#include <cstdint>
#include <cmath>
#include <cassert>
#include "utils/logger.h"
#include "render/ui.h"
#include "render/vertexbuffer.h"
#include "render/indexbuffer.h"
#include "render/renderdevice.h"
#include "render/shadersystem.h"
#include "render/texturesmanager.h"
#include "render/texture2d.h"

struct DrawInfo
{
	uint16_t vxcount;
	uint16_t idxcount;
};

struct UIGlobals {
	VertexBuffer* vb;
	IndexBuffer* ib;
	Shader* shader;
	Texture2D* activetexture = nullptr;
	Texture2D* defaultTexture = nullptr;

	UIVertex* vertices = nullptr;
	uint16_t* indices = nullptr;
	DrawInfo drawInfo[MAX_UI_VERTICES];
	uint16_t count = 0;
	uint16_t position = 0;
	uint16_t Indexposition = 0;
	uint16_t currentIdx = 0;
} g_ui;


void uiInit()
{
	//////////////////////////////////////////////////////////////////////////
	// Buffer and context state

	// Buffer creation
	g_ui.vb = g_renderDevice->CreateVertexBuffer(nullptr, MAX_UI_VERTICES, true);
	g_ui.ib = g_renderDevice->CreateIndexBuffer(nullptr, MAX_UI_INDICES, true);

	// Create shader

	InputLayoutDesc_t inputLayout[] =
	{
		{ VERTEXATTR_VEC2, SHADERSEMANTIC_POSITION },
		{ VERTEXATTR_VEC2, SHADERSEMANTIC_TEXCOORD },
		{ VERTEXATTR_VEC4, SHADERSEMANTIC_COLOR },
	};

	g_ui.shader = g_shaderSystem->CreateShader("ui", "content/shaders/ui_base.vs", "content/shaders/ui_tex.ps", inputLayout, sizeof(inputLayout) / sizeof(inputLayout[0]));
	g_ui.shader->m_stride = sizeof( UIVertex );

	g_ui.defaultTexture = g_texturesManager->LoadTexture2D("$white$");
}

void uiShutdown()
{
	delete g_ui.ib;
	delete g_ui.vb;
}

void uiDumpBuffers()
{
	Msg( "--- UI Vertex Buffer ---" );

	g_ui.vertices = (UIVertex*)g_ui.vb->MapBuffer(BufferAccess::WRITE_ONLY);
	assert(g_ui.vertices);

	for ( int i = 0; i < g_ui.position; i++ )
	{
		Msg( "%i: POSITION = %.2f %.2f", i, g_ui.vertices[ i ].position.x, g_ui.vertices[ i ].position.y );
		Msg( "%i: TEXCOORD = %.2f %.2f", i, g_ui.vertices[ i ].uv.x, g_ui.vertices[ i ].uv.y );
		Msg( "%i: COLOR = %.2f %.2f %.2f %.2f", i,
			g_ui.vertices[ i ].color.x,
			g_ui.vertices[ i ].color.y,
			g_ui.vertices[ i ].color.z,
			g_ui.vertices[ i ].color.w);
	}

	Msg( "------------------------" );

	g_ui.vb->UnmapBuffer();
}

void uiBeginRender()
{
	g_ui.vertices = (UIVertex*)g_ui.vb->MapBuffer(BufferAccess::WRITE_ONLY);
	assert(g_ui.vertices);

	g_ui.indices = (uint16_t*)g_ui.ib->MapBuffer(BufferAccess::WRITE_ONLY);
	assert(g_ui.indices);
}

void uiDrawQuad(const Vec2& a, const Vec2& b, const Vec2& c, const Vec2& d, const Vec4& color)
{
	DrawInfo& drawInfo = g_ui.drawInfo[g_ui.count];
	drawInfo.vxcount = 4;
	drawInfo.idxcount = 6;

