/*********************************************************************************************
*
*	raylib.text
*
*	Basic functions to load SpriteFonts and draw Text
*	
*	Uses external lib:
*		stb_image - Multiple formats image loading (JPEG, PNG, BMP, TGA, PSD, GIF, HDR, PIC)
*
*	Copyright (c) 2013 Ramon Santamaria (Ray San - raysan@raysanweb.com)
*	
*	This software is provided "as-is", without any express or implied warranty. In no event 
*	will the authors be held liable for any damages arising from the use of this software.
*
*	Permission is granted to anyone to use this software for any purpose, including commercial 
*	applications, and to alter it and redistribute it freely, subject to the following restrictions:
*
*	  1. The origin of this software must not be misrepresented; you must not claim that you 
*	  wrote the original software. If you use this software in a product, an acknowledgment 
*	  in the product documentation would be appreciated but is not required.
*
*	  2. Altered source versions must be plainly marked as such, and must not be misrepresented
*	  as being the original software.
*
*	  3. This notice may not be removed or altered from any source distribution.
*
**********************************************************************************************/

#include "raylib.h"

#include <GL/gl.h>			// OpenGL functions
#include <stdlib.h>			// Declares malloc() and free() for memory management
#include <string.h>			// String management functions (just strlen() is used)
#include <stdarg.h>			// Used for functions with variable number of parameters (FormatText())
#include "stb_image.h"		// Used to read image data (multiple formats support)

//----------------------------------------------------------------------------------
// Defines and Macros
//----------------------------------------------------------------------------------
#define FIRST_CHAR 		32
#define MAX_FONTCHARS  128

#define BIT_CHECK(a,b) ((a) & (1<<(b)))

//----------------------------------------------------------------------------------
// Types and Structures Definition
//----------------------------------------------------------------------------------
typedef unsigned char byte;

// SpriteFont one Character (Glyph) data
struct Character {
	int value;		//char value = ' '; (int)value = 32;
	int x;
	int y;
	int w;
	int h;
};

//----------------------------------------------------------------------------------
// Global variables
//----------------------------------------------------------------------------------
static SpriteFont defaultFont;				// Default font provided by raylib
											// NOTE: defaultFont is loaded on InitWindow and disposed on CloseWindow [module: core]

//----------------------------------------------------------------------------------
// Module specific Functions Declaration
//----------------------------------------------------------------------------------
static bool PixelIsMagenta(Color p);		// Check if a pixel is magenta
static int ParseImageData(Color *imgDataPixel, int imgWidth, int imgHeight, Character **charSet);	// Parse image pixel data to obtain character set measures
static int GetNextPOT(int num);				// Calculate next power-of-two value for a given value

//----------------------------------------------------------------------------------
// Module Functions Definition
//----------------------------------------------------------------------------------
extern void LoadDefaultFont() 
{
	defaultFont.numChars = 96;				// We know our default font has 94 chars
	defaultFont.texture.width = 128;		// We know our default font texture is 128 pixels width
	defaultFont.texture.height = 64;		// We know our default font texture is 64 pixels height
	
