#include "vk_triapi.h"
#include "vk_geometry.h"
#include "vk_render.h"
#include "vk_sprite.h" // R_GetSpriteTexture
#include "vk_logs.h"

#include "xash3d_mathlib.h"

#define MAX_TRIAPI_VERTICES 1024
#define MAX_TRIAPI_INDICES 4096

static struct {
	vk_vertex_t vertices[MAX_TRIAPI_VERTICES];
	uint16_t indices[MAX_TRIAPI_INDICES];

	int num_vertices;
	int primitive_mode;
	int texture_index;

	vk_render_type_e render_type;

	qboolean initialized;
} g_triapi = {0};

void TriSetTexture( int texture_index ) {
	g_triapi.texture_index = texture_index;
}

int TriSpriteTexture( model_t *pSpriteModel, int frame )
{
	int	gl_texturenum;

	if(( gl_texturenum = R_GetSpriteTexture( pSpriteModel, frame )) <= 0 )
		return 0;

	TriSetTexture( gl_texturenum );

	return 1;
}

void TriRenderMode( int render_mode ) {
	switch( render_mode )
	{
	case kRenderTransAlpha:
		g_triapi.render_type = kVkRenderType_A_1mA_R;
		break;
	case kRenderTransColor:
	case kRenderTransTexture:
		g_triapi.render_type = kVkRenderType_A_1mA_RW;
		break;
	case kRenderGlow:
	case kRenderTransAdd:
		g_triapi.render_type = kVkRenderType_A_1_R;
		break;
	case kRenderNormal:
	default:
		g_triapi.render_type = kVkRenderTypeSolid;
		break;
	}
}

void TriBegin( int primitive_mode ) {
	ASSERT(!g_triapi.primitive_mode);

	switch(primitive_mode) {
		case TRI_TRIANGLES: break;
		case TRI_TRIANGLE_STRIP: break;
		case TRI_QUADS: break;
		default:
			gEngine.Con_Printf(S_ERROR "TriBegin: unsupported primitive_mode %d\n", primitive_mode);
			return;
	}

	vk_vertex_t *const ve = g_triapi.vertices + 0;
	if (g_triapi.num_vertices > 1)
		*ve = g_triapi.vertices[g_triapi.num_vertices-1];

	if (!g_triapi.initialized) {
		Vector4Set(ve->color, 255, 255, 255, 255);
		g_triapi.initialized = true;
	}

	g_triapi.primitive_mode = primitive_mode + 1;
	g_triapi.num_vertices = 0;
}

/* static int genTrianglesIndices(void) { */
/* 	return 0; */
/* } */

static int genQuadsIndices(void) {
	int num_indices = 0;
	uint16_t *const dst_idx = g_triapi.indices;
	for (int i = 0; i < g_triapi.num_vertices - 3; i+=4) {
		if (num_indices > MAX_TRIAPI_INDICES - 6) {
			gEngine.Con_Printf(S_ERROR "Triapi ran out of indices space, max %d (vertices=%d)\n", MAX_TRIAPI_INDICES, g_triapi.num_vertices);
			break;
		}

		dst_idx[num_indices++] = 0 + i;
		dst_idx[num_indices++] = 1 + i;
		dst_idx[num_indices++] = 2 + i;

		dst_idx[num_indices++] = 0 + i;
		dst_idx[num_indices++] = 2 + i;
		dst_idx[num_indices++] = 3 + i;
	}
	return num_indices;
}

static int genTriangleStripIndices(void) {
	int num_indices = 0;
	uint16_t *const dst_idx = g_triapi.indices;
	for (int i = 2; i < g_triapi.num_vertices; ++i) {
		if (num_indices > MAX_TRIAPI_INDICES - 3) {
			gEngine.Con_Printf(S_ERROR "Triapi ran out of indices space, max %d (vertices=%d)\n", MAX_TRIAPI_INDICES, g_triapi.num_vertices);
			break;
		}

