#include <obs-module.h>
#include <graphics/vec2.h>

struct scroll_filter_data {
	obs_source_t                   *context;

	gs_effect_t                    *effect;
	gs_eparam_t                    *param_add;
	gs_eparam_t                    *param_mul;

	struct vec2                    scroll_speed;
	bool                           limit_cx;
	bool                           limit_cy;
	uint32_t                       cx;
	uint32_t                       cy;

	struct vec2                    size_i;
	struct vec2                    offset;
};

static const char *scroll_filter_get_name(void *unused)
{
	UNUSED_PARAMETER(unused);
	return obs_module_text("ScrollFilter");
}

static void *scroll_filter_create(obs_data_t *settings, obs_source_t *context)
{
	struct scroll_filter_data *filter = bzalloc(sizeof(*filter));
	char *effect_path = obs_module_file("crop_filter.effect");

	filter->context = context;

	obs_enter_graphics();
	filter->effect = gs_effect_create_from_file(effect_path, NULL);
	obs_leave_graphics();

	bfree(effect_path);

	if (!filter->effect) {
		bfree(filter);
		return NULL;
	}

	filter->param_add = gs_effect_get_param_by_name(filter->effect,
			"add_val");
	filter->param_mul = gs_effect_get_param_by_name(filter->effect,
			"mul_val");

	obs_source_update(context, settings);
	return filter;
}

static void scroll_filter_destroy(void *data)
{
	struct scroll_filter_data *filter = data;

	obs_enter_graphics();
	gs_effect_destroy(filter->effect);
	obs_leave_graphics();

	bfree(filter);
}

static void scroll_filter_update(void *data, obs_data_t *settings)
{
	struct scroll_filter_data *filter = data;

	filter->limit_cx = obs_data_get_bool(settings, "limit_cx");
	filter->limit_cy = obs_data_get_bool(settings, "limit_cy");
	filter->cx = (uint32_t)obs_data_get_int(settings, "cx");
	filter->cy = (uint32_t)obs_data_get_int(settings, "cy");

	filter->scroll_speed.x = (float)obs_data_get_double(settings,
			"speed_x");
	filter->scroll_speed.y = (float)obs_data_get_double(settings,
			"speed_y");

	if (filter->scroll_speed.x == 0.0f)
		filter->offset.x = 0.0f;
	if (filter->scroll_speed.y == 0.0f)
		filter->offset.y = 0.0f;
}

static bool limit_cx_clicked(obs_properties_t *props, obs_property_t *p,
		obs_data_t *settings)
{
	bool limit_size = obs_data_get_bool(settings, "limit_cx");
	obs_property_set_visible(obs_properties_get(props, "cx"), limit_size);

	UNUSED_PARAMETER(p);
	return true;
}

static bool limit_cy_clicked(obs_properties_t *props, obs_property_t *p,
		obs_data_t *settings)
{
	bool limit_size = obs_data_get_bool(settings, "limit_cy");
	obs_property_set_visible(obs_properties_get(props, "cy"), limit_size);

	UNUSED_PARAMETER(p);
	return true;
}

static obs_properties_t *scroll_filter_properties(void *data)
{
	obs_properties_t *props = obs_properties_create();
	obs_property_t *p;

	obs_properties_add_float_slider(props, "speed_x",
			obs_module_text("ScrollFilter.SpeedX"),
			-500.0f, 500.0f, 1.0f);
	obs_properties_add_float_slider(props, "speed_y",
			obs_module_text("ScrollFilter.SpeedY"),
			-500.0f, 500.0f, 1.0f);

	p = obs_properties_add_bool(props, "limit_cx",
			obs_module_text("ScrollFilter.LimitWidth"));
	obs_property_set_modified_callback(p, limit_cx_clicked);
	obs_properties_add_int(props, "cx",
			obs_module_text("Crop.Width"), 1, 8192, 1);

	p = obs_properties_add_bool(props, "limit_cy",
			obs_module_text("ScrollFilter.LimitHeight"));
	obs_property_set_modified_callback(p, limit_cy_clicked);
	obs_properties_add_int(props, "cy",
			obs_module_text("Crop.Height"), 1, 8192, 1);

	UNUSED_PARAMETER(data);
	return props;
}

static void scroll_filter_defaults(obs_data_t *settings)
{
	obs_data_set_default_bool(settings, "limit_size", false);
	obs_data_set_default_int(settings, "cx", 100);
	obs_data_set_default_int(settings, "cy", 100);
}

static void scroll_filter_tick(void *data, float seconds)
{
	struct scroll_filter_data *filter = data;

	filter->offset.x += filter->size_i.x * filter->scroll_speed.x * seconds;
	filter->offset.y += filter->size_i.y * filter->scroll_speed.y * seconds;

	if (filter->offset.x > 1.0f)
		filter->offset.x -= 1.0f;
	if (filter->offset.y > 1.0f)
		filter->offset.y -= 1.0f;
}

static void scroll_filter_render(void *data, gs_effect_t *effect)
{
	struct scroll_filter_data *filter = data;
	struct vec2 mul_val;
	uint32_t base_cx;
	uint32_t base_cy;
	uint32_t cx;
	uint32_t cy;

	obs_source_t *target = obs_filter_get_target(filter->context);
	base_cx = obs_source_get_base_width(target);
	base_cy = obs_source_get_base_height(target);

	cx = filter->limit_cx ? filter->cx : base_cx;
	cy = filter->limit_cy ? filter->cy : base_cy;

	if (base_cx && base_cy) {
		vec2_set(&filter->size_i,
				1.0f / (float)base_cx,
				1.0f / (float)base_cy);
	} else {
		vec2_zero(&filter->size_i);
		obs_source_skip_video_filter(filter->context);
		return;
	}

	vec2_set(&mul_val,
			(float)cx / (float)base_cx,
			(float)cy / (float)base_cy);

	if (!obs_source_process_filter_begin(filter->context, GS_RGBA,
				OBS_NO_DIRECT_RENDERING))
		return;

	gs_effect_set_vec2(filter->param_add, &filter->offset);
	gs_effect_set_vec2(filter->param_mul, &mul_val);

	obs_source_process_filter_end(filter->context, filter->effect, cx, cy);

	UNUSED_PARAMETER(effect);
}

static uint32_t scroll_filter_width(void *data)
{
	struct scroll_filter_data *filter = data;
	obs_source_t *target = obs_filter_get_target(filter->context);

	return filter->limit_cx ?
		filter->cx : obs_source_get_base_width(target);
}

static uint32_t scroll_filter_height(void *data)
{
	struct scroll_filter_data *filter = data;
	obs_source_t *target = obs_filter_get_target(filter->context);

	return filter->limit_cy ?
		filter->cy : obs_source_get_base_height(target);
}

struct obs_source_info scroll_filter = {
	.id                            = "scroll_filter",
	.type                          = OBS_SOURCE_TYPE_FILTER,
	.output_flags                  = OBS_SOURCE_VIDEO,
	.get_name                      = scroll_filter_get_name,
	.create                        = scroll_filter_create,
	.destroy                       = scroll_filter_destroy,
	.update                        = scroll_filter_update,
	.get_properties                = scroll_filter_properties,
	.get_defaults                  = scroll_filter_defaults,
	.video_tick                    = scroll_filter_tick,
	.video_render                  = scroll_filter_render,
	.get_width                     = scroll_filter_width,
	.get_height                    = scroll_filter_height
};