	// Default font is directly defined here (data generated from a sprite font image)
	// This way, we reconstruct SpriteFont without creating large global variables
	// This data is automatically allocated to Stack and automatically deallocated at the end of this function
	int defaultFontData[256] = {
		0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00200020, 0x0001b000, 0x00000000, 0x00000000, 0x8ef92520, 0x00020a00, 0x7dbe8000, 0x1f7df45f,
		0x4a2bf2a0, 0x0852091e, 0x41224000, 0x10041450, 0x2e292020, 0x08220812, 0x41222000, 0x10041450, 0x10f92020, 0x3efa084c, 0x7d22103c, 0x107df7de,
		0xe8a12020, 0x08220832, 0x05220800, 0x10450410, 0xa4a3f000, 0x08520832, 0x05220400, 0x10450410, 0xe2f92020, 0x0002085e, 0x7d3e0281, 0x107df41f,
		0x00200000, 0x8001b000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
		0x00000000, 0x00000000, 0x00000000, 0x00000000, 0xc0000fbe, 0xfbf7e00f, 0x5fbf7e7d, 0x0050bee8, 0x440808a2, 0x0a142fe8, 0x50810285, 0x0050a048,
		0x49e428a2, 0x0a142828, 0x40810284, 0x0048a048, 0x10020fbe, 0x09f7ebaf, 0xd89f3e84, 0x0047a04f, 0x09e48822, 0x0a142aa1, 0x50810284, 0x0048a048,
		0x04082822, 0x0a142fa0, 0x50810285, 0x0050a248, 0x00008fbe, 0xfbf42021, 0x5f817e7d, 0x07d09ce8, 0x00008000, 0x00000fe0, 0x00000000, 0x00000000,
		0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x000c0180,
		0xdfbf4282, 0x0bfbf7ef, 0x42850505, 0x004804bf, 0x50a142c6, 0x08401428, 0x42852505, 0x00a808a0, 0x50a146aa, 0x08401428, 0x42852505, 0x00081090,
		0x5fa14a92, 0x0843f7e8, 0x7e792505, 0x00082088, 0x40a15282, 0x08420128, 0x40852489, 0x00084084, 0x40a16282, 0x0842022a, 0x40852451, 0x00088082,
		0xc0bf4282, 0xf843f42f, 0x7e85fc21, 0x3e0900bf, 0x00000000, 0x00000004, 0x00000000, 0x000c0180, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
		0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x04000402, 0x41482000, 0x00000000, 0x00000800,
		0x04000404, 0x4100203c, 0x00000000, 0x00000800, 0xf7df7df0, 0x514bef85, 0xbefbefbe, 0x04513bef, 0x14414500, 0x494a2885, 0xa28a28aa, 0x04510820,
		0xf44145f0, 0x474a289d, 0xa28a28aa, 0x04510be0, 0x14414510, 0x494a2884, 0xa28a28aa, 0x02910a00, 0xf7df7df0, 0xd14a2f85, 0xbefbe8aa, 0x011f7be0,
		0x00000000, 0x00400804, 0x20080000, 0x00000000, 0x00000000, 0x00600f84, 0x20080000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
		0xac000000, 0x00000f01, 0x00000000, 0x00000000, 0x24000000, 0x00000901, 0x00000000, 0x00000000, 0x24000000, 0x00000901, 0x00000000, 0x00000000,
		0x24fa28a2, 0x00000901, 0x00000000, 0x00000000, 0x2242252a, 0x00000952, 0x00000000, 0x00000000, 0x2422222a, 0x00000929, 0x00000000, 0x00000000,
		0x2412252a, 0x00000901, 0x00000000, 0x00000000, 0x24fbe8be, 0x00000901, 0x00000000, 0x00000000, 0xac020000, 0x00000f01, 0x00000000, 0x00000000,
		0x0003e000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
		0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
		0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
		0x00000000, 0x00000000, 0x00000000, 0x00000000 };

	int charsHeight = 10;
	int charsDivisor = 1;	// Every char is separated from the consecutive by a 1 pixel divisor, horizontally and vertically
	
	int charsWidth[96] = { 3, 1, 4, 6, 5, 7, 6, 2, 3, 3, 5, 5, 2, 4, 1, 7, 5, 2, 5, 5, 5, 5, 5, 5, 5, 5, 1, 1, 3, 4, 3, 6,
						   7, 6, 6, 6, 6, 6, 6, 6, 6, 3, 5, 6, 5, 7, 6, 6, 6, 6, 6, 6, 7, 6, 7, 7, 6, 6, 6, 2, 7, 2, 3, 5, 
						   2, 5, 5, 5, 5, 5, 4, 5, 5, 1, 2, 5, 2, 5, 5, 5, 5, 5, 5, 5, 4, 5, 5, 5, 5, 5, 5, 3, 1, 3, 4, 4 };


	// Reconstruct charSet using charsWidth[], charsHeight, charsDivisor, numChars
	//------------------------------------------------------------------------------
	defaultFont.charSet = (Character *)malloc(defaultFont.numChars * sizeof(Character)); 	// Allocate space for our character data
																							// This memory should be freed at end! --> Done on CloseWindow()
	int currentLine = 0;
	int currentPosX = charsDivisor;
	int testPosX = charsDivisor;
	
	for (int i = 0; i < defaultFont.numChars; i++)
	{
		defaultFont.charSet[i].value = FIRST_CHAR + i;
		defaultFont.charSet[i].x = currentPosX;
		defaultFont.charSet[i].y = charsDivisor + currentLine * (charsHeight + charsDivisor);
		defaultFont.charSet[i].w = charsWidth[i];
		defaultFont.charSet[i].h = charsHeight;
		
		testPosX += (defaultFont.charSet[i].w + charsDivisor);
		
		if (testPosX >= defaultFont.texture.width)
		{
			currentLine++;
			currentPosX = 2 * charsDivisor + charsWidth[i];
			testPosX = currentPosX;
			
			defaultFont.charSet[i].x = charsDivisor;
			defaultFont.charSet[i].y = charsDivisor + currentLine * (charsHeight + charsDivisor);
		}
		else currentPosX = testPosX;
	}
	
