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

struct crop_filter_data {
	obs_source_t                   *context;

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

	int                            left;
	int                            right;
	int                            top;
	int                            bottom;
	uint32_t                       abs_cx;
	uint32_t                       abs_cy;
	uint32_t                       width;
	uint32_t                       height;
	bool                           absolute;
};

static const char *crop_filter_get_name(void *unused)
{
	UNUSED_PARAMETER(unused);
	return obs_module_text("CropFilter");
}

static void *crop_filter_create(obs_data_t *settings, obs_source_t *context)
{
	struct crop_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_mul = gs_effect_get_param_by_name(filter->effect,
			"mul_val");
	filter->param_add = gs_effect_get_param_by_name(filter->effect,
			"add_val");

	obs_source_update(context, settings);
	return filter;
}

static void crop_filter_destroy(void *data)
{
	struct crop_filter_data *filter = data;

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

	bfree(filter);
}

static void crop_filter_update(void *data, obs_data_t *settings)
{
	struct crop_filter_data *filter = data;

	filter->absolute = !obs_data_get_bool(settings, "relative");
	filter->left = (int)obs_data_get_int(settings, "left");
	filter->top = (int)obs_data_get_int(settings, "top");
	filter->right = (int)obs_data_get_int(settings, "right");
	filter->bottom = (int)obs_data_get_int(settings, "bottom");
	filter->abs_cx = (int)obs_data_get_int(settings, "cx");
	filter->abs_cy = (int)obs_data_get_int(settings, "cy");
}

static bool relative_clicked(obs_properties_t *props, obs_property_t *p,
		obs_data_t *settings)
{
	bool relative = obs_data_get_bool(settings, "relative");

	obs_property_set_description(obs_properties_get(props, "left"),
			relative ? obs_module_text("Crop.Left") : "X");
	obs_property_set_description(obs_properties_get(props, "top"),
			relative ? obs_module_text("Crop.Top") : "Y");

	obs_property_set_visible(obs_properties_get(props, "right"), relative);
	obs_property_set_visible(obs_properties_get(props, "bottom"), relative);
	obs_property_set_visible(obs_properties_get(props, "cx"), !relative);
	obs_property_set_visible(obs_properties_get(props, "cy"), !relative);

	UNUSED_PARAMETER(p);
	return true;
}

static obs_properties_t *crop_filter_properties(void *data)
{
	obs_properties_t *props = obs_properties_create();

	obs_property_t *p = obs_properties_add_bool(props, "relative",
			obs_module_text("Crop.Relative"));

	obs_property_set_modified_callback(p, relative_clicked);

	obs_properties_add_int(props, "left", obs_module_text("Crop.Left"),
			0, 8192, 1);
	obs_properties_add_int(props, "top", obs_module_text("Crop.Top"),
			0, 8192, 1);
	obs_properties_add_int(props, "right", obs_module_text("Crop.Right"),
			0, 8192, 1);
	obs_properties_add_int(props, "bottom", obs_module_text("Crop.Bottom"),
			0, 8192, 1);
	obs_properties_add_int(props, "cx", obs_module_text("Crop.Width"),
			0, 8192, 1);
	obs_properties_add_int(props, "cy", obs_module_text("Crop.Height"),
			0, 8192, 1);

	UNUSED_PARAMETER(data);
	return props;
}

static void crop_filter_defaults(obs_data_t *settings)
{
	obs_data_set_default_bool(settings, "relative", true);
}

static void calc_crop_dimensions(struct crop_filter_data *filter,
		struct vec2 *mul_val, struct vec2 *add_val)
{
	obs_source_t *target = obs_filter_get_target(filter->context);
	uint32_t width;
	uint32_t height;
	uint32_t total;

	if (!target) {
		width = 0;
		height = 0;
	} else {
		width = obs_source_get_base_width(target);
		height = obs_source_get_base_height(target);
	}

	if (filter->absolute) {
		uint32_t max_abs_cx = (filter->left + filter->abs_cx);
		if (max_abs_cx > width) max_abs_cx = width;
		max_abs_cx -= filter->left;

		total = max_abs_cx < width ? (width - max_abs_cx) : 0;
	} else {
		total = filter->left + filter->right;
	}
	filter->width = total > width ? 0 : (width - total);

	if (filter->absolute) {
		uint32_t max_abs_cy = (filter->top + filter->abs_cy);
		if (max_abs_cy > height) max_abs_cy = height;
		max_abs_cy -= filter->top;

		total = max_abs_cy < height ? (height - max_abs_cy) : 0;
	} else {
		total = filter->top + filter->bottom;
	}
	filter->height = total > height ? 0 : (height - total);

	if (width && filter->width) {
		mul_val->x = (float)filter->width / (float)width;
		add_val->x = (float)filter->left / (float)width;
	}

	if (height && filter->height) {
		mul_val->y = (float)filter->height / (float)height;
		add_val->y = (float)filter->top / (float)height;
	}
}

static void crop_filter_render(void *data, gs_effect_t *effect)
{
	struct crop_filter_data *filter = data;
	struct vec2 mul_val;
	struct vec2 add_val;

	vec2_zero(&mul_val);
	vec2_zero(&add_val);
	calc_crop_dimensions(filter, &mul_val, &add_val);

	obs_source_process_filter_begin(filter->context, GS_RGBA,
			OBS_NO_DIRECT_RENDERING);

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

	obs_source_process_filter_end(filter->context, filter->effect,
			filter->width, filter->height);

	UNUSED_PARAMETER(effect);
}

static uint32_t crop_filter_width(void *data)
{
	struct crop_filter_data *crop = data;
	return crop->width;
}

static uint32_t crop_filter_height(void *data)
{
	struct crop_filter_data *crop = data;
	return crop->height;
}

struct obs_source_info crop_filter = {
	.id                            = "crop_filter",
	.type                          = OBS_SOURCE_TYPE_FILTER,
	.output_flags                  = OBS_SOURCE_VIDEO,
	.get_name                      = crop_filter_get_name,
	.create                        = crop_filter_create,
	.destroy                       = crop_filter_destroy,
	.update                        = crop_filter_update,
	.get_properties                = crop_filter_properties,
	.get_defaults                  = crop_filter_defaults,
	.video_render                  = crop_filter_render,
	.get_width                     = crop_filter_width,
	.get_height                    = crop_filter_height
};