/*
  cl watch.c
*/

#include <time.h>

typedef enum {
  black, dblue, dgreen, dcyan, dred, dmagenta, dyellow, gray,
  dgray, blue, green, cyan, red, magenta, yellow, white,
} color;

typedef unsigned char uchar;
typedef unsigned short ushort;
typedef unsigned long ulong;

typedef struct _CHAR_INFO {
  union {
    ushort UnicodeChar;
    uchar AsciiChar;
  } Char;
  ushort Attributes;
} CHAR_INFO, *PCHAR_INFO;

typedef struct _COORD {
  ushort x, y;
} COORD, *PCOORD;

typedef struct _SMALL_RECT {
  ushort l, t, r, b;
} SMALL_RECT, *PSMALL_RECT;

void __stdcall Sleep(ulong);
ulong __stdcall GetStdHandle(ulong);
ulong __stdcall SetConsoleTextAttribute(ulong, ulong);
ulong __stdcall SetConsoleCursorPosition(ulong, ulong);
ulong __stdcall WriteConsoleOutputA(ulong,
  PCHAR_INFO, COORD, COORD, PSMALL_RECT);

#define HEIGHT 25
#define WIDTH 80

static ulong handle = 0;
static COORD curs = {0, 0};
static ushort attr = 0;
static CHAR_INFO consb[HEIGHT * WIDTH];
static COORD conssize = {WIDTH, HEIGHT};
static COORD conspos = {0, 0};
static SMALL_RECT consarea = {0, 0, WIDTH - 1, HEIGHT - 1};

void cursor(ushort y, ushort x){
  curs.y = y, curs.x = x;
}

void conattr(char bg, char fg){
  SetConsoleTextAttribute(handle, attr = (bg << 4) | (fg & 0x0F));
}

void cls(int t, int b, int l, int r, char c){
  int i, j;
  for(j = t; j <= b; ++j){
    for(i = l; i <= r; ++i){
      consb[j * WIDTH + i].Char.AsciiChar = c;
      consb[j * WIDTH + i].Attributes = attr;
    }
  }
}

void bputs(ushort y, ushort x, uchar *s){
  uchar *p;
  cursor(y, x);
  for(p = s; *p; ++p, ++curs.x){
    consb[curs.y * WIDTH + curs.x].Char.AsciiChar = *p;
    consb[curs.y * WIDTH + curs.x].Attributes = attr;
  }
}

#define ARTROWS 5
#define ARTCOLS 3
#define COLON_IDX 10
#define SPACE_IDX 11
#define DOT "\x81\xA1"
#define SPC "\x81\x40"
#define DOTWIDTH (sizeof(DOT) - 1)

uchar *col_str(uchar *b, int n, int r){
  static ushort art[] = { 0x56d4, 0xe934, 0xe746, 0x71c6, 0x93da,
    0x719e, 0xf79c, 0x925e, 0xf55e, 0x73de, 0x0820, 0x0000 };
  ushort i, j, c, d;
  for(i = 0, c = art[n]; i < r; ++i) c >>= ARTCOLS;
  for(i = 0; i < ARTCOLS * DOTWIDTH; i += DOTWIDTH)
    for(j = 0, d = (c >>= 1); j < DOTWIDTH; ++j)
      b[i + j] = d & 1 ? DOT[j] : SPC[j];
  b[i] = 0;
  return b;
}

void display(int f, time_t *ptimer){
  uchar b[ARTCOLS * DOTWIDTH + 1];
  int i, s = (ARTCOLS + 1) * DOTWIDTH;
  struct tm *t = localtime(ptimer);
  cls(0, HEIGHT - 1, 0, WIDTH - 1, ' ');
  for(i = 0; i < ARTROWS; ++i){
    int r = 10 + i, c = 10;
    bputs(r, c, col_str(b, t->tm_hour / 10, i));
    bputs(r, c += s, col_str(b, t->tm_hour % 10, i));
    bputs(r, c += s, col_str(b, f ? SPACE_IDX : COLON_IDX, i));
    bputs(r, c += s, col_str(b, t->tm_min / 10, i));
    bputs(r, c += s, col_str(b, t->tm_min % 10, i));
    bputs(r, c += s, col_str(b, f ? SPACE_IDX : COLON_IDX, i));
    bputs(r, c += s, col_str(b, t->tm_sec / 10, i));
    bputs(r, c += s, col_str(b, t->tm_sec % 10, i));
  }
  WriteConsoleOutputA(handle, consb, conssize, conspos, &consarea);
}

int main(int ac, char **av){
  time_t old = 0;
  int f = 0;
  handle = GetStdHandle(-11);
  conattr(dblue, cyan);
  while(1){
    time_t timer;
    Sleep(200);
    time(&timer);
    if(++f >= 5) f = 0;
    if(f == 3) display(f, &timer);
    if(timer < old + 1) continue;
    old = timer, f = 0;
    display(f, &timer);
  }
  return 0;
}