	// Re-construct image from defaultFontData and generate OpenGL texture
	//----------------------------------------------------------------------
	Color *imgDataPixel = (Color *)malloc(defaultFont.texture.width * defaultFont.texture.height * sizeof(Color));
	
	for (int i = 0; i < defaultFont.texture.width * defaultFont.texture.height; i++) imgDataPixel[i] = BLANK;		// Initialize array

	int counter = 0;		// Font data elements counter
	
	// Fill imgData with defaultFontData (convert from bit to pixel!)
	for (int i = 0; i < defaultFont.texture.width * defaultFont.texture.height; i += 32)
	{
		for (int j = 31; j >= 0; j--)
		{
			if (BIT_CHECK(defaultFontData[counter], j)) imgDataPixel[i+j] = WHITE;
		}
		
		counter++;
		
		if (counter > 256) counter = 0;		// Security check...
	}
	
	// Convert loaded data to OpenGL texture
	//----------------------------------------
	GLuint id;
	glGenTextures(1, &id);					// Generate pointer to the texture
	
	glBindTexture(GL_TEXTURE_2D, id);
	
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);			// Set texture to clamp on x-axis
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);			// Set texture to clamp on y-axis
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);  	// Filter for pixel-perfect drawing, alternative: GL_LINEAR 
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);  	// Filter for pixel-perfect drawing, alternative: GL_LINEAR 
	
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, defaultFont.texture.width, defaultFont.texture.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imgDataPixel);
	
	// NOTE: Not using mipmappings (texture for 2D drawing)
	// At this point we have the image converted to texture and uploaded to GPU
	
	free(imgDataPixel);					// Now we can free loaded data from RAM memory
	
	defaultFont.texture.glId = id;
}

extern void UnloadDefaultFont()
{
	glDeleteTextures(1, &defaultFont.texture.glId);
	free(defaultFont.charSet);
}

// Load a SpriteFont image into GPU memory
SpriteFont LoadSpriteFont(const char* fileName)      
{
	SpriteFont spriteFont;
	
	// Use stb_image to load image data!
	int imgWidth;
	int imgHeight;
	int imgBpp;
	
	byte *imgData = stbi_load(fileName, &imgWidth, &imgHeight, &imgBpp, 4);	// Force loading to 4 components (RGBA)
	
	// Convert array to pixel array for working convenience
	Color *imgDataPixel = (Color *)malloc(imgWidth * imgHeight * sizeof(Color));
	Color *imgDataPixelPOT = NULL;
	
    int pix = 0;
	
	for (int i = 0; i < (imgWidth * imgHeight * 4); i += 4)
	{
		imgDataPixel[pix].r = imgData[i];
		imgDataPixel[pix].g = imgData[i+1];
		imgDataPixel[pix].b = imgData[i+2];
		imgDataPixel[pix].a = imgData[i+3];
		pix++;
	}
	
	stbi_image_free(imgData);
	
	// At this point we have a pixel array with all the data...
	
	// Process bitmap Font pixel data to get measures (Character array)
	// spriteFont.charSet data is filled inside the function and memory is allocated!
	int numChars = ParseImageData(imgDataPixel, imgWidth, imgHeight, &spriteFont.charSet);
	
	spriteFont.numChars = numChars;
	
	// Convert image font to POT image before conversion to texture
	// Just add the required amount of pixels at the right and bottom sides of image...
    int potWidth = GetNextPOT(imgWidth);
    int potHeight = GetNextPOT(imgHeight);
	
	// Check if POT texture generation is required (if texture is not already POT)
	if ((potWidth != imgWidth) || (potHeight != imgWidth))
	{
		// Generate POT array from NPOT data
		imgDataPixelPOT = (Color *)malloc(potWidth * potHeight * sizeof(Color));
		
		for (int j = 0; j < potHeight; j++)
		{
			for (int i = 0; i < potWidth; i++)
			{
				if ((j < imgHeight) && (i < imgWidth)) imgDataPixelPOT[j*potWidth + i] = imgDataPixel[j*imgWidth + i];
				else imgDataPixelPOT[j*potWidth + i] = MAGENTA;
			}
		}
	}
	
	free(imgDataPixel);

	// Convert loaded data to OpenGL texture
	//----------------------------------------
	GLuint id;
	glGenTextures(1, &id);					// Generate pointer to the texture
	
	glBindTexture(GL_TEXTURE_2D, id);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);  		// Filter for pixel-perfect drawing, alternative: GL_LINEAR 
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);  		// Filter for pixel-perfect drawing, alternative: GL_LINEAR 
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, potWidth, potHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, imgDataPixelPOT);
	
