#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <SDL/SDL.h>

#define CELLW	12
#define CELLH	10

#define XRES	800
#define YRES	600

char xsize=CELLW, ysize=CELLH;
char base=7, top=2;
char font[256][CELLH][CELLW];
char width[256];

void blendpixel(unsigned *vid, int x, int y, int r, int g, int b, int a)
{
    int t;
    if(x<0 || y<0 || x>=XRES || y>=YRES)
	return;
    if(a!=255) {
	t = vid[y*XRES+x];
	r = (a*r + (255-a)*((t>>16)&255)) >> 8;
	g = (a*g + (255-a)*((t>>8)&255)) >> 8;
	b = (a*b + (255-a)*(t&255)) >> 8;
    }
    vid[y*XRES+x] = (r<<16)|(g<<8)|b;
}

int drawchar(unsigned *vid, int x, int y, int c, int r, int g, int b)
{
    int i, j;
    for(j=0; j<CELLH; j++)
	for(i=0; i<width[c]; i++)
	    blendpixel(vid, x+i, y+j, r, g, b, (font[c][j][i]*255)/3);
    return x + width[c];
}

int drawtext(unsigned *vid, int x, int y, char *s, int r, int g, int b)
{
    for(;*s;s++)
	x = drawchar(vid, x, y, *s, r, g, b);
    return x;
}

void drawline(unsigned *vid, int x1, int y1, int x2, int y2, int r, int g, int b, int a)
{
    int cp=abs(y2-y1)>abs(x2-x1), x, y, dx, dy, sy;
    float e, de;
    if(cp) {
	y = x1;
	x1 = y1;
	y1 = y;
	y = x2;
	x2 = y2;
	y2 = y;
    }
    if(x1 > x2) {
	y = x1;
	x1 = x2;
	x2 = y;
	y = y1;
	y1 = y2;
	y2 = y;
    }
    dx = x2 - x1;
    dy = abs(y2 - y1);
    e = 0.0f;
    de = dy/(float)dx;
    y = y1;
    sy = (y1<y2) ? 1 : -1;
    for(x=x1; x<=x2; x++) {
	if(cp)
	    blendpixel(vid, y, x, r, g, b, a);
	else
	    blendpixel(vid, x, y, r, g, b, a);
	e += de;
	if(e >= 0.5f) {
	    y += sy;
	    e -= 1.0f;
	}
    }
}

void drawcell(unsigned *vid, int i, int j, int c, int m)
{
    int x,y,x0=i*32+64,y0=j*32+64;
    for(y=1;y<32;y++)
	for(x=1;x<32;x++)
	    blendpixel(vid, x0+x, y0+y, 127*m, 127*m, 127*m, c);
    for(x=0;x<32;x+=2) {
	if(!j)
	    blendpixel(vid, x0+x, y0, 64*m, 64*m, 64*m, 255);
	if(!i)
	    blendpixel(vid, x0, y0+x, 64*m, 64*m, 64*m, 255);
	blendpixel(vid, x0+x, y0+32, 64*m, 64*m, 64*m, 255);
	blendpixel(vid, x0+32, y0+x, 64*m, 64*m, 64*m, 255);
    }
}

/***********************************************************
 *                       SDL OUTPUT                        *
 ***********************************************************/

SDL_Surface *sdl_scrn;
int sdl_key;
void sdl_open(void)
{
    if(SDL_Init(SDL_INIT_VIDEO)<0) {
        fprintf(stderr, "Initializing SDL: %s\n", SDL_GetError());
        exit(1);
    }
    atexit(SDL_Quit);
    sdl_scrn=SDL_SetVideoMode(XRES*SCALE,YRES*SCALE + 40*SCALE,32,SDL_SWSURFACE);
    if(!sdl_scrn) {
        fprintf(stderr, "Creating window: %s\n", SDL_GetError());
        exit(1);
    }
}

void sdl_blit(int x, int y, int w, int h, unsigned int *src, int pitch)
{
    unsigned *dst,i,j,k;
    if(SDL_MUSTLOCK(sdl_scrn))
        if(SDL_LockSurface(sdl_scrn)<0)
            return;
    dst=(unsigned *)sdl_scrn->pixels+y*sdl_scrn->pitch/4+x;
    for(j=0;j<h;j++) {
	for(k=0;k<SCALE;k++) {
	    for(i=0;i<w*SCALE;i++)
		dst[i]=src[i/SCALE];
	    dst+=sdl_scrn->pitch/4;
	}
	src+=pitch/4;
    }
    if(SDL_MUSTLOCK(sdl_scrn))
        SDL_UnlockSurface(sdl_scrn);
    SDL_UpdateRect(sdl_scrn,0,0,0,0);
}

