#include "render/debugrender.h"
#include "render/render_shared.h"
#include "render/render.h"
#include "render/renderdevice.h"
#include "render/vertexbuffer.h"
#include "render/shadersystem.h"

#include "glad/glad.h"

struct DebugVertex
{
	Vec3 position;
	Vec3 color;
};

static InputLayoutDesc_t g_debugRenderLayout[] =
{
	{ VERTEXATTR_VEC3, SHADERSEMANTIC_POSITION },
	{ VERTEXATTR_VEC3, SHADERSEMANTIC_COLOR }

};

const int kEllipseVertexBufferSize = 114;
const int kEllipseIndexBufferSize = 672;

void FillVertexBuffer( VertexBuffer* _pVertexBuffer, const Vec3& _Color )
{
	static Vec3 previousColor = Vec3(0.0f, 0.0f, 0.0f);

	if (previousColor.x == _Color.x &&
		previousColor.y == _Color.y &&
		previousColor.z == _Color.z)
		return;

	float vertices[] =
	{
			0.0000f,0.0000f,1.0000f,  0.0000f,0.3827f,0.9239f,  -0.1464f,0.3536f,0.9239f,
			-0.2706f,0.2706f,0.9239f,  -0.3536f,0.1464f,0.9239f,  -0.3827f,0.0000f,0.9239f,
			-0.3536f,-0.1464f,0.9239f,  -0.2706f,-0.2706f,0.9239f,  -0.1464f,-0.3536f,0.9239f,
			0.0000f,-0.3827f,0.9239f,  0.1464f,-0.3536f,0.9239f,  0.2706f,-0.2706f,0.9239f,
			0.3536f,-0.1464f,0.9239f,  0.3827f,0.0000f,0.9239f,  0.3536f,0.1464f,0.9239f,
			0.2706f,0.2706f,0.9239f,  0.1464f,0.3536f,0.9239f,  0.0000f,0.7071f,0.7071f,
			-0.2706f,0.6533f,0.7071f,  -0.5000f,0.5000f,0.7071f,  -0.6533f,0.2706f,0.7071f,
			-0.7071f,0.0000f,0.7071f,  -0.6533f,-0.2706f,0.7071f,  -0.5000f,-0.5000f,0.7071f,
			-0.2706f,-0.6533f,0.7071f,  0.0000f,-0.7071f,0.7071f,  0.2706f,-0.6533f,0.7071f,
			0.5000f,-0.5000f,0.7071f,  0.6533f,-0.2706f,0.7071f,  0.7071f,0.0000f,0.7071f,
			0.6533f,0.2706f,0.7071f,  0.5000f,0.5000f,0.7071f,  0.2706f,0.6533f,0.7071f,
			0.0000f,0.9239f,0.3827f,  -0.3536f,0.8536f,0.3827f,  -0.6533f,0.6533f,0.3827f,
			-0.8536f,0.3536f,0.3827f,  -0.9239f,0.0000f,0.3827f,  -0.8536f,-0.3536f,0.3827f,
			-0.6533f,-0.6533f,0.3827f,  -0.3536f,-0.8536f,0.3827f,  0.0000f,-0.9239f,0.3827f,
			0.3536f,-0.8536f,0.3827f,  0.6533f,-0.6533f,0.3827f,  0.8536f,-0.3536f,0.3827f,
