path: root/src/map/magic-stmt.c

#include "magic-interpreter.h"
#include "magic-expr.h"
#include "magic-expr-eval.h"
#include "magic-interpreter-aux.h"

int
clif_spawn_fake_npc_for_player(struct map_session_data *sd, int fake_npc_id);

#define INVISIBLE_NPC 127 /* used for local spell effects */

//#define DEBUG

#ifdef DEBUG
static void
print_val(val_t *v)
{
        switch (v->ty) {
        case TY_UNDEF: fprintf(stderr, "UNDEF"); break;
        case TY_INT: fprintf(stderr, "%d", v->v.v_int); break;
        case TY_DIR: fprintf(stderr, "dir%d", v->v.v_int); break;
        case TY_STRING: fprintf(stderr, "`%s'", v->v.v_string); break;
        default: fprintf(stderr, "ty%d", v->ty); break;
        }
}

static void
dump_env(env_t *env)
{
        int i;
        for (i = 0; i < env->base_env->vars_nr; i++) {
                val_t *v = &env->vars[i];
                val_t *bv = &env->base_env->vars[i];

                fprintf(stderr, "%02x %30s ", i, env->base_env->var_name[i]);
                print_val(v);
                fprintf(stderr, "\t(");
                print_val(bv);
                fprintf(stderr, ")\n");
        }
}
#endif

static void
clear_activation_record(cont_activation_record_t *ar)
{
        switch (ar->ty) {
        case CONT_STACK_FOREACH:
                free(ar->c.c_foreach.entities);
                break;
        case CONT_STACK_PROC:
                free(ar->c.c_proc.old_actuals);
                break;
        }
}

static int
invocation_timer_callback(int _, unsigned int __, int id, int data)
{
        invocation_t *invocation = (invocation_t *) map_id2bl(id);

        if (invocation) {
                invocation->timer = 0;
                spell_execute(invocation);
        }
        return 0;
}

static void
clear_stack(invocation_t *invocation)
{
        int i;

        for (i = 0; i < invocation->stack_size; i++)
                clear_activation_record(&invocation->stack[i]);

        invocation->stack_size = 0;
}

static void
free_invocation(invocation_t *invocation)
{
        if (invocation->status_change_refs)
                free(invocation->status_change_refs);

        if (invocation->flags & INVOCATION_FLAG_BOUND) {
                entity_t *e = map_id2bl(invocation->subject);
                if (e && e->type == BL_PC)
                        spell_unbind((character_t *) e, invocation); 
        }

        clear_stack(invocation);

        if (invocation->timer)
                delete_timer(invocation->timer, invocation_timer_callback);

        magic_free_env(invocation->env);

	map_delblock(&invocation->bl);
        map_delobject(invocation->bl.id); // also frees the object
//        free(invocation);
}

void
magic_stop_completely(character_t *c)
{
        while (c->active_spells)
                free_invocation(c->active_spells);
}

/* Spell execution has finished normally or we have been notified by a finished skill timer */
static void
try_to_finish_invocation(invocation_t *invocation)
{
        if (invocation->status_change_refs_nr == 0 && !invocation->current_effect) {
                if (invocation->end_effect) {
                        clear_stack(invocation);
                        invocation->current_effect = invocation->end_effect;
                        invocation->end_effect = NULL;
                        spell_execute(invocation);
                } else
                        free_invocation(invocation);
        }
}

static void
char_set_attack_info(character_t *subject, int speed, int range)
{
        subject->attack_spell_delay = speed;
        subject->attack_spell_range = range;

        if (speed == 0) {
                pc_calcstatus(subject, 1);
                clif_updatestatus(subject, SP_ASPD);
                clif_updatestatus(subject, SP_ATTACKRANGE);
        } else {
                subject->aspd = speed;
                clif_updatestatus(subject, SP_ASPD);
                clif_updatestatus(subject, SP_ATTACKRANGE);
        }
}

static void
char_set_weapon_icon(character_t *subject, int count, int icon, int look)
{
//        const int magic_item_inventory_index = -1;
//        const int weapon_position = 4;

        // The icon isn't working at the moment.

        subject->attack_spell_icon_override = icon;
        subject->attack_spell_look_override = look;

        clif_fixpcpos(subject);
        if (count) {
//                /* Set it to `override' */
//                clif_additem(subject, magic_item_inventory_index, count, 0, icon);
                clif_changelook(&subject->bl, LOOK_WEAPON, look);
//                clif_equipitemack(subject, magic_item_inventory_index, weapon_position, 1);
        } else {
                /* Set it to `normal' */
                clif_changelook(&subject->bl, LOOK_WEAPON, subject->status.weapon);