	g_ui.indices[g_ui.Indexposition + 0] = g_ui.currentIdx;
	g_ui.indices[g_ui.Indexposition + 1] = g_ui.currentIdx + 1;
	g_ui.indices[g_ui.Indexposition + 2] = g_ui.currentIdx + 2;
	g_ui.indices[g_ui.Indexposition + 3] = g_ui.currentIdx;
	g_ui.indices[g_ui.Indexposition + 4] = g_ui.currentIdx + 2;
	g_ui.indices[g_ui.Indexposition + 5] = g_ui.currentIdx + 3;
	g_ui.vertices[g_ui.position + 0].position = a; g_ui.vertices[g_ui.position + 0].color = color;
	g_ui.vertices[g_ui.position + 1].position = b; g_ui.vertices[g_ui.position + 1].color = color;
	g_ui.vertices[g_ui.position + 2].position = c; g_ui.vertices[g_ui.position + 2].color = color;
	g_ui.vertices[g_ui.position + 3].position = d; g_ui.vertices[g_ui.position + 3].color = color;

	// texcoord
	g_ui.vertices[g_ui.position + 0].uv = Vec2{ 0.0f, 1.0f };
	g_ui.vertices[g_ui.position + 1].uv = Vec2{ 1.0f, 1.0f };
	g_ui.vertices[g_ui.position + 2].uv = Vec2{ 1.0f, 0.0f };
	g_ui.vertices[g_ui.position + 3].uv = Vec2{ 0.0f, 0.0f };
	
	g_ui.currentIdx += 4;
	g_ui.Indexposition += 6;
	g_ui.position += 4;
	g_ui.count++;
}

static inline float  Rsqrt(float x) { return 1.0f / sqrtf(x); }
#define NORMALIZE2F_OVER_ZERO(VX,VY)     { float d2 = VX*VX + VY*VY; if (d2 > 0.0f) { float inv_len = Rsqrt(d2); VX *= inv_len; VY *= inv_len; } } (void)0

void uiDrawLines(const Vec2* drawPoints, const size_t pointsCount, bool closed, const Vec4& color)
{
	float thickness = 2.1f;

	const int count = closed ? pointsCount : pointsCount - 1;
	const int vtxCount = (count) * 4;
	const int idxCount = (count) * 6;

	for (int i1 = 0; i1 < count; i1++)
	{
		const int i2 = (i1 + 1) == pointsCount ? 0 : i1 + 1;
		const Vec2& p1 = drawPoints[i1];
		const Vec2& p2 = drawPoints[i2];

		float dx = p2.x - p1.x;
		float dy = p2.y - p1.y;
		NORMALIZE2F_OVER_ZERO(dx, dy);
		dx *= (thickness * 0.5f);
		dy *= (thickness * 0.5f);

		g_ui.vertices[g_ui.position + 0].position.x = p1.x + dy; g_ui.vertices[g_ui.position + 0].position.y = p1.y - dx; g_ui.vertices[g_ui.position + 0].color = color;
		g_ui.vertices[g_ui.position + 1].position.x = p2.x + dy; g_ui.vertices[g_ui.position + 1].position.y = p2.y - dx; g_ui.vertices[g_ui.position + 1].color = color;
		g_ui.vertices[g_ui.position + 2].position.x = p2.x - dy; g_ui.vertices[g_ui.position + 2].position.y = p2.y + dx; g_ui.vertices[g_ui.position + 2].color = color;
		g_ui.vertices[g_ui.position + 3].position.x = p1.x - dy; g_ui.vertices[g_ui.position + 3].position.y = p1.y + dx; g_ui.vertices[g_ui.position + 3].color = color;

		g_ui.indices[g_ui.Indexposition + 0] = g_ui.currentIdx;
		g_ui.indices[g_ui.Indexposition + 1] = g_ui.currentIdx + 1;
		g_ui.indices[g_ui.Indexposition + 2] = g_ui.currentIdx + 2;
		g_ui.indices[g_ui.Indexposition + 3] = g_ui.currentIdx;
		g_ui.indices[g_ui.Indexposition + 4] = g_ui.currentIdx + 2;
		g_ui.indices[g_ui.Indexposition + 5] = g_ui.currentIdx + 3;
		g_ui.currentIdx += 4;
		g_ui.Indexposition += 6;
		g_ui.position += 4;