			0.9239f,0.0000f,0.3827f,  0.8536f,0.3536f,0.3827f,  0.6533f,0.6533f,0.3827f,
			0.3536f,0.8536f,0.3827f,  0.0000f,1.0000f,0.0000f,  -0.3827f,0.9239f,0.0000f,
			-0.7071f,0.7071f,0.0000f,  -0.9239f,0.3827f,0.0000f,  -1.0000f,0.0000f,0.0000f,
			-0.9239f,-0.3827f,0.0000f,  -0.7071f,-0.7071f,0.0000f,  -0.3827f,-0.9239f,0.0000f,
			0.0000f,-1.0000f,0.0000f,  0.3827f,-0.9239f,0.0000f,  0.7071f,-0.7071f,0.0000f,
			0.9239f,-0.3827f,0.0000f,  1.0000f,0.0000f,0.0000f,  0.9239f,0.3827f,0.0000f,
			0.7071f,0.7071f,0.0000f,  0.3827f,0.9239f,0.0000f,  0.0000f,0.9239f,-0.3827f,
			-0.3536f,0.8536f,-0.3827f,  -0.6533f,0.6533f,-0.3827f,  -0.8536f,0.3536f,-0.3827f,
			-0.9239f,0.0000f,-0.3827f,  -0.8536f,-0.3536f,-0.3827f,  -0.6533f,-0.6533f,-0.3827f,
			-0.3536f,-0.8536f,-0.3827f,  0.0000f,-0.9239f,-0.3827f,  0.3536f,-0.8536f,-0.3827f,
			0.6533f,-0.6533f,-0.3827f,  0.8536f,-0.3536f,-0.3827f,  0.9239f,0.0000f,-0.3827f,
			0.8536f,0.3536f,-0.3827f,  0.6533f,0.6533f,-0.3827f,  0.3536f,0.8536f,-0.3827f,
			0.0000f,0.7071f,-0.7071f,  -0.2706f,0.6533f,-0.7071f,  -0.5000f,0.5000f,-0.7071f,
			-0.6533f,0.2706f,-0.7071f,  -0.7071f,0.0000f,-0.7071f,  -0.6533f,-0.2706f,-0.7071f,
			-0.5000f,-0.5000f,-0.7071f,  -0.2706f,-0.6533f,-0.7071f,  0.0000f,-0.7071f,-0.7071f,
			0.2706f,-0.6533f,-0.7071f,  0.5000f,-0.5000f,-0.7071f,  0.6533f,-0.2706f,-0.7071f,
			0.7071f,0.0000f,-0.7071f,  0.6533f,0.2706f,-0.7071f,  0.5000f,0.5000f,-0.7071f,
			0.2706f,0.6533f,-0.7071f,  0.0000f,0.3827f,-0.9239f,  -0.1464f,0.3536f,-0.9239f,
			-0.2706f,0.2706f,-0.9239f,  -0.3536f,0.1464f,-0.9239f,  -0.3827f,0.0000f,-0.9239f,
			-0.3536f,-0.1464f,-0.9239f,  -0.2706f,-0.2706f,-0.9239f,  -0.1464f,-0.3536f,-0.9239f,
			0.0000f,-0.3827f,-0.9239f,  0.1464f,-0.3536f,-0.9239f,  0.2706f,-0.2706f,-0.9239f,
			0.3536f,-0.1464f,-0.9239f,  0.3827f,0.0000f,-0.9239f,  0.3536f,0.1464f,-0.9239f,
			0.2706f,0.2706f,-0.9239f,  0.1464f,0.3536f,-0.9239f,  0.0000f,0.0000f,-1.0000f
	};

