallocateInactiveFireworks will deallocate for you
  // when firework is done
  bool addFirework(MovingObject *newFirework);

  // add background scene element; These objects are drawn to appear
  // behind fireworks.  Background objects are allowed to move.
  bool addBackgroundObject(MovingObject *newBackgroundObject);

  // starts fireworks show animation; infinite loop that increments
  // time as it updates the screen frame by frame
  void run();

protected:
  // launches fireworks scheduled for current time by adding them
  // to array fireworks
  void addScheduledFireworks();

  // updates whole screen by painting all fireworks, background
  void paintFrame();

  // paints objects in backgroundObjects array
  void paintBackground();

  // same as above for fireworks array
  void paintFireworks();
 
  // updates positions of background and active firework objects;
  // does not do any painting
  void updateObjects();

  // removes and deletes finished fireworks, checking each using 
  // method MovingObject::isDone
  void deallocateInactiveFireworks();
  
  // delay until time to draw next frame
  void waitUntilNextFrame();

  //
  // member variables
  //

  GP142Display display;
  int periodicEventsPerFrame;

  // incremented each time the frame is painted
  int time;

  // storage for ptrs. to dynamically allocated instances of 
  // MovingObject or subclasses, one for background objects, the 
  // other for fireworks.
  // count vars. used to keep track of how many elements are actually
  // being used in these arrays; initially all NULL;
  // invariant:  count var. holds number of non-NULL elements in
  // corresponding ptr. array
  // invariant:  For each background object, there is exactly one
  // pointer to it in the backgroundObjects array, and the 
  // remainder of this array's elements are NULL.
  // invariant:  Likewise, each non-NULL element of array fireworks
  // points to a unique active firework.
  MovingObject *backgroundObjects[MAX_BACKGROUND_OBJECT_COUNT];
  int backgroundObjectCount;
  MovingObject *fireworks[MAX_FIREWORK_COUNT];
  int fireworkCount;

  // get dyn. allocated MovingObjects through this instance
  FireworksScript script;

  // next scheduled firework and launch time; 
  // invariant:  nextFirework == NULL if no more fireworks
  MovingObject *nextFirework;
  int nextFireworkLaunchTime; 
};


#endif // _FIREWORKSDISPLAY_H_