		DrawInfo& drawInfo = g_ui.drawInfo[g_ui.count];
		drawInfo.vxcount = 4;
		drawInfo.idxcount = 6;
		g_ui.count++;
	}
}

void uiDrawRect(const Vec2& position, const Vec2& size, const Vec4& color)
{
	Vec2 quad[4];
	quad[0] = { position.x, position.y };
	quad[1] = { position.x + size.x, position.y };
	quad[2] = { position.x + size.x, position.y + size.y };
	quad[3] = { position.x, position.y + size.y };
	uiDrawQuad(quad[0], quad[1], quad[2], quad[3], color);
}

void uiSetTexture(Texture2D* texture)
{
	g_ui.activetexture = texture ? texture : g_ui.defaultTexture;
}

void uiSetTextureByName(const char* filename)
{
	uiSetTexture( g_texturesManager->LoadTexture2D( filename ) );
}

void uiEndRender()
{
	g_ui.indices = nullptr;
	g_ui.vertices = nullptr;

	g_ui.ib->UnmapBuffer();
	g_ui.vb->UnmapBuffer();

	int x = 0, y = 0, w = g_renderView.width, h = g_renderView.height;
	g_renderDevice->SetViewport(x, y, w, h);

	float L = x;
	float R = x + w;
	float T = y;
	float B = y + h;
#if defined(GL_CLIP_ORIGIN)
	if (!clip_origin_lower_left) { float tmp = T; T = B; B = tmp; } // Swap top and bottom if origin is upper left
#endif
	const float orthoProjection[4][4] =
	{
		{ 2.0f / (R - L),   0.0f,         0.0f,   0.0f },
		{ 0.0f,         2.0f / (T - B),   0.0f,   0.0f },
		{ 0.0f,         0.0f,        -1.0f,   0.0f },
		{ (R + L) / (L - R),  (T + B) / (B - T),  0.0f,   1.0f },
	};

	if ( g_ui.activetexture == nullptr  )
		 g_ui.activetexture = g_ui.defaultTexture;

	g_texturesManager->SetTexture( 0, g_ui.activetexture );
	g_ui.activetexture->setMin(TextureFilter::Linear);
	g_ui.activetexture->setMag(TextureFilter::Linear);
	g_ui.activetexture->setWrapS(TextureWrap::ClampToEdge);
	g_ui.activetexture->setWrapT(TextureWrap::ClampToEdge);

	g_shaderSystem->SetShader( g_ui.shader );
	g_shaderSystem->SetUniformMatrix( g_ui.shader, UNIFORM_PROJ_MATRIX, orthoProjection );

	g_renderDevice->SetVerticesBuffer( g_ui.vb );
	g_renderDevice->SetIndicesBuffer( g_ui.ib );

	// Enable blending
	g_renderDevice->SetBlending( true );
	g_renderDevice->SetBlendingFunction( BF_SRC_ALPHA, BF_ONE_MINUS_SRC_ALPHA );

	// Disable depth
	g_renderDevice->SetDepthTest( false );
	g_renderDevice->SetBackfaceCull( false );

	g_renderDevice->DrawElements( PT_TRIANGLES, g_ui.Indexposition, true );