//                if (subject->equip_index[weapon_position] == -1)
//                        clif_equipitemack(subject, 0, weapon_position, 1);
//                else
//                        clif_equipitemack(subject, subject->equip_index[weapon_position], weapon_position, 1);
        }
}

static int
trigger_spell(int subject, int spell)
{
        invocation_t *invocation = (invocation_t *)map_id2bl(spell);

        if (!invocation)
                return 0;

        invocation = spell_clone_effect(invocation);

        spell_bind((character_t *)map_id2bl(subject), invocation);
        magic_clear_var(&invocation->env->vars[VAR_CASTER]);
        invocation->env->vars[VAR_CASTER].ty = TY_ENTITY;
        invocation->env->vars[VAR_CASTER].v.v_int = subject;

        return invocation->bl.id;
}

static void
entity_warp(entity_t *target, int destm, int destx, int desty);

static void
char_update(character_t *character)
{
        entity_warp((entity_t *)character, character->bl.m, character->bl.x, character->bl.y);
}

static int
timer_callback_effect(int _, unsigned int __, int id, int data)
{
        clif_misceffect(map_id2bl(id), data);
        return 0;
}

static void
entity_effect(entity_t *entity, int effect_nr, int delay)
{
        add_timer(gettick() + delay,
                  &timer_callback_effect,
                  entity->id,
                  effect_nr);
}

void
magic_unshroud(character_t *other_char)
{
        other_char->state.shroud_active = 0;
        // Now warp the caster out of and back into here to refresh everyone's display
        char_update(other_char);
        clif_displaymessage(other_char->fd, "Your shroud has been dispelled!");
//        entity_effect(&other_char->bl, MAGIC_EFFECT_REVEAL);
}


static int
timer_callback_effect_npc_delete(int timer_id, unsigned int odelay, int npc_id, int _)
{
    struct npc_data *effect_npc = (struct npc_data *)map_id2bl(npc_id);
    npc_free(effect_npc);

    return 0;
}

static struct npc_data *
local_spell_effect(int m, int x, int y, int effect, int tdelay)
{
    int delay = 30000; /* 1 minute should be enough for all interesting spell effects, I hope */
    struct npc_data *effect_npc = npc_spawn_text(m, x, y,
                                                 INVISIBLE_NPC, "", NULL);
    int effect_npc_id = effect_npc->bl.id;

    entity_effect(&effect_npc->bl, effect, tdelay);
    add_timer(gettick() + delay,
              timer_callback_effect_npc_delete,
              effect_npc_id, 0);

    return effect_npc;
}


static int
op_sfx(env_t *env, int args_nr, val_t *args)
{
        int delay = ARGINT(2);

        if (TY(0) == TY_ENTITY) {
                entity_effect(ARGENTITY(0), ARGINT(1), delay);
        } else if (TY(0) == TY_LOCATION) {
                local_spell_effect(ARGLOCATION(0).m,
                                   ARGLOCATION(0).x,
                                   ARGLOCATION(0).y,
                                   ARGINT(1), delay);
        } else return 1;

        return 0;
}


static int
op_instaheal(env_t *env, int args_nr, val_t *args)
{
        entity_t *caster = (VAR(VAR_CASTER).ty == TY_ENTITY)
                         ? map_id2bl(VAR(VAR_CASTER).v.v_int)
                         : NULL;
        if (!caster)
                caster = ARGENTITY(0);
                
        battle_heal(caster, ARGENTITY(0), ARGINT(1), ARGINT(2), 0);
        return 0;
}


static int
op_itemheal(env_t *env, int args_nr, val_t *args)
{
        entity_t *subject = ARGENTITY(0);
        if (subject->type == BL_PC) {
                pc_itemheal((struct map_session_data *) subject,
                            ARGINT(1),
                            ARGINT(2));
        } else return op_instaheal(env, args_nr, args);

        return 0;
}


#define SHROUD_HIDE_NAME_TALKING_FLAG	(1 << 0)
#define SHROUD_DISAPPEAR_ON_PICKUP_FLAG	(1 << 1)
#define SHROUD_DISAPPEAR_ON_TALK_FLAG	(1 << 2)

#define ARGCHAR(n) (ARGENTITY(n)->type == BL_PC) ? (character_t *)(ARGENTITY(n)) : NULL

static int
op_shroud(env_t *env, int args_nr, val_t *args)
{
        character_t *subject = ARGCHAR(0);
        int arg = ARGINT(1);

        if (!subject)
                return 0;

        subject->state.shroud_active = 1;
        subject->state.shroud_hides_name_talking = (arg & SHROUD_HIDE_NAME_TALKING_FLAG) != 0;
        subject->state.shroud_disappears_on_pickup = (arg & SHROUD_DISAPPEAR_ON_PICKUP_FLAG) != 0;
        subject->state.shroud_disappears_on_talk = (arg & SHROUD_DISAPPEAR_ON_TALK_FLAG) != 0;
        return 0;
}

static int
op_reveal(env_t *env, int args_nr, val_t *args)
{
        character_t *subject = ARGCHAR(0);
        
        if (subject && subject->state.shroud_active)
                magic_unshroud(subject);

        return 0;
}

static int
op_message(env_t *env, int args_nr, val_t *args)
{
        character_t *subject = ARGCHAR(0);

        if (subject)
                clif_displaymessage(subject->fd, ARGSTR(1));

        return 0;
}

static int
timer_callback_kill_npc(int timer_id, unsigned int odelay, int npc_id, int data)
{
        struct npc_data *npc = (struct npc_data *) map_id2bl(npc_id);
        if (npc)
                npc_free(npc);

        return 0;
}

static int
op_messenger_npc(env_t *env, int args_nr, val_t *args)
{
        struct npc_data *npc;
        location_t *loc = &ARGLOCATION(0);

        npc = npc_spawn_text(loc->m, loc->x, loc->y,
                             ARGINT(1), ARGSTR(2), ARGSTR(3));

        add_timer(gettick() + ARGINT(4),
                  &timer_callback_kill_npc,
                  npc->bl.id,
                  0);

        return 0;
}

static void
entity_warp(entity_t *target, int destm, int destx, int desty)
{
        if (target->type == BL_PC
            || target->type == BL_MOB) {

                switch (target->type) {
                case BL_PC: {
                        character_t *character = (character_t *) target;
                        clif_clearchar_area(&character->bl, 3);
                        map_delblock(&character->bl);
                        character->bl.x = destx;
                        character->bl.y = desty;
                        character->bl.m = destm;

