/* vi: set ts=2:
 +-------------------+  Christian Schlittchen <corwin@amber.kn-bremen.de>
 |                   |  Enno Rehling <enno@eressea.de>
 | Eressea PBEM host |  Katja Zedel <katze@felidae.kn-bremen.de>
 | (c) 1998 - 2003   |  Henning Peters <faroul@beyond.kn-bremen.de>
 |                   |  Ingo Wilken <Ingo.Wilken@informatik.uni-oldenburg.de>
 +-------------------+  Stefan Reich <reich@halbling.de>

 This program may not be used, modified or distributed 
 without prior permission by the authors of Eressea.
*/
#include <platform.h>
#include <kernel/config.h>
#include "gate.h"

/* kernel includes */
#include <kernel/building.h>
#include <kernel/region.h>
#include <kernel/unit.h>
#include <kernel/version.h>

/* util includes */
#include <util/attrib.h>
#include <util/event.h>
#include <util/log.h>
#include <util/resolve.h>

#include <storage.h>

/* libc includes */
#include <stdlib.h>

typedef struct gate_data {
  struct building *gate;
  struct region *target;
} gate_data;

static int gate_handle(trigger * t, void *data)
{
  /* call an event handler on gate.
   * data.v -> ( variant event, int timer )
   */
  gate_data *gd = (gate_data *) t->data.v;
  struct building *b = gd->gate;
  struct region *r = gd->target;

  if (b && b->region && r) {
    unit **up = &b->region->units;
    while (*up) {
      unit *u = *up;
      if (u->building == b)
        move_unit(u, r, NULL);
      if (*up == u)
        up = &u->next;
    }
  } else {
    log_error("could not perform gate::handle()\n");
    return -1;
  }
  unused_arg(data);
  return 0;
}

static void gate_write(const trigger * t, struct storage *store)
{
  gate_data *gd = (gate_data *) t->data.v;
  building *b = gd->gate;
  region *r = gd->target;

  write_building_reference(b, store);
  write_region_reference(r, store);
}

static int gate_read(trigger * t, struct storage *store)
{
  gate_data *gd = (gate_data *) t->data.v;

  int bc =
    read_reference(&gd->gate, store, read_building_reference, resolve_building);
  int rc =
    read_reference(&gd->target, store, read_region_reference,
    RESOLVE_REGION(global.data_version));

  if (bc == 0 && rc == 0) {
    if (!gd->gate || !gd->target)
      return AT_READ_FAIL;
  }
  return AT_READ_OK;
}

static void gate_init(trigger * t)
{
  t->data.v = calloc(sizeof(gate_data), 1);
}

static void gate_done(trigger * t)
{
  free(t->data.v);
}

struct trigger_type tt_gate = {
  "gate",
  gate_init,
  gate_done,
  gate_handle,
  gate_write,
  gate_read
};

trigger *trigger_gate(building * b, region * target)
{
  trigger *t = t_new(&tt_gate);
  gate_data *td = (gate_data *) t->data.v;
  td->gate = b;
  td->target = target;
  return t;
}