	// Uncomment for UI VB debugging
	//uiDumpBuffers();

	g_ui.currentIdx = 0;
	g_ui.Indexposition = 0;
	g_ui.position = 0;
	g_ui.count = 0;
}

typedef struct Character {
	int codePoint, x, y, width, height, originX, originY;
} Character;

typedef struct Font {
	const char* name;
	int size, bold, italic, width, height, characterCount;
	Character* characters;
} Font;

static Character characters_Courier_New[] = {
  {' ', 36, 61, 3, 3, 1, 1},
  {'!', 498, 0, 10, 20, -1, 16},
  {'"', 423, 43, 14, 13, 1, 16},
  {'#', 160, 0, 16, 22, 2, 17},
  {'$', 47, 0, 16, 23, 2, 17},
  {'%', 357, 0, 16, 20, 2, 16},
  {'&', 202, 24, 15, 19, 1, 15},
  {'\'', 448, 43, 10, 13, -1, 16},
  {'(', 111, 0, 11, 23, -2, 16},
  {')', 122, 0, 11, 23, 1, 16},
  {'*', 357, 43, 16, 15, 2, 16},
  {'+', 392, 24, 18, 18, 3, 15},
  {',', 437, 43, 11, 13, -1, 6},
  {'-', 20, 61, 16, 9, 2, 10},
  {'.', 474, 43, 10, 10, -1, 6},
  {'/', 0, 0, 16, 24, 2, 18},
  {'0', 373, 0, 16, 20, 2, 16},
  {'1', 106, 24, 16, 19, 2, 16},
  {'2', 122, 24, 16, 19, 2, 16},
  {'3', 389, 0, 16, 20, 2, 16},
  {'4', 138, 24, 16, 19, 2, 16},
  {'5', 405, 0, 16, 20, 2, 16},
  {'6', 453, 0, 15, 20, 1, 16},
  {'7', 154, 24, 16, 19, 2, 16},
  {'8', 421, 0, 16, 20, 2, 16},
  {'9', 468, 0, 15, 20, 1, 16},
  {':', 292, 43, 10, 16, -1, 12},
  {';', 120, 43, 12, 18, 0, 12},
  {'<', 297, 24, 19, 18, 4, 15},
  {'=', 405, 43, 18, 13, 3, 12},
  {'>', 316, 24, 19, 18, 3, 15},
  {'?', 483, 0, 15, 20, 1, 16},
  {'@', 232, 0, 15, 21, 2, 16},
  {'A', 217, 24, 20, 18, 4, 15},
  {'B', 410, 24, 18, 18, 3, 15},
  {'C', 285, 0, 18, 20, 3, 16},
  {'D', 428, 24, 18, 18, 3, 15},
  {'E', 446, 24, 18, 18, 3, 15},
  {'F', 54, 43, 17, 18, 2, 15},
  {'G', 303, 0, 18, 20, 3, 16},
  {'H', 464, 24, 18, 18, 3, 15},
