/*
 *	keyboard.c
 *	written by Holmes Futrell
 *	use however you want
 */

#import "SDL.h"
#import "common.h"

#define GLYPH_SIZE_IMAGE 16		/* size of glyphs (characters) in the bitmap font file */
#define GLYPH_SIZE_SCREEN 32	/* size of glyphs (characters) as shown on the screen */

static SDL_TextureID textureID; /* texture where we'll hold our font */

/* iPhone SDL addition keyboard related function definitions */
extern DECLSPEC int SDLCALL SDL_iPhoneKeyboardShow(SDL_WindowID windowID);
extern DECLSPEC int SDLCALL SDL_iPhoneKeyboardHide(SDL_WindowID windowID);
extern DECLSPEC SDL_bool SDLCALL SDL_iPhoneKeyboardIsShown(SDL_WindowID windowID);
extern DECLSPEC int SDLCALL SDL_iPhoneKeyboardToggle(SDL_WindowID windowID);

/* function declarations */
void cleanup(void);
void drawBlank(int x, int y);

static int numChars = 0;						  /* number of characters we've typed so far */
static SDL_bool lastCharWasColon = 0;			  /* we use this to detect sequences such as :) */
static SDL_Color bg_color = { 50, 50, 100, 255 }; /* color of background */

/* this structure maps a scancode to an index in our bitmap font.
   it also contains data about under which modifiers the mapping is valid
   (for example, we don't want shift + 1 to produce the character '1',
   but rather the character '!')
*/
typedef struct {
	SDL_scancode scancode;	/* scancode of the key we want to map */	
	int allow_no_mod;		/* is the map valid if the key has no modifiers? */
	SDLMod mod;				/* what modifiers are allowed for the mapping */
	int index;				/* what index in the font does the scancode map to */
} fontMapping;

#define TABLE_SIZE 51		/* size of our table which maps keys and modifiers to font indices */

/* Below is the table that defines the mapping between scancodes and modifiers to indices in the
   bitmap font.  As an example, then line '{ SDL_SCANCODE_A, 1, KMOD_SHIFT, 33 }' means, map
   the key A (which has scancode SDL_SCANCODE_A) to index 33 in the font (which is a picture of an A),
   The '1' means that the mapping is valid even if there are no modifiers, and KMOD_SHIFT means the
   mapping is also valid if the user is holding shift.
*/
fontMapping map[TABLE_SIZE] = {

{ SDL_SCANCODE_A, 1, KMOD_SHIFT, 33 },			/* A */
{ SDL_SCANCODE_B, 1, KMOD_SHIFT, 34 },			/* B */ 
{ SDL_SCANCODE_C, 1, KMOD_SHIFT, 35 },			/* C */
{ SDL_SCANCODE_D, 1, KMOD_SHIFT, 36 },			/* D */
{ SDL_SCANCODE_E, 1, KMOD_SHIFT, 37 },			/* E */
{ SDL_SCANCODE_F, 1, KMOD_SHIFT, 38 },			/* F */
{ SDL_SCANCODE_G, 1, KMOD_SHIFT, 39 },			/* G */
{ SDL_SCANCODE_H, 1, KMOD_SHIFT, 40 },			/* H */
{ SDL_SCANCODE_I, 1, KMOD_SHIFT, 41 },			/* I */
{ SDL_SCANCODE_J, 1, KMOD_SHIFT, 42 },			/* J */
{ SDL_SCANCODE_K, 1, KMOD_SHIFT, 43 },			/* K */
{ SDL_SCANCODE_L, 1, KMOD_SHIFT, 44 },			/* L */
{ SDL_SCANCODE_M, 1, KMOD_SHIFT, 45 },			/* M */
{ SDL_SCANCODE_N, 1, KMOD_SHIFT, 46 },			/* N */
{ SDL_SCANCODE_O, 1, KMOD_SHIFT, 47 },			/* O */
{ SDL_SCANCODE_P, 1, KMOD_SHIFT, 48 },			/* P */
{ SDL_SCANCODE_Q, 1, KMOD_SHIFT, 49 },			/* Q */
{ SDL_SCANCODE_R, 1, KMOD_SHIFT, 50 },			/* R */
{ SDL_SCANCODE_S, 1, KMOD_SHIFT, 51 },			/* S */
{ SDL_SCANCODE_T, 1, KMOD_SHIFT, 52 },			/* T */
{ SDL_SCANCODE_U, 1, KMOD_SHIFT, 53 },			/* U */
{ SDL_SCANCODE_V, 1, KMOD_SHIFT, 54 },			/* V */
{ SDL_SCANCODE_W, 1, KMOD_SHIFT, 55 },			/* W */
{ SDL_SCANCODE_X, 1, KMOD_SHIFT, 56 },			/* X */
{ SDL_SCANCODE_Y, 1, KMOD_SHIFT, 57 },			/* Y */
{ SDL_SCANCODE_Z, 1, KMOD_SHIFT, 58 },			/* Z */
{ SDL_SCANCODE_0, 1, 0, 16 },					/* 0 */
{ SDL_SCANCODE_1, 1, 0, 17 },					/* 1 */
{ SDL_SCANCODE_2, 1, 0, 18 },					/* 2 */
{ SDL_SCANCODE_3, 1, 0, 19 },					/* 3 */
{ SDL_SCANCODE_4, 1, 0, 20 },					/* 4 */
{ SDL_SCANCODE_5, 1, 0, 21 },					/* 5 */
{ SDL_SCANCODE_6, 1, 0, 22 },					/* 6 */
{ SDL_SCANCODE_7, 1, 0, 23 },					/* 7 */
{ SDL_SCANCODE_8, 1, 0, 24 },					/* 8 */
{ SDL_SCANCODE_9, 1, 0, 25 },					/* 9 */
{ SDL_SCANCODE_SPACE, 1, 0, 0 },				/*' '*/
{ SDL_SCANCODE_1, 0, KMOD_SHIFT, 1 },			/* ! */
{ SDL_SCANCODE_SLASH, 0, KMOD_SHIFT, 31},		/* ? */
{ SDL_SCANCODE_SLASH, 1, 0, 15},				/* / */
{ SDL_SCANCODE_COMMA, 1, 0, 12},				/* , */
{ SDL_SCANCODE_SEMICOLON, 1, 0, 27},			/* ; */
{ SDL_SCANCODE_SEMICOLON, 0, KMOD_SHIFT, 26},	/* : */
{ SDL_SCANCODE_PERIOD, 1, 0, 14},				/* . */
{ SDL_SCANCODE_MINUS, 1, 0, 13},				/* - */
{ SDL_SCANCODE_EQUALS, 0, KMOD_SHIFT, 11},		/* = */
{ SDL_SCANCODE_APOSTROPHE, 1, 0, 7},			/* ' */
{ SDL_SCANCODE_APOSTROPHE, 0, KMOD_SHIFT, 2},	/* " */
{ SDL_SCANCODE_5, 0, KMOD_SHIFT, 5},			/* % */

