#include "world.h"

#include <stdlib.h>
#include <string.h>

World* world_create(void) {
    World* w = (World*)calloc(1, sizeof(World));
    w->next_entity = 1;
    return w;
}

void world_destroy(World* world) {
    if (!world) return;
    for (uint32_t i = 0; i < world->entity_count; i++) {
        Entity e = world->entities[i];
        for (uint32_t c = 0; c < world->component_count; c++) {
            if (world->components[c][e] && world->component_tables[c].destroy) {
                world->component_tables[c].destroy(world->components[c][e]);
            }
            free(world->components[c][e]);
        }
    }
    free(world);
}

Entity world_create_entity(World* world) {
    if (world->entity_count >= MAX_ENTITIES) return 0;
    Entity e = world->next_entity++;
    world->entities[world->entity_count++] = e;
    world->entity_masks[e] = 0;
    return e;
}

void world_destroy_entity(World* world, Entity entity) {
    for (uint32_t c = 0; c < world->component_count; c++) {
        if (world->components[c][entity] && world->component_tables[c].destroy) {
            world->component_tables[c].destroy(world->components[c][entity]);
        }
        free(world->components[c][entity]);
        world->components[c][entity] = NULL;
    }
    world->entity_masks[entity] = 0;

    for (uint32_t i = 0; i < world->entity_count; i++) {
        if (world->entities[i] == entity) {
            world->entities[i] = world->entities[--world->entity_count];
            break;
        }
    }
}

int world_entity_alive(World* world, Entity entity) {
    for (uint32_t i = 0; i < world->entity_count; i++) {
        if (world->entities[i] == entity) return 1;
    }
    return 0;
}

ComponentType world_register_component(World* world, uint32_t size, ComponentVTable vtable) {
    ComponentType type = world->component_count++;
    world->component_sizes[type] = size;
    world->component_tables[type] = vtable;
    return type;
}

void* world_add_component(World* world, Entity entity, ComponentType type) {
    if (world->components[type][entity]) return world->components[type][entity];
    void* comp = calloc(1, world->component_sizes[type]);
    world->components[type][entity] = comp;
    world->entity_masks[entity] |= (1ULL << type);
    return comp;
}

void* world_get_component(World* world, Entity entity, ComponentType type) {
    return world->components[type][entity];
}

void world_remove_component(World* world, Entity entity, ComponentType type) {
    if (world->components[type][entity]) {
        if (world->component_tables[type].destroy) {
            world->component_tables[type].destroy(world->components[type][entity]);
        }
        free(world->components[type][entity]);
        world->components[type][entity] = NULL;
        world->entity_masks[entity] &= ~(1ULL << type);
    }
}

int world_has_component(World* world, Entity entity, ComponentType type) {
    return (world->entity_masks[entity] & (1ULL << type)) != 0;
}

void world_each(World* world, uint64_t mask, SystemFunc func, void* data) {
    for (uint32_t i = 0; i < world->entity_count; i++) {
        Entity e = world->entities[i];
        if ((world->entity_masks[e] & mask) == mask) {
            func(world, e, data);
        }
    }
}