  {'I', 88, 43, 16, 18, 2, 15},
  {'J', 0, 24, 18, 19, 2, 15},
  {'K', 335, 24, 19, 18, 3, 15},
  {'L', 482, 24, 18, 18, 3, 15},
  {'M', 237, 24, 20, 18, 4, 15},
  {'N', 354, 24, 19, 18, 4, 15},
  {'O', 321, 0, 18, 20, 3, 16},
  {'P', 71, 43, 17, 18, 2, 15},
  {'Q', 142, 0, 18, 22, 3, 16},
  {'R', 373, 24, 19, 18, 3, 15},
  {'S', 437, 0, 16, 20, 2, 16},
  {'T', 0, 43, 18, 18, 3, 15},
  {'U', 18, 24, 18, 19, 3, 15},
  {'V', 257, 24, 20, 18, 4, 15},
  {'W', 277, 24, 20, 18, 4, 15},
  {'X', 18, 43, 18, 18, 3, 15},
  {'Y', 36, 43, 18, 18, 3, 15},
  {'Z', 104, 43, 16, 18, 2, 15},
  {'[', 63, 0, 12, 23, -1, 16},
  {'\\', 16, 0, 16, 24, 2, 18},
  {']', 75, 0, 12, 23, 1, 16},
  {'^', 389, 43, 16, 14, 2, 17},
  {'_', 0, 61, 20, 9, 4, -1},
  {'`', 484, 43, 10, 10, -1, 17},
  {'a', 132, 43, 18, 17, 3, 13},
  {'b', 247, 0, 19, 20, 4, 16},
  {'c', 186, 43, 17, 17, 2, 13},
  {'d', 266, 0, 19, 20, 3, 16},
  {'e', 150, 43, 18, 17, 3, 13},
  {'f', 72, 24, 17, 19, 2, 16},
  {'g', 214, 0, 18, 21, 3, 13},
  {'h', 36, 24, 18, 19, 3, 16},
  {'i', 170, 24, 16, 19, 2, 16},
  {'j', 32, 0, 15, 24, 2, 16},
  {'k', 54, 24, 18, 19, 3, 16},
  {'l', 186, 24, 16, 19, 2, 16},
  {'m', 219, 43, 20, 16, 4, 13},
  {'n', 239, 43, 18, 16, 3, 13},
  {'o', 168, 43, 18, 17, 3, 13},
  {'p', 176, 0, 19, 21, 4, 13},
  {'q', 195, 0, 19, 21, 3, 13},
  {'r', 275, 43, 17, 16, 2, 13},
  {'s', 203, 43, 16, 17, 2, 13},
  {'t', 89, 24, 17, 19, 2, 15},
  {'u', 257, 43, 18, 16, 3, 12},
  {'v', 302, 43, 19, 15, 3, 12},
  {'w', 321, 43, 18, 15, 3, 12},
  {'x', 339, 43, 18, 15, 3, 12},
  {'y', 339, 0, 18, 20, 3, 12},
  {'z', 373, 43, 16, 15, 2, 12},
  {'{', 87, 0, 12, 23, 0, 16},
  {'|', 133, 0, 9, 23, -2, 16},
  {'}', 99, 0, 12, 23, 0, 16},
  {'~', 458, 43, 16, 11, 2, 11},
};

