{

printf("\033[J");

}

#if !defined(_WIN32) && !defined(_WIN64)

/*

* Query terminal background color using OSC 11 escape sequence

*

* Protocol:

* Send: ESC ] 11 ; ? ESC \ (or BEL instead of ESC \)

* Recv: ESC ] 11 ; rgb:RRRR/GGGG/BBBB ESC \

*

* The response uses 16-bit color values (0000-FFFF per component).

* Some terminals use 8-bit (00-FF) format instead.

*/

mirb_bg_color

mirb_term_query_bg_color(int timeout_ms)

{

struct termios old_term, new_term;

char buf[64];

size_t total = 0;

ssize_t n;

int r, g, b;

mirb_bg_color result = MIRB_BG_UNKNOWN;

fd_set fds;

struct timeval tv;

const char *p;

/* Must be a terminal */

if (!isatty(STDIN_FILENO) || !isatty(STDOUT_FILENO)) {

return MIRB_BG_UNKNOWN;

}

/* Save original terminal settings */

if (tcgetattr(STDIN_FILENO, &old_term) < 0) {

return MIRB_BG_UNKNOWN;

}

/* Flush any pending input first */

tcflush(STDIN_FILENO, TCIFLUSH);

/* Disable echo and canonical mode for raw read */

new_term = old_term;

new_term.c_lflag &= ~(ICANON | ECHO | ECHOE | ECHOK | ECHONL);

new_term.c_iflag &= ~(IXON | IXOFF | ICRNL);

new_term.c_cc[VMIN] = 0;

new_term.c_cc[VTIME] = 0;

/* TCSAFLUSH: flush I/O and apply settings */

if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &new_term) < 0) {

return MIRB_BG_UNKNOWN;

}

/* Wait for terminal settings to take effect */

tcdrain(STDOUT_FILENO);

/* Send OSC 11 query: ESC ] 11 ; ? ESC \ */

if (write(STDOUT_FILENO, "\033]11;?\033\\", 8) != 8) {

goto restore;

}

/* Ensure query is sent to terminal */

tcdrain(STDOUT_FILENO);

/* Give terminal time to process and respond */

usleep(50000); /* 50ms */

/* Read response with timeout - loop to get complete response */

while (total < sizeof(buf) - 1) {

int sel;

FD_ZERO(&fds);

FD_SET(STDIN_FILENO, &fds);

tv.tv_sec = timeout_ms / 1000;

tv.tv_usec = (timeout_ms % 1000) * 1000;

sel = select(STDIN_FILENO + 1, &fds, NULL, NULL, &tv);

if (sel < 0) {

if (errno == EINTR) continue; /* Retry on signal interrupt */

break; /* Other error */

}

if (sel == 0) break; /* Timeout */

n = read(STDIN_FILENO, buf + total, sizeof(buf) - 1 - total);

if (n <= 0) {

if (n < 0 && errno == EINTR) continue; /* Retry on signal interrupt */

break;

}

total += (size_t)n;

/* Check for terminator: ESC \ (0x1b 0x5c) or BEL (0x07) */

if (total >= 2 && buf[total-2] == '\033' && buf[total-1] == '\\') break;

if (total >= 1 && buf[total-1] == '\007') break;

/* Reduce timeout for subsequent reads */

timeout_ms = 10;

}

if (total == 0) {

goto restore;

}

buf[total] = '\0';

/* Parse response: look for "rgb:" followed by hex values */

p = strstr(buf, "rgb:");

if (p) {

p += 4;

/* Try 16-bit format: rgb:RRRR/GGGG/BBBB */

if (sscanf(p, "%4x/%4x/%4x", &r, &g, &b) == 3) {

/* Normalize to 8-bit range */

r >>= 8; g >>= 8; b >>= 8;

}

/* Try 8-bit format: rgb:RR/GG/BB */

else if (sscanf(p, "%2x/%2x/%2x", &r, &g, &b) == 3) {

/* Already 8-bit */

}

else {

goto restore;

}

/* Calculate relative luminance (ITU-R BT.709 simplified) */

/* Y = 0.2126*R + 0.7152*G + 0.0722*B */

/* Scale: 0-255 input, threshold at ~127.5 */

int luminance = (2126 * r + 7152 * g + 722 * b) / 10000;

result = (luminance < 128) ? MIRB_BG_DARK : MIRB_BG_LIGHT;

}

restore:

/* Flush any remaining input before restoring terminal */

tcflush(STDIN_FILENO, TCIFLUSH);

tcsetattr(STDIN_FILENO, TCSAFLUSH, &old_term);

return result;

}

#else /* Windows */

mirb_bg_color

mirb_term_query_bg_color(int timeout_ms)

{

(void)timeout_ms;

/* Windows Terminal supports OSC 11, but implementation requires

* different I/O handling. For now, return unknown and rely on

* fallback detection methods. */

return MIRB_BG_UNKNOWN;

}

#endif /* _WIN32 */