int frame_idx=0;
void dump_frame(unsigned int *src, int w, int h, int pitch)
{
    char frame_name[32];
    unsigned j,i,c;
    FILE *f;
    sprintf(frame_name,"frame%04d.ppm",frame_idx);
    f=fopen(frame_name,"w");
    fprintf(f,"P6\n%d %d\n255\n",w,h);
    for(j=0;j<h;j++) {
	for(i=0;i<w;i++) {
	    c=((src[i]&0xFF0000)>>16)|(src[i]&0x00FF00)|((src[i]&0x0000FF)<<16);
	    fwrite(&c,3,1,f);
	}
	src+=pitch/4;
    }
    fclose(f);
    frame_idx++;
}

int sdl_poll(void)
{
    SDL_Event event;
    sdl_key=0;
    while(SDL_PollEvent(&event)) {
        switch (event.type) {
	case SDL_KEYDOWN:
	    sdl_key=event.key.keysym.sym;
	    break;
        case SDL_QUIT:
	    return 1;
        }
    }
    return 0;
}

/***********************************************************
 *                      MAIN PROGRAM                       *
 ***********************************************************/

char *tag = "(c) 2008 Stanislaw Skowronek";

int main(int argc, char *argv[])
{
    unsigned *vid_buf = calloc(XRES*YRES, sizeof(unsigned));
    int x, y, b = 0, lb, c = 0xA0, i, j, dc = 0;
    int mode = 0;
    FILE *f;

    f = fopen("font.bin", "r");
    if(f) {
	fread(&xsize, 1, 1, f);
	fread(&ysize, 1, 1, f);
	fread(&base, 1, 1, f);
	fread(&top, 1, 1, f);
	fread(width, 1, 256, f);
	fread(font, CELLW*CELLH, 256, f);
	fclose(f);
    }

    sdl_open();
    while(!sdl_poll()) {
	if(sdl_key=='q' || sdl_key==SDLK_ESCAPE)
	    break;
	if(sdl_key==' ' || sdl_key=='=') {
	    c++;
	    printf("Current: %02X '%c'\n", c, c);
	}
	if(sdl_key=='\b' || sdl_key=='-') {
	    c--;
	    printf("Current: %02X '%c'\n", c, c);
	}

	lb = b;
	b = SDL_GetMouseState(&x, &y);
	if(b) {
	    x /= SCALE;
	    y /= SCALE;
	}

	i = x/32-2;
	j = y/32-2;
	if(!lb && b && (i<0 || i>=CELLW)) {
	    if(abs(j-base) < abs(j-top))
		mode = 2;	// BASE
	    else
		mode = 3;	// TOP
	} else if(!lb && b && (j<0 || j>=CELLH))
	    mode = 4;		// LEFT
	else if(!lb && b) {
	    mode = 1;		// DRAW
	    if(b==1)
		dc = (font[c][j][i]+3)%4;
	    else
		dc = (font[c][j][i]+1)%4;
	}

	if(b)
	    switch(mode) {
	    case 1:
		if(i>=0 && j>=0 && i<CELLW && j<CELLH)
		font[c][j][i] = dc;
		break;
	    case 2:
		base = j;
		break;
	    case 3:
		top = j;
		break;
	    case 4:
		width[c] = i;
		break;
	    }

	memset(vid_buf, 0, XRES*YRES*4);
	for(j=0; j<CELLH; j++)
	    for(i=0; i<CELLW; i++)
		drawcell(vid_buf, i, j, (font[c][j][i]*255)/3, i>=width[c]?1:2);
	drawline(vid_buf, 32, 64+base*32, 128+32*CELLW, 64+base*32, 128, 255, 128, 255);
	drawline(vid_buf, 32, 64+top*32, 128+32*CELLW, 64+top*32, 128, 128, 255, 255);
	drawline(vid_buf, 64+width[c]*32, 32, 64+width[c]*32, 128+32*CELLH, 255, 128, 128, 255);

	drawtext(vid_buf, 64, 192+32*CELLH, "A quick brown fox jumps over the lazy dog.", 255, 255, 255);
	drawtext(vid_buf, 64, 192+33*CELLH, "A QUICK BROWN FOX JUMPS OVER THE LAZY DOG.", 255, 255, 255);
	drawtext(vid_buf, 64, 192+34*CELLH, "0123456789 ~`!@#$%^&*()-=_+[]{}\\|;:'\",./<>?", 255, 255, 255);

	drawchar(vid_buf, 32, 192+32*CELLH, c, 255, 255, 255);

	sdl_blit(0, 0, XRES, YRES, vid_buf, XRES*4);
    }

    f = fopen("font.bin", "w");
    fwrite(&xsize, 1, 1, f);
    fwrite(&ysize, 1, 1, f);
    fwrite(&base, 1, 1, f);
    fwrite(&top, 1, 1, f);
    fwrite(width, 1, 256, f);
    fwrite(font, CELLW*CELLH, 256, f);
    fclose(f);

    return 0;
}