///@param {Id.Buffer} memory
///@param {Pointer} system
///@param {Id.vertex_format} vertex_format
///@param {Id.vertex_buffer} vertex_buffer
///@param {Real} projectile_count
///@param {Struct.Texturepage} texturepage
///@param {Id.DsList} effects
function _ProjectileEffectSystem(memory, system, vertex_format, vertex_buffer, projectile_count, texturepage, effects) constructor {
    self.memory = memory;
    self.system = system;
    self.vertex_format = vertex_format;
    self.vertex_buffer = vertex_buffer;
    self.projectile_count = projectile_count;
    self.texturepage = texturepage;
    self.effects = effects;
}

///@param {Function} create_func
///@param {Real} interval
///@param {Id.DsList} list
function _ProjectileEffectSystemEffect(create_func, interval, list) constructor {
	self.interval = interval;
	self.time = 0;
	self.instances = list;
	self.create_func = create_func;
}

///@param {Real} projectile_count
///@return {_ProjectileEffectSystem}
function pem_create(projectile_count, texturepage) {
    vertex_format_begin();
    vertex_format_add_position_3d();
    vertex_format_add_color();
    vertex_format_add_texcoord();
    vertex_format_add_custom(vertex_type_float3, vertex_usage_color); // Position
    vertex_format_add_custom(vertex_type_float2, vertex_usage_color); // Scale
    vertex_format_add_custom(vertex_type_float1, vertex_usage_color); // Angle
    vertex_format_add_custom(vertex_type_float3, vertex_usage_color); // Rotation direction
    vertex_format_add_custom(vertex_type_float1, vertex_usage_color); // Animation
    vertex_format_add_custom(vertex_type_float3, vertex_usage_color); // Hue saturation value
    var _vertex_format = vertex_format_end();

    var _buffer = buffer_create(pem_get_size(projectile_count), buffer_fixed, 1);
    buffer_fill(_buffer, 0, buffer_u32, 0, buffer_get_size(_buffer));
    var _ptr = buffer_get_address(_buffer);
    pem_init(_ptr, projectile_count, TEXTUREPAGE_SIZE);
    var _vertex_buffer = vertex_create_buffer_from_buffer_ext(
        _buffer,
        _vertex_format,
        pem_get_vertex_buffer_offset(),
        projectile_count * 6);
    return new _ProjectileEffectSystem(_buffer, _ptr, _vertex_format, _vertex_buffer, projectile_count, texturepage, ds_list_create());
}

///@param {Struct._ProjectileEffectSystem} system
///@param {Function} create_func
///@param {Real} interval
function pem_effect_add(system, create_func, interval) {
	if (interval <= 0.0) {
		printerr("Interval cannot be equal or lower than 0.0", ERROR_LOC);
		return;
	}
	var _effect = new _ProjectileEffectSystemEffect(create_func, interval, ds_list_create());
	ds_list_add(system.effects, _effect);
}

///@param {Struct._ProjectileEffectSystem} system
///@param {Real} index
///@param {Id.Instance} inst
function pem_effect_instance_add(system, index, inst) {
	ds_list_add(system.effects[|index].instances, inst);
}

///@param {Struct._ProjectileEffectSystemEffect} effect
function _pem_effect_destroy(effect) {
	ds_list_destroy(effect.instances);
}

///@param {Struct._ProjectileEffectSystem} system
function pem_update_vertex_buffer(system) {
    vertex_update_buffer_from_buffer(
        system.vertex_buffer,
        0,
        system.memory,
        pem_get_vertex_buffer_offset(),
        pem_get_vertex_buffer_size(system.projectile_count));
}

///@param {Struct._ProjectileEffectSystem} system
function pem_destroy(system) {
    buffer_delete(system.memory);
    vertex_format_delete(system.vertex_format);
    vertex_delete_buffer(system.vertex_buffer);
    for (var i = 0, n = ds_list_size(system.effects); i < n; i++) {
    	_pem_effect_destroy(system.effects[|i]);
    }
    ds_list_destroy(system.effects);
}

///@param {Struct._ProjectileEffectSystem} system
function pem_update(system) {
	for (var i = 0, n = ds_list_size(system.effects); i < n; i++) {
		var _effect = system.effects[|i];
		_effect.time += 1.0;
		while (_effect.time >= _effect.interval) {
			_effect.time -= _effect.interval;
			for (var j = 0, nn = ds_list_size(_effect.instances); j < nn; j++) {
				if (!instance_exists(_effect.instances[|j])) {
					ds_list_delete(_effect.instances, j);
					j--;
					nn--;
					continue;
				}
				_effect.create_func(system, _effect.instances[|j]);
			}
		}
	}
    _pem_update(system.system);
    pem_update_vertex_buffer(system);
}

///@param {Struct._ProjectileEffectSystem} system
function pem_set(system) {
	_pem_set(system.system);
}

///@param {Struct._ProjectileEffectSystem} system
function pem_draw(system) {
    shader_set(shdProjectileEffect);
    vertex_submit(system.vertex_buffer, pr_trianglelist, system.texturepage.texture);
    shader_reset();
}

///@param {Struct._ProjectileEffectSystem} system
///@param {Real} x
///@param {Real} y
///@param {Asset.GMSprite} sprite_index
function pem_instance_create_from_sprite(system, x, y, sprite_index) {
	var _info = texturepage_sprite_get_info(system.texturepage, sprite_index);
	if (_info == -1) {
		printerr($"Couldn't create effect instance with sprite {sprite_get_name(sprite_index)}. It wasn't on the texture page", ERROR_LOC);
		return;
	}
    return pem_instance_create_from_info(x, y, _info);
}

///@param {Struct._ProjectileEffectSystem} system
///@param {Real} x
///@param {Real} y
///@param {Real} sprite_origin
///@param {Asset.GMSprite} sprite_index
function pem_instance_create_from_sprite_ext(system, x, y, origin, sprite_index) {
	var _info = texturepage_sprite_get_info(system.texturepage, sprite_index);
	if (_info == -1) {
		printerr("Couldn't create effect instance with sprite {sprite_get_name(sprite_index)}. It wasn't on the texture page", ERROR_LOC);
		return;
	}
    return pem_instance_create_from_info_ext(x, y, origin, _info);
}

///@param {Real} x
///@param {Real} y
///@param {Struct.TexturepageEntryInfo} info
function pem_instance_create_from_info(x, y, info) {
    return pem_instance_create(
        x, y,
        sprite_get_width(info.sprite_index), sprite_get_height(info.sprite_index),
        sprite_get_xoffset(info.sprite_index), sprite_get_yoffset(info.sprite_index),
        info.uvs[UvData.Left], info.uvs[UvData.Top], info.uvs[UvData.Right], info.uvs[UvData.Bottom],
        sprite_get_number(info.sprite_index));
}

///@param {Real} x
///@param {Real} y
///@param {Real} sprite_origin
///@param {Struct.TexturepageEntryInfo} info
function pem_instance_create_from_info_ext(x, y, sprite_origin, info) {
    return pem_instance_create_origin(
        x, y,
        sprite_get_width(info.sprite_index), sprite_get_height(info.sprite_index),
        sprite_origin,
        info.uvs[UvData.Left], info.uvs[UvData.Top], info.uvs[UvData.Right], info.uvs[UvData.Bottom],
        sprite_get_number(info.sprite_index));
}