                        pc_touch_all_relevant_npcs(character);

                        // Note that touching NPCs may have triggered warping and thereby updated x and y:
                        clif_changemap(character, map[character->bl.m].name, character->bl.x, character->bl.y);

                        break;
                }
                case BL_MOB:
                        target->x = destx;
                        target->y = desty;
                        target->m = destm;
                        clif_fixmobpos((struct mob_data *) target);
                        break;
                }
        }
}

static int
op_move(env_t *env, int args_nr, val_t *args)
{
        entity_t *subject = ARGENTITY(0);
        int dir = ARGDIR(1);

        int newx = subject->x + heading_x[dir];
        int newy = subject->y + heading_y[dir];

        if (!map_is_solid(subject->m, newx, newy))
                entity_warp(subject, subject->m, newx, newy);

        return 0;
}

static int
op_warp(env_t *env, int args_nr, val_t *args)
{
        entity_t *subject = ARGENTITY(0);
        location_t *loc = &ARGLOCATION(1);

        entity_warp(subject, loc->m, loc->x, loc->y);

        return 0;
}

static int
op_banish(env_t *env, int args_nr, val_t *args)
{
        entity_t *subject = ARGENTITY(0);

        if (subject->type == BL_MOB) {
                struct mob_data *mob = (struct mob_data *) subject;

                if (mob->mode & MOB_MODE_SUMMONED)
                        mob_catch_delete(mob, 3);
        }

        return 0;
}

static void
record_status_change(invocation_t *invocation, int bl_id, int sc_id)
{
        int index = invocation->status_change_refs_nr++;
        status_change_ref_t *cr;

        if (invocation->status_change_refs)
                invocation->status_change_refs = realloc(invocation->status_change_refs,
                                                         sizeof(status_change_ref_t)
                                                         * invocation->status_change_refs_nr);
        else
                invocation->status_change_refs = malloc(sizeof(status_change_ref_t));

        cr = &invocation->status_change_refs[index];

        cr->sc_type = sc_id;
        cr->bl_id = bl_id;
}

static int
op_status_change(env_t *env, int args_nr, val_t *args)
{
        entity_t *subject = ARGENTITY(0);
        int invocation_id = VAR(VAR_INVOCATION).ty == TY_INVOCATION
                          ? VAR(VAR_INVOCATION).v.v_int
                          : 0;
        invocation_t *invocation = (invocation_t *)map_id2bl(invocation_id);

        skill_status_effect(subject, ARGINT(1), ARGINT(2), ARGINT(3), ARGINT(4), ARGINT(5), ARGINT(6), 0, invocation_id);

        if (invocation)
                record_status_change(invocation, subject->id, ARGINT(1));

        return 0;
}

static int
op_override_attack(env_t *env, int args_nr, val_t *args)
{
        entity_t *psubject = ARGENTITY(0);
        int charges = ARGINT(1);
        int attack_delay = ARGINT(2);
        int attack_range = ARGINT(3);
        int icon = ARGINT(4);
        int look = ARGINT(5);
        character_t *subject;

        if (psubject->type != BL_PC)
                return 0;

        subject = (character_t *) psubject;

        if (subject->attack_spell_override) {
                invocation_t *old_invocation = (invocation_t *)map_id2bl(subject->attack_spell_override);
                if (old_invocation)
                        free_invocation(old_invocation);
        }

        subject->attack_spell_override = trigger_spell(subject->bl.id, VAR(VAR_INVOCATION).v.v_int);
        subject->attack_spell_charges = charges;

        if (subject->attack_spell_override) {
                char_set_weapon_icon(subject, charges, icon, look);
                char_set_attack_info(subject, attack_delay, attack_range);
        }

        return 0;
}

static int
op_create_item(env_t *env, int args_nr, val_t *args)
{
        struct item item;
        entity_t *entity = ARGENTITY(0);
        character_t *subject;
        int stackable;
        int count = ARGINT(2);
        if (count <= 0)
                return 0;

        if (entity->type == BL_PC)
                subject = (character_t *) entity;
        else
                return 0;

