/*  Copyright (C) 1996-2022 id Software LLC

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

    See file, 'COPYING', for details.
*/

void() SUB_Null = {};

void() SUB_Remove = {remove(self);};


/*
QuakeEd only writes a single float for angles (bad idea), so up and down are
just constant angles.
*/
void() SetMovedir =
{
  if (self.angles == '0 -1 0')
    self.movedir = '0 0 1';
  else if (self.angles == '0 -2 0')
    self.movedir = '0 0 -1';
  else
  {
    makevectors(self.angles);
    self.movedir = v_forward;
  }
  
  self.angles = '0 0 0';
};

/*
================
InitTrigger
================
*/
void() InitTrigger =
{
  // trigger angles are used for one-way touches.  An angle of 0 is assumed
  // to mean no restrictions, so use a yaw of 360 instead.
  if (self.angles != '0 0 0')
    SetMovedir ();

  self.solid = SOLID_TRIGGER;
  setmodel (self, self.model);  // set size and link into world
  self.movetype = MOVETYPE_NONE;
  self.modelindex = 0;
  self.model = string_null;
};

/*
=============
SUB_CalcMove

calculate self.velocity and self.nextthink to reach dest from
self.origin traveling at speed
===============
*/
void(entity ent, vector tdest, float tspeed, void() func) SUB_CalcMoveEnt =
{
  local entity  stemp;
  stemp = self;
  self = ent;

  SUB_CalcMove (tdest, tspeed, func);
  self = stemp;
};

void(vector tdest, float tspeed, void() func) SUB_CalcMove =
{
  local vector  vdestdelta;
  local float   len, traveltime;

  if (!tspeed)
    objerror("No speed is defined!");

  self.think1 = func;
  self.finaldest = tdest;
  self.think = SUB_CalcMoveDone;

  if (tdest == self.origin)
  {
    self.velocity = '0 0 0';
    self.nextthink = self.ltime + 0.1;
    return;
  }
    
  // set destdelta to the vector needed to move
  vdestdelta = tdest - self.origin;
  
  // calculate length of vector
  len = vlen (vdestdelta);
  
  // divide by speed to get time to reach dest
  traveltime = len / tspeed;

  if (traveltime < 0.1)
  {
    self.velocity = '0 0 0';
    self.nextthink = self.ltime + 0.1;
    return;
  }
  
  // set nextthink to trigger a think when dest is reached
  self.nextthink = self.ltime + traveltime;

  // scale the destdelta vector by the time spent traveling to get velocity
  self.velocity = vdestdelta * (1/traveltime);  // qcc won't take vec/float 
};

/*
============
After moving, set origin to exact final destination
============
*/
void()  SUB_CalcMoveDone =
{
  setorigin(self, self.finaldest);
  self.velocity = '0 0 0';
  self.nextthink = -1;

  if (self.think1)
    self.think1();
};


/*
=============
SUB_CalcAngleMove

calculate self.avelocity and self.nextthink to reach destangle from
self.angles rotating 

The calling function should make sure self.think is valid
===============
*/
void(entity ent, vector destangle, float tspeed, void() func) SUB_CalcAngleMoveEnt =
{
  local entity    stemp;
  stemp = self;
  self = ent;
  SUB_CalcAngleMove (destangle, tspeed, func);
  self = stemp;
};

void(vector destangle, float tspeed, void() func) SUB_CalcAngleMove =
{
  local vector  destdelta;
  local float   len, traveltime;

  if (!tspeed)
    objerror("No speed is defined!");
    
  // set destdelta to the vector needed to move
  destdelta = destangle - self.angles;
  
  // calculate length of vector
  len = vlen (destdelta);
  
  // divide by speed to get time to reach dest
  traveltime = len / tspeed;

  // set nextthink to trigger a think when dest is reached
  self.nextthink = self.ltime + traveltime;

  // scale the destdelta vector by the time spent traveling to get velocity
  self.avelocity = destdelta * (1 / traveltime);
  
  self.think1 = func;
  self.finalangle = destangle;
  self.think = SUB_CalcAngleMoveDone;
};

/*
============
After rotating, set angle to exact final angle
============
*/
void() SUB_CalcAngleMoveDone =
{
  self.angles = self.finalangle;
  self.avelocity = '0 0 0';
  self.nextthink = -1;

  if (self.think1)
    self.think1();
};


//=============================================================================

void() DelayThink =
{
  activator = self.enemy;
  SUB_UseTargets ();
  remove(self);
};

/*
==============================
SUB_UseTargets

the global "activator" should be set to the entity that initiated the firing.

If self.delay is set, a DelayedUse entity will be created that will actually
do the SUB_UseTargets after that many seconds have passed.

Centerprints any self.message to the activator.

Removes all entities with a targetname that match self.killtarget,
and removes them, so some events can remove other triggers.

Search for (string)targetname in all entities that
match (string)self.target and call their .use function

==============================
*/
void() SUB_UseTargets =
{
  local entity t, act, stemp, otemp;

//
// check for a delay
//
  if (self.delay)
  {
    // create a temp object to fire at a later time
    t = spawn();
    t.classname = "DelayedUse";
    t.nextthink = time + self.delay;
    t.think = DelayThink;
    t.enemy = activator;
    t.message = self.message;
    t.killtarget = self.killtarget;
    t.target = self.target;
    return;
  }
  
  
//
// print the message
//
  if (activator.classname == "player" && self.message != string_null)
  {
    centerprint (activator, self.message);

    if (!self.noise)
      sound (activator, CHAN_VOICE, "misc/talk.wav", 1, ATTN_NORM);
  }

  //
  // kill the killtagets
  //
  if (self.killtarget != string_null)
  {
    t = find (world, targetname, self.killtarget);
    
    while( t )
    {
      remove (t);
      t = find (t, targetname, self.killtarget);
    }
  }
  
  //
  // fire targets
  //
  if (self.target != string_null)
  {
    act = activator;
    t = find (world, targetname, self.target);
    while( t )
    {
      stemp = self;
      otemp = other;
      self = t;
      other = stemp;
      if (self.use != SUB_Null)
      {
        if (self.use)
        self.use ();
      }
      self = stemp;
      other = otemp;
      activator = act;
      t = find (t, targetname, self.target);
    }
  }
};