#include "asset.hpp"
#include "camera.hpp"
#include "debugdraw.hpp"
#include "video.hpp"
extern "C" {
#include "plat.h"
}

void Line_Renderer::init(Device* dev, Asset_Arena* assets) {
	vb.init(
		dev,
		"Line Renderer mesh",
		max_lines * sizeof(Vertex) * 2,
		Buffer_Flags::vertex_buffer
	);
	cb.init(
		dev,
		"Line Renderer cbuffer",
		sizeof(CBuffer),
		Buffer_Flags::constant_buffer
	);
	shader = (Shader*)assets->load("debug.csh");
	vert_binding = shader->binding_index("verts");
	cbuffer_binding = shader->descriptor_binding("cbuf");
	assert(vert_binding >= 0);
	assert(cbuffer_binding >= 0);
	verts = (Vertex*)vb.map(dev);
	cur = 0;
}

void Line_Renderer::destroy(Device* dev) {
	vb.unmap(dev);
	vb.destroy(dev);
	cb.destroy(dev);
}

void Line_Renderer::begin(int wi, int he) {
	cur = 0;
	w = wi;
	h = he;
	cur_col = v3f(1.0f, 1.0f, 1.0f);
}

void Line_Renderer::colour(const v3f& c) {
	cur_col = c;
}

void Line_Renderer::add_line(const v3f& s, const v3f& e) {
	if (cur >= max_lines) {
		assert(0);
		return;
	}
	Vertex& a = verts[cur * 2];
	Vertex& b = verts[cur * 2 + 1];
	a.x = s.x;
	a.y = s.y;
	a.z = s.z;
	b.x = e.x;
	b.y = e.y;
	b.z = e.z;
	a.r = cur_col.x;
	a.g = cur_col.y;
	a.b = cur_col.z;
	b.r = cur_col.x;
	b.g = cur_col.y;
	b.b = cur_col.z;
	cur++;
}

void Line_Renderer::add_arrow(const v3f& s, const v3f& e) {
	v3f tang(0.0f, 1.0f, 0.0f);
	v3f dir = v3f::normalised(e - s);
	v4f dir4 = v4f(dir, 0.0f);
	float d = v3f::dot(tang, dir);
	if (d > 0.999f || d < -0.999f)
		tang = v3f(1.0f, 0.0f, 0.0f);
	tang = v3f::cross(tang, dir);
	const m4f a = m4f::rotate(m4f::identity(), 2.8f, tang);
	const m4f b = m4f::rotate(m4f::identity(), 3.5f, tang);
	add_line(s, e);
	add_line(e, e + (a * dir4).xyz() * 0.1f);
	add_line(e, e + (b * dir4).xyz() * 0.1f);
}

void Line_Renderer::add_box(const AABB& b) {
	add_line(v3f(b.max.x, b.max.y, b.max.z), v3f(b.max.x, b.max.y, b.min.z));
	add_line(v3f(b.max.x, b.max.y, b.max.z), v3f(b.max.x, b.min.y, b.max.z));
	add_line(v3f(b.max.x, b.max.y, b.max.z), v3f(b.min.x, b.max.y, b.max.z));
	add_line(v3f(b.max.x, b.min.y, b.min.z), v3f(b.max.x, b.max.y, b.min.z));
	add_line(v3f(b.max.x, b.min.y, b.min.z), v3f(b.max.x, b.min.y, b.max.z));
	add_line(v3f(b.min.x, b.max.y, b.max.z), v3f(b.min.x, b.min.y, b.max.z));
	add_line(v3f(b.min.x, b.max.y, b.min.z), v3f(b.max.x, b.max.y, b.min.z));
	add_line(v3f(b.min.x, b.max.y, b.min.z), v3f(b.min.x, b.max.y, b.max.z));
	add_line(v3f(b.min.x, b.min.y, b.max.z), v3f(b.max.x, b.min.y, b.max.z));
	add_line(v3f(b.min.x, b.min.y, b.min.z), v3f(b.max.x, b.min.y, b.min.z));
	add_line(v3f(b.min.x, b.min.y, b.min.z), v3f(b.min.x, b.max.y, b.min.z));
	add_line(v3f(b.min.x, b.min.y, b.min.z), v3f(b.min.x, b.min.y, b.max.z));
}

void Line_Renderer::flush(
	const Camera& cam,
	Device* dev,
	Arena* a,
	Render_Pass& rp
) {
	if (!cur) return;
	CBuffer* c = (CBuffer*)cb.map(dev);
	c->vp = cam.get_proj() * cam.get_view();
	cb.unmap(dev);
	Pipeline_Builder pb(a, dev);
	Context& ctx = dev->get_ctx();
	cb.update(ctx);
	vb.update(ctx);
	pb.begin();
	pb.shader(shader->id);
	pb.cbuffer(cbuffer_binding, cb.gpuonly);
	pb.vertex_format(shader->vf);
	pb.geo(Geo_Type::lines);
	if (rp.depth.id)
		pb.depth(true, false, Depth_Mode::less);
	Pipeline& pip = pb.build();
	Vertex_Buffer_Binding binding[] = {{
		.id = vb.gpuonly,
		.offset = 0,
		.target = vert_binding
	}, {}};
	Draw d{};
	d.verts = binding;
	d.vertex_count = cur * 2;
	d.instance_count = 1;
	ctx.submit(d, pip, rp);
	cur = 0;
}