        GET_ARG_ITEM(1, item, stackable);

        if (!stackable)
                while (count--)
                        pc_additem(subject, &item, 1);
        else
                pc_additem(subject, &item, count);

        return 0;
}


#define AGGRAVATION_MODE_ATTACKS_CASTER(n) 	((n) == 0 || (n) == 2)
#define AGGRAVATION_MODE_MAKES_AGGRESSIVE(n)	((n) > 0)

static int
op_aggravate(env_t *env, int args_nr, val_t *args)
{
        entity_t *victim = ARGENTITY(2);
        int mode = ARGINT(1);
        entity_t *target = ARGENTITY(0);
        struct mob_data *other;

        if (target->type == BL_MOB)
                other = (struct mob_data *) target;
        else
                return 0;

        mob_target(other, victim, battle_get_range(victim));

        if (AGGRAVATION_MODE_MAKES_AGGRESSIVE(mode))
                other->mode = 0x85 | (other->mode & MOB_SENSIBLE_MASK); /* war */

        if (AGGRAVATION_MODE_ATTACKS_CASTER(mode)) {
                other->target_id = victim->id;
                other->attacked_id = victim->id;
        }

        return 0;
}

#define MONSTER_ATTITUDE_HOSTILE	0
#define MONSTER_ATTITUDE_FRIENDLY	1
#define MONSTER_ATTITUDE_SERVANT	2

static int
op_spawn(env_t *env, int args_nr, val_t *args)
{
        area_t *area = ARGAREA(0);
        entity_t *owner_e = ARGENTITY(1);
        int monster_id = ARGINT(2);
        int monster_attitude = ARGINT(3);
        int monster_count = ARGINT(4);
        int monster_lifetime = ARGINT(5);
        int i;

        character_t *owner = (monster_attitude == MONSTER_ATTITUDE_SERVANT && owner_e->type == BL_PC)
                           ? (character_t *) owner_e
                           : NULL;

        for (i = 0; i < monster_count; i++) {
                location_t loc;
                magic_random_location(&loc, area);

                int mob_id;
                struct mob_data *mob;

                mob_id = mob_once_spawn(owner, map[loc.m].name, loc.x, loc.y, "--ja--", // Is that needed?
                                        monster_id, 1, "");

                mob = (struct mob_data *)map_id2bl(mob_id);

                if (mob) {
                        mob->mode = mob_db[monster_id].mode;

                        switch (monster_attitude) {

                        case MONSTER_ATTITUDE_SERVANT:
                                mob->state.special_mob_ai = 1;
                                mob->mode |= 0x04;
                                break;

                        case MONSTER_ATTITUDE_FRIENDLY:
                                mob->mode = 0x81;
                                break;

                        case MONSTER_ATTITUDE_HOSTILE:
                                mob->mode = 0x85;
                                if (owner) {
                                        mob->target_id = owner->bl.id;
                                        mob->attacked_id = owner->bl.id;
                                }
                                break;
                        }

                        mob->mode |= MOB_MODE_SUMMONED | MOB_MODE_TURNS_AGAINST_BAD_MASTER;

                        mob->deletetimer = add_timer(gettick() + monster_lifetime,
                                                     mob_timer_delete,
                                                     mob_id, 0);

                        if (owner) {
                                mob->master_id = owner->bl.id;
                                mob->master_dist = 6;
                        }
                }
        }

        return 0;
}


static int
op_injure(env_t *env, int args_nr, val_t *args)
{
        entity_t *caster = ARGENTITY(0);
        entity_t *target = ARGENTITY(1);
        int damage_caused = ARGINT(2);
        int mp_damage = ARGINT(3);
        int target_hp = battle_get_hp(target);
        int mdef = battle_get_mdef(target);

        if (target->type == BL_PC
            && !map[target->m].flag.pvp)
                return 0; /* Cannot damage other players outside of pvp */

        if (target != caster) {
                /* Not protected against own spells */
                damage_caused = (damage_caused * (100 - mdef)) / 100;
                mp_damage = (mp_damage * (100 - mdef)) / 100;
        }

        damage_caused = (damage_caused > target_hp) ? target_hp : damage_caused;

        if (damage_caused < 0)
                damage_caused = 0;

        if (damage_caused || mp_damage) {
                // display damage first, because dealing damage may deallocate the target.
                clif_damage(caster, target, gettick(),
                            0, 0, damage_caused, 0, 0, 0);
                battle_damage(caster, target, damage_caused, mp_damage);
        }

        return 0;
}

static int
op_emote(env_t *env, int args_nr, val_t *args)
{
        entity_t *victim = ARGENTITY(0);
        int emotion = ARGINT(1);
        clif_emotion(victim, emotion);

        return 0;
}

static int
op_set_script_variable(env_t *env, int args_nr, val_t *args)
{
        character_t *c = (ETY(0) == BL_PC)? ARGPC(0) : NULL;

        if (!c)
                return 1;

        pc_setglobalreg(c, ARGSTR(1), ARGINT(2));

        return 0;
}


static int
op_set_hair_colour(env_t *env, int args_nr, val_t *args)
{
        character_t *c = (ETY(0) == BL_PC)? ARGPC(0) : NULL;

        if (!c)
                return 1;

        pc_changelook(c, LOOK_HAIR_COLOR, ARGINT(1));

        return 0;
}


static int
op_set_hair_style(env_t *env, int args_nr, val_t *args)
{
        character_t *c = (ETY(0) == BL_PC)? ARGPC(0) : NULL;

        if (!c)
                return 1;

        pc_changelook(c, LOOK_HAIR, ARGINT(1));

        return 0;
}

static int
op_drop_item_for(env_t *env, int args_nr, val_t *args)
{
        struct item item;
        int stackable;
        location_t *loc = &ARGLOCATION(0);
        int count = ARGINT(2);
        int time = ARGINT(3);
        character_t *c = ((args_nr > 4) && (ETY(4) == BL_PC))? ARGPC(4) : NULL;
        int delay = (args_nr > 5)? ARGINT(5) : 0;
        int delaytime[3] = { delay, delay, delay };
        character_t *owners[3] = { c, NULL, NULL };