	// NOTE: Not using mipmappings (texture for 2D drawing)
	// At this point we have the image converted to texture and uploaded to GPU
	
	free(imgDataPixelPOT);					// Now we can free loaded data from RAM memory
	
	spriteFont.texture.glId = id;
	spriteFont.texture.width = potWidth;
	spriteFont.texture.height = potHeight;

    return spriteFont;
}

// Unload SpriteFont from GPU memory
void UnloadSpriteFont(SpriteFont spriteFont)
{
	glDeleteTextures(1, &spriteFont.texture.glId);
	free(spriteFont.charSet);
}

// Draw text (using default font)
// NOTE: fontSize work like in any drawing program but if fontSize is lower than font-base-size, then font-base-size is used
void DrawText(const char* text, int posX, int posY, int fontSize, int spacing, Color color)
{
	Vector2 position = { (float)posX, (float)posY };
	
	DrawTextEx(defaultFont, text, position, fontSize, spacing, color);
}

// Formatting of text with variables to 'embed'
const char *FormatText(const char *text, ...)
{
	int length = strlen(text);
	char *buffer = malloc(length + 20);		// We add 20 extra characters, should be enough... :P

	va_list args;
	va_start(args, text);
	vsprintf(buffer, text, args);		// NOTE: We use vsprintf() defined in <stdarg.h>
	va_end(args);
	
	//strcat(buffer, "\0");		// We add a end-of-string mark at the end (not needed)
	
	return buffer;
}

// Draw text using SpriteFont
// NOTE: If font size is lower than base size, base size is used
void DrawTextEx(SpriteFont spriteFont, const char* text, Vector2 position, int fontSize, int spacing, Color tint)
{
	int length = strlen(text);
	int positionX = (int)position.x;
	float scaleFactor;
	
	Character c;
	
	if (fontSize <= spriteFont.charSet[0].h) scaleFactor = 1.0f;
	else scaleFactor = (float)fontSize / spriteFont.charSet[0].h;

	glDisable(GL_LIGHTING);		// When drawing text, disable LIGHTING
	glEnable(GL_TEXTURE_2D);

	glBindTexture(GL_TEXTURE_2D, spriteFont.texture.glId);

	glPushMatrix();
	
		// Optimized to use one draw call per string
		glBegin(GL_QUADS);
			for(int i = 0; i < length; i++)
			{
				c = spriteFont.charSet[(int)text[i] - FIRST_CHAR];
				
				glColor4ub(tint.r, tint.g, tint.b, tint.a);
				glNormal3f(0.0f, 0.0f, 1.0f);                  // Normal Pointing Towards Viewer
				glTexCoord2f((float)c.x / spriteFont.texture.width, (float)c.y / spriteFont.texture.height); 					glVertex2f(positionX, position.y);
				glTexCoord2f((float)c.x / spriteFont.texture.width, (float)(c.y + c.h) / spriteFont.texture.height); 			glVertex2f(positionX, position.y + (c.h) * scaleFactor);
				glTexCoord2f((float)(c.x + c.w) / spriteFont.texture.width, (float)(c.y + c.h) / spriteFont.texture.height); 	glVertex2f(positionX + (c.w) * scaleFactor, position.y + (c.h) * scaleFactor);
				glTexCoord2f((float)(c.x + c.w) / spriteFont.texture.width, (float)c.y / spriteFont.texture.height); 			glVertex2f(positionX + (c.w) * scaleFactor, position.y);
				
				positionX += (spriteFont.charSet[(int)text[i] - FIRST_CHAR].w + spacing) * scaleFactor;
			}
		glEnd();
		
	glPopMatrix();
		
	glDisable(GL_TEXTURE_2D);
}

// Measure string width for default font
int MeasureText(const char *text, int fontSize, int spacing)
{
	Vector2 vec;

	vec = MeasureTextEx(defaultFont, text, fontSize, spacing);

	return (int)vec.x;
}


// Measure string size for SpriteFont
Vector2 MeasureTextEx(SpriteFont spriteFont, const char *text, int fontSize, int spacing)
{
	int len = strlen(text);
	int textWidth = 0;
	float scaleFactor;
	
	for (int i = 0; i < len; i++)
	{
		textWidth += spriteFont.charSet[(int)text[i] - FIRST_CHAR].w;
	}
	
	textWidth += (int)((len - 1) * spacing);	// Adds chars spacing to measure
	
	if (fontSize <= spriteFont.charSet[0].h) scaleFactor = 1.0f;
	else scaleFactor = (float)fontSize / spriteFont.charSet[0].h;
	