	const int vcnt = sizeof(vertices) / (sizeof(float) * 3);
	DebugVertex verts[vcnt];
	for (int i = 0; i < vcnt; i++) {
		int k = i * 3;

		verts[i].position.x = vertices[k];
		verts[i].position.y = vertices[k + 1];
		verts[i].position.z = vertices[k + 2];
		verts[i].color = _Color;
	}

	DebugVertex* pAGPMemory = ( DebugVertex* )_pVertexBuffer->MapBuffer( BufferAccess::WRITE_ONLY );
	memcpy( pAGPMemory, verts, sizeof( verts ) );
	_pVertexBuffer->UnmapBuffer();

	previousColor = _Color;
}

IndexBuffer* CreateEllipseIndexBuffer()
{
	uint16_t faces[224 * 3] =
	{
			0,1,2, 0,2,3, 0,3,4, 0,4,5, 0,5,6, 0,6,7, 0,7,8, 0,8,9, 0,9,10,
			0,10,11, 0,11,12, 0,12,13, 0,13,14, 0,14,15, 0,15,16, 0,16,1, 1,17,18, 1,18,2,
			2,18,19, 2,19,3, 3,19,20, 3,20,4, 4,20,21, 4,21,5, 5,21,22, 5,22,6, 6,22,23,
			6,23,7, 7,23,24, 7,24,8, 8,24,25, 8,25,9, 9,25,26, 9,26,10, 10,26,27, 10,27,11,
			11,27,28, 11,28,12, 12,28,29, 12,29,13, 13,29,30, 13,30,14, 14,30,31, 14,31,15, 15,31,32,
			15,32,16, 16,32,17, 16,17,1, 17,33,34, 17,34,18, 18,34,35, 18,35,19, 19,35,36, 19,36,20,
			20,36,37, 20,37,21, 21,37,38, 21,38,22, 22,38,39, 22,39,23, 23,39,40, 23,40,24, 24,40,41,
			24,41,25, 25,41,42, 25,42,26, 26,42,43, 26,43,27, 27,43,44, 27,44,28, 28,44,45, 28,45,29,
			29,45,46, 29,46,30, 30,46,47, 30,47,31, 31,47,48, 31,48,32, 32,48,33, 32,33,17, 33,49,50,
			33,50,34, 34,50,51, 34,51,35, 35,51,52, 35,52,36, 36,52,53, 36,53,37, 37,53,54, 37,54,38,
			38,54,55, 38,55,39, 39,55,56, 39,56,40, 40,56,57, 40,57,41, 41,57,58, 41,58,42, 42,58,59,
			42,59,43, 43,59,60, 43,60,44, 44,60,61, 44,61,45, 45,61,62, 45,62,46, 46,62,63, 46,63,47,
			47,63,64, 47,64,48, 48,64,49, 48,49,33, 49,65,66, 49,66,50, 50,66,67, 50,67,51, 51,67,68,
			51,68,52, 52,68,69, 52,69,53, 53,69,70, 53,70,54, 54,70,71, 54,71,55, 55,71,72, 55,72,56,
			56,72,73, 56,73,57, 57,73,74, 57,74,58, 58,74,75, 58,75,59, 59,75,76, 59,76,60, 60,76,77,
			60,77,61, 61,77,78, 61,78,62, 62,78,79, 62,79,63, 63,79,80, 63,80,64, 64,80,65, 64,65,49,
			65,81,82, 65,82,66, 66,82,83, 66,83,67, 67,83,84, 67,84,68, 68,84,85, 68,85,69, 69,85,86,
			69,86,70, 70,86,87, 70,87,71, 71,87,88, 71,88,72, 72,88,89, 72,89,73, 73,89,90, 73,90,74,
			74,90,91, 74,91,75, 75,91,92, 75,92,76, 76,92,93, 76,93,77, 77,93,94, 77,94,78, 78,94,95,
			78,95,79, 79,95,96, 79,96,80, 80,96,81, 80,81,65, 81,97,98, 81,98,82, 82,98,99, 82,99,83,
			83,99,100, 83,100,84, 84,100,101, 84,101,85, 85,101,102, 85,102,86, 86,102,103, 86,103,87, 87,103,104,
			87,104,88, 88,104,105, 88,105,89, 89,105,106, 89,106,90, 90,106,107, 90,107,91, 91,107,108, 91,108,92,
			92,108,109, 92,109,93, 93,109,110, 93,110,94, 94,110,111, 94,111,95, 95,111,112, 95,112,96, 96,112,97,
			96,97,81, 113,98,97, 113,99,98, 113,100,99, 113,101,100, 113,102,101, 113,103,102, 113,104,103, 113,105,104,
			113,106,105, 113,107,106, 113,108,107, 113,109,108, 113,110,109, 113,111,110, 113,112,111, 113,97,112
	};

	return g_renderDevice->CreateIndexBuffer(faces, sizeof(faces));
}

bool g_drawDebug = false;
DebugRender* g_debugRender;

DebugRender::DebugRender()
{
	m_verticesBuffer = nullptr;
	m_ellipseVertexBuffer = nullptr;
	m_ellipseIndexBuffer = nullptr;
	m_shader = nullptr;
}

DebugRender::~DebugRender()
{
	m_verticesBuffer = nullptr;
	m_shader = nullptr;
}

void DebugRender::Initialize()
{
	float points[12];
	m_verticesBuffer = g_renderDevice->CreateVertexBuffer(points, sizeof(points), true);
	
	m_ellipseVertexBuffer = g_renderDevice->CreateVertexBuffer(nullptr, kEllipseVertexBufferSize * sizeof(DebugVertex), true);
	m_ellipseIndexBuffer = CreateEllipseIndexBuffer();

	m_shader = g_shaderSystem->CreateShader("debug_draw",
		"content/shaders/debug_draw.vs",
		"content/shaders/debug_draw.ps",
		g_debugRenderLayout,
		sizeof(g_debugRenderLayout) / sizeof(g_debugRenderLayout[0]));

	m_shader->m_stride = sizeof(DebugVertex);

	glGenVertexArrays(1, &m_vao);
}

void DebugRender::Shutdown()
{
	glDeleteVertexArrays(1, &m_vao);

	if (m_ellipseIndexBuffer) {
		delete m_ellipseIndexBuffer;
		m_ellipseIndexBuffer = nullptr;
	}

	if (m_ellipseVertexBuffer) {
		delete m_ellipseVertexBuffer;
		m_ellipseVertexBuffer = nullptr;
	}

	if (m_verticesBuffer) {
		delete m_verticesBuffer;
		m_verticesBuffer = nullptr;
	}
}

void DebugRender::DrawLine(const Vec3& from, const Vec3& to, const Vec3& color)
{
	if (!g_drawDebug)
		return;