        GET_ARG_ITEM(1, item, stackable);

        if (stackable)
                map_addflooritem_any(&item, count, loc->m, loc->x, loc->y,
                                     owners, delaytime,
                                     time, 0);
        else while (count-- > 0)
                map_addflooritem_any(&item, 1, loc->m, loc->x, loc->y,
                                     owners, delaytime,
                                     time, 0);

        return 0;
}

static op_t operations[] =
{
        { "sfx", ".ii", op_sfx },
        { "instaheal", "eii", op_instaheal },
        { "itemheal", "eii", op_itemheal },
        { "shroud", "ei", op_shroud },
        { "unshroud", "e", op_reveal },
        { "message", "es", op_message },
        { "messenger_npc", "lissi", op_messenger_npc },
        { "move", "ed", op_move },
        { "warp", "el", op_warp },
        { "banish", "e", op_banish },
        { "status_change", "eiiiiii", op_status_change },
        { "override_attack", "eiiiii", op_override_attack },
        { "create_item", "e.i", op_create_item },
        { "aggravate", "eie", op_aggravate },
        { "spawn", "aeiiii", op_spawn },
        { "injure", "eeii", op_injure },
        { "emote", "ei", op_emote },
        { "set_script_variable", "esi", op_set_script_variable },
        { "set_hair_colour", "ei", op_set_hair_colour },
        { "set_hair_style", "ei", op_set_hair_style },
        { "drop_item", "l.ii", op_drop_item_for },
        { "drop_item_for", "l.iiei", op_drop_item_for },
        { NULL, NULL, NULL }
};

static int operations_sorted = 0;
static int operation_count;


int
compare_operations(const void *lhs, const void *rhs)
{
        return strcmp(((op_t *)lhs)->name, ((op_t *)rhs)->name);
}


op_t *
magic_get_op(char *name, int *index)
{
        op_t key;

        if (!operations_sorted) {
                op_t *opc = operations;

                while (opc->name)
                        ++opc;

                operation_count = opc - operations;

                qsort(operations, operation_count, sizeof(op_t), compare_operations);
                operations_sorted = 1;
        }

        key.name = name;
        op_t *op = bsearch(&key, operations, operation_count, sizeof(op_t), compare_operations);

        if (op && index)
                *index = op - operations;

        return op;
}


void
spell_effect_report_termination(int invocation_id, int bl_id, int sc_id, int supplanted)
{
        int i;
        int index = -1;
        invocation_t *invocation = (invocation_t *) map_id2bl(invocation_id);

        if (!invocation)
                return;

        for (i = 0; i < invocation->status_change_refs_nr; i++) {
                status_change_ref_t *cr = &invocation->status_change_refs[i];
                if (cr->sc_type == sc_id && cr->bl_id == bl_id) {
                        index = i;
                        break;
                }
        }

        if (index == -1) {
                fprintf(stderr, "[magic] INTERNAL ERROR: spell-effect-report-termination:  tried to terminate on unexpected bl %d, sc %d\n", bl_id, sc_id);
                return;
        }

        if (index == invocation->status_change_refs_nr -1)
                invocation->status_change_refs_nr--;
        else /* Copy last change ref to the one we are deleting */
                invocation->status_change_refs[index] = invocation->status_change_refs[--invocation->status_change_refs_nr];

        try_to_finish_invocation(invocation);
}

static effect_t *
return_to_stack(invocation_t *invocation)
{
        if (!invocation->stack_size)
                return NULL;
        else {
                cont_activation_record_t *ar = invocation->stack + (invocation->stack_size - 1);
                switch (ar->ty) {

                case CONT_STACK_PROC: {
                        effect_t *ret = ar->return_location;
                        int i;

                        for (i = 0; i < ar->c.c_proc.args_nr; i++) {
                                val_t *var = &invocation->env->vars[ar->c.c_proc.formals[i]];
                                magic_clear_var(var);
                                *var = ar->c.c_proc.old_actuals[i];
                        }

                        clear_activation_record(ar);
                        --invocation->stack_size;

                        return ret;
                }

                case CONT_STACK_FOREACH: {
                        int entity_id;
                        val_t *var = &invocation->env->vars[ar->c.c_foreach.id];

                        do {
                                if (ar->c.c_foreach.index >= ar->c.c_foreach.entities_nr) {
                                        effect_t *ret = ar->return_location;
                                        clear_activation_record(ar);
                                        --invocation->stack_size;
                                        return ret;
                                }

                                entity_id = ar->c.c_foreach.entities[ar->c.c_foreach.index++];
                        } while (!entity_id || !map_id2bl(entity_id));

                        magic_clear_var(var);
                        var->ty = TY_ENTITY;
                        var->v.v_int = entity_id;