};

/*
	This function maps an SDL_keysym to an index in the bitmap font.
	It does so by scanning through the font mapping table one entry
	at a time.
 
	If a match is found (scancode and allowed modifiers), the proper
	index is returned.
 
	If there is no entry for the key, -1 is returned
*/
int keyToIndex(SDL_keysym key) {
	int i, index = -1;
	for (i=0; i<TABLE_SIZE; i++) {
		fontMapping compare = map[i];
		if (key.scancode == compare.scancode) {
			/* if this entry is valid with no key mod and we have no keymod, or if
			   the key's modifiers are allowed modifiers for that mapping */
			if ((compare.allow_no_mod && key.mod == 0) ||  ( key.mod & compare.mod ) ) {
				index = compare.index;
				break;
			}
		}
	}
	return index;
}
/* 
	This function returns and x,y position for a given character number.
    It is used for positioning each character of text
*/
void getPositionForCharNumber(int n, int *x, int *y) {
	int x_padding = 16; /* padding space on left and right side of screen */
	int y_padding = 32; /* padding space at top of screen */
	/* figure out the number of characters that can fit horizontally across the screen */
	int max_x_chars = (SCREEN_WIDTH - 2 * x_padding) / GLYPH_SIZE_SCREEN;
	int line_separation = 5; /* pixels between each line */
	*x = (n % max_x_chars) * GLYPH_SIZE_SCREEN + x_padding;
	*y = (n / max_x_chars) * (GLYPH_SIZE_SCREEN + line_separation) + y_padding;
}
void drawIndex(int index) {
	int x, y;
	getPositionForCharNumber(numChars, &x, &y);
	SDL_Rect srcRect = { GLYPH_SIZE_IMAGE * index, 0, GLYPH_SIZE_IMAGE, GLYPH_SIZE_IMAGE };
	SDL_Rect dstRect = { x, y, GLYPH_SIZE_SCREEN, GLYPH_SIZE_SCREEN };
	drawBlank(x, y);
	SDL_RenderCopy(textureID, &srcRect, &dstRect);
}
/*  draws the cursor icon at the current end position of the text */
void drawCursor(void) {
	drawIndex(29);	/* cursor is at index 29 in the bitmap font */
}
/* paints over a glyph sized region with the background color
   in effect it erases the area
*/
void drawBlank(int x, int y) {
	SDL_Rect rect = { x, y, GLYPH_SIZE_SCREEN, GLYPH_SIZE_SCREEN };
	SDL_RenderFill(bg_color.r, bg_color.g, bg_color.b, bg_color.unused, &rect);
}
/* moves backwards one character, erasing the last one put down */
void backspace(void) {
	int x, y;
	if (numChars > 0) {
		getPositionForCharNumber(numChars, &x, &y);
		drawBlank(x, y);
		numChars--;
		getPositionForCharNumber(numChars, &x, &y);
		drawBlank(x, y);
		drawCursor();
	}
}
/* this function loads our font into an SDL_Texture and returns the SDL_TextureID */
SDL_TextureID loadFont(void) {
	
