// (c) 2020 Vlad-Stefan Harbuz <vlad@vladh.net>

#include "spatial.hpp"
#include "logs.hpp"
#include "engine.hpp"


spatial::State *spatial::state = nullptr;


void
spatial::print_spatial_component(spatial::Component *spatial_component)
{
    logs::info("spatial::Component:");
    logs::info("  entity_handle: %d", spatial_component->entity_handle);
    logs::info("  position:");
    logs::print_v3(&spatial_component->position);
    logs::info("  rotation:");
    logs::info("(don't know how to print rotation, sorry)");
    /* logs::print_v4(&spatial_component->rotation); */
    logs::info("  scale:");
    logs::print_v3(&spatial_component->scale);
    logs::info("  parent_entity_handle: %d", spatial_component->parent_entity_handle);
}


bool
spatial::does_spatial_component_have_dimensions(spatial::Component *spatial_component)
{
    return (
        spatial_component->scale.x > 0.0f &&
        spatial_component->scale.y > 0.0f &&
        spatial_component->scale.z > 0.0f
    );
}


bool
spatial::is_spatial_component_valid(spatial::Component *spatial_component)
{
    return does_spatial_component_have_dimensions(spatial_component) ||
        spatial_component->parent_entity_handle != entities::NO_ENTITY_HANDLE;
}


m4
spatial::make_model_matrix(
    spatial::Component *spatial_component,
    ModelMatrixCache *cache
) {
    m4 model_matrix = m4(1.0f);

    if (spatial_component->parent_entity_handle != entities::NO_ENTITY_HANDLE) {
        spatial::Component *parent = spatial::get_component(
            spatial_component->parent_entity_handle);
        model_matrix = make_model_matrix(parent, cache);
    }

    if (does_spatial_component_have_dimensions(spatial_component)) {
        // TODO: This is somehow really #slow, the multiplication in particular.
        // Is there a better way?
        if (
            spatial_component == cache->last_model_matrix_spatial_component
        ) {
            model_matrix = cache->last_model_matrix;
        } else {
            model_matrix = glm::translate(model_matrix, spatial_component->position);
            model_matrix = glm::scale(model_matrix, spatial_component->scale);
            model_matrix = model_matrix *
                glm::toMat4(normalize(spatial_component->rotation));
            cache->last_model_matrix = model_matrix;
            cache->last_model_matrix_spatial_component = spatial_component;
        }
    }

    return model_matrix;
}


Array<spatial::Component> *
spatial::get_components()
{
    return &spatial::state->components;
}


spatial::Component *
spatial::get_component(entities::Handle entity_handle)
{
    return spatial::state->components[entity_handle];
}


void
spatial::init(spatial::State *spatial_state, memory::Pool *asset_memory_pool)
{
    spatial::state = spatial_state;
    spatial::state->components =  Array<spatial::Component>(
        asset_memory_pool, MAX_N_ENTITIES, "spatial_components", true, 1);
}