                        return ar->c.c_foreach.body;
                }

                case CONT_STACK_FOR:
                        if (ar->c.c_for.current > ar->c.c_for.stop) {
                                effect_t *ret = ar->return_location;
                                clear_activation_record(ar);
                                --invocation->stack_size;
                                return ret;
                        }

                        magic_clear_var(&invocation->env->vars[ar->c.c_for.id]);
                        invocation->env->vars[ar->c.c_for.id].ty = TY_INT;
                        invocation->env->vars[ar->c.c_for.id].v.v_int = ar->c.c_for.current++;

                        return ar->c.c_for.body;

                default:
                        fprintf(stderr, "[magic] INTERNAL ERROR: While executing spell `%s':  stack corruption\n", invocation->spell->name);
                        return NULL;
                }
        }
}

static cont_activation_record_t *
add_stack_entry(invocation_t *invocation, int ty, effect_t *return_location)
{
        cont_activation_record_t *ar = invocation->stack + invocation->stack_size++;
        if (invocation->stack_size >= MAX_STACK_SIZE) {
                fprintf(stderr, "[magic] Execution stack size exceeded in spell `%s'; truncating effect\n", invocation->spell->name);
                invocation->stack_size--;
                return NULL;
        }

        ar->ty = ty;
        ar->return_location = return_location;
        return ar;
}

static int
find_entities_in_area_c(entity_t *target, va_list va)
{
        int *entities_allocd_p = va_arg(va, int *);
        int *entities_nr_p = va_arg(va, int *);
        int **entities_p = va_arg(va, int **);
        int filter = va_arg(va, int);

        switch (target->type) {

        case BL_PC:
                if (filter == FOREACH_FILTER_PC
                    || filter == FOREACH_FILTER_ENTITY
                    || (filter == FOREACH_FILTER_TARGET
                        && map[target->m].flag.pvp))
                        break;
                else
                        return 0;

        case BL_MOB:
                if (filter == FOREACH_FILTER_MOB
                    || filter == FOREACH_FILTER_ENTITY
                    || filter == FOREACH_FILTER_TARGET)
                        break;
                else
                        return 0;

        default:
                return 0;
        }

        if (*entities_nr_p == *entities_allocd_p) {
                /* Need more space */
                (*entities_allocd_p) += 32;
                *entities_p = realloc(*entities_p, sizeof(int) * (*entities_allocd_p));
        }

        (*entities_p)[(*entities_nr_p)++] = target->id;

        return 0;
}

static void
find_entities_in_area(area_t *area, int *entities_allocd_p, int *entities_nr_p, int **entities_p, int filter)
{
        switch (area->ty) {
        case AREA_UNION:
                find_entities_in_area(area->a.a_union[0], entities_allocd_p, entities_nr_p, entities_p, filter);
                find_entities_in_area(area->a.a_union[1], entities_allocd_p, entities_nr_p, entities_p, filter);
                break;

        default: {
                int m, x, y, width, height;
                magic_area_rect(&m, &x, &y, &width, &height, area);
                map_foreachinarea(find_entities_in_area_c,
                                  m, x, y, x+width, y+height,
                                  0 /* filter elsewhere */,
                                  entities_allocd_p, entities_nr_p, entities_p, filter);
        }
        }
}

static effect_t *
run_foreach(invocation_t *invocation, effect_t *foreach, effect_t *return_location)
{
        val_t area;
        int filter = foreach->e.e_foreach.filter;
        int id = foreach->e.e_foreach.id;
        effect_t *body = foreach->e.e_foreach.body;

        magic_eval(invocation->env, &area, foreach->e.e_foreach.area);

        if (area.ty != TY_AREA) {
                magic_clear_var(&area);
                fprintf(stderr, "[magic] Error in spell `%s':  FOREACH loop over non-area\n", invocation->spell->name);
                return return_location;
        } else {
                cont_activation_record_t *ar = add_stack_entry(invocation, CONT_STACK_FOREACH, return_location);
                int entities_allocd = 64;
                int *entities_collect = malloc(entities_allocd * sizeof(int));
                int *entities;
                int *shuffle_board;
                int entities_nr = 0;
                int i;

                if (!ar)
                        return return_location;

                find_entities_in_area(area.v.v_area, &entities_allocd, &entities_nr, &entities_collect, filter);

                /* Now shuffle */
                shuffle_board = malloc((sizeof(int) * (1 + entities_nr))); // +1: to avoid spurious warnings in memory profilers
                entities = malloc((sizeof(int) * (1 + entities_nr))); // +1: to avoid spurious warnings in memory profilers
                for (i = 0; i < entities_nr; i++)
                        shuffle_board[i] = i;

                for (i = entities_nr - 1 ; i >= 0; i--) {
                        int random_index = rand() % (i + 1);
                        entities[i] = entities_collect[shuffle_board[random_index]];
                        shuffle_board[random_index] = shuffle_board[i]; // thus, we are guaranteed only to use unused indices
                }

                free(entities_collect);
                free(shuffle_board);
                /* Done shuffling */

                ar->c.c_foreach.id = id;
                ar->c.c_foreach.body = body;
                ar->c.c_foreach.index = 0;
                ar->c.c_foreach.entities_nr = entities_nr;
                ar->c.c_foreach.entities = entities;

                magic_clear_var(&area);

