#include "debug_line3d.h"

#include "math/geometry.h"
#include "math/kmath.h"
#include "math/math_types.h"
#include "memory/kmemory.h"
#include "renderer/renderer_frontend.h"
#include "strings/kname.h"
#include "systems/ktransform_system.h"

static void recalculate_points (debug_line3d *line);
static void update_vert_colour (debug_line3d *line);

b8 debug_line3d_create (vec3 point_0, vec3 point_1, ktransform parent_ktransform, debug_line3d *out_line) {
	if (!out_line) {
		return false;
	}
	out_line->ktransform = ktransform_create(0);
	out_line->ktransform_parent = parent_ktransform;
	// out_line->name // TODO: name?
	out_line->point_0 = point_0;
	out_line->point_1 = point_1;
	out_line->colour = vec4_one(); // Default to white.

	out_line->geometry.type = KGEOMETRY_TYPE_3D_STATIC_COLOUR;
	out_line->geometry.generation = INVALID_ID_U16;
	out_line->is_dirty = true;

	return true;
}

void debug_line3d_destroy (debug_line3d *line) {
	if (line) {
		geometry_destroy(&line->geometry);
		kzero_memory(line, sizeof(debug_line3d));
	}
}

void debug_line3d_parent_set (debug_line3d *line, ktransform parent_ktransform) {
	if (line) {
		line->ktransform_parent = parent_ktransform;
	}
}

void debug_line3d_colour_set (debug_line3d *line, vec4 colour) {
	if (line) {
		if (colour.a == 0) {
			colour.a = 1.0f;
		}
		line->colour = colour;
		if (line->geometry.generation != INVALID_ID_U16 && line->geometry.vertex_count && line->geometry.vertices) {
			update_vert_colour(line);
			line->is_dirty = true;
		}
	}
}

void debug_line3d_points_set (debug_line3d *line, vec3 point_0, vec3 point_1) {
	if (line) {
		if (line->geometry.generation != INVALID_ID_U16 && line->geometry.vertex_count && line->geometry.vertices) {
			line->point_0 = point_0;
			line->point_1 = point_1;
			recalculate_points(line);
			line->is_dirty = true;
		}
	}
}

void debug_line3d_render_frame_prepare (debug_line3d *line, const struct frame_data *p_frame_data) {
	if (!line || !line->is_dirty) {
		return;
	}

	// Upload the new vertex data.
	renderer_geometry_vertex_update(&line->geometry, 0, line->geometry.vertex_count, line->geometry.vertices, true);

	line->geometry.generation++;

	// Roll this over to zero so we don't lock ourselves out of updating.
	if (line->geometry.generation == INVALID_ID_U16) {
		line->geometry.generation = 0;
	}

	line->is_dirty = false;
}

b8 debug_line3d_initialize (debug_line3d *line) {
	if (!line) {
		return false;
	}

	line->geometry = geometry_generate_line3d(line->point_0, line->point_1, INVALID_KNAME);

	recalculate_points(line);
	update_vert_colour(line);

	return true;
}

b8 debug_line3d_load (debug_line3d *line) {
	// Send the geometry off to the renderer to be uploaded to the GPU.
	return renderer_geometry_upload(&line->geometry);
}

b8 debug_line3d_unload (debug_line3d *line) {
	renderer_geometry_destroy(&line->geometry);

	return true;
}

b8 debug_line3d_update (debug_line3d *line) {
	return true;
}

static void recalculate_points (debug_line3d *line) {
	if (line) {
		colour_vertex_3d *verts = (colour_vertex_3d *)line->geometry.vertices;
		verts[0].position = vec4_from_vec3(line->point_0, 1.0f);
		verts[1].position = vec4_from_vec3(line->point_1, 1.0f);
	}
}

static void update_vert_colour (debug_line3d *line) {
	if (line) {
		if (line->geometry.vertex_count && line->geometry.vertices) {
			colour_vertex_3d *verts = (colour_vertex_3d *)line->geometry.vertices;
			for (u32 i = 0; i < line->geometry.vertex_count; ++i) {
				verts[i].colour = line->colour;
			}
		}
	}
}