	SDL_Surface *surface = SDL_LoadBMP("kromasky_16x16.bmp");

	if (!surface) {
		printf("Error loading bitmap: %s\n", SDL_GetError());
		return 0;
	} 
	else {
		/* set the transparent color for the bitmap font (hot pink) */
		SDL_SetColorKey(surface, 1, SDL_MapRGB(surface->format, 238, 0, 252 ));
		/* now we convert the surface to our desired pixel format */
		int format = SDL_PIXELFORMAT_ABGR8888; /* desired texture format */
		Uint32 Rmask, Gmask, Bmask, Amask;	   /* masks for desired format */
		int bpp;							   /* bits per pixel for desired format */
		SDL_PixelFormatEnumToMasks(format, &bpp, &Rmask, &Gmask, &Bmask, &Amask);
		SDL_Surface *converted = SDL_CreateRGBSurface(0, surface->w, surface->h, bpp, Rmask, Gmask, Bmask, Amask);	
		SDL_BlitSurface(surface, NULL, converted, NULL);
		/* create our texture */
		textureID = SDL_CreateTextureFromSurface(SDL_PIXELFORMAT_ABGR8888, converted);
		if (textureID == 0) {
			printf("texture creation failed: %s\n", SDL_GetError());
		}
		else {
			/* set blend mode for our texture */
			SDL_SetTextureBlendMode(textureID, SDL_TEXTUREBLENDMODE_BLEND);								  
		}
		SDL_FreeSurface(surface);
		SDL_FreeSurface(converted);
		return textureID;
	}
}

int main(int argc, char *argv[]) {
	
	int index;				/* index of last key we pushed in the bitmap font */
	SDL_Event event;		/* last event received */
	SDLMod mod;				/* key modifiers of last key we pushed */
	SDL_scancode scancode;  /* scancode of last key we pushed */
	
	if (SDL_Init(SDL_INIT_VIDEO) < 0) {
		printf("Error initializing SDL: %s", SDL_GetError());
	}
	/* create window */
	SDL_WindowID windowID = SDL_CreateWindow("iPhone keyboard test", 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, 0);
	/* create renderer */
	SDL_CreateRenderer(windowID, 0, 0);		
		
	/* load up our font */
	loadFont();

	/* draw the background, we'll just paint over it */
	SDL_RenderFill(bg_color.r, bg_color.g, bg_color.b, bg_color.unused, NULL);
	SDL_RenderPresent();
	
	int done = 0;
	/* loop till we get SDL_Quit */
	while (SDL_WaitEvent(&event)) {
		switch (event.type) {
			case SDL_QUIT:
				done = 1;
				break;
			case SDL_KEYDOWN:
				index = keyToIndex(event.key.keysym);
				scancode = event.key.keysym.scancode;
				mod		 = event.key.keysym.mod;
				if (scancode == SDL_SCANCODE_DELETE) {
					/* if user hit delete, delete the last character */
					backspace();
					lastCharWasColon = 0;
				}
				else if (lastCharWasColon && scancode == SDL_SCANCODE_0 && (mod & KMOD_SHIFT)) {
					/* if our last key was a colon and this one is a close paren, the make a hoppy face */
					backspace();
					drawIndex(32); /* index for happy face */
					numChars++;
					drawCursor();
					lastCharWasColon = 0;
				}
				else if (index != -1) {
					/* if we aren't doing a happy face, then just draw the normal character */
					drawIndex(index);
					numChars++;
					drawCursor();
					lastCharWasColon = (event.key.keysym.scancode == SDL_SCANCODE_SEMICOLON\
										&& (event.key.keysym.mod & KMOD_SHIFT));
				}
				/* check if the key was a colon */
				/* draw our updates to the screen */
				SDL_RenderPresent();
				break;
#ifdef __IPHONEOS__
			case SDL_MOUSEBUTTONUP:
				/*	mouse up toggles onscreen keyboard visibility
					this function is available ONLY on iPhone OS
				 */
				SDL_iPhoneKeyboardToggle(windowID);
				break;
#endif
		}
	}
	cleanup();
	return 0;
}

/* clean up after ourselves like a good kiddy */
void cleanup(void) {
	SDL_DestroyTexture(textureID);
	SDL_Quit();
}