                return return_to_stack(invocation);
        }
}

static effect_t *
run_for(invocation_t *invocation, effect_t *for_, effect_t *return_location)
{
        cont_activation_record_t *ar;
        int id = for_->e.e_for.id;
        val_t start;
        val_t stop;

        magic_eval(invocation->env, &start, for_->e.e_for.start);
        magic_eval(invocation->env, &stop, for_->e.e_for.stop);

        if (start.ty != TY_INT || stop.ty != TY_INT) {
                magic_clear_var(&start);
                magic_clear_var(&stop);
                fprintf(stderr, "[magic] Error in spell `%s':  FOR loop start or stop point is not an integer\n", invocation->spell->name);
                return return_location;
        }

        ar = add_stack_entry(invocation, CONT_STACK_FOR, return_location);

        if (!ar)
                return return_location;

        ar->c.c_for.id = id;
        ar->c.c_for.current = start.v.v_int;
        ar->c.c_for.stop = stop.v.v_int;
        ar->c.c_for.body = for_->e.e_for.body;

        return return_to_stack(invocation);
}

static effect_t *
run_call(invocation_t *invocation, effect_t *return_location)
{
        effect_t *current = invocation->current_effect;
        cont_activation_record_t *ar;
        int args_nr = current->e.e_call.args_nr;
        int *formals = current->e.e_call.formals;
        val_t *old_actuals = aCalloc(sizeof(val_t), args_nr);
        int i;

        ar = add_stack_entry(invocation, CONT_STACK_PROC, return_location);
        ar->c.c_proc.args_nr = args_nr;
        ar->c.c_proc.formals = formals;
        ar->c.c_proc.old_actuals = old_actuals;
        for (i = 0; i < args_nr; i++) {
                val_t *env_val = &invocation->env->vars[formals[i]];
                val_t result;
                magic_copy_var(&old_actuals[i], env_val);
                magic_eval(invocation->env, &result, current->e.e_call.actuals[i]);
                *env_val = result;
        }

        return current->e.e_call.body;
}

#ifdef DEBUG
static void
print_cfg(int i, effect_t *e)
{
        int j;
        for (j = 0; j < i; j++)
                printf("    ");

        printf("%p: ", e);

        if (!e) {
                puts(" -- end --");
                return;
        }

        switch (e->ty) {
        case EFFECT_SKIP:
                puts("SKIP"); break;
        case EFFECT_END:
                puts("END"); break;
        case EFFECT_ABORT:
                puts("ABORT"); break;
        case EFFECT_ASSIGN:
                puts("ASSIGN"); break;
        case EFFECT_FOREACH:
                puts("FOREACH");
                print_cfg(i+1, e->e.e_foreach.body);
                break;
        case EFFECT_FOR:
                puts("FOR");
                print_cfg(i+1, e->e.e_for.body);
                break;
        case EFFECT_IF:
                puts("IF");
                for (j = 0; j < i; j++)
                        printf("    ");
                puts("THEN");
                print_cfg(i+1, e->e.e_if.true_branch);
                for (j = 0; j < i; j++)
                        printf("    ");
                puts("ELSE");
                print_cfg(i+1, e->e.e_if.false_branch);
                break;
        case EFFECT_SLEEP:
                puts("SLEEP"); break;
        case EFFECT_SCRIPT:
                puts("SCRIPT"); break;
        case EFFECT_BREAK:
                puts("BREAK"); break;
        case EFFECT_OP:
                puts("OP"); break;
        }
        print_cfg(i, e->next);
}
#endif


/**
 * Execute a spell invocation until we abort, finish, or hit the next `sleep'.
 *
 * Use spell_execute() to automate handling of timers
 *
 * Returns: 0 if finished (all memory is freed implicitly)
 *          >1 if we hit `sleep'; the result is the number of ticks we should sleep for.
 *          -1 if we paused to wait for a user action (via script interaction)
 */
static int
spell_run(invocation_t *invocation, int allow_delete)
{
#ifdef DEBUG
        fprintf(stderr, "Resuming execution:  invocation of `%s'\n", invocation->spell->name);
        print_cfg(1, invocation->current_effect);
#endif        
        while (invocation->current_effect) {
                effect_t *e = invocation->current_effect;
                effect_t *next = e->next;
                int i;

#ifdef DEBUG
                fprintf(stderr, "Next step of type %d\n", e->ty);
                dump_env(invocation->env);
#endif        

                switch (e->ty) {
                case EFFECT_SKIP:
                        break;

                case EFFECT_ABORT:
                        invocation->flags |= INVOCATION_FLAG_ABORTED;
                        invocation->end_effect = NULL;
                case EFFECT_END:
                        clear_stack(invocation);
                        next = NULL;
                        break;

                case EFFECT_ASSIGN:
                        magic_eval(invocation->env, &invocation->env->vars[e->e.e_assign.id], e->e.e_assign.expr);
                        break;

                case EFFECT_FOREACH:
                        next = run_foreach(invocation, e, next);
                        break;

                case EFFECT_FOR:
                        next = run_for(invocation, e, next);
                        break;

                case EFFECT_IF:
                        if (magic_eval_int(invocation->env, e->e.e_if.cond))
                                next = e->e.e_if.true_branch;
                        else
                                next = e->e.e_if.false_branch;
                        break;