	Line line;
	line.from = from;
	line.color0 = color;
	line.to = to;
	line.color1 = color;
	m_lines.push_back(line);
}

void DebugRender::DrawBoundingBox(const BoundingBox& box, const glm::vec3& color)
{
	glm::vec3 from = glm::vec3(box.min.x, box.min.y, box.min.z);
	glm::vec3 to = glm::vec3(box.max.x, box.max.y, box.max.z);

	glm::vec3 halfExtents = (to - from) * 0.5f;
	glm::vec3 center = (to + from) * 0.5f;
	int i, j;

	glm::vec3 edgecoord(1.f, 1.f, 1.f), pa, pb;
	for (i = 0; i < 4; i++)
	{
		for (j = 0; j < 3; j++)
		{
			pa = glm::vec3(edgecoord[0] * halfExtents[0], edgecoord[1] * halfExtents[1],
				edgecoord[2] * halfExtents[2]);
			pa += center;

			int othercoord = j % 3;
			edgecoord[othercoord] *= -1.f;
			pb = glm::vec3(edgecoord[0] * halfExtents[0], edgecoord[1] * halfExtents[1],
				edgecoord[2] * halfExtents[2]);
			pb += center;

			DrawLine(Vec3(pa.x, pa.y, pa.z), Vec3(pb.x, pb.y, pb.z) , Vec3(color.x, color.y, color.z) );
		}

		edgecoord = glm::vec3(-1.f, -1.f, -1.f);
		if (i < 3)
			edgecoord[i] *= -1.f;
	}
}

void DebugRender::DrawEllipse(const glm::mat4& trans, const Vec3& color)
{
	EllipseDrawCmd drawCmd = {};
	drawCmd.trans = trans;
	drawCmd.color = color;
	m_ellipseDrawCmd.push_back(drawCmd);
}

void DebugRender::RenderFrame()
{
	if (!g_drawDebug)
		return;

	BeginDraw();

	// draw lines
	DrawLinesInternal();

	// and clear them
	m_lines.clear();

	// Draw cmds
	DrawCmds();
	
	// and clear them
	m_ellipseDrawCmd.clear();

	EndDraw();
}

void DebugRender::DrawAxis(const Vec3& vec)
{
	const float length = 0.2f;
	DrawLine(vec, Vec3(vec.x + length, vec.y, vec.z), Vec3(1.0f, 0.0, 0.0f));
	DrawLine(vec, Vec3(vec.x, vec.y + length, vec.z), Vec3(0.0f, 0.0f, 1.0f));
	DrawLine(vec, Vec3(vec.x, vec.y, vec.z + length), Vec3(0.0f, 1.0f, 0.0f));
}

void DebugRender::BeginDraw()
{
	glGetIntegerv(GL_VERTEX_ARRAY_BINDING, (int*)&m_savedVao);

	glBindVertexArray(m_vao);
}

void DebugRender::EndDraw()
{
	glBindVertexArray(m_savedVao);
}

void DebugRender::DrawLinesInternal()
{
	if (m_lines.empty())
		return;

	g_renderDevice->SetDepthTest(true);
	g_renderDevice->SetDepthWrite(true);

	g_renderDevice->SetVerticesBuffer(m_verticesBuffer);

	m_verticesBuffer->UpdateBuffer(m_lines.data(), m_lines.size() * sizeof(Line));

	// Bind our shader
	g_shaderSystem->SetShader(m_shader);

	// #TODO: Fix stupid bug, when we get very far from wireframe and lines can start cliping
	View view = g_renderView;
	view.proj[2][3] -= 0.0001f;

	glm::mat4 mv = glm::identity<glm::mat4>();
	mv = view.proj * view.view;

	g_shaderSystem->SetUniformMatrix(m_shader, UNIFORM_MVP_MATRIX, &mv[0]);

	// draw stuff
	g_renderDevice->DrawArrays(PT_LINES, 0, m_lines.size() * 2);
}

void DebugRender::DrawCmds()
{
	if (m_ellipseDrawCmd.empty())
		return;

	g_renderDevice->SetDepthTest(true);
	g_renderDevice->SetDepthWrite(true);

	g_renderDevice->SetVerticesBuffer(m_ellipseVertexBuffer);
	g_renderDevice->SetIndicesBuffer(m_ellipseIndexBuffer);

	// Bind our shader
	g_shaderSystem->SetShader(m_shader);

	for (int i = 0; i < m_ellipseDrawCmd.size(); i++)
	{
		const EllipseDrawCmd& cmd = m_ellipseDrawCmd[i];

		FillVertexBuffer(m_ellipseVertexBuffer, cmd.color);

		// #TODO: Fix stupid bug, when we get very far from wireframe and lines can start cliping
		View view = g_renderView;
		view.proj[2][3] -= 0.0001f;

		glm::mat4 mv = glm::identity<glm::mat4>();
		mv = view.proj * view.view * cmd.trans;

		g_shaderSystem->SetUniformMatrix(m_shader, UNIFORM_MVP_MATRIX, &mv[0]);

		// draw stuff
		g_renderDevice->DrawElements( PT_LINES, 672, true );
	}
}