static Font font_Courier_New = { "Courier New", 20, 1, 0, 512, 128, 95, characters_Courier_New };

static Character characters_Arial[] = {
  {' ', 10, 61, 3, 3, 1, 1},
  {'!', 205, 34, 5, 15, 0, 14},
  {'"', 202, 49, 8, 7, 1, 14},
  {'#', 187, 19, 12, 15, 1, 14},
  {'$', 71, 0, 12, 18, 1, 15},
  {'%', 162, 0, 16, 15, 0, 14},
  {'&', 208, 0, 14, 15, 1, 14},
  {'\'', 210, 49, 5, 7, 1, 14},
  {'(', 35, 0, 7, 19, 0, 14},
  {')', 42, 0, 7, 19, 0, 14},
  {'*', 193, 49, 9, 7, 1, 14},
  {'+', 161, 49, 11, 10, 0, 11},
  {',', 215, 49, 5, 7, 0, 3},
  {'-', 246, 49, 8, 4, 1, 6},
  {'.', 0, 61, 5, 4, 0, 3},
  {'/', 177, 34, 7, 15, 1, 14},
  {'0', 199, 19, 12, 15, 1, 14},
  {'1', 184, 34, 7, 15, -1, 14},
  {'2', 84, 34, 11, 15, 1, 14},
  {'3', 211, 19, 12, 15, 1, 14},
  {'4', 223, 19, 12, 15, 1, 14},
  {'5', 235, 19, 12, 15, 1, 14},
  {'6', 0, 34, 12, 15, 1, 14},
  {'7', 12, 34, 12, 15, 1, 14},
  {'8', 24, 34, 12, 15, 1, 14},
  {'9', 36, 34, 12, 15, 1, 14},
  {':', 156, 49, 5, 11, 0, 10},
  {';', 223, 34, 5, 14, 0, 10},
  {'<', 134, 49, 11, 11, 0, 12},
  {'=', 182, 49, 11, 8, 0, 10},
  {'>', 145, 49, 11, 11, 0, 12},
  {'?', 95, 34, 11, 15, 1, 14},
  {'@', 0, 0, 19, 19, 0, 14},
  {'A', 222, 0, 14, 15, 1, 14},
  {'B', 48, 34, 12, 15, 0, 14},
  {'C', 236, 0, 14, 15, 0, 14},
  {'D', 70, 19, 13, 15, 0, 14},
  {'E', 60, 34, 12, 15, 0, 14},
  {'F', 72, 34, 12, 15, 0, 14},
  {'G', 0, 19, 14, 15, 0, 14},
  {'H', 83, 19, 13, 15, 0, 14},
  {'I', 210, 34, 5, 15, 0, 14},
  {'J', 139, 34, 10, 15, 1, 14},
  {'K', 96, 19, 13, 15, 0, 14},
  {'L', 106, 34, 11, 15, 0, 14},
  {'M', 178, 0, 15, 15, 0, 14},
  {'N', 109, 19, 13, 15, 0, 14},
  {'O', 193, 0, 15, 15, 0, 14},
  {'P', 122, 19, 13, 15, 0, 14},
  {'Q', 83, 0, 16, 16, 1, 14},
  {'R', 14, 19, 14, 15, 0, 14},
  {'S', 135, 19, 13, 15, 1, 14},
  {'T', 148, 19, 13, 15, 1, 14},
  {'U', 161, 19, 13, 15, 0, 14},
  {'V', 28, 19, 14, 15, 1, 14},
  {'W', 143, 0, 19, 15, 1, 14},
  {'X', 42, 19, 14, 15, 1, 14},
  {'Y', 56, 19, 14, 15, 1, 14},
  {'Z', 174, 19, 13, 15, 1, 14},
  {'[', 49, 0, 6, 19, 0, 14},
  {'\\', 191, 34, 7, 15, 1, 14},
  {']', 55, 0, 6, 19, 1, 14},
  {'^', 172, 49, 10, 9, 1, 14},
  {'_', 232, 49, 14, 4, 2, -1},
  {'`', 5, 61, 5, 4, 0, 14},
  {'a', 15, 49, 12, 12, 1, 11},
  {'b', 117, 34, 11, 15, 0, 14},
  {'c', 51, 49, 11, 12, 1, 11},
  {'d', 128, 34, 11, 15, 1, 14},
  {'e', 27, 49, 12, 12, 1, 11},
  {'f', 169, 34, 8, 15, 1, 14},
  {'g', 99, 0, 11, 16, 1, 11},
  {'h', 149, 34, 10, 15, 0, 14},
  {'i', 215, 34, 4, 15, 0, 14},
  {'j', 61, 0, 6, 19, 2, 14},
  {'k', 159, 34, 10, 15, 0, 14},
  {'l', 219, 34, 4, 15, 0, 14},
  {'m', 228, 34, 15, 12, 0, 11},
  {'n', 106, 49, 10, 12, 0, 11},
  {'o', 39, 49, 12, 12, 1, 11},
  {'p', 110, 0, 11, 16, 0, 11},
  {'q', 121, 0, 11, 16, 1, 11},
  {'r', 126, 49, 8, 12, 0, 11},
  {'s', 62, 49, 11, 12, 1, 11},
  {'t', 198, 34, 7, 15, 1, 14},
  {'u', 116, 49, 10, 12, 0, 11},
  {'v', 73, 49, 11, 12, 1, 11},
  {'w', 0, 49, 15, 12, 1, 11},
  {'x', 84, 49, 11, 12, 1, 11},
  {'y', 132, 0, 11, 16, 1, 11},
  {'z', 95, 49, 11, 12, 1, 11},
  {'{', 19, 0, 8, 19, 1, 14},
  {'|', 67, 0, 4, 19, 0, 14},
  {'}', 27, 0, 8, 19, 1, 14},
  {'~', 220, 49, 12, 5, 1, 9},
};

static Font font_Arial = { "Arial", 18, 0, 0, 256, 128, 95, characters_Arial };