                case EFFECT_SLEEP: {
                        int sleeptime = magic_eval_int(invocation->env, e->e.e_sleep);
                        invocation->current_effect = next;
                        if (sleeptime > 0)
                                return sleeptime;
                        break;
                }

                case EFFECT_SCRIPT: {
                        character_t *caster = (character_t *) map_id2bl(invocation->caster);
                        if (caster) {
                                env_t *env = invocation->env;
                                character_t *caster = (character_t *)map_id2bl(invocation->caster);
                                argrec_t arg[] = { {"@target", .v.i = VAR(VAR_TARGET).ty == TY_ENTITY ? 0 : VAR(VAR_TARGET).v.v_int },
                                                   {"@caster", .v.i = invocation->caster },
                                                   {"@caster_name$", .v.s = caster ? caster->status.name : "" }};
                                int message_recipient = VAR(VAR_SCRIPTTARGET).ty == TY_ENTITY
                                                        ? VAR(VAR_SCRIPTTARGET).v.v_int
                                                        : invocation->caster;
                                character_t *recipient = (character_t *) map_id2bl(message_recipient);

                                if (recipient->npc_id && recipient->npc_id != invocation->bl.id)
                                        break; /* Don't send multiple message boxes at once */

                                if (!invocation->script_pos) // first time running this script?
                                        clif_spawn_fake_npc_for_player(recipient,
                                                                       invocation->bl.id);
                                // We have to do this or otherwise the client won't think that it's
                                // dealing with an NPC

                                int newpos = run_script_l(e->e.e_script,
                                                          invocation->script_pos,
                                                          message_recipient,
                                                          invocation->bl.id,
                                                          3, arg);
                                /* Returns the new script position, or -1 once the script is finished */
                                if (newpos != -1) {
                                        /* Must set up for continuation */
                                        recipient->npc_id = invocation->bl.id;
                                        recipient->npc_pos = invocation->script_pos = newpos;
                                        return -1; /* Signal `wait for script' */
                                } else
                                        invocation->script_pos = 0;
                                clif_clearchar_id(invocation->bl.id, 1, caster->fd);
                        }
                        break;
                }

                case EFFECT_BREAK:
                        next = return_to_stack(invocation);
                        break;

                case EFFECT_OP: {
                        op_t *op = &operations[e->e.e_op.id];
                        val_t args[MAX_ARGS];

                        for (i = 0; i < e->e.e_op.args_nr; i++)
                                magic_eval(invocation->env, &args[i], e->e.e_op.args[i]);

                        if (!magic_signature_check("effect", op->name, op->signature,
                                                   e->e.e_op.args_nr, args,
                                                   e->e.e_op.line_nr, e->e.e_op.column))
                                op->op(invocation->env, e->e.e_op.args_nr, args);

                        for (i = 0; i < e->e.e_op.args_nr; i++)
                                magic_clear_var(&args[i]);
                        break;
                }

                case EFFECT_CALL:
                        next = run_call(invocation, next);
                        break;

                default:
                        fprintf(stderr, "[magic] INTERNAL ERROR: Unknown effect %d\n", e->ty);
                }


                if (!next)
                        next = return_to_stack(invocation);

                invocation->current_effect = next;
        }

        if (allow_delete)
                try_to_finish_invocation(invocation);
        return 0;
}


extern void
spell_update_location(invocation_t *invocation);

void
spell_execute_d(invocation_t *invocation, int allow_deletion)
{
        int delta;

        spell_update_location(invocation);
        delta = spell_run(invocation, allow_deletion);

        if (delta > 0)
                invocation->timer = add_timer(gettick() + delta,
                                              &invocation_timer_callback,
                                              invocation->bl.id, 0);

        /* If 0, the script cleaned itself.  If -1 (wait-for-script), we must wait for the user. */
}

void
spell_execute(invocation_t *invocation)
{
        spell_execute_d(invocation, 1);
}

int
spell_attack(int caster_id, int target_id)
{
        character_t *caster = (character_t *)map_id2bl(caster_id);
        invocation_t *invocation = (invocation_t *)map_id2bl(caster->attack_spell_override);

        if (invocation
            && caster->attack_spell_charges > 0) {
                magic_clear_var(&invocation->env->vars[VAR_TARGET]);
                invocation->env->vars[VAR_TARGET].ty = TY_ENTITY;
                invocation->env->vars[VAR_TARGET].v.v_int = target_id;

                invocation->current_effect = invocation->trigger_effect;
                invocation->flags &= ~INVOCATION_FLAG_ABORTED;
                spell_execute_d(invocation, 0 /* don't delete the invocation if done */);

                if (!(invocation->flags & INVOCATION_FLAG_ABORTED)) // If we didn't abort:
                        caster->attack_spell_charges--;
        }

        if (invocation
            && caster->attack_spell_override != invocation->bl.id) {
                /* Attack spell changed / was refreshed */
                free_invocation(invocation);
        } else if (!invocation
                   || caster->attack_spell_charges <= 0) {
                caster->attack_spell_override = 0;
                char_set_weapon_icon(caster, 0, 0, 0);
                char_set_attack_info(caster, 0, 0);

                if (invocation)
                        free_invocation(invocation);
        }

        return 1;
}