	Vector2 vec;
	vec.x = (float)textWidth * scaleFactor;
	vec.y = (float)spriteFont.charSet[0].h * scaleFactor;
	
	return vec;
}

// Returns the base size for a SpriteFont (chars height)
int GetFontBaseSize(SpriteFont spriteFont)
{
	return spriteFont.charSet[0].h;
}

// Shows current FPS on top-left corner
// NOTE: Uses default font
void DrawFps(int posX, int posY)
{
	// NOTE: We are rendering fps every second for better viewing on high framerates
	static float fps;
	static int counter = 0;
	static int refreshRate = 0;
	
	char buffer[20];
	
	if (counter < refreshRate)
	{
		sprintf(buffer, "%2.0f FPS", fps);
		DrawText(buffer, posX, posY, 20, 1, LIME);
		
		counter++;
	}
	else
	{
		fps = GetFPS();
		refreshRate = fps;
		sprintf(buffer, "%2.0f FPS", fps);
		DrawText(buffer, posX, posY, 20, 1, LIME);
		
		counter = 0;
	}
}

//----------------------------------------------------------------------------------
// Module specific Functions Definition
//----------------------------------------------------------------------------------

// Check if a pixel is magenta
static bool PixelIsMagenta(Color p)
{
	return ((p.r == 255) && (p.g == 0) && (p.b == 255) && (p.a == 255));
}

// Parse image pixel data to obtain character set measures
static int ParseImageData(Color *imgDataPixel, int imgWidth, int imgHeight, Character **charSet)
{
	int charSpacing = 0;
	int lineSpacing = 0;
	
	int x = 0;
	int y = 0;
	
	Character tempCharSet[MAX_FONTCHARS];	// We allocate a temporal array for charData, once we get the actual charNumber we copy data to a sized array.
	
	for(y = 0; y < imgHeight; y++)
	{	
		for(x = 0; x < imgWidth; x++)
		{	
			if (!PixelIsMagenta(imgDataPixel[y*imgWidth + x])) break;
		}
		if (!PixelIsMagenta(imgDataPixel[y*imgWidth + x])) break;
	}
	
	charSpacing = x;
	lineSpacing = y;
	
	int charHeight = 0;
	int j = 0;
	
	while(!PixelIsMagenta(imgDataPixel[(lineSpacing + j)*imgWidth + charSpacing])) j++;
	
	charHeight = j;
	
	// Check array values to get characters: value, x, y, w, h
	int index = 0;
	int lineToRead = 0;
	int xPosToRead = charSpacing;
	
	while((lineSpacing + lineToRead * (charHeight + lineSpacing)) < imgHeight)
	{
		while((xPosToRead < imgWidth) &&
			  !PixelIsMagenta((imgDataPixel[(lineSpacing + (charHeight+lineSpacing)*lineToRead)*imgWidth + xPosToRead])))
		{
			tempCharSet[index].value = FIRST_CHAR + index;
			tempCharSet[index].x = xPosToRead;
			tempCharSet[index].y = lineSpacing + lineToRead * (charHeight + lineSpacing);
			tempCharSet[index].h = charHeight;
			
			int charWidth = 0;
			
			while(!PixelIsMagenta(imgDataPixel[(lineSpacing + (charHeight+lineSpacing)*lineToRead)*imgWidth + xPosToRead + charWidth])) charWidth++;
	
			tempCharSet[index].w = charWidth;
			
			index++;
			
			xPosToRead += (charWidth + charSpacing);
		}
		
		lineToRead++;
		xPosToRead = charSpacing;
	}
	
	// We got tempCharSet populated with char data and the number of chars (index)
	// Now we move temp data to real charSet (passed as parameter to the function)
	(*charSet) = (Character *)malloc(index * sizeof(Character));		// BE CAREFUL! This memory should be freed!

	for (int i = 0; i < index; i++) (*charSet)[i] = tempCharSet[i];

	return index;
}

// Calculate next power-of-two value for a given num
static int GetNextPOT(int num)
{
    if (num != 0)
    {
        num--;
        num |= (num >> 1);	// Or first 2 bits
        num |= (num >> 2); 	// Or next 2 bits
        num |= (num >> 4); 	// Or next 4 bits
        num |= (num >> 8); 	// Or next 8 bits
        num |= (num >> 16); // Or next 16 bits
        num++;
    }

	return num;
}