		if( i & 1 )
		{
			// draw triangle [n-1 n-2 n]
			dst_idx[num_indices++] = i - 1;
			dst_idx[num_indices++] = i - 2;
			dst_idx[num_indices++] = i;
		}
		else
		{
			// draw triangle [n-2 n-1 n]
			dst_idx[num_indices++] = i - 2;
			dst_idx[num_indices++] = i - 1;
			dst_idx[num_indices++] = i;
		}
	}
	return num_indices;
}

void TriEnd( void ) {
	if (!g_triapi.primitive_mode)
		return;

	const vk_vertex_t *const v = g_triapi.vertices + g_triapi.num_vertices - 1;
	const vec4_t color = {v->color[0] / 255.f, v->color[1] / 255.f, v->color[2] / 255.f, 1.f};
	TriEndEx( color, "unnamed triapi" );
}

void TriEndEx( const vec4_t color, const char* name ) {
	if (!g_triapi.primitive_mode)
		return;

	int num_indices = 0;
	switch(g_triapi.primitive_mode - 1) {
		/* case TRI_TRIANGLES: */
		/* 	num_indices = genTrianglesIndices(); */
		/* 	break; */
		case TRI_TRIANGLE_STRIP: num_indices = genTriangleStripIndices(); break;
		case TRI_QUADS: num_indices = genQuadsIndices(); break;
		default:
			gEngine.Con_Printf(S_ERROR "TriEnd: unsupported primitive_mode %d\n", g_triapi.primitive_mode - 1);
			break;
	}

	if (num_indices) {
		R_RenderDrawOnce((r_draw_once_t){
			.name = name,
			.vertices = g_triapi.vertices,
			.indices = g_triapi.indices,
			.vertices_count = g_triapi.num_vertices,
			.indices_count = num_indices,
			.render_type = g_triapi.render_type,
			.material = R_VkMaterialGetForTexture(g_triapi.texture_index),
			.ye_olde_texture = g_triapi.texture_index,
			.emissive = (const vec4_t*)color,
			.color = (const vec4_t*)color,
		});
	}

	g_triapi.num_vertices = 0;
	g_triapi.primitive_mode = 0;
}

void TriTexCoord2f( float u, float v ) {
	vk_vertex_t *const ve = g_triapi.vertices + g_triapi.num_vertices;
	Vector2Set(ve->gl_tc, u, v);
}

void TriVertex3fv( const float *v ) {
	TriVertex3f(v[0], v[1], v[2]);
}

void TriVertex3f( float x, float y, float z ) {
	if (g_triapi.num_vertices == MAX_TRIAPI_VERTICES - 1) {
		ERROR_THROTTLED(1, "vk TriApi: trying to emit more than %d vertices in one batch\n", MAX_TRIAPI_VERTICES);
		return;
	}

	vk_vertex_t *const ve = g_triapi.vertices + g_triapi.num_vertices;
	VectorSet(ve->pos, x, y, z);

	// Emit vertex preserving previous vertex values
	++g_triapi.num_vertices;
	g_triapi.vertices[g_triapi.num_vertices] = g_triapi.vertices[g_triapi.num_vertices-1];
}

void TriColor4ub_( byte r, byte g, byte b, byte a ) {
	Vector4Set(g_triapi.vertices[g_triapi.num_vertices].color, r, g, b, a);
}

void TriColor4f( float r, float g, float b, float a ) {
	TriColor4ub_(
		clampi32(r*255.f, 0, 255),
		clampi32(g*255.f, 0, 255),
		clampi32(b*255.f, 0, 255),
		clampi32(a*255.f, 0, 255));
}

void TriNormal3fv( const float *v ) {
	TriNormal3f(v[0], v[1], v[2]);
}

void TriNormal3f( float x, float y, float z ) {
	vk_vertex_t *const ve = g_triapi.vertices + g_triapi.num_vertices;
	VectorSet(ve->normal, x, y, z);
}